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It is well known that the digastric posterior belly is one of the essential landmarks for facial nerve identification during parotid surgery. While there were multiple reports about variations of the digastric anterior belly, only a few anatomical variations of the posterior belly of the digastric muscle have been described.In this article, we describe an anatomical variation of the posterior belly of digastric muscle found during superficial parotidectomy of a patient with pleomorphic adenoma. This anatomical variation also led to an anatomical variation in the position of the facial nerve.To our knowledge, this is the first report of an absent posterior belly of digastric muscle found during live parotid surgery. The knowledge of current anatomical variation may help to avoid facial nerve injury during parotid surgery and preserve the function of muscles of facial expression., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Sternohyoid, sternothyroid, omohyoid, and thyrohyoid muscles are collectively known as infrahyoid muscles. These muscles frequently show variations in their attachments. Here, an extremely rare variant muscle belonging to this group has been presented. During cadaveric dissection for undergraduate medical students, an additional muscle was found between sternohyoid and superior belly of omohyoid muscles bilaterally in a male cadaver aged approximately 70 years. This muscle took its origin from posterior surface of the manubrium sterni, capsule of the sternoclavicular joint and the posterior surface of the medial part of the clavicle. It was inserted to the hyoid bone between the attachments of sternohyoid and superior belly of omohyoid muscles and was supplied by a branch of ansa cervicalis profunda. There is no report on such a muscle in the literature and it could be named as "sternocleidohyoid muscle". Knowledge of this muscle could be useful in neck surgeries., (© 2021. The Author(s).)

Objective: Report a unique case of absent posterior belly of digastric muscle, with a literature review and discussion of its clinical importance., Methods: Present a case report and review the current literature including PUBMED search terms; "absent posterior digastric", "digastric muscle", "posterior belly"., Results: While there were multiple reports of accessory anterior and posterior bellies and absence of anterior belly, there is a paucity of literature on absence of posterior belly of digastric muscle., Conclusion: To our knowledge, this is the first report of an absent posterior belly of the digastric muscle. The posterior belly of the digastric muscle is an important landmark in neck dissection, and its absence makes knowledge of other anatomic landmarks critically important. Laryngoscope, 131:1501-1502, 2021., (© 2020 American Laryngological, Rhinological and Otological Society Inc, "The Triological Society" and American Laryngological Association (ALA).)

Purpose: Anatomical variations of the sternocleidomastoid muscle (SCM) have been observed to occupy multiple origins and insertion points and have supernumerary heads, sometimes varying in thickness., Methods: An 85-year-old Korean male cadaver was dissected and a SMC with unilateral supernumerary heads was identified., Results: Three heads and an accessory belly of the sternal head were recorded on the left side. There were two clavicular heads, one lateral and one medial. The sternal head originated inferior to the manubrium of the sternum. A small belly arose from the sternal head and merged to the lateral clavicular head on the C5 vertebrae level. These bellies inserted into the mastoid process of the temporal bone., Conclusions: These variants may be problematic during surgical approaches to the upper neck and occipital, and should thus be appreciated by the clinician.

Objective: Variations of the bellies of the digastric muscle is reported for a long time and is not uncommon. However, there is still not a full consensus about the classifications and many different types of variations. The aim of this study was to examine the variations of the digastric muscle on cadaver dissections and to create a pictorial collection of variations related to present-day by combining with existing knowledge., Method: In the present study, a total of 40 formalin-fixed cadavers and head specimens' digastric muscles were analyzed bilaterally., Results: Previous results were utilized for classification of the variations. Anterior belly, intermediate tendon, and posterior belly variations were evaluated according to unilateral, bilateral and unclassified types. 10 variations were identified in the digastric muscle of 40 cadavers. Thus, five of the variations were unilateral and rest of them were bilateral. Two of the variations were residing in the central area. One accessory muscle bundle was found obliquely residing between the left and right sides of the anterior bellies. Remaining variation was the crossing of the accessory anterior belly of digastric muscle fibers at the central line. Intermediate tendon variation as piercing the stylohyoid muscle was observed in only one case. Posterior belly exhibited no variation., Conclusion: Reporting the abnormalities and variations of the digastric muscle is very important in surgical attempts and evaluation of the lymphadenopathy of the submental area and in the floor of the mouth tumors, numerous clinically significant esthetic surgeries for head and neck surgeons, radiologists and plastic surgeons., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

The outcomes of surgical treatment for congenital muscular torticollis (CMT) are poor in many cases, primarily from surgeon's fear of damage to important blood vessels in the carotid sheath. The current research aimed to establish a novel, safer and more effective surgical approach for the treatment of CMT based on the anatomic relationship between the fascial sheath of the sternocleidomastoid muscle and the carotid sheath.A total of 12 formalin-fixed cadaveric specimens (including 9 males and 3 females with average age of 48.1 years at the time of death) were used to observe the anatomical integrity and the compactness of the sternocleidomastoid fascial sheath and its relationship with the carotid sheath. From January 2013 to December 2015, 22 patients with CMT were treated surgically, including 12 males and 10 females with an average age of 13 years (range: 6-28 years). All patients underwent surgical treatment using the novel approach designed by the author, that is, separation of the fascial sheath of the sternocleidomastoid and the carotid sheath was performed.The fascial sheath of the sternocleidomastoid muscle is easily isolated from the carotid sheath in all specimens. All procedures were successfully completed. The space between the fascial sheath of the sternocleidomastoid muscle and the carotid sheath can be accessed in all patients. Carotid sheath contracture was identified in 1 patient and divided successfully. The average follow-up period was 19 months (range: 5 to 43 months). No postoperative lateral band was noted in the neck in any of the patients. Satisfaction regarding cosmetic and functional outcomes was considered excellent in 13 patients, good in 7 patients, and fair in 2 patients.The fascial sheath of the sternocleidomastoid muscle is easily isolated from the carotid sheath. This anatomical feature is the basis of division of the sternocleidomastoid muscle and can improve the safety and effectiveness of surgical treatment for CMT in patients older than 6 years old.

Many anatomical variants on the sternocleidomastoid muscle have been reported. In this study, supernumerary clavicular heads of sternocleidomastoid muscle in a Korean female cadaver were bilaterally displayed. The observed supernumerary heads were classified as follows: one sterno-mastoid, one cleido-occipital and one cleido-mastoid on the right side, and one sterno-mastoid-occipital, four cleido-occipitals, and one cleido-mastoid on the left side. The sterno-mastoid and sterno-mastoid-occipital and the cleido-occipital made the superficial layer of the sternocleidomastoid muscle, while others made deep layer. We discussed clinical relevance and developmental basis of these muscular variations important for clinicians and anatomists.

Introduction: Duplicate omohyoid muscles are uncommon anomalies and exceedingly rare causes of progressive clinical symptoms. The goals of this case report are to describe the clinical characteristics, cross-sectional imaging, intraoperative findings, and curative treatment of our patient, to develop a differential diagnosis for this condition, and to review the pertinent literature regarding this particular type of anomalous omohyoid muscle as one among many variations., Case Presentation: A 20 year-old man presented with progressive limited neck range of motion followed by dysphagia and then dyspnea caused by his duplicate omohyoid muscle. He underwent curative surgery in 2015 at our tertiary care center., Discussion: Although rare, a duplicate omohyoid muscle should be considered in the differential diagnosis of dysphagia and dyspnea with concurrent central neck deformity. We report the first case, to our knowledge, of an anomalous omohyoid that caused significant progressive clinical symptoms. Direct excision of the restrictive anomalous tissue proved curative.

Omohyoid muscle present in cervical region is of particular importance to anatomists as it defines anteriorly the carotid triangle and divides the posterior cervical triangle. It has superior and inferior bellies and an intermediate common tendon. Like sternohyoid, sternothyroid and thyrohyoid muscles, omohyoid is also an infrahyoid muscle, but it differs from them in its course. The infrahyoid muscles are formed from a muscle primordium occurring in the anterior cervical area. Anderson (Anderson, 1881) theorized that the superior belly of the omohyoid muscle is a true infrahyoid muscle, whereas the inferior belly most likely shares a common embryology with the subclavius muscle. In the present study, during routine dissection in the neck region of an adult male cadaver of 50 years age, an anomalous origin of inferior belly of omohyoid with absence of intermediate tendon was observed bilaterally. It was arising from clavicle on both sides. Both the muscle bellies were measured from the lateral end of fascial sling. The inferior belly of omohyoid extending from the lateral margin of sling to clavicular surface was measured 3.3cm in length on left side and 3.6cm on right side. The omohyoid is important in neck dissections because it is considered as an ideal landmark for level III and IV lymph node metastases. Knowledge of variations of this muscle is very important for surgeries in neck region because of its close relation to the internal jugular vein and brachial plexus. Its crucial relationship to vascular structures in the neck makes it an important landmark during neck surgeries., (Copyright © 2017. Published by Elsevier Masson SAS.)

A three-headed anterior belly of the digastric muscle (ABDM) on the right side of a 54-year old Greek male cadaver coexisted with two accessory muscle bundles (AMB) in the submental region. The left ABDM was typical. Typical ABDM was attached to the digastric fossa, while the accessory right anterior bellies to the lower border of the mandible. A muscle bundle arising from the attachment of the left ABDM to the hyoid bone was also observed fusing with the AMB of the ipsilateral side. It is of extreme importance to be aware of the submental region anatomical variations during surgery, imaging interpretation or differential diagnosis of neck masses., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Unlabelled: Mutations in SEPN1 cause selenoprotein N (SEPN)-related myopathy (SEPN-RM) characterized by early-onset axial and neck weakness, spinal rigidity, respiratory failure and histopathological features, ranging from mild dystrophic signs to a congenital myopathy pattern with myofibrillar disorganization. We report on clinical and instrumental features in three patients affected with a congenital myopathy characterized by prevalent neck weakness starting at different ages and mild myopathy, in whom we performed diagnosis of SEPN-RM. The patients presented myopathic signs since their first years of life, but the disease remained unrecognized because of a relatively benign myopathic course. In two cases, myopathic features were stable after 2 years of follow-up, but respiratory involvement worsened. The muscle MRI and muscle biopsy showed a typical pattern of SEPN-RM. Molecular diagnosis revealed two novel homozygous mutations in SEPN1, c.1176delA and c.726_727InsTCC., Conclusion: This report underlines the clinical diagnostic clues of early neck and axial weakness to suspect a SEPN-RM and the usefulness of muscle MRI in conjunction with clinical features to achieve the diagnosis. Our data confirm the slow progression of respiratory involvement in spite of the relatively stable course of myopathy. We report two previously undescribed mutations in SEPN1., What Is Known: • Mutations in SEPN1 cause myopathy characterized by early-onset axial and neck weakness spinal rigidity and respiratory failure. • SEPN-related myopathies have been initially associated with four distinct histopathological entities that however appear more mixed in recently described cases. What is New: • SEPN-related myopathies can remain unrecognized because of the normal early motor development and relatively benign myopathic course of the disease. • Our study adds two novel homozygous mutations to the number of reported pathogenic SEPN1 variants.

The levator claviculae muscle is an uncommonly encountered muscle variant, occurring in 1% to 2% of the human population. Most accounts of the levator claviculae muscle have been reported in association with routine cadaveric examination and as an incidental finding by computed tomography (CT) and magnetic resonance (MR) imaging. We report a case of this variant muscle presenting as a soft-tissue mass within the neck of a young male. Furthermore, we discuss the embryologic origin, imaging features and clinical implication.

The sternocleidomastoid muscle shows a wide range of variations including supernumerary muscular heads. We found a rare variation in the sternocleidomastoid muscle with bilateral supernumerary heads in a 67-year-old Korean male cadaver. Bilateral four muscle bellies were recorded: two sternomastoids, one cleido-occipital and one cleido-mastoid occipital on the right side, and one sternomastoid, one cleido-occipital and two cleido-mastoids on the left side. The variation of bilateral four heads on sternocleidomastoid muscle is important to surgeons and anesthetists for clinical using.

Purpose: We report a unique case of duplicated posterior belly of digastric muscle and absence of omohyoid muscle, review literatures and discuss its clinical importance., Materials and Methods: An abnormal strip of muscle was found during the routine functional neck dissection in a 58-year-old man, who suffered from moderately differentiated squamous cell carcinoma of right tongue. We check the anatomical features and search for similar variations in the past literatures., Results: The abnormal strip of muscle was attached to mastoid process, passed anteroinferiorly into the infrahyoid muscles. The muscle was as long as, but narrower than the posterior belly of the digastric muscle. So far, only one case of this anomaly was reported. Meanwhile, the omohyoid muscle was confirmed to be absent in the right neck of this patient., Conclusions: To our knowledge, report of variations of both digastric muscle and omohyoid muscle, this variation mostly derives from abnormal development of the mesenchyme in the branchial arches. Attention should be paid to such variations, which might influence surgical procedures.

Purpose: Although anatomical variations were continuously found in the infrahyoid muscles, muscular variations of the sternothyroid muscle are still rare., Materials and Methods: We found an accessory belly of the sternothyroid muscle in a 46-year-old Korean male cadaver during routine dissection course, whose cause of death was 'chronic renal failure'., Results: The accessory belly attached to the oblique line of the lamina of the thyroid cartilage, covered the thyroid gland anteriorly, and attached to posterior surface of left sternothyroid muscle and pretracheal layer of the cervical fascia from side to side. It was supplied by the inferior thyroid artery from the left thyrocervical trunk and innervated by the nerve to sternothyroid muscle from the left ansa cervicalis., Conclusion: The present case is worth because it requires special attention performing procedures on the anterior neck.

Objectives: Patients presenting with neck mass are challenging for many otolaryngologists. If a mass on the lower lateral neck exists with swallowing and disappears after swallowing, it has been diagnosed as an omohyoid syndrome in most literature. The mechanism of sternohyoid syndrome has not been proven or investigated before. We investigated sternohyoid syndrome, commonly misdiagnosed as an omohyoid syndrome., Methods and Patients: Two patients were investigated. Outpatient photography, computed tomography and operating findings were reviewed. We found that the sternohyoid muscle was inserted at an abnormal site, the midportion of the clavicle. There was no abnormality of other muscles. We also reviewed all literature that previously diagnosed this condition as an omohyoid syndrome., Results: There was no literature about sternohyoid syndrome. We found that the abnormal muscle is a sternohyoid muscle and not omohyoid muscle. The color of the left sternohyoid muscle was dark red, and the fascia covering the muscle was denuded. The muscle had lost elasticity and moved abnormally., Conclusion: Our patients did not have omohyoid syndrome. The symptoms of omohyoid syndrome are the same as sternohyoid syndrome but the problematic muscle is different. This is the first known report diagnosing sternohyoid syndrome, and should be a consideration in the diagnosis of a lateral neck mass., (Copyright © 2015 Elsevier Inc. All rights reserved.)

The congenital absence of a skeletal muscle is a rare cause of congenital muscular torticollis, and the condition is associated with various unusual anatomical structures. We describe a rare case of congenital absence of the sternocleidomastoid muscle associated with squamous cell carcinoma of the tongue in a patient who underwent neck dissection. In this case, both the external jugular vein and the spinal accessory nerve were absent. However, we found that branches of the C3 nerve extended from the cervical plexus to the trapezius muscle and seemed to be acting as trapezius muscle motor nerves in place of the accessory nerve. After the operation, the patient was able to lift and abduct his right arm, and his shoulder did not droop.

This case report describes the rare anomaly of an absent right anterior scalene muscle presenting with the symptoms and signs of the thoracic outlet syndrome. The thoracic outlet syndrome in our patient can be attributed to the absence of the right anterior scalene muscle, which resulted in the brachial plexus being in proximity to the subclavian vein and artery in a narrowed and abnormal interscalene space. In addition, the absence of the anterior scalene muscle resulted in the neurovascular structures being compressed onto the first rib in the costoclavicular space. The most likely cause of the presentation is, however, the possibility of the presence of aberrant muscle slips, which would cause compression of the structures in the anterior (venous) and posterior (neurological) sections of the thoracic outlet.

Congenital torticollis is characterized by shortening and fibrosis of the sternocleidomastoid (SCM) muscle detected at birth or shortly after birth. This leads to a lateral inclination of the head to the ipsilateral shoulder and chin deviation to the opposite side. When diagnosed early, most cases can be conservatively managed with excellent results. In neglected adult cases, the treatment of this entity is more controversial. A review of the different treatment options in neglected adult cases of congenital torticollis is presented, and a case successfully treated by SCM bipolar release is reported. A 35-year-old woman diagnosed with congenital torticollis was referred to the authors' department. She had been diagnosed at 32 years of age and had been conservatively treated, with no success. Physical examination showed a posterior region of the left SCM muscle hard to palpation, with head tilt to the same side and chin deviation to the right. Bipolar release of the SCM muscle was performed under general anesthesia using the harmonic scalpel. Immobilization with a brace was applied during the first 2 weeks and manual stretching was performed after removal of the brace. Head tilt and movement limitation were resolved, achieving good functional and cosmetic results. Although the best treatment results in congenital torticollis are achieved during the first years of childhood, bipolar release of the SCM muscle followed by postsurgical physical therapy can be effective in neglected adult cases., (Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of this research was to contribute to minimizing arterial disruption during mandibular surgical procedures by clarifying the course of the arteries supplying the sublingual and submental regions., Study Design: Heads of 75 human cadavers were dissected to identify the arterial supply of the sublingual and submental regions. Computed tomography scans were performed to visualize the lateral lingual foramina of the mandibles., Results: The facial artery was found to contribute to the composition of almost half of the sublingual arteries studied. Furthermore, it was demonstrated that the arterial supply to an incisor tooth is often from the submental artery., Conclusions: Our data provide important information for coping with bleeding or hematoma occurring during surgical procedures in the mandibular region., (Copyright © 2014 Elsevier Inc. All rights reserved.)

A 70-year-old woman was referred to us for evaluation of a presumed left-sided neck mass. The referral was based on the visual appearance of subtle neck asymmetry. The patient reported no ENT symptoms. Clinical examination and ultrasonography identified no pathology, but computed tomography revealed that the asymmetry was present because the patient's right sternocleidomastoid muscle (SCM) was absent. The SCM on the left side was normal. Congenital absence of an SCM is uncommon, and to the best of our knowledge, an initial presentation in an adult has not been previously reported in the literature.

We report on a rare case of anatomical variations of the infrahyoid muscles with prominent clinical significance. The aberrant anatomy was on the right side of the neck and involved the omohyoid and sternohyoid muscles. The superior belly of the omohyoid was duplicated in width due to an aberrant belly anteriorly and merged with fibers of the inferior belly inferiorly and the sternohyoid muscle medially. An additional aberrant muscle slip extended between the inferior third of the sternohyoid muscle and united with the inferior belly of the omohyoid. The intermediate tendon between the two bellies of the omohyoid was absent, whereas the so-called muscular triangle of the neck was diminished. Due to the arrangement and fusion of myofibers the muscle could be termed as omo-sternohyoid muscle. A profound hematoma was noted in the aberrant muscle at the area overlying the internal jugular vein indicating difficulty in obtaining jugular venous access for catheter placement. Clinicians and surgeons should be aware of muscular anatomic variations when intervening in the lateral neck area as the classical anatomical landmarks might be misinterpreted and confuse.

During routine dissection of the submental region of a 65-year-old female cadaver, a bilateral supernumerary muscle, medial to the anterior bellies of the digastric muscle, was observed. The accessory muscle bundle was attached proximally to the digastric fossa of the mandible, with an intermediate attachment to the body of hyoid bone and a distal attachment to the medial margin of the lower end of the anterior belly of the digastric muscle and its intermediate tendon on the respective side. These types of bilaterally symmetrical accessory muscles of the submental region may be erroneously identified as an infarcted submental lymph node or a pseudomass on radiological examinations.

We report here an anatomical study of the levator claviculae discovered during an anatomical dissection course for medical students. The muscle was identified on the left side, and followed a typical topography to previous detections, originating from the transverse process of the fourth cervical vertebra and attaching to the upper facet of the middle part of the clavicle. Innervation to this muscle came from both the third and fourth rami of the cervical spinal nerves. Blood supply to the muscle could not be identified clearly. In this report, we undertook a comprehensive literature survey of this muscle dating back ca. 170 years, and attempted to ascertain the phylogenic and ontogenetic explanations for the development of this muscle.

Congenital torticollis is most commonly caused by sternomastoid contracture. Aplasia of sternomastoid muscle causing congenital torticollis, though rare, has been reported. However the association of cerebellar hypoplasia with sternomastoid aplasia is extremely rare. The authors describe a case of congenital torticollis due to absence of the left sternomastoid with ipsilateral cerebellar hypoplasia, confirmed by MRI.

Objective: The aim of this study was to primarily investigate the usefulness of computerized tomographic (CT) fistulography in the diagnosis and management of branchial cleft fistulae and sinuses., Study Design: Fifteen patients with confirmed branchial fistulae or sinuses who had undergone CT fistulography were included. The diagnoses were confirmed by clinical, radiologic, or histopathologic examinations. The internal openings, distribution, and neighboring relationship of the lesions presented by CT fistulography were analyzed to evaluate the usefulness in comparison with x-ray fistulography., Results: Nine patients were diagnosed with first branchial fistulae or sinuses, 2 with second branchial fistulae, and 4 with third or fourth branchial fistulae. The presence and location of the lesions could be seen on x-ray fistulography. The distribution of the lesions, internal openings, and neighboring relationship with parotid gland, carotid sheath, and submandibular gland could be clearly demonstrated on CT cross-sectional or volume-rendering images., Conclusions: CT fistulography could provide valuable information and benefit surgical planning by demonstrating the courses of branchial anomalies in detail., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Congenital midline cervical cleft (CMCC) is a rare developmental defect of the anterior neck normally characterized by an atrophic mucosal plaque with a cranial nipple-like skin tag, a short caudal sinus, and may be attached to a subcutaneous fibrous cord of variable length. Clinically, patients present at an early age with, white females being the most commonly affected population. In addition to aesthetic concerns, CMCC can prevent full extension of the neck, result in micrognathia and torticollis, predispose patients to infection, and can coexist with other clefting defects or cysts. Fewer than 50 cases have been published in the English-language literature. Herein, we report a case of CMCC that also presented with a mild contracture of the right sternohyoid muscle. The embryopathogenesis, histopathology, diagnosis, and treatment of this rare condition are also discussed.

Our previous study of whiplash injury found that abnormalities in the cervical muscles cause autonomic dystonia. Further research has found that abnormalities in the cervical muscles cause headache, chronic fatigue syndrome, vertigo, and dizziness. We named this group of diseases cervical neuro-muscular syndrome. Patients treated within a 2-year period from April 1, 2002 to March 31, 2004 reported good outcomes in 83.8% for headache, 88.4% for vertigo and dizziness, 84.5% for chronic fatigue syndrome, 88.0% for autonomic dystonia, and 83.7% for whiplash-associated disorder. A large number of outpatients present with general malaise, including many general physical complaints without identifiable cause. We propose that treatment of the cervical muscle is effective for general malaise.

Background: The most common clinical presentation of thoracic outlet syndrome stems from compression of the lower trunk of the brachial plexus or ulnar nerve. A plethora of anatomical variations have been implicated in the cause of thoracic outlet syndrome. Roos' identification and classification of scalene muscle and fibrous bands have added an additional dimension to understanding its cause and subsequent treatment. Understanding the anatomy and relationship of this band with the lower trunk of the brachial plexus is of paramount importance., Methods: As part of the authors' long-term study of the type 3 band in relation to the brachial plexus, 70 embalmed cadavers were dissected to yield 100 first thoracic ribs. Fibrous bands, when present, were studied in relation to the brachial plexus., Results: A fibrous band consistent with Roos' type 3 was identified and found to occur in 35 percent of first ribs and 41 percent of cadavers. The mean size was 3.45 × 0.27 cm. Origins and insertions are described. Contrary to Roos' own description, however, the authors observed that Roos' type 3 band was anterior to the T1 nerve root, creating a tunnel through which the T1 nerve root must pass before joining the C8 nerve root., Conclusions: The authors believe that the type 3 band, when present, can create a tunnel that compresses the T1 nerve root against the first rib, potentially predisposing susceptible individuals to thoracic outlet syndrome. Clinical studies are needed to determine whether correlations between type 3 bands and thoracic outlet syndrome exist.

The embryologic origin of the omohyoid muscle is different from that of the other neck muscles. A number of variations such as the absence of muscle, variable sites of origin and insertion, and multiple bellies have been reported. However, variations in the inferior belly of the omohyoid muscle are rare. There have been no reports of the combined occurrence of the omohyoid muscle variation with the appearance of the levator glandulase thyroideae muscle. Routine dissection of a 51- year-old female cadaver revealed a duplicated omohyoid muscle and the appearance of the levator glandulae thyroideae muscle. In this case, the two inferior bellies of the omohyoid muscle were found to originate inferiorly from the superior border of the scapula. One of the inferior bellies generally continued to the superior belly with the tendinous intersection. The other inferior belly continued into the sternohyoid muscle without the tendinous intersection. In this case, the levator glandulae thyroideae muscle appeared on the left side, which attached from the upper border of the thyroid gland to the inferior border of the thyroid cartilage. These variations are significant for clinicians during endoscopic diagnosis and surgery because of the arterial and nervous damage due to iatrogenic injuries. The embryologic origins of the omohyoid and levator glandulae thyroideae muscles may be similar based on the descriptions in the relevant literature.

Background: : The study examined the incidence of anterior belly of digastric muscle agenesis in patients with hemifacial microsomia, to determine the need for routine imaging of the floor of the mouth in patients within this group requesting dynamic lower lip reanimation., Methods: : Patients presenting with microtia were assessed according to the OMENS [orbital deformity, mandibular hypoplasia, ear deformity, nerve (cranialnerve VII) involvement, and soft-tissue deficiency] criteria, and also imaged to establish the presence or absence of the anterior belly of the digastric muscle. Each affected hemiface was treated as an individual case (n = 50), with unaffected hemifaces being assigned as controls (an additional group of unaffected controls were also included). The hemifaces with microtia were then subdivided into three groups: those with isolated microtia (with anterior belly of the digastric muscle present), those with features consistent with hemifacial microsomia (with the anterior belly of the digastric muscle present), and those with absent anterior belly of the digastric muscle., Results: : Anterior belly of the digastric muscle agenesis rate was 40 percent in those patients displaying features consistent with hemifacial microsomia. Median OMENS scores were significantly different in intergroup analysis (p < 0.0001), with a trend noticed between the median value for the hemifacial microsomia group and those with absent anterior belly of the digastric muscle. There were no noted incidences of anterior belly of the digastric muscle agenesis in the control group., Conclusions: : The incidence of anterior belly of the digastric muscle agenesis in patients with hemifacial microsomia is high. Before any attempt to undertake lower lip reanimation using this muscle, the floor of the mouth should be imaged to check for its presence.

Unilateral congenital agenesis of sternocleidomastoid and trapezius muscles is a rare occurrence. To date, there are only two case reports in the literature. We present a case of a 7-year-old Caucasian boy who was born with torticollis and a cosmetic defect in his neck. An MRI scan of the cervical spine and shoulder confirmed the absence of the right sternocleidomastoid and trapezius muscles. No other significant congenital anomalies were detected. The patient has been followed-up for 7 years with no functional disabilities.

Congenital muscular torticollis (CMT) is caused by shortening of the sternocleidomastoid (SCM) muscle, which may lead to neck movement limitation and craniofacial deformity. The authors retrospectively reviewed clinical experiences of CMT at their hospital from February 2007 to June 2008. During the study period, 20 CMT patients underwent complete tight fibrous band release and resection. Mean patient age was 47.6 months at operation. Eighteen of the 20 patients started a programme of physical therapy preoperatively. All patients received well-controlled postoperative physical therapy and wore a soft neck collar to correct head position for at least 3 months. At 3 months postoperatively, passive ranges of neck motion were determined, and compared with those of uninvolved sides. Eighteen patients showed a full range of motion of neck rotation and lateral flexion, but one patient showed a 10 degrees limitation in lateral flexion, and another showed 10 degrees limitations of neck rotation and lateral flexion. The authors recommended that the described operative technique involving complete fibrous band release and resection, combined with intensive postoperative physical therapy and application of a soft neck collar, provides good functional and cosmetic results., (Copyright 2009 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

The presence of a unusual appearance of the stylohyoid and digastric muscles may lead to a confusion in some pathological cases, during the radiological examination and aesthetic facial surgery. These differences may cause pharyngeal pain and foreign body sensation in the throat. During the dissection, unusual insertions, origin, insertion, shape and bilaterality were investigated in 28 cadavers' heads. In a total of 56, the presence of unusual insertions which belong to the stylohyoid muscle were observed in 22 sides (39.3%), and atypical fibers which belong to the digastric muscle were observed in 39 sides (69.6%). Bilaterality of the presence of atypical appearance was observed for stylohyoid and digastric muscles, in 10 (35.7%) and 19 (67.8%) specimens, respectively. In 12 heads (42.9%), atypical fibers, the stylohyoid and the digastric coexisted. These fibers which were shaped like a circular spiral were realized to have the shape of an arch or circle in front of the hyoid bone. The posterior bellies of the digastric muscle, the mylohyoid and the remaining suprahyoid muscles of both sides were normal. The unusual insertion of the stylohyoid muscles which cover the hyoid bone as a collar was not described in the classification of the previous studies. These fibers may give an variant mobility to the hyoid and they occur depending on the differences in the stylohyoid chains. Although the styloid process was in normal size, unusual insertions of the stylohyoid muscle that cover the hyoid as a belt or collar may give symptoms similar to those of the stylohyoid syndrome.

A rare muscle named Levator Submandibuli (LS) or Banjo muscle (after the author) is present in few persons. It is situated in the submandibular region superficial to the mylohyoid muscle. It consists of two triangular right and left halves whose fibres originate by interdigitating with each other from a median intermuscular septum attached above to the mandible, below to the hyoid bone, parallel and continuous with the intermuscular septum of the mylohyoid muscle. Levator Submandibuli muscle fibres of each side insert into a tendon which is continuous at each side with the central tendon of the digastric muscles. Contraction of the muscle would elevate and support the submandibular region particularly during swallowing and during any activity which increases the oro-pharyngeal pressure such as blowing a trumpet. The muscle is not an accessory/anomaly of the digastric nor of mylohyoid muscle. Its anatomy indicated that, it is a separate muscle innervated by a branch from the mylohyoid nerve. It is suggested that, there is predilection for the appearance of a separate muscle in the submandiblar region distinct from mylohyoid and digastric muscles. It is further suggested that during myogenesis when the migrating myogenic (myoblasts) cells destined to form levator submandibuli are halted at the proximity of the site of formation of anterior belly of the digastric muscle, an anomalous/accessory muscle of the digastric is formed. But when the myoblasts reach their predestined position in the submandibular region, an independent muscle, levator submandibuli (Banjo muscle) is formed. The muscle has an incidence of about 0.3% in Caucasian and 0.4% in black Africans.

The sternocleidomastoid muscle (SCM) functions as a landmark for physicians such as anatomists, orthopaedic surgeons, neurosurgeons, and anaesthesiologists, who intervene in the minor supraclavicular fossa located at the base of the neck. The variability of SCM anatomy may cause complications while trying to access the vital elements that are located in the minor supraclavicular fossa. This study aims to present a case of supernumerary heads of the sternocleidomastoid muscle and to discuss its clinical significance. The cervical region of an elderly male cadaver was dissected and the findings were recorded and photographed. On both sides, the SCM muscle had an additional sternal head, and simultaneously there were three additional clavicular heads, four in total. These additional heads, the sternal and the clavicular, reduced the interval between them causing significant stenosis of the minor supraclavicular fossa. Sternocleidomastoid muscle variations with regard to the number of its heads are very rare in the literature, but this variation may cause severe complications. The minor supraclavicular fossa is important for anaesthesiologists because of the anterior central venous catheterization approach. Physicians should be aware of this anatomical variation in order to prevent complications.

Congenital torticollis is most commonly caused by benign fibrosis of the sternocleidomastoid muscle. Absence of the sternocleidomastoid muscle is a rare cause of congenital torticollis. There have been fewer than a dozen reported cases of agenesis of the sternocleidomastoid muscle. We describe a case of congenital absence of the sternocleidomastoid diagnosed by US and confirmed on MRI.

The sternothyroid muscle and other infrahyoid muscles play a vital role in the process of vocalization, swallowing and mastication by mobilizing the hyoid bone and thyroid cartilage. During routine dissection of a 70-year-old male cadaver, we observed an anomalous sternothyroid muscle. It was arising from the posterior surface of the manubrium sterni and partly from the cartilage of the first rib. After a distance of 3.3 cm, the belly of sternothyroid muscle was divided into lateral and medial fibers. The lateral belly was inserted above the oblique line on the lamina of the thyroid cartilage, but the medial additional belly turned into a tendon, which was crossing over the thyroid artery and inserted to the hyoid bone and intermediate tendon of digastric muscles. The superior thyroid artery was below the above tendon on its way to the thyroid gland. The muscle was innervated by a branch from the ansa cervicalis.

Anatomical variations in the musculature surrounding the thyroid gland have the potential to cause iatrogenic injuries during neck and thyroid surgical procedures. Herein is presented a unilateral case found in an 83-year-old Caucasian female cadaver during a surgical mock thyroidectomy. The thyroid gland had a small pyramidal lobe with three muscular slips of levator glandulae thryroideae (LGT) muscle and a large tributary of the inferior thyroid vein descending posteriorly along the muscular slips. The nerve and arterial supply of the LGT was a twig of the ansa cervicalis and muscular branches from the superior thyroid artery, respectively. Clinicians who interpret imaging of the neck or surgeons who operate in the neck and especially on or near the thyroid gland should be aware of such a variation.

Vertebral artery dissection as a cause of stroke is rarely reported in children. The association between vertebral artery dissection and Klippel-Feil syndrome is also very rare. We report on a case of vertebral artery dissection with posterior circulation involvement in a child with Klippel-Feil syndrome after a hard physical-training lesson. She was also diagnosed with Wildervanck syndrome, with additional clinical findings. Vertebral artery dissection should be considered in patients with Klippel-Feil syndrome who present with acute-onset neurologic signs. Movements such as hyperextension with rotation of the neck should be avoided in these cases.

Objective: The omohyoid muscle is a long, thin muscle consisting of superior and inferior bellies and an intermediate tendon, which runs obliquely in the lateral cervical region. The omohyoid is important in neck dissections because it is the surgical landmark for level III and IV lymph node metastases., Methods: In the present study, the anterior and posterior triangle of the neck was dissected in 35 male cadavers and observed for variations in the omohyoid bilaterally. Observations were focused on variations in number, attachments, and position of omohyoid., Results: Among the 35 cadavers studied, double omohyoid was present in one cadaver, inferior belly originated from the clavicle in three cadavers, superior belly merged with the sternohyoid in two cadavers, and the omohyoid received additional slips from the sternum in one cadaver. Standard attachment and position of the omohyoid was observed in the remaining cadavers., Conclusion: Variations of this muscle are important because of its close relation to the large vessels and brachial plexus. Because of the direct adhesion of the intermediate tendon to the anterior wall of the internal jugular vein and its connection with it through a thin lamina of the pretracheal layer of the cervical fascia, the contraction of the omohyoid muscle has a direct effect on the lumen of this vessel.