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Objective The aim of the present paper was to evaluate the strength and the magnitude of the association between ossification of the nuchal ligament (ONL) and the risk of cervical ossification of the posterior longitudinal ligament (COPLL) and to determine whether there is a direct association or whether COPLL is a consequence of shared risk factors. Methods Medline, Web of Science, Cochrane Library, and Embase databases were searched for studies evaluating the association of COPLL‐ONL published before July 2020. Eligible studies were selected based on certain inclusion and exclusion criteria. Two investigators independently conducted the quality assessment and extracted the data, including study designs, countries, patients' age, gender, body mass index (BMI), and the risk of COPLL between individuals with and without ONL. A meta‐analysis of homogenous data, a sensitivity analysis, a publication bias assessment, and a subgroup analysis were performed using Stata 12.0 software. Results A total of 10 cohort studies involving 8429 participants were incorporated into this analysis. Pooled results demonstrated a statistically significant association between the presence of ONL and the increased COPLL risk (odds ratio [OR] 3.84; 95% confidence interval [CI] 2.68–5.52, P 2.5 vs 2.91‐fold in male–female ratio, Recent published studies have established that there is a relationship between ONL and COPLL. We conducted the first meta‐analysis evaluating the possible link between ONL and the incidence and extent of COPLL. The results demonstrated that ONL was associated with an increased risk of COPLL. Further study is needed to understand the underlying mechanisms of this correlation.

BACKGROUND: In the craniocervical junction, the ligaments between the anterior foramen magnum and the anterior arch of the atlas are not well defined, and ossification of the ligaments in this region has rarely been reported. Characterizing the anatomy and ossification of these ligaments may help in the diagnosis and treatment of disorders in this region. QUESTIONS/PURPOSES: (1) What is the prevalence of an unrecognized ossification at the craniocervical junction in patients with cervical spine disorders, and what are the patient characteristics associated with this ossification? (2) Do patients with this ossification have a greater risk of ossification of other structures at the craniocervical junction or cervical spine? (3) Is there an unreported ligament at this ossified site? METHODS: We conducted a retrospective study of 578 hospitalized patients who underwent CT for cervical spine disorders between January 2016 and July 2020. Based on the inclusion criteria, 11% (66 of 578) were excluded because of a cervical or craniocervical tumor, deformity, infection, fracture or dislocation, or prior surgery, leaving 89% (512 of 578) for analysis. These 512 patients had diagnoses of cervical radiculopathy, cervical myelopathy, cervical spondylotic amyotrophy, cervical spinal cord injury without a radiographic abnormality, or axial neck pain. Their mean age was 57 years (range 22-90 years), and 60% of the patients were men. Patient characteristics including age, gender, and diagnosis were retrieved from a longitudinally maintained institutional database. CT images were used to assess the presence of a previously unrecognized ossification and ossification of other structures in the craniocervical junction and cervical spine, including the posterior longitudinal ligament, anterior longitudinal ligament, nuchal ligament, ligamentum flavum, transverse ligament, and apical ligament, as well as diffuse idiopathic skeletal hyperostosis (DISH). The association between these structures was also assessed. This unreported ossification was called the capped dens sign. It was defined and graded from 1 to 3. Grade 3 was defined as the typical capped dens sign. Cervical spine MRI was used to assess whether there was an unreported structure in the same region as where the capped dens sign was detected on CT images. In the database of a recent study, there were 33 patients younger than 41 years. Nine percent (three of 33) were excluded because they did not have cervical spine MRI. MRIs of the remaining 30 patients were assessed. Their mean age was 35 years (range 22-40 years), and 58% were men. All cervical spine CT images and MRIs were reviewed by one senior spine surgeon and one junior spine surgeon twice with a 2-week interval. Blinding was accomplished by removing identifying information from the radiographs and randomly assigning them to each examiner. Any discrepancy with respect to the grade of the capped dens sign was adjudicated by a third blinded senior spine surgeon. Intrarater and interrater reliabilities were assessed by calculating weighted kappa statistics. No ligament or membrane was reported at this site. MRI is not sensitive to identify thin tissue in this region, especially when severe degeneration has occurred. A cadaveric study was conducted to discover a potential ligament between the inferior margin of the foramen magnum and the anterior arch of the atlas, as prompted by the newly discovered ossification in the clinical analysis of this study. Six embalmed human cadaveric craniocervical regions (three male and three female cadavers; median age 56 years, range 45-78 years) were dissected by a senior anatomist and a senior anatomy technician. A mid-sagittal section of the craniocervical junction was created, allowing us to explore the interval between the anterior foramen magnum and anterior arch of the atlas. A histologic analysis was conducted in two of the six cadavers (a male cadaver, 45 years; and a female cadaver, 51 years). Slides were made with 4-µm sections and stained with hematoxylin and eosin. RESULTS: A novel capped dens sign was detected in 39% (198 of 512) of the patients and the most typical capped dens sign was detected in 19% (96 of 512) of patients. The prevalence of this sign was the highest in patients with cervical spondylotic amyotrophy (12 of 25 patients). The prevalence of ossification of the anterior longitudinal ligament, ligamentum nuchae, and apical ligament, as well as DISH, was higher in patients with a capped dens sign than in those without (p = 0.04, p < 0.001, p < 0.001, and p = 0.001, respectively). The capped dens sign was identified in 69% (18 of 26) of the patients with DISH. A thin and short band-like structure or osteophyte was detected on MRI in 87% (26 of 30), in the same region as the capped dens sign. In the cadaveric study, an unreported, distinct ligamentous structure was identified at this ossified site. It originated from the posterosuperior rim of the anterior arch of the atlas to the inferior margin of the foramen magnum, which we called the inter-atlanto-occipital ligament. It was found in all six dissected craniocervical junctions. The histologic analysis revealed dense connective tissue. CONCLUSION: More than one-third of the patients in this series demonstrated CT evidence of a previously unrecognized ossification in the craniocervical junction, which we called the capped dens sign. Anatomic evidence of this sign, which was a previously unidentified ligament, was also newly discovered in this region. This study was conducted among Asian patients and specimens. Further studies among diverse ethnic groups may be needed to generalize the results. An additional well-designed prospective study will be needed to provide further evidence regarding the potential pathophysiology and clinical relevance of the capped dens sign. Furthermore, the cadaveric analysis in this study was only a preliminary report of the ligament; further biomechanical research is needed to investigate its function. CLINICAL RELEVANCE: Knowledge of this novel ligament may improve the diagnosis and treatment of craniocervical stability and dislocation. Ossification of this ligament is correlated with age, cervical spondylotic amyotrophy, and DISH. We wonder whether patients with cervical degenerative disorders who also have a capped dens sign may be at risk for the formation of osteophytes of an uncovertebral joint, which may result in palsy of the upper limb muscles. The capped dens sign may be the craniocervical manifestation of DISH. This possible association between the capped dens sign and DISH should be considered when performing surgery on patients with the capped dens sign.

Ossification of the posterior longitudinal ligament (OPLL) and other types of spinal ligament ossification are common in Japan and are known to frequently cause neuropathy. Cervical OPLL is a common form of OPLL that often involves ossification of not only the cervical vertebrae but also ligaments in other parts of the spine, and therefore evaluation of ossification by 360° whole-spine imaging is considered important. In this study, we analyzed data from a large multicenter retrospective study to evaluate the distribution of spinal ligament ossification across the entire spine in patients with cervical OPLL with a focus on correlations between OPLL, ossification of the nuchal ligament, ossification of the supraspinous and interspinous ligaments, and diffuse idiopathic skeletal hyperostosis.

Background Ossification of the nuchal ligament (ONL) caused by chronic injury to the nuchal ligament (NL) is very common in instability-related cervical disorders. Purpose To determine possible correlations between ONL, sagittal alignment, and segmental stability of the cervical spine. Material and Methods Seventy-three patients with cervical spondylotic myelopathy (CSM) and ONL (ONL group) and 118 patients with CSM only (control group) were recruited. Radiographic data included the characteristics of ONL, sagittal alignment and segmental stability, and ossification of the posterior longitudinal ligament (OPLL). We performed comparisons in terms of radiographic parameters between the ONL and control groups. The correlations between ONL size, cervical sagittal alignment, and segmental stability were analyzed. Multivariate logistic regression was used to identify the independent risk factors of the development of ONL. Results C2–C7 sagittal vertical axis (SVA), T1 slope (T1S), T1S minus cervical lordosis (T1S-CL) on the lateral plain, angular displacement (AD), and horizontal displacement (HD) on the dynamic radiograph increased significantly in the ONL group compared with the control group. The size of ONL significantly correlated with C2–C7 SVA, T1S, AD, and HD. The incidence of ONL was higher in patients with OPLL and segmental instability. Cervical instability, sagittal malalignment, and OPLL were independent predictors of the development of ONL through multivariate analysis. Conclusion Patients with ONL are more likely to have abnormal sagittal alignment and instability of the cervical spine. Thus, increased awareness and appreciation of this often-overlooked radiographic finding is warranted during diagnosis and treatment of instability-related cervical pathologies and injuries.

The Yonaguni pony is a rare breed of pony that has remained isolated on the westernmost island of Japan and may well retain normal morphological traits currently lost in most domestic horses (Equus caballus), such as the attachment of the nuchal ligament lamellae (NLL) from C2-C7. Recent research has found that NLL attachments are no longer present at C6 and C7 in most modern domesticated horses. This study investigated the attachments of the NLL in three Yonaguni ponies; 2 were examined in situ(deceased), and 1 was examined in vivo via ultrasound. The aim was to verify the attachments and compare the morphology to that in equids from previous studies. The in situ (2/2) and in vivo (1/1) findings revealed that the NLL was attached from C2-C7 in the Yonaguni ponies.

For over 200 years, equine anatomic literature has chiefly portrayed the attachment points of the nuchal ligament lamellae (NLL) from the second to the seventh cervical vertebrae (C2–C7). However, recent studies have shown that the modern domestic horse, Equus caballus, primarily exhibits the attachments points from C2–C5. Here we present the rare finding of a complete NLL attached from C2–C7 in one Australian Stock Horse (ASH) and discuss the potential implications of these findings. Previously, this trait has only been confirmed among close descendants of Equus ferus ferus; namely the primitive Dutch Konik and Bosnian Mountain Horse. The examination of the NLL attachment points in 55 unrelated horses of mixed breeds revealed that 52 horses had attachments from C2–C5; 1 horse (Welsh Cob) had attachments from C2–C6; and only 2 horses (ASH and Dutch Konik) presented with a complete NLL attached from C2–C7. In light of earlier findings that suggest this loss of NLL attachment at C6 and C7 occurred after domestication, a possible explanation for this finding in 1 ASH is that it is a remnant trait from the founder population of Waler horses that contributed to the early development of the ASH breed. The reported rare occurrence of a complete NLL (C2–C7) in a modern domesticated equine (ASH) suggests that there may be other individuals expressing this unique trait, providing opportunity for its preservation.

Laminoplasty is a standard technique for treating patients with multilevel cervical spondylotic myelopathy. Modified expansive open-door laminoplasty (MEOLP) preserves the unilateral paraspinal musculature and nuchal ligament and prevents facet joint violation. The purpose of this study was to elucidate the midterm surgical outcomes of this less invasive technique. We retrospectively recruited 65 consecutive patients who underwent MEOLP at our institution in 2011 with at least 4 years of follow-up. Clinical conditions were evaluated by examining neck disability index, Japanese Orthopaedic Association (JOA), Nurick scale, and axial neck pain visual analog scale scores. Sagittal alignment of the cervical spine was assessed using serial lateral static and dynamic radiographs. Clinical and radiographic outcomes revealed significant recovery at the first postoperative year and still exhibited gradual improvement 1–4 years after surgery. The mean JOA recovery rate was 82.3% and 85% range of motion was observed at the final follow-up. None of the patients experienced aggravated or severe neck pain 1 year after surgery or showed complications of temporary C5 nerve palsy and lamina reclosure by the final follow-up. As a less invasive method for reducing surgical dissection by using various modifications, MEOLP yielded satisfactory midterm outcomes.

Ultrasound is a well-established modality in equine investigative and diagnostic procedures. Although to date, it has not been utilized in examining the attachments of the equine nuchal ligament lamellae (NLL) onto the cervical vertebrae, for which a noninvasive technique is currently lacking. This study presents a standardized methodology for investigating the equine NLL using ultrasonography, and further evaluates the ultrasound images against postmortem dissection in two nonrelated horses. The ultrasound images in both horses clearly presented the attachment points of the NLL to the dorsal spines of the cervical vertebrae from C2 to C5, whereas no attachment points could be seen from C6 to C7. The ultrasound images were confirmed through close, comparative inspection of the NLL postmortem. Therefore, ultrasound provides a noninvasive alternative to gross anatomic dissections for investigating the NLL attachments in members of the family Equidae. Importantly, this provides an opportunity to examine endangered breeds or isolated populations without the detrimental loss to the gene pool of rare anatomic and or primitive traits.

Background Previous studies have shown that patients with cervical ossification of the posterior longitudinal ligament (OPLL) often have co-existing ossification of the nuchal ligament (ONL). However, no studies have focused on ONL and its relevance to the severity of OPLL or ossification of other spinal ligaments, such as anterior longitudinal ligament (OALL), ligamentum flavum (OLF), and supraspinous/interspinous ligament (OSIL). Methods In this multicenter study, we investigated ossification of the spinal ligaments in the whole spine computed tomography (CT) images of 233 cervical OPLL patients. The severity of ossification was evaluated using ossification index for each spinal ligament, calculated as the sum of the level of ossification. We compared the severity of ossification in each spinal ligament between patients with ONL and those without ONL. Furthermore, we investigated how the number of segments, where ONL exists, affects the severity of ossification in each spinal ligament. Results One hundred thirty patients (55.8%) had co-existing ONL in the cervical OPLL patients included in this study. The ONL (+) group included more male and aged patients. The cervical ossification indexes of OPLL and OALL were higher in ONL (+) patients than in ONL (−) patients. The thoracolumbar ossification indexes of OALL and OSIL were also higher in ONL (+) patients. Logistic regression analysis revealed that age, gender and cervical OA-index were independent factors correlating to the existence of ONL. In the cervical spine, both the ossification indexes of OALL and OPLL increased as the levels of ONL increased. Similarly, in the thoracolumbar spine, both the ossification indexes of OALL and OSIL were increased as the levels of cervical ONL increased. In the multiple regression analysis, cervical OA-index and thoracolumbar OSI-index showed significant correlation with the number of ONL levels. Conclusions Co-existence of ONL in cervical OPLL patients was associated with the severity of spinal hyperostosis especially in cervical OPLL, OALL, thoracolumbar OALL and OSIL.

Objective: The nuchal ligament (NL) extends from the external occipital protuberance and median nuchal line to the spinous process of the 7th cervical vertebrae. In this study, we evaluated the incidence, location level, and size of ossifications of the NL (ONL) in patients who underwent cervical computed tomography (CT) for various reasons.Materials and Methods: The present study included 481 patients (187 females and 294 males) who underwent cervical CT from February 2011 to November 2016 due to reasons such as trauma, cervical spondylosis, neck pain, and screening for metastasis. CT was performed using 2- or 8-slice scanners. Archive images of patients on picture archiving and communication system were retrospectively evaluated by two radiologists. The structures in bone density and form detected in NL were evaluated as nuchal ossification. ONL location levels, numbers, and dimensions were determined. The relationship between both sexes and age and the incidence of ONL was investigated.Results: ONL was detected in 44 patients (9.14%). The mean ages of patients with ONL and without ONL were 62.27±13.92 (23-86) and 41.78±20.76 (4-101) years, respectively. There was a statistically significant relationship between ONL and age (p

Objective To investigate the incidence, distribution characteristics, and radiographic features of the ossification of the posterior longitudinal ligament (OPLL) combined with ossification of the nuchal ligament (ONL) and to analyze the correlation between the location of ONL and degree of ossification in patients with cervical OPLL. Methods From January 2010 to December 2016, the clinical data of 217 patients with cervical OPLL were reviewed retrospectively. Type and location of OPLL and ONL were determined on computed tomography images and lateral radiograph films. For patients with the local type of ONL, the segment with the largest spinal canal occupation ratio (COR) of OPLL was determined on cross-sectional computed tomography slices. The correlation between the location of ONL and segment with the largest COR of OPLL was evaluated. Results Of the 217 patients with cervical OPLL, 118 patients (54.4%) had OPLL combined with ONL (92 male and 26 female patients). The incidence of ONL was almost 1.4 times greater in males than in female patients (P = 0.03). C5–C6 (49.5%) was the segment at which ONL occurred most. Of 60 patients with the local type of ONL, 34 patients' ONL was located at the segment with largest COR of OPLL. The matching ratio was the largest (77.8%) when the type of OPLL was locally circumscribed (P = 0.003). Conclusions The incidence of ONL was 54.4% in patients with cervical OPLL, and male patients were affected more than female patients. ONL occurred most in segment C5–C6. The location of local-type ONL commonly corresponded to the segment with the largest COR of OPLL when type of OPLL was circumscribed.

We investigated the effects of extracorporeal shockwave therapy (ESWT) on the rehabilitation of cervical spondylosis with nuchal ligament (NL) calcification under X-ray and ultrasound guidance. Sixty patients with cervical spondylosis and calcification of NL were selected and randomly assigned to three groups: A, B, and C. Patients in Group A received rehabilitation with 20 minutes of hot packs and underwent 15 minutes of intermittent cervical traction three times/week for 6 weeks. Patients in Group B received the same rehabilitation as those in Group A and ESWT (2000 impulses, 0.27 mJ/mm 2 ) over the calcified NL guided by X-ray image. Patients in Group C received the same treatment as those in Group B, but the ESWT was guided by musculoskeletal sonography. The therapeutic effects were evaluated by: changes in range of motion (ROM) of the cervical spine including flexion, extension, lateral bending, and rotation; visual analog pain scale; and Neck Disability Index before and after treatment and at follow up 3 months later. We found a significant reduction in pain in each treated group after treatment and at follow up. However, patients in Groups B and C showed more improvements in ROM and neck pain relief after treatment and a decrease in Neck Disability Index. Furthermore, patients in Group C showed better cervical ROM at follow up than Group B. ESWT is an adjuvant treatment in the management of cervical spondylosis with calcification of NL and ultrasound-guided ESWT results in more functional improvements.

Study design A cross-sectional study. Objective To examine the prevalence of ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) of the cervical spine in the San Francisco area. Summary of background data The prevalence of OPLL and ONL is unknown in the non-Asian population. Methods This computed tomography-based cross-sectional study assessed the prevalence of OPLL and ONL within the cervical spine of patients treated at a level 1 trauma center between 2009 and 2012. The prevalence of both OPLL and ONL was compared between racial groups. Results Of the 3161 patients (mean age, 51.2 ± 21.6 yr; 66.1% male), there were 1593 Caucasians (50.4%), 624 Asians (19.7%), 472 Hispanics (14.9%), 326 African Americans (10.3%), 62 Native Americans (2.0%), and 84 Others (2.7%). The prevalence of cervical OPLL was 2.2% (95% confidence interval [CI]: 1.7-2.8). The adjusted prevalence was 1.3% in Caucasian Americans (95% CI: 0.7-2.3), 4.8% in Asian Americans (95% CI: 2.8-8.1), 1.9% in Hispanic Americans (95% CI: 0.9-4.0), 2.1% in African Americans (95% CI: 0.9-4.8), and 3.2% in Native Americans (95% CI: 0.8-12.3). The prevalence of OPLL in Asian Americans was significantly higher than that in Caucasian Americans (P = 0.005). ONL was detected in 346 patients and the prevalence was 10.9% (95% CI: 10.0-12.0). The adjusted prevalence of ONL was 7.3% in Caucasian Americans (95% CI: 5.8-9.3), 26.4% in Asian Americans (95% CI: 21.9-31.5), 7.4% in Hispanic Americans (95% CI: 5.2-10.5), 2.5% in African Americans (95% CI: 1.2-4.9), and 25.8% in Native Americans (95% CI: 16.5-37.5). ONL was significantly more common in Asian Americans than in Caucasian Americans, Hispanic Americans, and African Americans (P = 0.001). Conclusion This study also demonstrated that OPLL and ONL were significantly more common in Asian Americans than in Caucasian Americans. Level of evidence 3.

Background Context Studies over the past 20 years have revealed that there are fibrous connective tissues between the suboccipital muscles, nuchal ligament, and cervical spinal dura mater (SDM). This fibrous connection with the SDM is through the posterior atlanto-occipital or atlantoaxial interspaces and is called the myodural bridge (MDB). Researchers have inferred that the MDB might have important functions. It was speculated that the function of MDB might be related to proprioception transmission, keeping the subarachnoid space and the cerebellomedullary cistern unobstructed, and affecting the dynamic circulation of the cerebrospinal fluid. In addition, clinicians have found that the pathologic change of the MDB might cause cervicogenic or chronic tension-type headache. Previous gross anatomical and histologic studies only confirmed the existence of the MDB but did not reveal the fiber properties of the MDB. This is important to further mechanical and functional research on the MDB. Purpose Multiple histologic staining methods were used in the present study to reveal the various origin and fiber properties of the MDB. Muscles and ligaments participating in forming the MDB at the posterior atlanto-occipital or atlantoaxial interspaces were observed, and the fiber properties of the MDB were confirmed. The present study provides a basis for speculating the tensile force values of the MDB on the SDM and a morphologic foundational work for exploring the physiological functions and clinical significances of the MDB. Study Design Anatomical and histologic analyses of suboccipital structures that communicate with the SDM at the posterior atlanto-occipital or atlantoaxial interspaces were carried out. Methods Multiple histologic staining methods were used to evaluate the histologic properties and composition of the MDB at the posterior atlanto-occipital or atlantoaxial interspaces in five formalin-fixed head-neck human specimens. Results The results show that the MDB traversing the atlanto-occipital interspace originated from the rectus capitis posterior minor (RCPmi). The MDB traversing the atlantoaxial interspace originated mainly from the RCPmi, rectus capitis posterior major, and obliquus capitis inferior. These fibers form the vertebral dural ligament in the atlantoaxial interspace and connect with SDM. The MDB is mainly formed by parallel running type I collagen fibers; thus, suboccipital muscle could pull SDM strongly through the effective force propagated by the MDB during head movement. Conclusions Myodural bridge is mainly formed by parallel running type I collagen fibers; thus, it can transmit the strong pull from the diverse suboccipital muscles or ligaments during head movement. The results of the present study will serve as a basis for further biomechanical and functional MDB research.

Early literature depicting equine anatomy began with stylized illustrations portraying anatomic structures in a congenial format. This study shows that modern day literature often reflects those early portrayals and, in particular, the description and depiction of the nuchal ligament lamellae (NLL) and its attachments from the second to seventh cervical vertebrae. In the dissection of 35 horses of no specific breed, which were unrelated and of mixed gender and age, it was noted that the NLL was not attached to the sixth and seventh cervical vertebrae. Furthermore, the attachment of the NLL on the fifth cervical vertebrae was quite thin and feeble in nine of those horses and that incomplete fibers were noted in the caudal attachments of the NLL in 15 horses. These variations do not correlate to those early depictions or to most of the existing equine anatomic text. This new information on the equine NLL has functional and clinical implications, with particular reference in the way we currently understand the postural and locomotive properties of the equine neck and cervicothoracic junction.

STUDY DESIGN Retrospective clinical data analysis. OBJECTIVE This study was conducted to investigate the incidence, related factors, and radiography findings of ossification of the nuchal ligament (ONL) in patient with cervical spondylosis, which could serve as a basis for further studies of the relationships between ONL and cervical spondylosis. SUMMARY OF BACKGROUND DATA Injury to nuchal ligament, which might cause ONL, may aggravate cervical spine instability, leading to cervical spondylosis. Thus, it is important to understand the characteristics of ONL in patients who are diagnosed with cervical spondylosis. METHODS Medical records of 372 patients with cervical spondylosis were reviewed. Data analysis included patients' sex, age, location and classification of ONL, and ossification of the posterior longitudinal ligament (OPLL). Radiological features were evaluated by lateral plain radiography and computed tomography for 2-dimensional sagittal plane reconstruction. RESULTS Of the 372 patients with cervical spondylosis, 49.7% had a diagnosis of ONL; the incidence of ONL was higher in males than in females (P = 0.001) and in elderly patients than in young patients (P = 0.005). The varying pictures of ONL on the plain radiography were classified into 5 types: local, continuous, segmental, mixed, and unclassified, and the distribution was 49.7%, 33.0%, 3.2%, 8.6%, and 5.4%, respectively. ONL occurred mostly at the level of C4,5 (75.7%) and C5,6 (81.1%). The incidence of ONL was higher in patients with OPLL than others (P < 0.001), and the incidence of multilevel ONL was higher in patients with OPLL than in patients with ONL only (P = 0.038). CONCLUSION The incidence of ONL is 49.7% in patients with cervical spondylosis. Sex, age, and OPLL are related factors of ONL. ONL can be classified into different types through morphology. Local type is the most common type of ONL, and multilevel ONL occurs mostly in patients with OPLL. C4,5 and C5,6 are the levels where ONL occurs mostly. LEVEL OF EVIDENCE 4.

ObjectivesTo investigate the association between ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) in terms of incidence and size.MethodsThis retrospective study evaluated 297 patients who underwent CT of the cervical spine (C-spine). Two radiologists worked in consensus. The incidence of OPLL from patients with and without ONL was compared using Chi Square tests. The mean lengths of ONL from patients with and without OPLL were compared using Student t-test. The correlations between the length of ONL and the presence of OPLL and between the length of ONL and the length of OPLL were analyzed with Pearson correlations.ResultsWe found that OPLL occurred more frequently in patients with ONL than in patients without ONL (odd ratio = 2.524, p = 0.037); however, the mean length of ONL did not differ significantly patients with and without OPLL (p = 0.874). We found no significant correlation between the length of ONL and the length of OPLL (p = 0.233).ConclusionThe presence of ONL was associated with the presence of OPLL. The length of OPLL and ONL showed no correlation.

Pressure in the atlanto-axial region due to hyperflexion ('rollkur') may influence the development of a nuchal bursa, as adventitious bursae may be caused by pressure. Investigating the pressure between the nuchal ligament and atlas/axis in a flexed position may provide information on the pathogenesis of nuchal bursitis. In this study, ten equine head and neck specimens with one side of the soft tissues over the cervical vertebral spine removed were placed in lateral recumbency on a table in neutral, mildly flexed, and hyperflexed head and neck positions. Angulations of the neck were measured using markers placed on the nuchal ligament and drilled into the skull, vertebrae and withers. In six specimens, the pressure between the nuchal ligament and the atlas and the axis was measured using an inflatable air pouch. Hyperflexion was associated with the highest nuchal ligament length and with the highest pressure values at the site of the nuchal bursa over the atlas (99±24mmHg, more than four times the pressure in the neutral position) and over the axis (77±30mmHg, more than twice the pressure values of the neutral position). Also, over the three head and neck positions, neck flexion angles were highly correlated with pressure values and with nuchal ligament length. This marked increase in pressure at the level of atlas and axis caused by head and neck hyperflexion should be considered during training of horses at risk of, or diagnosed with, nuchal bursitis.

Object Modified cervical laminoplasty techniques have been developed to reduce postoperative axial neck pain and preserve function in patients with cervical spondylotic myelopathy (CSM). However, the previous studies demonstrating satisfactory surgical outcomes had a retrospective design. Here, the authors aimed to prospectively evaluate the 2-year outcomes of a modified cervical laminoplasty technique for CSM that preserves the paravertebral muscles. Methods Outcomes were analyzed for 40 patients (22 men and 18 women; mean age, 66.6 years; age range 44–92 years) with CSM who underwent C4–6 laminoplasty with C-3 and C-7 partial laminectomies or C-3 total and C-7 partial laminectomies and received hydroxyapatite spacers. Neurological, pain severity, and spinal radiographic evaluations were performed preoperatively and at 3, 6, 12, 18, and 24 months postoperatively. Plain radiography and MRI of the cervical spine were performed to evaluate the range of motion (ROM), sagittal alignment, and cross-sectional areas of the deep extensor muscles. The extent of bone–spacer bonding and bony union at the gutter was assessed by CT. Results The mean preoperative Japanese Orthopaedic Association CSM score was 10.2, but it increased to 14.4 by 24 months after surgery. Eleven patients had axial neck pain preoperatively, but only 3 reported mild pain at 24 months, and in all 3 cases the pain was mild. The mean angle of lordosis was 11.7° preoperatively and 12.0° 2 years postoperatively. Although the ROM at the C2–7 levels was significantly reduced 3 months postoperatively, an increasing trend was observed up to 12 months, and 86% of the preoperative ROM was achieved by 2 years postoperatively. The mean paravertebral muscle cross-sectional areas were 833 ± 215 mm2 preoperatively and 763 ± 197 mm2 24 months postoperatively, but the difference was not statistically significant. The rates of bone–spacer bonding and bony union at the gutter were low during the early stages but increased to 90% and 93%, respectively, by 2 years after surgery. Conclusions The modified laminoplasty technique used in this study ensured very good neurological status and ROM after 2 years and was associated with low incidences of axial neck pain and serious complications. This simple and easy operative method could benefit future laminoplasty protocols.

Radio-opaque formations behind the spinous processes of the cervical spine are really rare. They were described in 1929 for the first time. Sesamoid ossicles are found close to a bone or a joint and are usually small. Some sesamoids form part of normal human anatomy, while others are normal anatomical variants. We report a case of a 73-year-old Caucasian male who visited the outpatient clinic complaining about chronic cervical pain. An oblong sesamoid accidentally discovered during routine anteroposterior (AP) and lateral x-ray, within the nuchal ligament (NL) at the C3-C6 spinous processes level. A cervical MRI scan was performed and the result showed ‘fabella nuchae’. This type of sesamoids are rarely symptomatic, but it should be differentially diagnosed anyway. We review its morphology, the mechanical factors of the region acting throughout life and last, but not least, the differential diagnosis.

STUDY DESIGN: A cadaver and clinical study investigated the attachment of the nuchal ligament to the cervical spinous process. OBJECTIVE: To investigate the anatomical details of the attachment of the nuchal ligament to the spinous process and the relationship between the morphology of the nuchal ligament and postoperative axial pain after laminoplasty. SUMMARY OF BACKGROUND DATA: The relationship between the length of the C6 spinous process and the morphology of the nuchal ligament and occurrence of postoperative axial pain has not been elucidated. METHODS: The morphology of the nuchal ligament was investigated in 35 cadavers and 60 patients on preoperative computed tomography and magnetic resonance imaging. The lengths of the C6 and C7 spinous processes were measured, and the C6:C7 ratio (C6 spinous process length/C7 spinous process length) was calculated. The relationship between the morphology of the attachment of nuchal ligament to the C6 spinous process and the C6:C7 ratio were investigated. In addition, the effects of the anatomy of the nuchal ligament around the C6 spinous process and different procedures of surgical invasion to C6 or C7 on postoperative axial pain were investigated for 113 patients who underwent laminoplasty. RESULTS: The nuchal ligament was attached to not only the C7 spinous process, but also the C6 spinous process when the C6:C7 ratio was more than 0.8. When the nuchal ligament was attached to the C6 spinous process and to C7, postoperative axial pain after C3-C7 laminoplasty occurred more often compared with C3-C6 laminoplasty for patients without the nuchal ligament attached to the C6 spinous process. CONCLUSION: This study shows that there is an association between the individual anatomical differences of the nuchal ligament and the occurrence of postoperative axial pain after laminoplasty. Careful attention should be paid to the morphology of the attachment of the nuchal ligament to the C6 spinous process to reduce postoperative axial pain.

This is a correlation analysis between severity of the ossification of the nuchal ligament (ONL) and clinical cervical disorders including neck dysfunction, cervical malalignment, and morphologic changes of the cervical neural foramen (CNF). The clinical effects of ONL on active range of motion (AROM) of neck, cervical radiculopathy, abnormal cervical curvature, and the degree of CNF stenosis in patients with painful neck stiffness are investigated. Studies have investigated the predisposing factors to cervical dysfunction and degenerative disorders; however, few studies have examined the influence of the ONL on neck function and cervical spine. A total of 31 participants with painful neck stiffness were recruited. They accepted measurement of cervical AROM and serial cervical radiographs at anterior–posterior view, lateral view, and bilateral oblique views. Parameters of radiographs measurement included cervical lordotic curve, and cross-sectional areas (CSA) of the ONL and CNF (C2–C3, C4–C5, C5–C6, and C6–C7 levels). The ratio of CSA of the lower CNF (C4–C5, C5–C6, C6–C7) to CSA of the upper CNF (C2–C3) was used as a CNF stenosis ratio. The correlations of ONL size, neck symptoms, cervical AROM, lordotic curve, and CNF stenosis ratio were analyzed. More than half of all patients were positive in cervical root signs and prone to have larger ONL. Neck AROM of all participants was significantly below normal average in all directions, and a moderate negative association was found between the ONL CSA and AROM in flexion–extension. Most patients had moderate loss of cervical lordotic curve despite there being no significant correlation between ONL CSA and cervical curvature. Moreover, CNF stenosis ratio significantly negatively correlated with ONL CSA. Patients with larger ONL had more severe cervical radiculopathy, more stiffness in flexion–extension direction, more complex degenerative change of spine, and worse CNF stenosis.

Reasons for performing study: Head and neck positions (HNP) in sport horses are under debate in the equine community, as they could interfere with equine welfare. HNPs have not been quantified objectively and no information is available on their head and neck loading. Objectives: To quantify in vivo HNPs in sport horses and develop o a model to estimate loading on the cervical vertebrae in these positions. Methods: Videos were taken of 7 Warmbloods at walk on a straight line in 5 positions, representing all HNPs during Warmblood training and competition. Markers were glued at 5 anatomical landmarks. Two-dimensional angles and distances were determined from video frames for the 5 HNPs and statistically compared (P < 0.05). A new simulation model was developed to estimate nuchal ligament cervical loading at these HNPs. Results: The mean angles were significantly different between the 5 HNPs for the line between C1 and T6 with the horizontal and for the line connecting the facial crest (CF) and C1 with the vertical, while the vertical distance from CF to the lateral styloid process of the radius (PS) was significantly different between all 5 positions (P < 0.05). The estimated nuchal ligament loading appeared to be largest at the origin of C2 for all HNPs, except for the 'hyperextended' HNP5; the 'hyperflexed' HNP4 showed the largest loading values on the nuchal ligament origins at all locations. Conclusions: HNPs can be accurately quantified in the sagittal plane from angles and distances based on standard anatomical landmarks and home-video captured images. Nuchal ligament loading showed the largest estimated values at its origin on C2 in hyperflexion (HNP4). Potential relevance: Modelling opens further perspectives to eventually estimate loading for individual horses and thus ergonomically optimise their HNP, which may improve the welfare of the sport horse during training and competition.

Study design Prospective study. Objective To examine whether preservation of the funicular section of the nuchal ligament attached to the C6 and C7 spinous processes could prevent unfavorable radiologic changes such as kyphotic deformity and destabilization at the C6/7 segment, and to investigate possible correlations between adverse radiologic changes and neurologic recovery or incidence of axial neck pain after laminoplasty in patients with cervical spondylotic myelopathy. Summary of background data Adverse radiologic changes after cervical laminoplasty have been reported to result from detachment of cervical extensor muscles. Methods Subjects comprised 37 patients who underwent modified C3-6 laminoplasty. Our procedure preserves the funicular section of the nuchal ligament attached to the C6 and/or C7 spinous processes in addition to all muscles attached to the C2 and C7 spinous processes and the subaxial deep extensor muscles on the hinged side. The funicular section of the ligament attached only to the C7 spinous process was preserved in 18 patients (C7 group). This funicular section attaching both to the C7 and C6 spinous processes was preserved in 19 patients (C6+7 group). Radiologic and clinical data were prospectively collected. Results Postoperative loss of lordosis and destabilization at the C6/7 segment were significantly reduced in the C6+7 group compared with the C7 group. As of final follow-up, neurologic recovery was significantly poorer in the 3 patients with kyphosis than in the 34 patients with straight spinal alignment or lordosis. Frequencies of axial pain showed no significant differences between groups. This value did not vary with the differences in sagittal alignment. Conclusions These results indicate that the preserved funicular section of the nuchal ligament attached both to the C6 and C7 spinous processes plays an important role in preventing undesirable radiologic changes after laminoplasty.

OBJECTIVE: Although considered a basic maneuver for neurosurgical procedures, dissection of the musculature of the posterior cervical spine can be a source of complications during surgery. These complications include excessive blood loss, a loss of the plane of dissection, and injury to important structures such as the vertebral artery and nerve roots. Inappropriate closing of the muscular plane might also contribute to leakage of spinal fluid and postoperative deformation of the cervical spine. We review the anatomy of the nuchal ligament and describe a technical nuance based on the characteristics of the ligament's components, which can be used to assure the midline for a bloodless and atraumatic dissection. METHODS: We set out to determine whether or not the nuchal ligament could be used as a natural plane of dissection for splitting the posterior cervical musculature. We studied the anatomy of the nuchal ligament in five cadavers. RESULTS: The nuchal ligament extends from the external occipital protuberance to the spinous process of the seventh cervical vertebra (C7). It is covered by layers of cervical fascia and the aponeurosis of the trapezius muscle. It is composed of two portions: 1) the lamellar portion, an anterior double-layered portion with fatty areolar tissue interposed between its layers that inserts into the medial side of the bifid spinous process of the cervical vertebra; and 2) the funicular portion, a posterior fibrous portion that corresponds to the fusion of the layers of the lamellar portion. CONCLUSION: Several steps can assure that the midline plane is respected, thereby decreasing risk and reducing trauma and blood loss during dissection: 1) dissection of the nuchal ligament within the fatty areolar tissue of the lamellar portion, 2) isolation and incision of the funicular portion from inside to outside, and 3) retrograde dissection of the cerviconuchal muscles attached to the occipital bone in a subperiosteal plane.

The previous reports suggest that obstructive sleep apnoea (OSA) is related to metabolic syndrome, mineral metabolism disorders and cardiovascular disease. In addition, a possible relationship between obesity and the calcification of ligaments has been implied. However, the potential link between OSA and the calcification of ligaments has not been directly studied. In this present study, to investigate the potential link between OSA and the calcification of ligaments, we examined the prevalence of the calcification of ligaments in OSA patients and the relationship between these findings and OSA severity. Eighty consecutive patients (60 males, 20 females) diagnosed as OSA or a heavy snorer based on full-night polyso-mnography were retrospectively recruited from May 2006 to July 2008. Each patient underwent cephalometric imaging examination before the arrangement of an oral appliance. One calibrated observer (YS) reviewed the cephalometric images for the presence of calcification of the nuchal ligament and osteophytes of the cervical spine. The prevalence of calcification of the nuchal ligament in OSA patients and snorers was 46.3% (males: 52%, females: 30%) There was a significant positive correlation between the severity of OSA (AHI) and the calcification of the nuchal ligament before and after adjusting for BMI. The prevalence of the calcification of the nuchal ligament in OSA subjects and snorers was higher than in previous studies with non-OSA subjects. In addition, it is suggested that the severity of OSA correlates with the presence of calcification of the nuchal ligament.

A 25-year-old man who suffered a traffic accident was admitted to our emergency department. Computer tomography was performed. Computer tomography images showed an osseous structure mimicking avulsion fracture at the level of C5–C6 (Fig. 1). There was no bone defect corresponding to spinous process and so, the diagnosis was consistent with sesamoid ossicles of the nuchal ligament. Sesamoid ossicles of the nuchal ligament are an anatomical variant that are usually asymptomatic. Prominent differential diagnosis includes avulsion fractures of the spinal processes and myositis ossificans. Focal well-defined osseous masses, well-circumscribed with regular shape, are in favor of sesamoid ossicle of nuchal ligament, whereas triangular dense bony fragment with bony defect of the adjacent spinous process are in favor of spinous process fracture. Ihsan Yuce, MD Berhan Pirimoglu, MD Gokhan Polat, MD Recep Sade, MD Mucahit Emet, MD Mecit Kantarci, MD, PhD Department of Radiology, School of Medicine Ataturk University 25100 Erzurum, Turkey Department of Emergency Medicine, School of Medicine Ataturk University 25100 Erzurum, Turkey

Introduction Microendoscopic techniques through a unilateral paramedian approach or muscle-preserving techniques using a microscope have been reported as minimally invasive spinal decompression procedures for the cervical spine. In this study, we developed a novel technique, cervical microendoscopic interlaminar decompression (CMID) through a midline approach, for treating cervical compression myelopathy. Methods A total of 29 consecutive patients with single- or two-level cervical compression myelopathy were reviewed. For the single-level cases (e.g., C5–C6), a midline skin incision, ∼ 2 cm in length, was made at the spinal level to be decompressed (C5–C6) under fluoroscopic guidance. The nuchal ligament was longitudinally cut, and tips of the spinous processes (C5 and C6) were exposed. A 16-mm tubular retractor was inserted between the tips of the C5 and C6 spinous processes. A dome-like laminectomy of C5, partial laminectomy of the upper part of C6, and flavectomy were performed. For the two-level cases (e.g., C4–C5 and C5–C6), the decompression procedure was completed by splitting the spinous process (C5). Pre- and postoperative neurologic status was evaluated using the Japanese Orthopedic Association (JOA) score. Neck and arm pain was also evaluated using a numerical rating scale (NRS). Results Overall, 10 patients underwent single-level decompression, and 19 patients underwent two-level decompression. The average age was 67 years (range: 40–83 years), and the mean follow-up period was 11 months (range: 4–14 months). The average pre- and postoperative JOA scores were 10.2 and 13.5, with a mean recovery rate of 49%. The mean preoperative and postoperative NRS scores were 3.5 and 1.5 for neck pain and 4.6 and 2.9 for arm pain, respectively. One patient showed transient mild weakness of the leg that recovered neurologically within a few weeks. No other postoperative complications were observed. Conclusion This procedure revealed good short-term surgical results. This technique has advantages including (1) a symmetrical orientation of the surgical field, (2) an intermuscular incision that minimizes blood loss and muscle trauma, and (3) the ability to safely complete the decompression procedure without retracting the cervical spinal cord compared with the unilateral approach. Although long-term surgical results are required, this technique is not only safe but also minimally invasive as a treatment for cervical compression myelopathy.

Few studies have been conducted specifically on the dense connective tissue located in the posterior medial part of the cervical epidural space. This study was undertaken to examine the presence of this connection between the cervical dura mater and the posterior wall of spinal canal at the level of C1-C2. 30 head-neck specimens of Chinese adults were used. Gross dissection was performed on the suboccipital regions of the 20 specimens. Having been treated with the P45 plastination method, 10 specimens were sliced (9 sagittal and 1 horizontal sections). As a result, a dense fibrous band was identified in the nuchal ligament of 29 specimens (except for one horizontal section case). This fascial structure arose from the tissue of the posterior border of the nuchal ligament and then projected anteriorly and superiorly to enter the atlantoaxial interspace. It was termed as to be named ligament (TBNL). In all 30 specimens the existence of a fibrous connection was found between the posterior aspect of the cervical dura mater and the posterior wall of the spinal canal at the level of the atlas to the axis. This fibrous connection was identified as vertebrodural ligament (VDL). The VDL was mainly subdivided into three parts, and five variations of VDL were identified. These two structures, TBNL and VDL, firmly link the posterior aspect of cervical dura mater to the rear of the atlas-axis and the nuchal region. According to these findings, the authors speculated that the movements of the head and neck are likely to affect the shape of the cervical dural sleeve via the TBNL and VDL. It is hypothesized that the muscles directly associated with the cervical dural sleeve, in the suboccipital region, may work as a pump providing an important force required to move the CSF in the spinal canal.

To assess the consequences of cervical laminoplasty on postoperative lordosis, a retrospective radiographic analysis of 31 patients undergoing laminoplasty for spondylotic myelopathy was completed. Special attention was paid to lordotic changes occurring at each level over more than 2 years. Preoperative lordosis remained unchanged with the patients wearing a cervical orthosis 1 week postoperatively. However the lordosis subsequently demonstrated a significant decrease in 87% of patients over an average of 3.1 years. Lordotic alignment at C2-C3 and C6-C7 before surgery significantly decreased in 81% and 58% of patients 1 week postoperatively, and 84% and 81% at last follow up, respectively, while lordotic alignment at other levels pre- and postoperatively did not significantly change. Loss of lordotic alignment was largely attributed to detachment of semispinalis cervicis muscle on C2 and nuchal ligament on C6/C7 with a posterior approach and/or section of yellow ligament at C2-C3.

The muscular and skeletal systems of the long neck were morphologically examined in order to clarify their modification and their functional significance in the giraffe (Giraffa camelopardalis). The longissimus, the thoracic and cervical, spinalis and semispinalis, the cranial and caudal head oblique, and the multifidus muscles, and the nuchal ligament were observed at their origin and insertion. The atlas, axis, and the third cervical vertebra were measured and examined. The modified spinous processes provided the large attachment surface for the strong nuchal ligament and for the muscles of the axis and other cervical vertebrae, while the muscle tendons had their origin in the ventrocaudally-enlarged transverse process. It is concluded that the modified muscles with their expanded belly and tendon have the functions of occupying the interspace among long vertebrae, and also of supporting the head and neck by means of their wide attachment to the altered vertebral processes.

Soft-tissue tumors with a predilection to involve the head and neck region include spindle cell lipoma, pleomorphic lipoma, and nuchal fibroma. We have recently studied three patients with distinctive soft-tissue fibrocartilaginous masses in the posterior aspect of the base of the neck, at the junction of the nuchal ligament and the deep cervical fascia. Two of the patients were women (ages 37 and 40) and one a man (age 53). All three had sustained neck injuries in automobile accidents in the past (27 years, 20 years, and 2 months before surgery, respectively). Each patient presented with a soft-tissue nodule overlying the spinous process of one of the lower cervical vertebrae. Two were painful. Computed tomography and magnetic resonance imaging performed in two patients showed focal thickening of the ligamentum nuchae at the C4-5 and C5-6 levels. All three masses were completely excised. They ranged in size from 1.0 to 1.5 cm. The three lesions were histologically identical, and each consisted of a poorly defined, moderately cellular fibrocartilage nodule located within the nuchal ligament at its junction with the deep cervical fascia. Atypia or mitotic activity was not present. The ligamentous tissue adjacent to the mass was irregular and degenerated. None of the masses have recurred in follow-up periods of 3 to 6 months, and all patients are currently asymptomatic. The lesion we describe is a distinctive soft-tissue pseudotumor that occurs in the mid-line of the lower cervical spine within the nuchal ligament. It is likely non-neoplastic and probably develops as a reaction to soft-tissue injury, in an analogous manner to fibrocartilage metaplasia seen in degenerated tendoligamentous structures. We propose the term "nuchal fibrocartilaginous pseudotumor" for these lesions.

Study Design. The present study investigated the relationship of obesity and glucose metabolism in persons with ossification of the anterior longitudinal ligament, ossification of the nucal ligament, and ossification of the posterior longitudinal ligament of the cervical spine. Objective. To provide a insight into the etiology of ligamentous ossification of the cervical spine. Summary of Background Data. The high incidence of ligamentous ossification of the cervical spine with obese patients has been reported, but no definite association was reported between the incidence of ossification of the anterior longitudinal ligament, ossification of the nucal ligament, and ossification of the posterior longitudinal ligament and their bone mass index values. Methods. Lateral cervical radiographs and 75 g oral glucose tolerance tests of more than 4802 Japanese men aged 48-57 years at the Self Defense Force Hansin Hospital were evaluated. Results. The incidences of ossification of the anterior longitudinal ligament, ossification of the nucal ligament, and ossification of the posterior longitudinal ligament were 23.1% (1110 of 4802), 23.3% (1117 of 4802) and 4.1% (198 of 4802), respectively. In the groups whose body mass index was 25 or more, the incidences of ossification of the anterior longitudinal ligament, ossification of the nucal ligament, and ossification of the posterior longitudinal ligament were significantly high (P

STUDY DESIGN Observational anatomic study. OBJECTIVE To give precise information on the surgical anatomy of the medial branches of the cervical dorsal rami. SUMMARY OF BACKGROUND DATA The anatomy of the medial branches has not been sufficiently described. METHODS We recorded the location of the medial branches in 94 consecutive patients who underwent laminoplasty for cervical compression myelopathy. A posterior cervical approach was made along the edge of the nuchal ligament, and, after carefully detaching the trapezius muscle from the nuchal ligament; we identified the right-side branches around the semispinalis capitis muscle. We recorded the location of the branches with reference to the spinous processes and the semispinalis capitis and trapezius muscles. In 52 patients, we electrically stimulated the branches and observed the contraction of these muscles. RESULTS Branches were identified between C3 and C6 spinous process levels in 92 patients. A single branch was identified in 56 patients, 2 branches were identified in 35 patients, and 3 branches were identified in the remaining 1 patient. Branches were located between C3 and C4 (n = 12), between C4 and C5 (n = 80), between C5 and C6 (n = 2), and at C6 (n = 35). There were 4 patterns of final course: 52 branches passed through the medial side of the semispinalis capitis and trapezius muscles and terminated in a subcutaneous area; 50 branches penetrated the semispinalis capitis and trapezius muscles and terminated in a subcutaneous area; 12 branches terminated in the semispinalis capitis muscle; and 15 branches penetrated the semispinalis capitis and terminated at the nuchal ligament. In 19 of 52 patients tested, the semispinalis capitis muscle contracted after electrical stimulation. CONCLUSION Medial branches of the cervical dorsal rami were discernible in cervical posterior approach laminoplasty and were frequently found adjacent to C4 and C5 spinous processes. The medial branches sometimes supplied motor fibers to the semispinalis capitis muscle. Knowledge of the course of these branches might be helpful for avoiding injury during laminoplasty.

Sesamoid ossicles are ovoid or round nodular small bones found usually within a joint or tendon of the upper and lower limb and rarely at other regions. They are usually asymptomatic, resulting in an increased propensity to injuries. We report on two cases where sesamoid ossicles were detected within the nuchal ligament. The first one was a 55-years-old Caucasian male office employee, complaining of chronic pain in the cervical spine region accompanied by numbness of the left upper limb. During the routine lateral X-ray imaging two sesamoid ossicles were found within the nuchal ligament at the C4 and C5 spinous processes level. The second case was a 64-years-old Caucasian female store employee, complaining of chronic cervical spine pain. The routine lateral X-ray exhibited two sesamoid ossicles within the nuchal ligament at the C5 and C6 spinous processes level. Sesamoid ossicles found in the nuchal ligament in rare cases may become symptomatic and the pathogenesis mechanism should be differentially diagnosed by the physician. We discuss the precise morphology of the trait, the possible etiological mechanisms for their appearance, the histological features, as well as differential diagnosis.

Purpose.To evaluate the morphologies of congenital C2–3 synostosis in 25 patients.Methods.Radiographs of 11 males and 14 females aged 5 to 74 years with congenital C2–3 synostosis were reviewed. All cases were found incidentally on radiographs when presenting with neck/shoulder discomfort/pain.Results.13 of the patients had spondylosis in 21 segments: C1–2 (n=1) and C3–4 (n=1), C4–5 (n=7), C5–6 (n=9), and C6–7 (n=3). Of whom 12 had normal sagittal alignment and one had kyphotic synostosis (who developed compensatory hyperlordosis of the caudal mobile segments and subsequent spondylosis at C3–4 and C5 retrolisthesis). The remaining 12 patients had no spondylosis and had normal sagittal alignment, but had other associated pathologies including disc herniation at C3–4, C1 ring hypoplasia, and calcification of the nuchal ligament.Conclusion.Normally aligned congenital synostosis of C2–3 is rarely associated with a junctional problem, whereas a kyphotic synostosis is associated with a caudal junctional problem. Spondylosis developing after age 40 years is not associated with C2–3 synostosis.

Study Design. Technical report on harvesting method for human cadaveric cervical spine. Objectives. Description of a new method for harvesting the intact cervical spine during routine autopsies, including the atlanto-occipital and cervico-thoracic joints, without visible disfigurement above the suprasternal notch. Summary of Background Data. Despite the need for cervical spine specimens, there are only few articles describing procedures for harvesting an intact cervical spine. Presently available techniques either do not preserve the atlanto-occipital joint or leave visible disfigurement. Methods. The body was placed in a prone position with the head flexed, and a posterior midline incision was performed. The spine was separated from surrounding tissue, then the caudal end was cut off through the Th1/Th2 disc space. A circular craniotomy provided access to the cranial base. A square window surrounding the foramen magnum was cut at the cranial base (through the sella turcica, the internal occipital protuberance, and 5 cm parasagittal on either side), and the entire cervical spine extracted through the posterior incision. The defect was reconstructed using wood and plaster materials. Results. Eighteen specimens were harvested to date using this method. The average time of harvesting the cervical spine was less than 30 minutes. Reconstruction using wood and plaster resulted in a nearly normal appearance of the neck. Conclusions. Using this technique, the nuchal ligament providing stability to the cervical spine can be preserved. The suggested method was found simple, efficient, and reproducible for harvesting the intact cervical spine, including the atlanto-occipital and cervico-thoracic joints, from any routine autopsy.

This aim of this study was to test the hypothesis that the stiffness of the equine cervical spine depends on the direction of force applied and on spinal position. Muscles and nuchal ligament were removed from the cervical spines of 17 horses that were without a history of cervical or neurological disease. The cervical spines were then flexed/extended dorsoventrally (with the spine straight and with the occiput rotated 30° against T1) and laterolaterally. Mean dorsoventral stiffness was 297 N/m (± 135) in flexion, 1347 N/m (± 2083) in extension, 421 N/m (± 164) in lateral flexion, 279 N/m (± 93) in rotated flexion, and 386 N/m (± 191) in rotated extension. There was a positive correlation between the length of cervical spine and stiffness for dorsoventral flexion (r = 0.63; P0.01) and extension (r = 0.53; P0.05). The stiffness of the equine cervical spine depended on the direction of the loading and was 2-7 times less than thoracolumbar stiffness in horses.

A comparative clinical trial was conducted to clarify the importance of preserving the C7 spinous process and attached nuchal ligament for the reduction of the axial symptoms after French-door laminoplasty in cervical spondylotic myelopathy patients. Forty-one cervical spondylotic myelopathy patients were enrolled. French-door laminoplasty from C3 to C7 in 22 patients (group 1), and from C3 to C6 in 19 patients (group 2) was performed. The whole structure of the C7 spinous process and the attached nuchal ligament were preserved in group 2. The pre- and post-operative evaluation regarding severity of clinical symptoms was assessed using the Japanese Orthopaedic Association (JOA) score. Pre-operative and subjective outcome regarding axial symptoms were also assessed using a visual analog pain scale questionnaire (VAS: 10-0, where a higher score indicates greater pain) at 1- and 2-year follow-up. Non-parametric testing (Mann-Whitney's U test) was used to establish differences between the two groups for categorical data (P0.05). There was no significant difference between the two groups in pre- and post-operative JOA score. The mean VAS was 5.6 +/- 1.4 in group 1, 5.4 +/- 1.7 in group 2 pre-operatively, and 6.4 +/- 1.7 in group 1 and 2.4 +/- 1.9 in group 2 at 1-year follow-up. The mean VAS score at 2-year follow-up exhibited 6.2 +/- 1.9 in Group 1, 2.3 +/- 1.8 in group 2. There was no significant difference in VAS between the two groups before surgery (P = 0.506), but significant differences were noticed at 1-year and 2-year follow-up (P0.05), indicating the presence of significantly fewer post-operative axial symptoms in group 2. Laminoplasty of the entire C7 structure is not necessary to obtain satisfactory recovery based on JOA score. Preservation of the C7 spinous process and the attached nuchal ligamentous structures is important to reduce post-laminoplasty axial symptoms.

Twelve amateur veteran soccer players (average age 40.1 +/- 5.4 years), who began playing in their teens and who were admitted with symptoms most likely to be related to cervical spondylosis, were examined by cervical radiography. Abnormal radiographic findings included: calcification of anterior longitudinal ligament (25%), anterior (75%) and posterior vertebral spurs (75%), ossicle between spinous processes (75%), calcification of nuchal ligament (Barsony) (58%), ossicle on spinous process (25%), and bony spur of Luschka's joints (83%). It was shown in the stress distribution by finite element method analysis that the stress in heading the ball was applied mainly to the lower parts of the cervical spine. The results of this analysis also corresponded well with some of the radiographic findings.

Study design An anatomic study of the posterior midline structures of the cervical spine was performed using a new sheet-plastination (E12) technique in conjunction with gross anatomic dissection. Objectives To clarify the structural status of the human ligamentum nuchae. Summary of background data Little is known about the arrangement of connective tissue attachments of the neighboring neck muscles to the ligamentum nuchae. In addition, it is not clear whether the cervical supraspinous ligaments form part of the ligamentum nuchae. Methods This study used a combined approach of a detailed gross anatomic study on eight cadavers and a macroscopic and microscopic study of the connective tissue organization of the posterior midline structures on serial horizontal thin (2.5 mm) plastinated slices of the cervical spine (occiput-T1) from an adult female cadaver. Results The dorsal and ventral portions of the ligamentum nuchae are a single entity formed by the aponeurotic fibers of the trapezius, splenius capitis, rhomboideus minor, and serratus posterior superior muscles. Conclusions The regional differences in the connective tissue organization of the ligamentum nuchae and its well-defined attachments to the C6 and C7 vertebrae suggest that it is designed to function in the lower cervical spine.

Further studies of the response of cervical vertebrae on lateroflexion of the head and neck in 437 individuals have shown that in 85,4% of cases there exists a definite tendency to preserve a systematic pattern of direction of vertebral tiltings. The appearance of type I patterns, with cephalad increase of the values of tilting is considered to be the result of the cranial traction of the cervico-cranial muscles. On the contrary, the type II patterns, with caudad increase of the values of tilting, probably arise as the result of cranial pull of the stretched nuchal ligament on the spinous processes of the lower cervical vertebrae. Those cases, in whom no systematic pattern appeared (14,6%) result most probably from the concurrence of various, partly pathologic factors.

In 80 subjects the comparison of the dynamics in sitting position and in recumbency showed that the postural factors exert a significant influence on the reaction of cervical vertebrae on lateroflexion of the head and neck. The postural change from sitting to supine position tends to increase the incidence of the type II pattern, in which the values of tilting of vertebrae increase in caudal direction. This can be explained by a strengthening of the effect of nuchal traction component in consequence of a reduction of the action of the muscular component and the increase in the tension of the nuchal ligament. The influence of postural factors on the dynamics in the horizontal and frontal planes was much less evident.

Background Supra/interspinous ligaments connect adjacent spinous processes and act as a stabilizer of the spine. As with other spinal ligaments, it can become ossified. However, few report have discussed ossification supra/interspinous ligaments (OSIL), so its epidemiology remains unknown. We therefore aimed to investigate the prevalence and distribution of OSIL in symptomatic patients with cervical ossification of the posterior longitudinal ligament (OPLL). Methods The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. The whole spine CT data as well as clinical parameters such as age and sex were obtained from 20 institutions belong to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament (JOSL). The prevalence and distribution of OSIL and the association between OSIL and clinical parameters were reviewed. The sum of the levels involved by OPLL (OP-index) and OSIL (OSI-index) as well as the prevalence of ossification of the nuchal ligament (ONL) were also investigated. Results A total of 234 patients with a mean age of 65 years was recruited. The CT-based evidence of OSIL was noted in 68 (54 males and 14 females) patients (29%). The distribution of OSIL showed a significant thoracic preponderance. In OSIL-positive patients, single-level involvement was noted in 19 cases (28%), whereas 49 cases (72%) presented multi-level involvement. We found a significant positive correlation between the OP-index grade and OSI-index. ONL was noted at a significantly higher rate in OSIL-positive patients compared to negative patients. Conclusions The prevalence of OSIL in symptomatic patients with cervical OPLL was 29%. The distribution of OSIL showed a significant thoracic preponderance.