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Background: Coccydynia is one of the most overlooked symptoms in daily clinical practice. Definitions for radiologic evaluation are controversial., Objectives: We aimed to compare the morphology and morphometric measurements of the sacrococcygeal region with those of a healthy population to support radiologic decision-making., Materials and Methods: In total, 26 traumatic and 50 idiopathic cases of coccydynia as well as 74 healthy control cases were retrospectively compared. The morphologic type of the coccyx, the presence of fusion, and the number of coccygeal segments were evaluated in both groups. Morphometric parameters such as sacrococcygeal angle (SCA), sacrococcygeal joint angle (SCJA), intercoccygeal angle (ICA), sacral slope (SS), coccyx curved length (CCL), sacrum curved length (SCL), coccyx length (CL), sacrum length (SL), and sacrococcygeal total length (SCTL) were investigated., Results: Significant differences were found between the coccydynia group and the healthy control group in morphologic parameters such as female gender, coccyx segment, coccyx morphology, presence of sacrococcygeal joint, and segment of sacrococcygeal joint fusion (p < 0.05). In morphologic measurements, SCJA, SCL, SL, coccyx and sacrum curvature indexes were significantly increased (p < 0.05). No significant difference was found in the morphologic and morphometric parameters evaluated when compared with the duration of coccydynia (p > 0.05)., Conclusion: An increase in the SCJA, SCL, SL, SCI, and coccyx curvature index measurements predisposes to coccydynia. It would be more accurate to perform radiological evaluation by familiarization with these morphologic and morphometric parameters., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Dzharatitanis kingi gen. et sp. nov. is based on an isolated anterior caudal vertebra (USNM 538127) from the Upper Cretaceous (Turonian) Bissekty Formation at Dzharakuduk, Uzbekistan. Phylogenetic analysis places the new taxon within the diplodocoid clade Rebbachisauridae. This is the first rebbachisaurid reported from Asia and one of the youngest rebbachisaurids in the known fossil record. The caudal is characterized by a slightly opisthocoelous centrum, 'wing-like' transverse processes with large but shallow PRCDF and POCDF, and the absence of a hyposphenal ridge and of TPRL and TPOL. The neural spine has high SPRL, SPDL, SPOL, and POSL and is pneumatized. The apex of neural spine is transversely expanded and bears triangular lateral processes. The new taxon shares with Demandasaurus and the Wessex rebbachisaurid a high SPDL on the lateral side of the neural spine, separated from SPRL and SPOL. This possibly suggests derivation of Dzharatitanis from European rebbachisaurids. This is the second sauropod group identified in the assemblage of non-avian dinosaurs from the Bissekty Formation, in addition to a previously identified indeterminate titanosaurian., Competing Interests: The authors have declared that no competing interests exist.

During ganglion impar block, the needle may approach the presacral space and the sacrum may be penetrated during caudal anesthesia. Because the rectum is in front of the sacrococcyx and is thus at risk for puncture, it is important to determine the distance between the sacrococcyx and rectum, as well as the thickness of the sacrococcyx.Computed tomography was used to measure the distance between the rectum and sacrococcyx, as well as the thickness of the sacrococcyx. The distances between the coccyx and rectum, sacrococcygeal joint and rectum, sacral level 5 ('sacrum 5') and rectum, and 'sacrum 4 to 5 junction' and rectum were measured. The results were compared based on the presence or absence of stools in the rectum. The thickness of the sacrococcyx was measured at the sacrum 4 to 5 junction and sacrococcygeal joint.In total, 1264 patients were included in this study. All distances were less than 1 mm in both males and females, with the exception of the distance between the coccyx and rectum in males. In both males and females, there was no significant difference in distance between the sacrococcyx and rectum according to the presence or absence of feces in the rectum, but there was a difference in the distance between sacrum 5 and the rectum in males (P = .048). Several male and female patients showed thicknesses of less than 5 mm at the sacrococcygeal joint.Some patients have a distance of less than 1 mm between the sacrum and rectum. Practitioners should exercise caution when applying a needle to the presacral space. If the sacrum is accidentally penetrated during caudal block, rectum puncture cannot be ruled out. Excretion of feces does not influence the distance between the sacrococcyx and rectum in females.

Developmental novelties often underlie the evolutionary origins of key metazoan features. The anuran urostyle, which evolved nearly 200 MYA, is one such structure. It forms as the tail regresses during metamorphosis, when locomotion changes from an axial-driven mode in larvae to a limb-driven one in adult frogs. The urostyle comprises of a coccyx and a hypochord. The coccyx forms by fusion of caudal vertebrae and has evolved repeatedly across vertebrates. However, the contribution of an ossifying hypochord to the coccyx in anurans is unique among vertebrates and remains a developmental enigma. Here, we focus on the developmental changes that lead to the anuran urostyle, with an emphasis on understanding the ossifying hypochord. We find that the coccyx and hypochord have two different developmental histories: First, the development of the coccyx initiates before metamorphic climax whereas the ossifying hypochord undergoes rapid ossification and hypertrophy; second, thyroid hormone directly affects hypochord formation and appears to have a secondary effect on the coccygeal portion of the urostyle. The embryonic hypochord is known to play a significant role in the positioning of the dorsal aorta (DA), but the reason for hypochordal ossification remains obscure. Our results suggest that the ossifying hypochord plays a role in remodeling the DA in the newly forming adult body by partially occluding the DA in the tail. We propose that the ossifying hypochord-induced loss of the tail during metamorphosis has enabled the evolution of the unique anuran bauplan ., Competing Interests: The authors declare no competing interest., (Copyright © 2020 the Author(s). Published by PNAS.)

Purpose: This study aims to evaluate the morphology of the coccyx in adults with multidetector computed tomography and to contribute to the classification of the coccyx using intercoccygeal and sacrococcygeal angle measurements., Methods: The pelvic computed tomography images of 224 patients were retrospectively evaluated. The multiplanar reconstruction and 3D volume rendering images of the coccyx were obtained from all patients at sagittal and coronal planes. The morphology of the coccyx, number of bone segments, the presence of scoliosis, and presence of sacrococcygeal and intercoccygeal fusion were evaluated. After the measurement of coccygeal length, width, and thickness, intercoccygeal and sacrococcygeal angles were also calculated in all patients., Results: The morphological classification showed that 136 patients (60.7%) had type 1, 65 patients (29%) had type 2, and 17 patients (7.6%) had type 3 coccyx. The intercoccygeal angle was zero degree in five patients (type 0) and one patient had retroverted coccyx (type 5). The coccyx had four segments in 155 patients (69.2%), three segments in 52 patients (23.2%), five segments in 15 patients (6.7%), two segments in one patient (0.4%), and one segment in one patient (0.4%)., Conclusion: We determined patients with an intercoccygeal angle of zero degree, which is not mentioned in the literature before, and we propose to use the term "type 0" for these patients in the classification of coccyx. The coccygeal measurements and classification will be instructive for the radiologists and have a guiding role for the future studies.

The present study is an attempt to estimation of stature and sex from sacrum and coccyx measurements by multidetector computed tomography (MDCT) in a contemporary Chinese population. Nine measurements for every sacrum and coccyx were taken from CT image of 350 Chinese. The sample is composed of 190 males and 160 females with an average age of 55 and 50 years, respectively. Discriminant function was used in sex estimation and regression analysis was used in stature estimation from these two bones. The stepwise analysis of all measurements yielded a sex classification accuracy rate of 84.9%. The classification accuracy rates of the univariate discriminant function analyses are 58.3%-76.9%. For stature estimation, the accuracy of stature prediction ranged from 4.891 to 6.107 cm for male, from 4.474 to 5.606 cm for female, respectively. This paper provides indications that the sacrum and coccyx are important bones for sex estimation and they could be effectively used as alternatives in forensic cases when the skull and pelvis are unavailable. Furthermore, the regression equations presented in this study may be useful for forensic estimation of the stature of Chinese individuals, particularly in cases where better predictors such as the long bones are not available., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: Sciatic nerve blocks provide intraoperative and prolonged postoperative pain management after lower limb surgery (posterior knee, foot, skin graft surgery). Accurate needle placement requires sound anatomical knowledge. Anatomical studies on children are uncommon; most have been performed on adult cadavers. We studied the location of the sciatic nerve at the gluteal level in neonatal cadavers to establish useful anatomical landmarks., Methods: We identified the sciatic nerve in the gluteal and thigh region of 20 neonatal cadavers. The skin covering the gluteal and thigh region was reflected laterally, and the underlying structures and muscles were identified. We located the sciatic nerve and measured the distance from the nerve to the greater trochanter of the femur and to the tip of the coccyx with a mechanical dial caliper. The total distance between the two landmarks was then recorded., Results: We combined measurements from both sides to form a sample size n = 40. The sciatic nerve was 14.9 ± 2.4 mm lateral to the tip of the coccyx. The total distance between the greater trochanter and the tip of the coccyx was 27.3 ± 4.0 mm., Conclusion: Our results provide anatomical evidence that the optimal needle insertion point is approximately halfway between the greater trochanter and the tip of the coccyx-a landmark readily palpable in neonates and infants., (© 2017 John Wiley & Sons Ltd.)

Aim: The human coccyx varies considerably in shape and size. The objective of this study was to investigate the morphology and morphometry of the coccyx on pelvic magnetic resonance imaging in asymptomatic individuals among Turkish adults., Materials and Methods: This study was conducted retrospectively on the pelvic magnetic resonance images of 456 adult patients without a history of trauma in the coccyx region. The coccygeal vertebrae count, number of bone segments, and intercoccygeal and sacrococcygeal joint fusions were determined from the sagittal plane images. In addition, the length and angles (the sacrococcygeal angle, intercoccygeal joint angle, and sacrococcygeal joint angle) were measured., Statistical Analysis Used: Data were analyzed using the T-test or Mann-Whitney U-test, the ANOVA, or Kruskal-Wallis tests, and the chi-square test was used for the categorical variables., Results: The coccyx is formed by four, five, or three vertebrae in a decreasing ratio. The coccyx is composed of one to five bone segments; one bone segment was found in 2.8% of the cases. Intercoccygeal joint fusions been observed predominantly in the last intercoccygeal joint, with or without sacrococcygeal joint fusion. The coccyx was found to be longer in adult males than in adult females. The sacrococcygeal angle might be anteverted or retroverted., Conclusion: The findings are contrary to the conventional knowledge in that the vertebrae shaping the coccyx were completely fused and consisting of a single bone in very few cases. Better understanding of the anatomical variation of the coccyx may be useful for clinicians evaluating patients presenting with conditions in the coccygeal region.

To examine how the median sacral artery (MSA) is involved with the coccygeal body or glomus coccygeum, we studied serial frontal or sagittal sections of 14 embryos (approximately 5-6 weeks of gestation) and 12 fetuses (10-18 weeks). At five weeks, the caudal end of the dorsal aorta (i.e., MSA) accompanied putative sympathetic ganglion cells in front of the upper coccygeal and lower sacral vertebrae. At six weeks, a candidate for the initial coccygeal body was identified as a longitudinal arterial plexus involving nerve fibers and sympathetic ganglion cells between arteries. At 10-18 weeks, the MSA exhibited a highly tortuous course at the lower sacral and coccygeal levels, and was attached to and surrounded by veins, nerve fibers, and sympathetic ganglion cells near and between the bilateral origins of the levator ani muscle. Immunohistochemistry demonstrated expression of tyrosine hydroxylase and chromogranin A in the nerves. However, throughout the stages examined, we found no evidence suggestive of an arteriovenous anastomosis, such as well-developed smooth muscle. An acute anterior flexure of the vertebrae at the lower sacrum, as well as regression of the secondary neural tube, seemed to induce arterial plexus formation from an initial straight MSA. Nerves and ganglion cells were likely to be secondarily involved with the plexus because of the close topographical relationship. However, these nerves might play a major role in the extreme change into adult morphology. An arteriovenous anastomosis along the MSA might be an overinterpretation, at least in the prenatal human. Anat Rec, 299:819-827, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

To provide anatomical and morphological data regarding the coccyx using three-dimensional images, with a view to aiding the diagnosis of idiopathic coccydynia, one hundred and thirty-six normal adult pelvises were investigated. Three-dimensional models of the pelvis were reconstructed using software from computed tomography images of whole specimens. The following six coccyx parameters were measured: (1) width, (2) straight length, (3) thickness, (4) sacrococcygeal angle, (5) intercoccygeal angle, and (6) angle of lateral deviation of the coccyx. The presence of fusion between the sacral and coccygeal cornua, and between the sacrum and the transverse process of the coccyx was also investigated, and lateral deviations of the coccyx were classified and analyzed. Most of the measured coccyx parameters were larger in males than in females, with the exception of the sacrococcygeal and intercoccygeal angles. Unilateral or bilateral fusion of the sacral cornu and the coccygeal cornu was not a rare finding. With respect to the sacrum and the transverse process of coccyx, the separated type was more common than the fused type. The incidence and angle of lateral deviation of the coccyx varied widely between individuals. The present detailed description of the gross anatomy of the coccyx obtained using three-dimensional modeling will help toward understanding the mechanism underlying the development of idiopathic coccydynia. Fusion of the sacrum and coccyx or lateral deviation of the coccyx may cause coccydynia by compressing the coccygeal nerves., (© 2015 Wiley Periodicals, Inc.)

The term "anococcygeal ligament (ACL)" has been used to refer to two distinct structures: a superficial fibrous band originating from the myosepta of the external anal sphincter (EAS) and running upwards to the coccyx (the superficial ACL); and a deep fibrous band originating from the periosteum of the coccyx, merging with the thick presacral fascia and attaching to the superior end of the EAS (the deep ACL). In the present work, elastic fiber histology and muscle immunohistochemistry of sagittal sections obtained from 15 donated elderly male cadavers showed that superficial ACL, corresponding to a superficial fascia or skin ligament, was composed of very tortuous elastic fibers, with a fine elastic fiber mesh at their coccygeal attachment; whereas the deep ACL was composed of almost straight collagen and elastic fibers, intermingled with the coccygeal periosteum. Due to the weak insertion into the coccyx and the wavy course, the superficial ACL is unlikely to provide, even in association with contraction of the longitudinal anal muscle, a stable mechanical support to maintain the configuration of the EAS. Being similar to the suspensory ligament of breast, tissue repair of the skin ligament would not have a mechanical role. In contrast, the deep ACL, in association with the thick presacral fascia, likely plays a role in maintaining a suitable positioning of the anorectum to the coccyx. However, their relative lack of smooth muscles compared with rich elastic fibers indicates that both ACLs may become permanently overextended under conditions of long-term mechanical stress., (© 2015 Wiley Periodicals, Inc.)

Introduction and Hypothesis: Standard external landmarks have been suggested as a guide for in-office percutaneous nerve evaluation (PNE), but validity of these landmarks has not been assessed. Our objective was to determine whether the standard 9 cm from the tip of the coccyx indicates the position of the S3 sacral foramen and whether other boney landmarks and measurements improved positioning., Methods: Measurements and distances between external boney landmarks were obtained in 22 embalmed cadavers. Spinal needles were placed 9 cm superior to the coccyx and 2 cm lateral to midline bilaterally. After dissection, internal measurements relating to sacral length, position of S3, and location of the needle in relation to S3 were recorded. Correlations among measured variables were assessed using descriptive statistics., Results: Mean distance from the tip of coccyx to S3 was 9.26 cm (±0.84), from S3 to midline 2.30 cm (±0.2); from needle to S3 1.25 cm, and needle placement was as likely to be placed above or below S3; and S2-S3 and S3-S4 interforamenal distance 1.48 cm (±0.30) and 1.48 cm (±0.24), respectively. Mean distance from S3 to sacroiliac joint (SIJ) was shorter than S2 to SIJ. All associations between external measurements and length from tip of coccyx to S3 were not significant., Conclusion: A distance 9 cm from the tip of the coccyx is a reasonable starting landmark for in-office blind PNE. However, given the variability in coccyx length, caution should be taken; also, sensory-motor response is necessary to confirm proper placement.

A "long-backed" scenario of hominin vertebral evolution posits that early hominins possessed six lumbar vertebrae coupled with a high frequency of four sacral vertebrae (7:12-13:6:4), a configuration acquired from a hominin-panin last common ancestor (PLCA) having a vertebral formula of 7:13:6-7:4. One founding line of evidence for this hypothesis is the recent assertion that the "Lucy" sacrum (A.L. 288-1an, Australopithecus afarensis) consists of four sacral vertebrae and a partially-fused first coccygeal vertebra (Co1), rather than five sacral vertebrae as in modern humans. This study reassesses the number of sacral vertebrae in Lucy by reexamining the distal end of A.L.288-1an in the context of a comparative sample of modern human sacra and Co1 vertebrae, and the sacrum of A. sediba (MH2). Results demonstrate that, similar to S5 in modern humans and A. sediba, the last vertebra in A.L. 288-1an exhibits inferiorly-projecting (right side) cornua and a kidney-shaped inferior body articular surface. This morphology is inconsistent with that of fused or isolated Co1 vertebrae in humans, which either lack cornua or possess only superiorly-projecting cornua, and have more circularly-shaped inferior body articular surfaces. The level at which the hiatus' apex is located is also more compatible with typical five-element modern human sacra and A. sediba than if only four sacral vertebrae are present. Our observations suggest that A.L. 288-1 possessed five sacral vertebrae as in modern humans; thus, sacral number in "Lucy" does not indicate a directional change in vertebral count that can provide information on the PLCA ancestral condition., (© 2015 Wiley Periodicals, Inc.)

The predisposing factors for the development of sacrococcygeal pilonidal disease (SPD) still remain undetermined. Here, we investigate the sacrococcygeal angle as a possible predisposing factor for the development of disease. Consecutive male patients admitted to our clinic with the diagnosis of SPD were included. Sex, age and BMI matched healthy controls without SPD were enrolled to the study. The predefined sacrococcygeal angles of patients and controls were measured on lateral pelvic radiographs by a single experienced radiologist. Thirty patients were included in each group. Sacrococcygeal angles of patients and control group were measured as 37.3±14.5 and 36.81±10.23 in patients and controls, respectively. The difference with respect to sacrococcygeal angle was not statistically significant between two groups. Sacrococcygeal angle which is the main skeletal determinant of intergluteal sulcus is not a predisposing factor for the development of sacrococcygeal pilonidal disease.

Prehensile tails, capable of suspending the entire body weight of an animal, have evolved in parallel in New World monkeys (Platyrrhini): once in the Atelinae (Alouatta, Ateles, Brachyteles, Lagothrix), and once in the Cebinae (Cebus, Sapajus). Structurally, the prehensile tails of atelines and cebines share morphological features that distinguish them from nonprehensile tails, including longer proximal tail regions, well-developed hemal processes, robust caudal vertebrae resistant to higher torsional and bending stresses, and caudal musculature capable of producing higher contractile forces. The functional significance of shape variation in the articular surfaces of caudal vertebral bodies, however, is relatively less well understood. Given that tail use differs considerably among prehensile and nonprehensile anthropoids, it is reasonable to predict that caudal vertebral body articular surface area and shape will respond to use-specific patterns of mechanical loading. We examine the potential for intervertebral articular surface contour curvature and relative surface area to discriminate between prehensile-tailed and nonprehensile-tailed platyrrhines and cercopithecoids. The proximal and distal intervertebral articular surfaces of the first (Ca1), transitional and longest caudal vertebrae were examined for individuals representing 10 anthropoid taxa with differential patterns of tail-use. Study results reveal significant morphological differences consistent with the functional demands of unique patterns of tail use for all vertebral elements sampled. Prehensile-tailed platyrrhines that more frequently use their tails in suspension (atelines) had significantly larger and more convex intervertebral articular surfaces than all nonprehensile-tailed anthropoids examined here, although the intervertebral articular surface contour curvatures of large, terrestrial cercopithecoids (i.e., Papio sp.) converge on the ateline condition. Prehensile-tailed platyrrhines that more often use their tails in tripodal bracing postures (cebines) are morphologically intermediate between atelines and nonprehensile tailed anthropoids., (© 2014 Wiley Periodicals, Inc.)

There has been no systematic study of the anatomy of the region between the sacral and coccygeal cornua. Reference texts describe an intercornual ligament connecting these structures. The aim of this study was to investigate the anatomy of this region, which may be relevant to unexplained cases of coccygeal pain (coccydynia) and local nerve blocks. The bony anatomy of the sacrococcygeal (SC) cornual region was analyzed in 33 CT scans obtained from supine adults of mostly European origin with no known SC pathology, 7 μCT scans of cadaver SC specimens, and 105 Asian Indian adult skeletons. A further five cadaver SC specimens were examined histologically. SC cornual fusion was seen in 45% of CT/μCT scans (mean age 67 years, 20 males) and in 20% of adult skeletons (78 males); there was no association with age or sex. In the absence of SC fusion, the mean intersacrococcygeal cornual gap was 7.1 ± 2.4 mm; this was bridged by an intercornual ligament composed of parallel vertical collagen fibers reinforced by elastin fibers on its anterior surface. Small nerve branches were observed adjacent to the ventral aspect of the intercornual ligament and, in one case, traversing the ligament. Ipsilateral sacral and coccygeal cornua are therefore normally bridged by an intercornual ligament that is probably innervated. The cornua are fused on one or both sides in 20-45% of adults. These findings may have implications for some cases of coccydynia and for anesthetists performing local nerve blocks.

The coccygeal plexus is variably described in anatomy texts and has rarely been studied despite the idiopathic nature of coccydynia in up to one-third of affected patients. The plexus was therefore investigated using a combination of microdissection and histology. The distal sacrum and coccyx in continuity with ischiococcygeus were removed en bloc from 16 embalmed cadavers (mean age 78 ± 10 years, 7 females) with no local disease. Ten specimens underwent microdissection of the coccygeal plexus and the remaining six were examined histologically after staining with hematoxylin and eosin and S100 immunohistochemistry to demonstrate nerve fibers. The coccygeal plexus is formed within ischiococcygeus from the ventral rami of S4, S5, and Co1 with a contribution (gray rami communicantes) from the sacral sympathetic trunk. It gives rise to anococcygeal nerves which pierce ischiococcygeus and the sacrospinous ligament to supply the subcutaneous tissue on the dorsal aspect of the coccyx. Some branches from the plexus pass medially anterior to the coccyx. The coccycgeal plexus is formed within ischiococcygeus rather than on its pelvic surface and appears to supply skin in the anococcygeal region. It probably also contributes to the innervation of ischiococcygeus, the sacrospinous ligament, coccygeal ligaments, and periosteum. It deserves to be considered as a potential pain generator that may be implicated in some patients with coccydynia., (Copyright © 2013 Wiley Periodicals, Inc.)

Purpose: We have discussed the importance of sacrococcygeal sinus angle (SSA), which is a new anatomical landmark in the surgery of presacral lesions. Because of its anatomical structure, the sacrum limits the surgical exposure like a compact barrier for the posterior surgical approach. The main aim of this paper is to explain the anatomical description and clinical importance of SSA in the surgery of presacral lesions., Methods: Three groups were designated, consisting of ten patients in each group, as early childhood (group 1), late childhood (group 2) and adulthood (group 3). Patients were selected randomly. The degree of SSA measurement was performed between the line tangent to the anterior margin of the first sacral vertebra and the line from the promontorium to the tip of the coccyx. The measurement of SSA was performed on patients' lumbosacral magnetic resonance images. When the SSA forms a triangle via a parallel line starting from the inferior tip of the sacrum and running parallel to the ground, the area of the triangle also covers the field of view of the presacral region. In addition, the sacral region needed to be resected for maximum exposure is also within this area., Results: The mean SSA was measured to be 53.9 ± 11.4° in group 1, 77.8 ± 11.2° in group 2 and 74.5 ± 12.5° in group 3. Intergroup comparisons revealed a significant difference between group 1 and the other two groups statistically. It was found that the SSA was 20° less in group 1 as compared to the other age groups (p = 0.0005). The area of a triangle is calculated using the sine area formula, and according to this formula the area of a triangle increases when the degree of the angle increases, thus comprising larger part of the sacrum. This condition requires more and wide sacral resection to obtain maximum exposure in the presacral zone., Conclusions: We have observed that the SSA is significantly smaller during early childhood compared with the other age groups. This feature provides an anatomical superiority in this age group for the posterior approach in the surgical treatment of presacral masses.

We evaluated the relationship between stature and the length of the sacrum and coccyx using multidetector computed tomography (MDCT) and derived regression equations for stature estimation in the modern Japanese population. Two hundred and sixteen Japanese subjects (110 males and 106 females) who underwent postmortem computed tomography with subsequent forensic autopsy between January 2010 and August 2013 were measured. A sagittal-plane image of the sacrum and coccyx was used. Anterior sacral length (ASL) was defined as the linear distance from the anterosuperior edge of the first sacral vertebra (S1) to the anteroinferior edge of the fifth sacral vertebra (S5), and posterior sacral length (PSL) was defined as the linear distance from the posterosuperior edge of S1 to the anteroinferior edge of S5. Anterior sacrococcygeal length (ASCL) was defined as the linear distance from the anterosuperior edge of S1 to the anteroinferior edge of the last coccygeal vertebra (LCV), and posterior sacrococcygeal length (PSCL) was defined as the linear distance from the posterosuperior edge of S1 to the anteroinferior edge of the LCV. The correlation between stature and each parameter was evaluated by simple regression analysis using Pearson product-moment correlation coefficients. Each parameter was significantly and positively correlated with stature among both males and females. Cadaver stature (CS, cm)=0.39×PSL (mm)+123.70 [Corrected] provided the most accurate stature prediction (R=0.507, SEE=5.83 cm) in males. CS (cm)=0.56×PSCL (mm)+85.29 provided the most accurate stature prediction (R=0.659, SEE=6.68 cm) in females. We conclude that sacral/sacrococcygeal length measured with MDCT is a potentially useful tool for stature estimation, particularly in cases where better predictors such as the long bones are not available., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Purpose: Lack of data on the in vivo morphology and morphometry of the normal adult coccyx hampers understanding of radiological abnormalities in idiopathic coccydynia. The aim of this study was to investigate normal adult sacrococcygeal morphometry., Methods: Retrospective analysis of 112 adult CT scans (mean age 63 ± 14.6 years, 50 males) evaluated the following: number of coccygeal segments; joint fusion; coccygeal spicules, subluxation, sacralization, and scoliosis; sacrococcygeal straight and curved lengths and curvature indices; sacrococcygeal and intercoccygeal angles; and lateral deviation of the coccyx tip., Results: Four coccygeal segments were present in 76 % of scans. Sacrococcygeal fusion was present in 57 % and intercoccygeal fusion was increasingly common more caudally; there was no significant association with age or gender. A bony spicule was present in 23 %. Subluxation was rare. Nine of 12 coccyges with a retroverted tip were female. Mean coccygeal curved length was 4.4 ± 0.8 cm in men and 4.0 ± 0.8 cm in women (P < 0.01). Mean angle between first and last coccygeal segments was 138° ± 25° in men and 147° ± 25° in women (P = 0.08). There was no significant correlation between coccygeal length or curvature and stature, age or BMI., Conclusions: In this first detailed study of the CT morphology and morphometry of the adult coccyx, sacrococcygeal and intercoccygeal joint fusion was common. Female coccyges were shorter, straighter, and may be more prone to retroversion, factors that may be relevant to the markedly higher prevalence of idiopathic coccydynia in women.

The multisystem nature of female chronic pelvic pain (CPP) makes this condition a challenge for physical therapists and other health care providers to manage. This article uses a case scenario to illustrate commonly reported somatic, visceral, and neurologic symptoms and their associated health and participation impact in a female with CPP. Differential diagnosis of pain generators requires an in-depth understanding of possible anatomic and physiologic contributors to this disorder. This article provides a detailed discussion of the relevant clinical anatomy with specific attention to complex interrelationships between anatomic structures potentially leading to the patient's pain. In addition, it describes the physical therapy management specific to this case, including examination, differential diagnosis, and progression of interventions., (Copyright © 2012 Wiley Periodicals, Inc.)

We measured the thickness of the transverse structures associated with the bovine coccygeal transverse processes (bone specimen) by using ultrasonic waves and examined the reliability of this measurement for use in spinal surgery. We first measured the velocity of ultrasonic waves propagating in the spinous process. We then made a hole in the transverse process with an air drill and placed an ultrasonic transducer with a center frequency of 10 MHz in the hole. The time of reflection of the ultrasonic wave from the underside of the transverse process was detected to estimate the remaining bone thickness. The thickness estimated by using ultrasound was compared with the thickness measured by microscopic examination. We could detect reflection waves from the underside of the transverse process in 91.7% of cases (i.e., 22 of 24 measurements using 6 bones from 3 cows). The thickness of the transverse processes in which we detected the waves varied from 0.24 to 6.8 mm. The 95% limit of agreement between ultrasonic and histological measurement was 0.71 mm. Pearson's correlation coefficient showed a strong and positive relationship between the two measurements (r = 0.97, n = 22, P <0.0001).

Purpose: The caudal epidural space is a popular site for analgesia in pediatrics. High variation in blind needle placement is common during caudal epidurals, increasing the risk of intravascular and intrathecal spread. Knowledge of safe distances and angles for accessing the caudal epidural space in premature infants can improve the safety of caudal epidural blocks., Methods: Thirty-nine fetuses with crown-heel length between 33 and 50 cm, corresponding to gestational age of 7-9 months, were included. The dorsal surface of the sacrum from the fourth lumbar vertebra to the tip of the coccyx was dissected, following which measurements were taken on dorsal surface and midsagittal sections. The angle of depression of the needle was measured using a goniometer following the two-step method of needle insertion., Results: Right and left sacral cornua were palpable in 23 of 39 fetuses (58.97%). Termination of dural sac was at S2 in most of the fetuses (53.84%), whereas the apex of the sacral hiatus was at S3 in most (58.97%). The distance from the apex of the hiatus to the termination of dura ranged from 3 to 13 mm; the anteroposterior distance of the canal at the apex of the hiatus ranged from 1.72 to 4.38 mm. All sacral parameters correlated with crown-heel length except inter-cornual distance, depth of canal at hiatus, and height of sacral hiatus., Conclusion: Distances and angles for accessing the caudal epidural space in fetuses do not provide all parameters for safe performance of caudal epidural blocks in premature and low birth weight infants because the apex of the sacral hiatus and the termination of the dura show wide variation in location.

The coccyx has been relatively neglected in anatomical research which is surprising given the population prevalence of coccydynia and our inadequate understanding of its etiology. This systematic review analyzes available information on the clinical anatomy of the coccyx. A literature search using five electronic databases and standard anatomy reference texts was conducted yielding 61 primary and 7 secondary English-language sources. This was supplemented by a manual search of selected historical foreign language articles. The coccygeal vertebrae, associated joints, ligaments and muscles, coccygeal movements, nerves, and blood supply were analyzed in detail. Although the musculoskeletal aspects of the coccyx are reasonably well described, the precise anatomy of the coccygeal plexus and its distribution, the function of the coccygeal body, and the anatomy of the sacrococcygeal zygapophyseal joints are poorly documented. Further research into the anatomy of the coccyx may clarify the etiopathogenesis of coccydynia which remains uncertain in one-third of affected patients., (Copyright © 2011 Wiley-Liss, Inc.)

In the present work, our goal was to match high-resolution computed tomography (CT) scans with cross-sectional anatomical pictures of the turkey (Meleagris gallopavo). Two male BUT 6 (a commercial line) turkeys were used. CT scans with 1 mm slice thickness were performed. The images covered the trunk from the level of the 9th cervical vertebra to the end of the coccyx. The anatomical sections and the CT scans were matched, and the important structures were identified and labelled on the corresponding pictures. The aim of this study was to create a reference for evaluating CT scans of avian species., (© 2011 Blackwell Verlag GmbH.)

Aims: The pubococcygeal line (PCL) is an important reference line for determining measures of pelvic organ support on sagittal-plane magnetic resonance imaging (MRI); however, there is no consensus on where to place the posterior point of the PCL. As coccyx movement produced during pelvic floor muscle (PFM) contractions may affect other measures, optimal placement of the posterior point is important. This study compared two methods for measuring the PCL, with different posterior points, on T2-weighted sagittal MRI to determine the effect of coccygeal movement on measures of pelvic organ support in older women., Methods: MRI of the pelvis was performed in the midsagittal plane, at rest and during PFM contractions, on 47 community-dwelling women 60 and over. The first PCL was measured to the tip of the coccyx (PCLtip) and the second to the sacrococcygeal joint (PCLjnt). Four measures of pelvic organ support were made using each PCL as the reference line: urethrovesical junction height, uterovaginal junction height, M-line and levator plate angle., Results: During the PFM contraction the PCLtip shortened and lifted (P < 0.001); the PCLjnt did not change (P > 0.05). The changes in the four measures of pelvic organ support were smaller when measured relative to the PCLtip as compared to those to the PCLjnt (P < 0.001)., Conclusions: Coccyx movement affected the length and position of the PCLtip, which resulted in underestimates of the pelvic-organ lift produced by the PFM contraction. Therefore, we recommend that the PCL be measured to the sacrococcygeal joint and not to the tip of the coccyx., (Copyright © 2011 Wiley Periodicals, Inc.)

Humans do not have a tail, but we have four rudimentary coccygeal vertebrae. This study considers several issues pertaining to fusion of the coccyx to the sacrum, including prevalence, sexual differences, effect on pelvic size, and obstetrical and evolutionary implications. Previous research on sacral-coccygeal fusion has reported: (1) lower prevalence in females than males, (2) prevalence increases with age, (3) range in prevalence among 13 samples from 0 to 72%, and (4) obstetrical complications. This study uses a sample of 2,354 American skeletons of known sex, age 20 years and older to ascertain prevalence of sacral-coccygeal fusion and to evaluate some of its correlates. Results show that the sexes do not differ in prevalence of sacral-coccygeal fusion for five of seven decades of life, but that prevalence does increase with advancing age-from 24 to 47% from the third to eighth decades of life in females. Pelvimetric analysis of 132 females shows that those with sacral-coccygeal fusion have a shorter posterior sagittal diameter of the outlet compared to those without fusion; more than half of those with sacral-coccygeal fusion have an obstetrically contracted posterior sagittal diameter. Shortening of the posterior sagittal diameter is important, because its conjoint occurrence with a narrow subpubic arch may result in an obstetrically inadequate outlet. This study concludes that sacral-coccygeal fusion is a principal contributor to the evolution of sexual dimorphism in sacral angulation, which is a determinant of the length of the posterior sagittal diameter of the outlet., (Copyright © 2011 Wiley-Liss, Inc.)

Background: With the development and spread of surgical procedures for total mesorectal excision and intersphincteric resection, rectal surgeons have gained frequent opportunities to observe connective tissues around the anal canal. However, uncertainty remains as to the exact identity and location of these structures., Objective: The aim of this study was therefore to identify and describe the morphology of connective tissue structures extending between the coccyx and anal canal., Design and Setting: This was a descriptive study carried out at university facilities for anatomic research. The study comprised histologic evaluation of paraffin-embedded tissue specimens from preserved cadavers of 20 elderly adults and examination of frozen pelves from 6 fresh cadavers., Main Outcome Measures: From each cadaver, we obtained a tissue mass containing the dorsal wall of the distal rectum and anal canal, the coccyx, and the covering skin. Most sections were stained with Masson-Trichrome solution for collagen and smooth muscle fibers., Results: Dissection of fresh cadaver demonstrated the anococcygeal ligament extending from the coccyx to the anal canal between bilateral slings of the levator ani. Histologic examination showed that the anococcygeal ligament was divided into a ventral and a dorsal layer and contained abundant smooth muscles, elastic fibers, and small vessels. The ventral layer extended from the presacral fascia to the conjoint longitudinal layer of the anal canal. The dorsal layer was recognized as a bundle extending between the coccyx and external anal sphincter. The dorsal layer was much thicker along and near the midsagittal plane than the lateral areas. The levator ani was located independently of and dorsal to the anococcygeal ligament., Limitations: This study used cadavers from elderly donors; thus, the specimens might have had age-related degeneration., Conclusions: The anococcygeal ligament is divided into 2 layers: a thick ventral layer, rich in thin vessels and extending from the presacral fascia to the conjoint longitudinal layer of the anal canal, and a thin dorsal layer extending between the coccyx and external anal sphincter. The anococcygeal ligament is one of the critical structures for decision-making regarding rectal and upper anal canal mobilization.

The paper summarizes the experience of Russian and foreign specialists in dealing with the theoretical and practical aspects of sacral anesthesia. It presents anatomic data and information on the pathophysiological aspects and potentialities of clinical use of sacral anesthesia in modern anesthesiological practice that estimate its perspectives at this stage.

Introduction: Normal defecation is a combination of several elements of reflex and voluntary functions. The issue of external anal sphincter innervation is of theoretical and clinical significance; however, literature on the subject is still scarce. Most study reports discuss the course of the pudendal nerve with no close insight into inferior rectal nerves supply to the external anal sphincter. We have not found any statistical "mapping" of the site of the nerve branches insertion into the external anal sphincter. Thus, the purpose of the present study was to determine the least and most typical location of nerve branches to the external anal sphincter. One hundred and ten pudendal nerve preparations were analysed. Following the dissection of the pudendal nerve and its branches, a beam compass was used to take linear measurements from the apex of the coccygeal bone to the point of nerve branch insertion to the external anal sphincter. The distance between coccygeal bone apex and the central tendon of the perineum was also measured. For the purpose of comparison, results are presented as relative Bi/A values. Computer programmes devised by the author of this paper within Turbo Pascal were then used to determine the probability of finding nerve branches to the external anal sphincter., Results: Based on the analysis of 110 preparations of the pudendal nerve and its branches, one might conclude that the former was the main although not necessarily the only source of external anal sphincter innervation. While analysing the most and the least probable location of nerve branches to the external anal sphincter, the muscle length was expressed as percentage, i.e., 0% of sphincter length = the apex of the coccygeal bone; 100% of sphincter length = the central tendon of the perineum. The length was then divided into 5% intervals with the probability of finding nerve branches determined by programmes written in Pascal. Within 30-85% of external anal sphincter length, the probability of finding nerve branches to the external anal sphincter is greater than 0.3 with peak probability of 0.68 in the interval between 55 and 65%., Discussion: Sphincter innervation and clinicoanatomical function of anal canal closure apparatus has been discussed with reference to external anal sphincter injury. Transcutaneous electrostimulation of the pudendal nerve and the use of anal canal electrodes have also been mentioned., Conclusions: The most probable location of nerve branches to the external anal sphincter is half way of its length, i.e., at hour 3 or 9 of the knee-elbow position or lithotomy position. The external anal sphincter can also be directly supplied by nerve branches originating from the sacral nerve root S4; the branches then go towards the posterior part of the sphincter.

Study Design: This is a biomechanical study using human cadaveric lumbar spine., Objective: To evaluate the biomechanics of paracoccygeal transsacral rod fixation., Summary of Background Data: Various types of transsacral fixation either by posterior and paracoccygeal approaches have been described in the literature. The biomechanical advantage of transsacral rod fixation is the preservation of supporting structures at L5-S1 level. No biomechanical data on human cadavers have been reported in the literature. The aim of this study is to evaluate the biomechanics of the transsacral rod fixation., Methods: Six fresh human cadaveric L5-S1 motion segments (mean age 67.5 y; range 46 to 82 y ) were used in the study. Unconstrained and nondestructive pure moments in axial torsion (AT), lateral bending (LB), and flexion-extension (FE) were applied to each specimen after applying transsacral rod and after additional augmentation methods, including bilateral screws, facet screws, and pedicle screw and rod system. Range of motion (ROM) was calculated for each surgical treatment. The disc space was measured with lateral plain radiographs of intact specimens and after transsacral rod insertion to evaluate the amount of distraction., Results: The mean ROM of the intact specimens was 3.5, 6.4, and 11.0 degrees in AT, LB, and FE, respectively. Standalone transsacral rod reduced ROM more than 40% compared with the intact condition (P=0.002). Bilateral screws further reduced the ROM in AT (64%) and LB (70%), but not in FE (53%). Both facet screws and pedicle screw and rod system achieved high construct stability under all loading conditions. The transsacral rod augmented with facet screws reduced ROM by 70%, 80%, and 90% compared with the intact condition. When augmented with pedicle screw and rod system, the transsacral rod reduced ROM by 73%, 87%, and 88% in AT, LB, and FE, respectively. There was no statistical difference between these 2 facet screws and pedicle screw and rod system (P>0.8)., Conclusions: Transsacral rod fixation provides strong ligamentotaxis due to intact annulus. Standalone transsacral rod is able to reduce ROM significantly and achieve indirect decompression by distracting L5-S1 disc space. However, additional posterior fixation, such as facet screws or pedicle screws, is required to achieve better construct stability for successful fusion.

Purpose: To assess the intercoccygeal angle of asymptomatic patients (without coccydynia), to study if there is a difference of angle between types of coccyx and between genders with the same type of coccyx., Materials and Methods: Ninety-two patients (42 females, 50 males, range of ages 8-86, mean 50) who underwent computed tomography (CT) angiography and colonoscopy were included in the study. CT images with slice thickness of 1 or 1.5 mm were evaluated with 3D sagittal reformats and intercoccygeal angle, type of coccyx were examined., Results: Twenty-one females and 18 males had type 1 coccyx with mean intercoccygeal angle 36.4 degrees +/- 10.56 (33.29 degrees for females and 40.05 degrees for males) and the difference of the angles between genders is statistically significant (P = 0.044). Among 36 patients (14 were females and 22 were males) with type 2 coccyx demonstrated mean intercoccygeal angle of 56.36 degrees +/- 10.8. 15 patients were shown to have type 3 coccyx and the mean intercoccygeal angle was 72.1 degrees +/- 31.86. No significant difference of angles was seen between genders. Type 4 coccyx was not seen and two coccyx could not be classified. There was a significant difference of intercoccygeal angle between the groups overall., Conclusion: Type 1 is the most common coccyx type in asymptomatic patients. Significant difference of intercoccygeal angle was defined between the types of coccyx. These values may be reference for the patients underwent surgery for the coccydynia and a new classification may be needed since exceptional shape of coccyx exists that could not be defined according to the known classification.

Background: Coccydynia is a rare but painful disorder characterized by axial coccygeal pain which is typically exacerbated by pressure. Management includes physical therapy/rectal manipulation, use of anti-inflammatory medications, modality use, coccygectomy, and fluoroscopically guided steroid injections. There are no studies documenting the efficacy of fluoroscopically guided coccygeal steroid injections in patients with coccydynia., Methods: Retrospective chart review was used to collect data on 14 consecutive patients diagnosed with coccydynia who underwent a fluoroscopically guided coccygeal injection of 80 mg triamcinolone acetate and 2mg of 1% lidocaine over a 3-year period at a tertiary care academic medical center., Results: Using stepwise logistic regression, acute pain was determined to be the best predictor of relief. Fisher's exact test showed that those patients with pain lasting less then 6 months were significantly more likely to have greater than 50% relief (P=0.055). Patients with chronic pain longer than 6 months were not found to have pain relief of >50% to any statistical significance, but every patient with acute pain showed improvement., Conclusion: Patients with acute pain (less then 6 months) are more likely to respond to fluoroscopically guided coccygeal steroid injections.

Identification of the lumbosacral (L-S) segment on magnetic resonance (MR) images is important for appropriate treatment of disease in the lumbosacral (L-S) area. In the study, data obtained from plain A-P radiographs of the L-S spine and sagittal MR imaging scans (sagittal T1- and T2-weighted sequences) of the L-S spine and sacrum with the coccygeal bone, are analyzed. Twenty-six children aged 10 to 14 years were examined for back pain. On the standard A-P radiographs of the L-S spine, a L-S transitional vertebra as classified according to the method of Castellvi et al. was found in 17 subjects. The problem arose as to whether this was lumbalisation or sacralisation, and how to determine which vertebra was L5 wich S1. On the sagittal MR imaging studies the same question applied. A need emerged for a simple method which would identify the L-S segment on the sagittal MR imaging studies of the L-S spine in children so that in case of a tumor, inflammation, spondilolystesis, or protrusion of a disc, the level in the L-S spine where the problem is localized can be accurately identified. To this objective we selected the method using detection of the S1 vertebra. This involved that, in addition to the sagittal MR imaging scans of the L-S spine, sagittal images of the sacrum and coccygeal bone be also obtained. on the T2-weighted sequence, the sacrum can be clearly distinquished from the coccygeal bone. By counting from the S5 up, the S1 vertebra can be accurately identified. Determination of the S1 vertebra enables detection of the L5 vertebra and, in turn, of all other lumbar vertebrae. In patients in whom a T2-weighted MR studies were done S1 could be precisely determined and so could the L5 vertebra. In this process, whether the patient had a transitional vertebra or whether there was lumbarisation or sacralisation was irrelevant.

Perineal neuralgias may be considered as nerve entrapment syndromes, which have been anatomically poorly studied. The pudendal nerve could be compressed between the sacrospinal and the sacrotuberal ligaments. This study tries to find a correlation between the pelvis and the lumbosacral junction morphometry, and sacrospinal and sacrotuberal ligaments morphometry. We did an anatomical study of eight anatomic specimens, and we performed the measures by using the computed tomography scanner. No correlations were found.

Analgesia of the pudendal nerve is used in patients undergoing gynecologic, obstetric and penile surgery. Stimulation techniques are used to determine the functions of the nerve. In these interventions, different landmarks are used to describe the localization of this nerve. Although some authors use perineal approaches, others prefer a transvaginal (rectal in males) approach. Knowledge regarding the anatomy of the pudendal nerve and its blockade allows an easy approach to the clinical problems like perineal neuralgia, neurogenic bladder dysfunction and penile implant operations. However, in the descriptions of these different approaches, there is no clear information regarding the depth of the nerve and the branches of the pudendal nerve that are blocked. The aim of the present study was to determine the depth and location of the pudendal nerve and, thus, describe certain and easily identified surface landmarks for clinical use. According to our examinations, the distance between the ischial tuberosity and the coccyx (the base of a triangle defined by the ischial tuberosity, coccyx and ischial spine) was 8.62 +/- 0.92 cm (range 6.74-9.77 cm). The distance between the ischial tuberosity and the ischial spine was 5.23 +/- 0.33 cm (range 4.76-5.81 cm) and the distance from the ischial spine to the coccyx was 5.42 +/- 0.52 cm (range 4.02-6.32 cm). Because the pudendal nerve intersected the distance between the posterior superior iliac spine and the ischial tuberosity, the distance between these two landmarks was also measured and found to be 13.31 +/- 0.91 cm (range 10.58-15.13 cm); the depth of the nerve was 4.14 +/- 0.83 cm (range 3.13-5.25 cm).

Inter-population variability in long-bone and pelvic-bone growth during the Early Medieval period is examined. The materials comprise four archaeological populations: two Slavonic (Gars-Thunau, Zwentendorf, Austria, 10th-century AD), one Avar (Zwölfaxing, Austria, 8th-century AD), and one Anglo-Saxon (Raunds, England, 10th-century AD). Bone measurements are analyzed against dental age estimates in order to assess inter-population differences in growth rates for long-bone and os coxae bone dimensions. Growth curves of the upper and lower extremities of additional archaeological populations and a modern North-American population are also assessed. The expectation was that the greatest differences in growth patterns would be found between the Anglo-Saxon and the Austrian samples, due to their distinct genetic and biocultural background. Minimal differences were expected between the two Slavonic populations, as these were approximately contemporaneous, recovered from geographically close locations, and shared relatively similar archaeological contexts. Growth curves were estimated for each bone dimension by fitting least-squares fourth-order polynomials (which allowed testing of population differences by analysis of covariance), and iteratively estimating Gompertz growth curves. The results showed differences between bones in the extent of inter-population variability, with diaphyseal long-bone growth showing equivalent patterns across the four populations, but significant differences between populations in the growth patterns of distal diaphyseal dimensions of the femur and humerus and the dimensions of the ilium. Varying growth patterns are therefore associated with inter-population differences in absolute dimensions in relation to age as well as variations in growth velocities. Inter-population variability in growth curves in the case of femoral and humeral dimensions were most pronounced during infancy (0-2 years). The most consistent differences in bone growth and related dimensions are between Zwölfaxing and the other samples. No significant differences in growth were detected between the Anglo-Saxon and the Austrian populations., (Copyright 2005 Wiley-Liss, Inc)

This study is to evaluate whether it is possible to predict living stature from sacral and coccygeal vertebral dimensions. Individual vertebral body heights, sacral height (SH), and sacrococcygeal height (SCH) were recorded from the magnetic resonance images of 42 adult males. Sum of the heights of five sacral vertebrae (sigmaS), the first four coccygeal vertebrae (sigmaC), and the total height of the sacral and the first four coccygeal vertebrae together (sigmaSC) were also recorded. Linear regression equations for stature estimation were produced using the above mentioned variables. The regression equations were constructed and tested by using jack-knife procedure. Statistical analyses indicated that the combined variables (SH, SCH, sigmaS, sigmaC, sigmaSC) were more accurate predictors of stature than the heights of individual vertebrae. The results of the study pointed out that the equations derived from sacrococcygeal dimensions perform somewhat better than ones based on foot and head variables, but worse than those based on long-bone length. As a conclusion, the dimensions of sacral and coccygeal vertebrae could be used for stature estimation when long bones are not available.

Background and Aims: So far there is no agreement between clinical and radiological measurements and reference points for the quantification of pelvic organ descent in women. The aim of this study was to find out which of three reference lines on functional cine-magnetic resonance imaging (MRI) correlates best with the respective clinical diagnoses., Methods: We retrospectively evaluated the functional cine-MRI studies of 41 asymptomatic volunteers. Our golden standard was the results of the clinical examination using the International Continence Society (ICS)-score. On MRI, we measured the distance of the bladder-neck, distal edge of cervix/posterior fornix, and the most ventrocaudal point of the ventral rectal wall, respectively, to the pubococcygeal line (PCL), the horizontal tangent of the inferior rim of the pubic bone, and the line drawn through the long axis of the pubic bone. The results were correlated with the respective clinical findings using descriptive analysis alone., Results: The volunteers either showed a Stage 0 (16 cases), Stage I (12 cases), or a Stage II (13 cases) organ descent on clinical examination with 10 women (24.4%) having a pathological ICS-score in the anterior, 15 women (36.1%) in the superior, and 4 women (9.8%) in the posterior compartment. On functional MRI the best correlation with the clinical results was achieved using the PCL for the anterior compartment (22.0%), the PCL with an offset of +3 cm for the superior (36.6%), and the hymenal line (HL) for the posterior compartment (9.8%)., Conclusions: Organ descent on functional cine-MRI cannot be described using only one reference line. In order to optimize clinical exploitation of functional MRI of the pelvic floor a consensus regarding imaging protocols and evaluation criteria should be aimed for., (Copyright 2003 Wiley-Liss, Inc.)

Coccygodynia is pain in the region of the coccyx. In most cases, abnormal mobility is seen on dynamic standing and seated radiographs, although the cause of pain is unknown in other patients. Bone scans and magnetic resonance imaging may show inflammation and edema, but neither technique is as accurate as dynamic radiography. Treatment for patients with severe pain should begin with injection of local anesthetic and corticosteroid into the painful segment. Coccygeal massage and stretching of the levator ani muscle can help. Coccygectomy is done only when nonsurgical treatment fails, which is infrequent. Coccygectomy usually is successful in carefully selected patients, with the best results in those with radiographically demonstrated abnormalities of coccygeal mobility.

The three-dimensional reconstructions of the human coccygeal bodies were undertaken using semi-thin serial sections which were cut from the tissue specimens taken from the ventral parts of the tip of the coccyges of four patients. The coccygeal bodies were observed in the form of convoluted, irregular helical tubes. The diameters of the coccygeal bodies in serial sections were measured and a statistical analysis performed. The lumens of the coccygeal bodies were not observed in the twisted parts of the tissue specimens. Depending upon to the irregular courses of the lumens and their lack of appearances in the twisted areas, we are unable to show the three-dimensional reconstructions of the lumens of the coccygeal bodies. In conclusion, this is the first study reporting the three-dimensional reconstruction of the contours of the coccygeal body. These type of studies, which were done by using serial sections will be very helpful for the understanding of the little known organs of the human body.

The lengthy, continuous, slender extradural neural axis compartment (EDNAC), which extends from the coccyx to the orbit, has been not so much discovered as recognized. Through this compartment run arteries, myelinated and unmyelinated nerves, and valveless veins. Adipose tissue is abundant in the orbital and spinal segments, possibly due to movement requirements, although it is very sparse in the skull base segment, the last segment to be recognized as a continuation of the EDNAC, which connects Breschet's veins to the orbit. The lateral sellar compartment (in older terminology, the cavernous sinus) is an enlarged segment of this EDNAC along the skull base connecting the orbit with the extradural space through the superior orbital fissure and down the dorsum to Breschet's veins of the basilar process of the occipital bone. Understanding the continuity of the EDNAC should help the student understand any segment, particularly the skull base. As Batson noted, "Living anatomy is slowly editing and replacing the anatomy of the dead room."