跟内侧神经与神经源性跟痛症关系的解剖学基础

目的　探讨跟内侧神经的局部解剖特点及其与神经源性跟痛症的关系，为临床诊断治疗提供解剖学依据。 方法　32侧防腐成人尸体下肢标本，解剖观察跟内侧神经的起源、分支、走行和分布特点。 结果　跟内侧神经41.42%起源于胫神经，28.57%起源于胫神经分叉处，18.57%起源于足底内侧神经，11.42%起源于足底外侧神经。起点距O点（内踝尖最下缘与跟骨结节内侧突连线中点）(30.22±15.34)mm。跟内侧神经穿出屈肌支持带后分布于足跟内侧及跟底的皮肤和跟垫组织。 结论　跟内侧神经在踝管内，浅出屈肌支持带处及跟管内可能被卡压；神经卡压或病变可能与足底腱膜炎发生及疼痛有关。     

Relation of the radial nerve with the sulcus nervi radialis: a morphometric study

The radial nerve's course from the axillary region, branch patterns and the relation of the nerve to fixed anatomical landmarks in the arm region were studied in 27 embalmed intact cadavers. The radial nerve and its relation with the sulcus nervus radialis (SNR) was analyzed. The direct contact of the nerve with humerus in SNR was observed during the dissections. The following measurements were made: the total length of the humerus (the palpable uppermost point of the tuberculum majus and the lateral epicondyle); proximal safe zone (the tuberculum majus and the proximal beginning of the SNR); distal safe zone (the intercondylar axis and the middle of SNR); lateral safe zone (the lateral epicondyle and the distal end of SNR). In conclusion, it was aimed to correlate the osseus palpable landmarks of humerus with the course of the radial nerve for a safe surgery as the sulcus nervi radialis region is one of the main risky areas for the radial nerve palsies.     

Three-Dimensional Morphological Variations of the Human Calcaneus Investigated Using Geometric Morphometrics

The shape of the calcaneus determines the mechanical interaction of the foot with the ground during the heel-strike in human walking. Detailed knowledge of the pattern of sexual dimorphism of the human calcaneus could help to clarify the pathogenetic mechanism of foot and knee disorders, which are more prevalent in females. Therefore, the aim of this study was to characterize and visualize the three-dimensional shape variations of the calcaneus in relation to sex and age using geometric morphometrics. Computed tomography images of 56 feet without subtalar injuries or disorders were used in this study. Thirty-seven anatomical landmarks were identified on the bone model of the calcaneus to calculate principal components (PCs) of shape variations among specimens. The PC scores were compared between males and females, and their correlations with age were also analyzed. The female calcaneus was longer in length and shorter in height than that of males. The medial process of the calcaneal tuberosity in females was more inferiorly projected and the tuberosity was shifted more laterally. Also, the calcaneus was wider and the sustentaculum tali thickened with aging. Female structural features of the calcaneus alter the kinematics of the foot during walking and could be a structural factor in foot and knee disorders. This study contributes to a comprehensive understanding of shape variations in the human calcaneus. Clin. Anat., 33:751–758, 2020. © 2019 Wiley Periodicals, Inc.     

Innervation of the supinator muscle and its relationship to two‐incision distal biceps tendon repair: An anatomic study

Reinsertion of the ruptured distal biceps tendon has been performed using either a single‐anterior incision or a two‐incision approach. A systematic review of these two repair methods has identified a higher incidence of supination weakness following the two‐incision approach. The objective of this study was to describe the innervation of the supinator muscle and its implications regarding a two‐incision distal biceps repair. Twelve fresh upper extremity specimens from 12 males were dissected with the forearm in full pronation. The number of branches of the posterior interosseous nerve (PIN) to the supinator, their site of exit from the PIN trunk, and their distance from a variety of known anatomic landmarks were recorded. Specimens were characterized as high (<5 mm), moderate (6–10 mm), or low (>10 mm) risk of nerve branch injury depending on the proximity of nerve branches to the bicipital tuberosity. In general, we found the innervation of the supinator to be highly variable. There were from two to nine branches of the PIN which supplied the supinator, with 0–3 arising from the ulnar side of the nerve. Four specimens were at low, five at moderate, and three at high risk of nerve branch injury during dorsal exposure of the bicipital tuberosity. We conclude that there is a substantial amount of variability in the innervation of the supinator, with certain patterns being at higher risk of nerve branch injury if dissection of the supinator is carried out over the bicipital tuberosity. Clin. Anat. 23:413–419, 2010. © 2010 Wiley‐Liss, Inc.     

Surgical anatomy of the radial nerve at the elbow

An anatomical study of the brachial portion of the radial nerve with surgical implications is proposed. Thirty specimens of arm from 20 fresh cadavers (11 male, 9 female) were used to examine the topographical relations of the radial nerve with reference to the following anatomical landmarks: acromion angle, medial and lateral epicondyles, point of division between the lateral and long heads of the triceps brachii, lateral intermuscular septum, site of division of the radial nerve into its superficial and posterior interosseous branches and entry and exit point of the posterior interosseous branch into the supinator muscle. The mean distances between the acromion angle and the medial and lateral levels of crossing the posterior aspect of the humerus were 109 (±11) and 157 (±11) mm, respectively. The mean length and calibre of the nerve in the groove were 59 (±4) and 6 (±1) mm, respectively. The division of the lateral and long heads of the triceps was found at a mean distance of 126 (±13) mm from the acromion angle. The mean distances between the lateral point of crossing the posterior aspect of the humerus and the medial and lateral epicondyles were 125 (±13) and 121 (±13) mm, respectively. The mean distance between the lateral point of crossing the posterior aspect of the humerus and the entry point in the lateral intermuscular septum (LIS) was 29 (±6) mm. The mean distances between the entry point of the nerve in the LIS and the medial and lateral epicondyles were 133 (±14) and 110 (±23) mm, respectively. Our study provides reliable and objective data of surgical anatomy of the radial nerve which should be always kept in mind by surgeons approaching to the surgery of the arm, in order to avoid iatrogenic injuries.     

Clinical anatomy of the calcaneal tuberosity.

The aim of the study was a qualitative anatomical analysis of the macroscopic features of the surface of the calcaneal tuberosity, of the architecture of its cancellous bone and histological structure of the whole region. Dry human bones and pathological dissection material 24-36 h post mortem were used in the study. On the tuberosity, the variability of its surface relief and the two borders between the superior, middle and inferior facets were studied. More frequent medial declination of the inferior line, corresponding to the distal circumference of the Achilles tendon attachment, was found. Two systems of expressive condensation of cancellous bone just below the surface of the calcaneal tuberosity were described. In the histological part of the study, the distribution and different thickness of the fibrous cartilage layer covering the attachment region of Achilles tendon, the bottom of retro-calcaneal bursa and the whole surface of the calcaneal tuberosity were described. The functional and clinical relevance of results obtained are evaluated from the point of view of disciplines dealing with the pathology and surgery of the heel region. The relationships of official anatomical terms and a wide spectrum of clinical synonyms designating this region are discussed.     

载距突解剖形态学分型及特征分析

目的 基于CT三维重建的载距突,探讨其解剖形态学分型及特征,为螺钉植入治疗跟骨骨折提供解剖学支持。 方法 2019年3月~2020年3月,经纳入标准排除后,最终共收集336例来自西南医科大学附属中医医院的成年人跟骨CT三维重建图像,依据载距突冠状位轴线与跟骨轴线的夹角（β）进行分型,研究参数：β、载距突内侧中点与后距关节面内侧中点的距离（AB）,载距突内侧中点与后距关节面外侧中点的距离（AC）,载距突内侧中点冠状位轴线与跟骨最外侧交点的距离（AD）,载距突内侧中点与跟骨结节内侧突中点的距离（AE）,载距突内侧中点与跟骨结节中点的距离（AF）,载距突内侧中点与跟骨结节外侧突中点的距离（AG）,根据分型和男女、左右分别对测量结果进行统计学分析。 结果 根据 β,我们将载距突分为3型：Ⅰ型（β<70°,68例,20.24%）、Ⅱ型（70°≤β<80°,153例,45.54%）、Ⅲ型（80°≤β<90°,115例,34.23%）。其中Ⅲ型与其他型别在 β、AB、AF上具有差异（P<0.05）,Ⅲ型和Ⅰ型在AE上具有差异（P<0.05）。此外,男性和女性的载距突在AB、AC、AD、AE、AF、AG上均具有差异（P<0.05）,左右两侧的载距突在 β、AB上具有差异（P<0.05）。 结论 载距突可以分为3型,以Ⅱ型为主,内固定治疗跟骨骨折时,螺钉植入角度可以尽量在70°~ 80°,其解剖形态学分型对螺钉植入有一定的临床指导意义。     

Size and separability of the calcaneal and the medial and lateral plantar nerves in the distal tibial nerve

The tibial nerve (TN) has three main terminal branches: the medial and lateral plantar nerves and the calcaneal branch (CB), which innervates the foot sole. The design and implantation of nerve cuff electrodes with separate channels for each of these three terminal branches would provide significant sensory information, which can be used in functional electrical stimulation systems to assist standing or to correct foot drop. Detailed quantitative anatomical data about fascicular size and separability of the terminal branches of TN are needed for the design and implantation of such cuff electrodes. Therefore, the branching pattern, the fascicular separability and the fascicular size of the TN posterior to the medial malleolar-calcaneal axis were examined in this study, using ten human TN specimens. The TN branching patterns were highly dispersed. For the CBs, multiple branches were identified in five (50%) of the specimens. For the TN, the bifurcation point was located within the tarsal tunnel in eight (80%) of the cases. The distance proximal to the medial malleolar-calcaneal axis for which the TN could be split ranged form 0 to 41 mm. Quantitative and qualitative data were obtained for the fascicular size and separability of the TN. Only the CB of the TN proved separable for a sufficient length for nerve cuff electrode implantation. The results suggest the use of a two-channel cuff with one common channel for the lateral and medial plantar nerves, having multiple electrodes for selective recording, and one channel for the CB.     

Easily identifiable bony landmarks as an aid in targeted regional ankle blockade

Regional anesthesia around the ankle joint is well suited to a large number of surgical procedures of the foot. Previous studies have alluded to the variable nerve distribution of the foot, which may result in incomplete blocks. The aim of the study was to determine the position of the nerves in relation to the ankle joint to easily identifiable bony and prominent soft tissue landmarks to aid more accurate targeting of these nerves. A number of 94 ankles (47 left; 47 right) were dissected to expose the tibial, sural, deep fibular (peroneal), superficial fibular (peroneal), and saphenous nerves. The distance of the nerves relative to easy to find bony landmarks was measured. A distance (alpha) was measured from the middle of the tibial nerve to the most medial aspect of the medial malleolus. Measurement beta was considered from the inferior tip of the lateral malleolus to the anterior border of the sural nerve on a horizontal plane. Measurement delta was taken from the medial border of the deep fibular (peroneal) nerve to the most anterior aspect of the medial malleolus. epsilon was measured from the middle of the superficial fibular (peroneal) nerve to the most anterior aspect of the medial malleolus on a horizontal plane. The saphenous nerve was measured (gamma) from its medial border to the most anterior aspect of the medial malleolus on a horizontal plane. Factors such as sex, length, and ankle side were also analyzed concerning their influence on the position of the nerves. This study suggests that a greater degree of certainty may possibly be attained when palpable and easy to find bony landmarks are used to determine the position of the nerves around the ankle and ensure a simple to perform, predictable, and selectively targeted block.     

Anatomic variations of the musculotendinous junction of the soleus muscle and its clinical implications

The soleus muscle, like the gastrocnemius, is a powerful plantarflexor muscle in the lower limb. The soleus muscle joins the aponeurosis of the gastrocnemius muscle to form the calcaneal (Achilles) tendon. While the basic anatomy of the soleus muscle has been previously described, no study has addressed the anatomical variations of its distal attachment. We found considerable anatomic variation in the distance between this musculotendinous junction and the most proximal point of the proximal edge. This distal measuring point was defined as the most proximal point of the proximal edge of the posterior surface of the calcaneal tuberosity. Eighty human cadaver specimens were preserved according to Thiel's method; we examined one limb from each cadaver, studying 80 lower extremities in total. Following careful dissection of the lower limb, we measured the distance between the distal point of attachment of the soleus muscle fibers (the musculotendinous junction) and the designated measuring point. Our findings were divided into three groups: Group 1 (10 cases, 12.5%), where the distance between the musculotendinous junction and the designated point on the calcaneal tuberosity was between 0 and 1 inches; Group 2 (56 cases, 70%), where the distance was between 1 and 3 inches; and Group 3 (14 cases, 17.5%), where the distance was greater than 3 inches. Detailed knowledge of the anatomic variations of the soleus muscle at its insertion point onto the calcaneal tendon has clinical implications in calcaneal tendon repair following rupture and in the planning of reconstructive surgery using soleus muscle flaps.     

Cutaneous innervation of the ankle: An anatomical study showing danger zones for ankle surgery

Three nerves innervate the skin in the foot and ankle region: the saphenous, sural, and superficial peroneal nerves. Because they are close to the medial and lateral malleoli, these nerves are at significant risk during orthopedic interventions. The aims of this study were to investigate the distal courses of the three cutaneous nerves of the ankle and to determine their exact relationships with easily identifiable bony landmarks. Ten freshly frozen and 40 embalmed lower extremities of adults were dissected. The positions of the superficial peroneal, sural, and saphenous nerves were determined using reference lines based on easily palpable osseous landmarks. The frequencies and distributions of all three nerves and their branches were converted into absolute numbers. A danger zone for each nerve was established on the basis of the distribution of crossings between the nerves and the different reference lines. Determination of the exact orientation of the nerves around the ankle should help minimize the nerve injury rate during surgical approaches in this area. Using this easily translatable new grid system, the course and danger zones of each cutaneous nerve around the ankle can be estimated clinically. Clin. Anat. 653–658, 2014. © 2013 Wiley Periodicals, Inc.     

Coracobrachialis muscle: morphology,morphometry and gender differences

Purpose

Coracobrachialis (CBM) is a complex muscle with a wide range of variations in its morphology and innervation. The goal of this study was to elucidate the morphology, morphometry, gender differences of CBM and precise anatomical position of the musculocutaneous nerve (MCN) with reference to surrounding anatomical landmarks in an adult Sri Lankan population.

Method

Cadaveric upper limbs (n = 312) were examined for the proximal and distal attachments, length, width, thickness of CBM and its relationship with the MCN.

Results

The CBM originated from the tip of the coracoid process of the scapula and lateral, posterior and medial aspects of the tendon of short head of biceps brachii. Gender differences were observed in all morphometrical parameters of CBM. In 83.33 %, MCN perforated the CBM. In 50 % the MCN pierced the middle one-third of CBM while none pierced the lower one-third. The distance from the coracoid process to the point of entry of MCN into CBM (distance P) was 50.62 mm. A positive correlation was observed between the arm length and distance P indicating that arm length provides an accurate and reliable means of gauging the distance P of an individual.

Conclusion

The present study provides new evidence pertaining to the origin of CBM. Further, it was revealed that the predicted distance P of any upper extremity can be calculated by dividing the arm length by 5. Precise anatomical location of MCN in relation to CBM using unequivocal and well-defined anatomical landmarks will be imperative in modern surgical procedures.

     

Isolated flexor muscles of the little toe in the feet of an individual with atrophied or lacking 4 head of the M. extensor digitorum brevis and lacking the 4 tendon of the M. extensor digitorum longus

While dissecting the body of a 75-year-old male we observed variations in the Mm. flexor digitorum brevis and longus of both feet. In the left foot, the 4th tendon of the M. flexor digitorum brevis was atrophied and the respective tendon of the M. flexor digitorum longus to the little toe was absent. In the right foot, the 4th tendons of both the Mm. flexor digitorum brevis and longus to the little toe were absent. The lacking deep flexor tendon to the little toe in the left foot was replaced by an isolated flexor muscle originating from the medial and lateral processes of the calcaneal tuberosity, which additionally had connections to the tendinous plate of the M. flexor digitorum longus and the M. quadratus plantae. The absent superficial and deep flexor tendons to the little toe in the right foot were replaced by an isolated flexor muscle arising from the M. quadratus plantae distal from the medial process of the calcaneal tuberosity. The tendon of both isolated flexor muscles inserted in the distal phalanx of the little toe. The left isolated flexor muscle for the little toe had connections to the M. flexor digitorum longus and the M. quadratus plantae. From these results it seems likely that the M. quadratus plantae could be regarded as additional flexor head (caput breve or plantare) of the M. flexor digitorum longus as is described in classic textbooks. In the individual's lifetime the described variation perhaps led to the possibility of an isolated flexion of the little toe.     

小趾展肌神经与神经源性跟痛症关系的解剖学基础

目的　探讨小趾展肌神经的局部解剖特点及其与神经源性跟痛症的关系,为临床诊断治疗提供解剖学依据。 方法　32侧防腐成人尸体下肢标本,解剖观察小趾展肌神经的起源、分支、走行和分布特点。 结果　小趾展肌神经81.25%起源于足底外侧神经,起点59.38%位于后上象限;起点与参考线的垂直深度,左侧（10.81±0.96）mm,右侧（10.24±1.10）mm;小趾展肌神经发出1～3支骨膜支到达跟骨结节内侧突的骨膜;小趾展肌神经与跟骨结节内侧突该的水平距离左侧（19.95±1.82）mm,右侧（20.89±2.48）　mm 。 结论　小趾展肌神经行经　展肌和足底方肌内侧头之间,跟骨结节内侧突前可能被卡压,卡压或病变（特别是骨膜支）可能与足底腱膜炎发生有关;跟骨骨刺不一定会造成神经源性跟痛症。     

内镜经鼻入路视神经管和眼眶的解剖学

目的通过研究对视神经管和眼眶的解剖研究,为内镜经鼻入路视神经管减压和治疗眼眶内病变提供解剖基础。方法国人尸头5例,采用大体解剖和内镜下经鼻入路两种方法,观察重要的解剖标志;使用内直肌内移技术,观察视神经管和眼眶内结构的暴露情况以及重要结构的位置、毗邻、走行等。结果钩突位于中鼻甲的前下方;筛泡在钩突的后方,切开筛泡可进入筛窦;筛前后动脉是筛窦内的重要解剖标志;视神经管隆突、颈内动脉隆突和视神经管颈内动脉隆突(OCR)是蝶窦内重要的解剖标志;纸样板位于筛窦的外侧壁,切开纸样板可暴露眶内容物;在眶内,可从内直肌与下直肌之间的通路暴露视神经。在本次10侧标本中,9侧眼动脉起自于颈内动脉的床突上段;1侧眼动脉起自于颈内动脉海绵窦段。7侧眼动脉在视神经管内走行于视神经的下外侧;2侧走行于视神经的正下方;1侧走行于视神经的下内侧。结论内镜下经鼻入路可以进行视神经管和眼眶内侧部分的暴露。钩突、筛泡、筛前后动脉及后组筛窦是本入路重要解剖标志。视神经管隆突、颈内动脉隆突及视神经管颈内动脉隆突(OCR)是进行视神经管减压的重要标志。眼动脉及其眼眶内分支、筛前后动脉和颈内动脉是重要的血管结构。眼内直肌内移技术可以有助于暴露眶内解剖结构。     

The gluteal sling: an anatomical study

Introduction

Sciatic nerve palsy is a devastating complication which may be seen after acetabular exposure in total hip resurfacing via a posterior approach. An anatomical structure termed as the “gluteal sling” was suggested to play a role in sciatic nerve palsies during this operation. “Gluteal sling” is formed by the attachment of the deep fibers of the inferior part of the gluteus maximus on the gluteal tuberosity of the femur and the lateral intermuscular septum. It is suggested to be released to avoid such compressive injuries. The purpose of this study is to demonstrate how much of the gluteal sling should be released to decrease the tension on sciatic nerve during posterior hip arthroplasties. We also aimed to study the anatomical structures at risk during releasing procedure.

Materials and methods

The gluteal sling was examined in 17 sides of 9 adult cadavers. Its relation with the sciatic nerve, first perforating artery, the tip of greater trochanter and the ischial tuberosity were evaluated.

Results

The closest distance between the gluteal sling and the sciatic nerve was measured as 1.9 ± 0.6 cm. This point was corresponding to the distal 2/3 part of the gluteal sling. The distance of the proximal edge of the gluteal sling to the first perforating artery was 3.7 ± 0.9 cm, while its ascending branch was closer, being 1.8 ± 0.8 cm.

Conclusions

Theoretically, it is enough to release the proximal 2/3 of the gluteal sling to avoid its compression on the sciatic nerve. However, further clinical studies would need to be undertaken to properly determine the effects of this procedure.     

Clinical anatomy of the posterior maxilla pertaining to Le Fort I osteotomy in Thais

This article studies the anatomy of the posterior maxilla pertaining to bone-cut design of Le Fort I osteotomy to avoid the injury to the descending palatine artery in Thais. Fifty-five skulls (38 males, 17 females) were assessed for the anatomical landmarks by a combination of direct inspection, computerized imaging, and computed tomography scan analysis. The results showed that 27.28% of the pterygomaxillary junction (PMJ) became synostosis. The mean heights of the PMJ, posterior maxilla, and maxillary tuberosity were 15.14 +/- 2.46 mm, 22.51 +/- 3.50 mm, and 7.45 +/- 2.76 mm, respectively. The mean length of the medial sinus wall measuring from the piriform rim to the descending palatine canal at the Le Fort I level was 34.40 +/- 2.96 mm. The mean widths of the posterior incision of Le Fort I osteotomy at the maxillary tuberosity and PMJ were 20.38 +/- 2.82 mm and 11.60 +/- 1.57 mm. The mean length of the posterior maxilla was 27.18 +/- 2.49 mm. Distances from the greater palatine foramen to the maxillary tuberosity incision and PMJ incision were 1.76 +/- 1.12 mm and 3.59 +/- 1.40 mm. The mean angle between the descending palatine canal and the hard palate was 57.33 +/- 4.54 degrees . There were no significant differences in any measurements between sides and genders, except the pterygoid process width and posterior maxilla length of males were longer than those of females (P < 0.05). This study could provide better understanding of the posterior maxillary anatomy that is important for the bone-cut design of Le Fort I osteotomy to avoid excessive intraoperative and postoperative hemorrhage including ischemia of the mobilized maxilla.     

Landmarks of the facial nerve: implications for parotidectomy

Facial nerve paralysis is a daunting potential complication of parotid surgery and is widely reported. Knowledge of the key landmarks of the facial nerve trunk is essential for safe and effective surgical intervention in the region of the parotid gland. In current practice, wide ranges of landmarks are used to identify the facial nerve trunk, however, there is much debate in the literature about the safety and reliability of each of these landmarks. The aim of this study, therefore, was to evaluate the relation of the surrounding anatomical structures and surgical landmarks to the facial nerve trunk. The anatomical relationship of the facial nerve trunk to the surrounding structures was determined after micro-dissection on 40 adult cadavers. The shortest distances between the facial nerve and the “tragal pointer”, attachment of the posterior belly of digastric muscle, tympanomastoid suture, external auditory canal, transverse process of the axis, angle of the mandible and the styloid process were measured. In addition, these distances were compared in the right and left sides, males and females and edentulous and non-edentulous mandibles. The distance of the facial nerve trunk from each of the surrounding landmarks ranged from (mm): tragal pointer, 24.3 to 49.2 (mean 34); posterior belly of digastric, 9.7 to 24.3 (mean 14.6); external auditory canal, 7.3 to 21.9 (mean 13.4); tympanomastoid suture, 4.9 to 18.6 (mean 10.0); styloid process, 4.3 to 18.6 (mean 9.8); transverse process of the axis, 9.7 to 36.8 (mean 16.9); angle of the mandible, 25.3 to 48.69 (mean 38.1). The length of the facial nerve trunk from its point of exit from the stylomastoid foramen to its bifurcation into upper and lower divisions ranged from (mm) 8.6 to 22.8 (mean 14.0). The results demonstrated that the posterior belly of digastric, tragal pointer and transverse process of the axis are consistent landmarks to the facial nerve trunk. However, it should be noted that the tragal pointer is cartilaginous, mobile, asymmetrical and has a blunt, irregular tip. This study advocates the use of the transverse process of the axis as it is easily palpated, does not require a complex dissection and ensures minimum risk of injury to the facial nerve trunk.     

Meckel腔及毗邻结构显微解剖在中颅底入路中的应用研究

目的　研究Meckel腔及毗邻结构的显微外科解剖关系,为临床手术治疗相关疾病提供解剖学依据。 方法　成人尸头标本10例（20侧）,采用手术显微镜观察Meckel腔及毗邻结构。 结果 　Meckel腔是颅后窝向颅中窝后内侧突入的硬脑膜凹陷,内有三叉神经运动根和感觉根、三叉神经节及三叉神经池,腔前后长（14.53±0.98）mm,内外宽(15.24±1.29)mm,上下厚(4.95±0.54)mm。三叉神经孔至Dorello管开口(9.25±1.14)mm,至内耳道开口(15.30±1.14)mm。Meckel腔内侧壁为各壁中比较薄的,内侧壁后部与颞骨岩尖部岩蝶韧带相贴,毗邻Dorell管;下壁前方隔岩舌韧带与颈内动脉破裂孔段相邻。 结论　Meckel腔内侧壁的硬膜脑膜层较为菲薄,并直接与海绵窦静脉腔隙相邻,可能是肿瘤侵入海绵窦的薄弱点之一。岩蝶韧带和岩舌韧带可以作为前部经岩手术识别展神经和颈内动脉破裂孔段的解剖结构。     

Undescribed variant muscle – “Deep abductor-flexor” of the little finger, in relation to ulnar nerve compression at the wrist

During routine anatomical dissection in the hypothenar region of the left hand of a 64-year-old female cadaver, a number of variant structures were observed. The most prominent finding in our case was a supernumerary muscle hitherto unknown in the anatomical literature. This variant muscle had a muscular body formed by the connection of two deeply situated muscular bellies--medial and lateral. The lateral belly originated from the flexor retinaculum, the medial one--from the hamate bone. The common muscular body inserted to the antero-lateral surface of the base of the fifth proximal phalanx. Due to its location and possible function, we named the variant muscle "deep abductor-flexor" of the little finger. The flexor digiti minimi brevis muscle showed two proximal tendons--the medial tendon was attached to the hamulus of the hamate bone while the aberrant lateral tendon originated from the lateral part of the flexor retinaculum. Both, the aberrant lateral tendon of the flexor digiti minimi brevis and the lateral belly of the "deep abductor-flexor", passed over the palmar branch of the ulnar nerve, which define their possible clinical significance in ulnar nerve compression. Therefore, the variations of the hypothenar muscles are reviewed and their relation to the compression of the ulnar nerve is discussed.