Two unusual anatomic variations create a diagnostic dilemma in distal ulnar nerve compression

Diagnosis of peripheral neuropathies is based upon patterns of functional deficits and electrodiagnostic testing. However, anatomic variations can lead to confounding patterns of physical and electrodiagnostic findings. Authors present a case of ulnar nerve compression due to a rare combination of anatomic variations, aberrant branching pattern, and FCU insertion at the wrist, which posed a diagnostic and therapeutic dilemma. The literature related to isolated distal ulnar motor neuropathy and anatomic variations of the ulnar nerve and adjacent structures is also reviewed. This case demonstrates how anatomic variations can complicate the interpretation of clinical and electrodiagnostic findings and underscores the importance of thorough exploration of the nerve in consideration for possible variations.     

Pseudoganglion on the connecting branch between the deep branch of the lateral plantar nerve and medial plantar nerve

The connecting branch between the deep branch of the lateral plantar nerve and medial plantar nerve often has an enlarged site. We investigated these enlarged sites of the connecting branches. We observed the 22 human feet of 20 Japanese cadavers. We investigated the connecting branch macroscopically and histologically. We found the connecting branches between the deep branch of the lateral plantar nerve and medial plantar nerve in 19 feet out of 22 feet. This connecting nerve branch was interposed between the tendon of the flexor hallucis longus and the flexor hallucis brevis, and there enlarged in the anteroposterior direction. After penetration, numbers of fascicles of this connecting branch were increased at the enlarged site. In this region, the connective tissues surrounding the nerve fascicles and vessels were more developed compared with the adjoining sides of this branch. A few fascicles at this enlarged site innervated the first metatarsophalangeal joint capsule. Other nerve fascicles arose from the connecting branch and branched off muscular branches to the flexor hallucis brevis. This branch possibly receives the physical exertion or friction during gait due to its position. Deformity and overload of the foot can cause sensory disorders of the foot, but the anatomical basis for the relationship between the deformity/overload and sensory disorders of the foot is unclear. We discussed that this connecting branch can be a potential cause of pressure neuropathies in the human foot.     

Anatomical study of the communicating branches between the medial and lateral plantar nerves

The plantar areas of the foot have specific biomechanical characteristics and play a distinct role in balance and standing. For the forefoot surgeon, knowledge of the variations in the anatomy of communicating branches is important for plantar reconstruction, local injection therapy and an excision of interdigital neuroma. The anatomy of the communicating branches of the plantar nerves between the fourth and third common plantar digital nerves in the foot were studied in 50 adult men cadaveric feet. A communicating branch was present between the third and fourth intermetatarsal spaces nerves in all eight left feet and in six right feet (overall, 28%), and absent in 36 (72%). A communicating branch was found in 14 ft. Ten of the 14 communications were from the lateral to the medial plantar nerve. The length of the communicating branch ranged from 8 to 56 mm (average 16.4 mm) and its diameter was 0.2–0.6 times of the fourth common plantar digital nerve. The angle of the communicating branch with the common plantar digital nerve from which it originated was less than 30° in 11 ft, 30–59° in 27 ft, 60–80° in 8 ft, and more than 80° in 4 ft. Classification of the branch is based on the branching pattern of the communicating branch and explains variations in plantar sensory innervations. We think that the perpendicular coursing communicating branch is at higher risk to be severed during surgery.     

The effects of the communicating branch between medial and lateral plantar nerves on the innervations of the foot lumbrical muscles

Introduction

The communicating branches between the medial (MPN) and lateral (LPN) plantar nerves aren’t frequently observed in relation to the innervation of the foot muscles in previous studies. In this study, the number and localization of the communicating branch on the innervations of foot muscles were evaluated to open a new sight considering the innervations of lumbrical muscles.

压力对周围神经传导功能影响的实验研究

用雄性SD大白鼠24只,研究了压力对神经传导功能的影响。结果表明:受压后运动神经传导速度与动作电位电压呈正相关:压力与运动神经传导速度和动作电位电压呈负相关,持续压力下,压迫时间与运动神经传导速度和动作电位的电压呈负相关。周围神经虽然有一定的抗挤压能力,但如果在压力26.7KPa下压迫超过一小时或压力超过40KPa均可造成神经传导功能阻滞。     

Ramification pattern of the deep branch of the lateral plantar nerve in the human foot

To understand how the oblique and transverse heads of the adductor hallucis muscle of the human foot are phylogenitically and ontogenetically developed, it is essential to know nerve supplies of these two heads of the muscle. In the present study, we dissected seven feet of five Japanese cadavers in detail to clarify the ramification patterns of the deep branch of the lateral plantar nerve by peeling off its epineurium (the nerve fascicle analysis method). We found that the muscular branch to the oblique head of the adductor hallucis muscle directly separated from nerve fascicles constituting the deep branch of the lateral plantar nerve, whereas the muscular branch to the transverse head arose in common with branches which innervated other intrinsic muscles of the foot, i.e., the 2nd and 3rd lumbrical muscles and the 1st and 2nd dorsal interossei muscles. The present study revealed that two heads of the adductor hallucis muscle, the oblique and transverse, had different innervating patterns, suggesting that two heads of the human adductor hallucis muscle develop from different primordia, and not from common ancestors.     

正中神经返支卡压及易损伤部位的解剖学基础

目的：探讨腕管综合征术后大鱼际功能恢复不良的原因与返支易损伤部位。方法：对20侧成人新鲜上肢标本进行显微解剖，观测正中神经返支走行中存在的卡压因素以及易损伤部位。结果：(1)拇短屈肌浅头尺侧存在腱弓及腱纤维束结构，对正中神经返支形成卡压；(2)住屈肌支持带远侧返支与掌腱膜关系密切，在此部位掌腱膜可对返支形成卡压或术中易误伤返支；(3)走行中返支与拇长屈肌腱和示指屈肌腱存在交叉走行关系。结论：(1)返支走行中存在易卡压因素，治疗腕管综合征时应常规探查松解返支；(2)涉及拇长屈肌腱，示指屈肌腱和掌腱膜手术时，应注意防止损伤返支。     

The medial branch of the lateral branch of the posterior ramus of the spinal nerve

In the needle insertion of epidural anesthesia with the paramedian approach, the needle can pass through the longissimus muscle in the dorsum of the patients. When the needle touches a nerve in the muscles, the patients may experience pain in the back. Obviously, the needle should avoid the nerve tract. To provide better anesthetic service, analysis of the structure and where the concerned nerves lie in that region is inevitable. Material and method: We studied five cadavers in this study. Two cadavers were fixed with Thiel’s method. With these cadavers, we studied the nerve running of the posterior rami of the spinal nerve from the nerve root to the distal portion. Three of them were used for the study of transparent specimen, with which we studied the course and size of the nerve inside the longissimus muscle. Results: We observed there were three branches at the stem of the posterior rami of the spinal nerves between the body segment T3 and L5, i.e. medial branch, medial branch of the lateral branch and lateral branch of the lateral branch. The medial branch of the lateral branch supplied to the longissimus muscle. With the transparent specimen, we found that there were different nerve layouts between the upper thoracic, lower thoracic, upper lumbar, and lower lumbar segments in the medial branch of the lateral branch in the longissimus muscle. In the lower thoracic and upper lumbar segments, the medial branch of the lateral branch of the upper lumbar segments produced layers nerve network in the longissimus muscle. L1 and L2 nerves were large in size in the muscle. Conclusion: In the upper lumbar segments the medial branch of the lateral branch of the posterior rami of the spinal nerve produced dense network in the longissimus muscle, where the epidural needle has high possibility to touch the nerve. Anesthetists have to consider the existence of the medial branch of the lateral branch of the posterior rami of the spinal nerve when they insert the needle in the paramedical approach to the spinal column.     

三叉神经痛大鼠三叉神经根区Fyn的表达变化

目的:在三叉神经痛(trigeminal neuralgia,TN)动物模型基础上,研究三叉神经根区(trigeminal nerve root entry zone,TREZ)Fyn蛋白的表达。方法:通过三叉神经根慢性压迫损伤诱导建立大鼠TN动物模型,von Frey丝检测大鼠口面部术前1 d和术后1、3、7、14、21 d和28 d的机械性痛敏,然后在大鼠分别存活7、14、21 d和28 d时灌注取材,采用免疫荧光染色方法以及蛋白质印迹(Western Blot)技术检测三叉神经根区Fyn的表达变化。结果:(1)行为学结果显示:TN模型组大鼠术后14 d的机械性痛敏阈值明显降低,与假手术(Sham)组相比有显著性差异(P0.05);(2)免疫荧光染色显示:TN模型组大鼠术后三叉神经根区Fyn阳性细胞增多,Sham组未见明显变化。(3)Western Blot显示:TN模型组大鼠术后7 d Fyn表达量相对Sham组降低(P0.05),术后14 d降至最低;术后21 d Fyn表达上调,但仍低于Sham组;术后28 d TN组Fyn表达量明显上升且高于Sham组。结论:大鼠TREZ慢性压迫损伤后,Fyn表达在TN早期降低,而在TN后期Fyn表达升高,提示Fyn可能参与TN动物模型的发病过程。     

Linear and Angular Measurements of the Foot of Modern Humans: A Test of Morton'S Foot Types

In his classic research, Morton established two functionally different configurations of the bipedal and non‐bipedal primate foot: one optimized for stability, with a stiff longitudinal arch and adducted first metatarsal, and the other for compliance. Modern human feet were seen as conforming to the bipedal norm and variation from it as pathology, even though clinical evidence has been clear that variation from the norm of a stiff longitudinal arch or adducted first metatarsal exists. This study aims to document the variation in linear and angular measurements of the foot, using weight‐bearing radiographs of 50 randomly selected people (25 men) from an urban US Level 1 trauma center. The radiographs were obtained to “rule‐out” a foot fracture after trauma or as comparison films for a contralateral foot injury. Measurements were made using Osirix and correlations among the angular and length measurements were determined using Stata with P < 0.05 and Bonferroni correction for multiple comparisons. We found that foot length was not correlated with angular measurements, except for the angle between the first and fifth metatarsal. People with lower medial longitudinal arches also had more abducted first metatarsals and more vertical posterior facets, in accordance with Morton's foot types. Whether or not this variation in modern humans is linked to functionally important consequences remains to be determined in future research. With the new evidence of a more variable foot structure in fossil hominins, understanding the relationship between foot morphology and function becomes more urgent. Anat Rec, 296:1526–1533, 2013. © 2013 Wiley Periodicals, Inc.     

The role of fasciae in Civinini–Morton's syndrome

This study evaluates the pathogenetic role of the perineural connective tissue and foot fasciae in Civinini–Morton's neuroma. Eleven feet (seven male, four female; mean age: 70.9 years) were dissected to analyse the anatomy of inter‐metatarsal space, particularly the dorsal and plantar fasciae and metatarsal transverse ligament (DMTL). The macrosections were prepared for microscopic analysis. Ten Civinini–Morton neuromas obtained from surgery were also analysed. Magnetic resonance images (MRIs) from 40 patients and 29 controls were compared. Dissections showed that the width of the inter‐metatarsal space is established by two fibrous structures: the dorsal foot fascia and the DMTL, which, together, connect the metatarsal bones and resist their splaying. Interosseous muscles spread out into the dorsal fascia of the foot, defining its basal tension. The common digital plantar nerve (CDPN) is encased in concentric layers of fibrous and loose connective tissue, continuous with the vascular sheath and deep foot fascia. Outside this sheath, fibroelastic septa, from DMTL to plantar fascia, and little fat lobules are present, further protecting the nerve against compressive stress. The MRI study revealed high inter‐individual variability in the forefoot structures, although only the thickness of the dorsal fascia represented a statistically significant difference between cases and controls. It was hypothesized that alterations in foot support and altered biomechanics act on the interosseous muscles, increasing the stiffness of the dorsal fascia, particularly at the points where these muscles are inserted. Chronic rigidity of this fascia increases the stiffness of the inter‐metatarsal space, leading to entrapment of the CDPN.     

The communicating branch of the 4th cervical nerve to the brachial plexus: the double constitution, anterior and posterior, of its fibers

Twenty-four adult cadavers (48 sides) were used to investigate the incidence of a branch arising from the ventral ramus of the fourth cervical nerve (C4) with the phrenic nerve and subsequently joining the brachial plexus. Six brachial plexuses with spinal cords and phrenic nerves were dissected under a surgical microscope to investigate localization of fibers contained in the C4 branch to the brachial plexus. The incidence of the C4 branch was 23% (11/48 sides). Branches from C4 to the brachial plexus divided into anterior and posterior divisions on four sides (4/6 sides). On two sides, the branch did not divide but consisted entirely of an anterior division (2/6 sides). In the brachial plexus, anterior division fibers of the C4 branch were intertwined with fibers from the anterior divisions of the ventral rami of the fifth and sixth cervical nerves. They then passed to the suprascapular nerve and the anterior division of the superior trunk (6/6 sides). On the other hand, posterior division fibers of the C4 branch were intertwined with fibers from the posterior divisions of the ventral rami of the fifth and sixth cervical nerves. They then passed to the suprascapular nerve (2/6 sides) and the posterior division of the superior trunk (4/6 sides). The anterior division of the C4 branch received fibers from the ventral rootlets of the entire fourth cervical segment, whereas the posterior division received fibers from the ventral rootlets of the caudal half of the fourth cervical segment only. The fact that the suprascapular nerve received fibers from both the anterior and posterior divisions of the C4 branch was considered to support our claim that the human suprascapular nerve belongs to both the anterior and posterior divisions of the brachial plexus.     

隐神经髌下支神经痛诊断与治疗

目的探讨隐神经髌下支神经痛诊断与注射治疗的解剖学基础。方法收集门诊自2001年10月至2009年9月间确诊的隐神经髌下支自发性神经痛16例,采用强的松龙加局部麻醉药注射至神经穿出深筋膜处的方法治疗。结果所有病例均在注射后数分钟内止痛。10例1周后痊愈,未再复发。其余6例1周后仍然有轻度疼痛,经再次注射后止痛,未再复诊,应属痊愈。结论对于非创伤或膝部手术而自发产生的隐神经髌下支神经痛,采用强的松龙加局部麻药注射神经穿出深筋膜处进行治疗,可以获得满意的效果,不失为首选的治疗方法。     

腓肠外侧皮神经痛诊治的解剖学基础(系列介绍之十六)

目的 介绍腓肠外侧皮神经痛的诊断与局部注射的治疗方法。方法 选择门诊确诊为腓肠外侧皮神经痛的患者11例，采用强的松龙混悬液加麻药局部注射神经通过胭窝的外下部穿出阔筋膜的局部治疗方法。结果 所有病例皆在注射后短时完全止痛，经1～3次注射后痊愈。结论 对诊断明确的病例，采取强的松龙局部注射法，可以获得满意的疗效。     

An anatomic study of the lateral femoral cutaneous nerve

Summary In this study, the course of the lateral femoral cutaneous n. was examined bilaterally in 22 cadavers. Seven of these 44 lateral femoral cutaneous nn. showed variations in their course, especially in their number of branches under the inguinal ligament. During operations where the lateral femoral cutaneous n. may be damaged or in its decompression surgery, the nerve is to be found under the inguinal ligament. 1.52±0.84 cm medial to the anterior superior iliac spine. This nerve can be found passing through the inguinal ligament in as many as four branches.

---

Une étude anatomique du nerf cutané latéral de la cuisse

Résumé Le trajet du n. cutané latéral de la cuisse a été étudié sur 22 pièces cadavériques des deux côtés. Sept nerfs sur 44 présentaient des variations dans leur trajet, portant essentiellement sur le nombre de branches de division sous le lig. inguinal. Pendant les interventions chirurgicales où le n. cutané latéral de la cuisse peut être endommagé ou lors de sa décompression chirurgicale, il est possible de le retrouver sous le lig. inguinal à 1.52±0.84 cm de l'épine iliaque antérosupérieure. Le nerf ou ses branches de division peuvent passer à travers le lig. inguinal.

     

Anatomic variations in the course of the hypoglossal nerve: A case report

To achieve a successful surgical anatomy a detailed knowledge of regional anatomy and anatomical variations is an important fundamental. The extra cranial hypoglossal nerve has a well described course as it traverses the neck, and is frequently identified during neck dissection. This serves a guide to the surgeon of such atypical variations in anatomy to avoid injury to important structures during dissection. We are presenting a case report which demonstrates the extra cranial variation of Hypoglossal nerve.     

Sensory nerve supply of the human oro‐ and laryngopharynx: A preliminary study

To date, the details of human sensory innervation to the pharynx and upper airway have not been demonstrated. In this study, a single human oro‐ and laryngopharynx obtained from autopsy was processed with a whole‐mount nerve staining technique, Sihler's stain, to determine its entire sensory nerve supply. The Sihler's stain rendered all mucosa and soft tissue translucent while counterstaining nerves. The stained specimen was then dissected and the nerves were traced from their origins to the terminal branches. It was found that the sensory innervation of the human pharynx is organized into discrete primary branches that innervate specific areas, although these areas are often connected by small neural anastomoses. The density of innervation varied, with some areas receiving almost no identifiable nerve supply (e.g., posterior wall of the hypopharynx) and certain areas contained much higher density of sensory nerves: the posterior tonsillar pillars; the laryngeal surface of the epiglottis; and the postcricoid and arytenoid regions. The posterior tonsillar pillar was innervated by a dense plexus formed by the pharyngeal branches of the IX and X nerves. The epiglottis was densely innervated by the internal superior laryngeal nerve (ISLN) and IX nerve. Finally, the arytenoid and postcricoid regions were innervated by the ISLN. The postcricoid region had higher density of innervation than the arytenoid area. The use of the Sihler's stain allowed the entire sensory nerve supply of the pharyngeal areas in a human to be demonstrated for the first time. The areas of dense sensory innervation are the same areas that are known to be the most sensitive for triggering reflex swallowing or glottic protection. The data would be useful for further understanding swallowing reflex and guiding sensory reinnervation of the pharynx to treat neurogenic dysphagia and aspiration disorders. Anat Rec 258:406–420, 2000. © 2000 Wiley‐Liss, Inc.