Martin-Gruber anastomosis revisited

Based on a study of 70 human cadavers (31 male, 39 female) and on cases described previously, we propose a new classification of the Martin-Gruber anastomosis, a neural connection between the median and ulnar nerves in the forearm. The anastomosis was found in 16 (22.9%) cadavers, being bilateral in three (18.7%) and unilateral in 13 (81.3%), five right and eight left. It occurred in eight (25.8%) of the 31 male cadavers and in eight (20.5%) of the 39 females. Therefore, the anastomosis was found in 19 (13.6%) of the 140 forearms. In Pattern I (89.5%) the anastomosis was made by only one branch, whereas in Pattern II (10.5%) it was made by two. The individual branches were classified as Types a, b, and c based on the nature of their origin from the median nerve. Type a (47.3%) arose from the branch to the superficial forearm flexor muscles, Type b (10.6%) from the common trunk, and Type c (31.6%) from the anterior interosseous nerve. Pattern II was a duplication of Type c (10.5%). The anastomotic branch took an oblique or arched course before joining the ulnar nerve, undivided in 15 cases, but divided into two branches in four cases. The anastomosis passed in front of the ulnar artery in four cases, behind it in six, and in nine cases it was related to the anterior ulnar recurrent artery.     

An anatomic study on the Martin-Gruber anastomosis

Summary The incidence of Martin-Gruber anastomosis was studied. Anatomical dissection of 108 cadaveric arms was performed. The Martin-Gruber anastomosis was found in 23 arms. This anastomosis was classified into four types: Type Ia: Communication between the anterior interosseous and the ulnar nn. (n=13), Type Ib: Communication between the median and ulnar nn. (n=1), Type II: Communication between muscular branches of the flexor digitorum profundus m. (n=8), Type III: Combination of Type Ia or Ib and Type II (n=1). The incidence of Martin-Gruber anastomosis was found to be significantly higher in the present study than in previous studies.

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Etude anatomique de l'anastomose de Martin-Gruber

Résumé La fréquence de l'anastomose de Martin-Gruber a été étudiée sur les dissections de 108 membres supérieurs de cadavres. L'anastomose a été trouvée 23 fois. Cette anastomose est classée en 4 types : type Ia : anastomose entre le nerf interosseux antérieur et le nerf ulnaire (n=13) ; type Ib : anastomose entre le nerf médian et le nerf ulnaire (n=1) ; type II : anastomose entre les rameaux musculaires du m. fléchisseur profond des doigts (n=8); type III : combinaison du type Ia ou Ib et du type II (n=1). La fréquence de l'anastomose de Martin-Gruber apparait plus élevée que dans les travaux précédents.

     

Innervation of the medial epicondylar muscles: an anatomic study in 50 cases

The median nerve is classically distributed to the medial epicondylar muscles by two branches (superior and inferior) for the pronator teres muscle, a common trunk for the flexor carpi radialis and palmaris longus muscles, and a branch for the flexor digitorum superficialis muscle. The 50 dissections were made by two workers on 30 upper limbs of formolized cadavers and 20 limbs from fresh-frozen cadavers. The innervation of the pronator teres m. was classical in only 26% of cases, and the “normal” pattern for the flexor carpi radialis and palmaris longus mm. was found in only 40% of cases. The innervation of the flexor digitorum superficialis m. was the least subject to variations, a single branch being observed in 68% of cases. We found a solitary medio-ulnar anastomosis of Martin-Gruber to the flexor carpi ulnaris muscle. This study confirmed the great variability of the branches of the median nerve at the elbow, and the importance of identifying them in surgical procedures for transposition of the medial epicondyle.     

Martin-Gruber communicating branch: anatomical and histological study

We dissected 72 upper limbs of fresh cadavers and found 17 cases with a Martin-Gruber communicating branch (23.6%). These were classified into 4 types: type I (n=5, 29.4%): communicating branch between the anterior interosseous and ulnar nn, type II (n=3, 17.6%): Communicating branch between the median and ulnar nn., type III (n=3, 17.6%): Communicating branch between the muscular branches to the flexor digitorum profundus m., type IV (n=6, 35.3%): combination of type I or II and type III. At histologic examination the number and size of the nerve bundles each communicating branch contained proved to be very different. In one case of type II only a single nerve bundle was found. We suggest that the different numbers of nerve bundles innervate different amounts of the intrinsic hand musculature. The communicating branch with a single nerve bundle probably innervated only the first dorsal interosseous muscle.     

The Muscular Branching Patterns of the Ulnar Nerve to the Flexor Carpi Ulnaris and Flexor Digitorum Profundus Muscles

The branching pattern of the ulnar nerve in the forearm is of great importance in anterior transposition of the ulnar nerve for decompression after neuropathy of cubital tunnel syndrom and malformations resulting from distal end fractures of the humerus. In this study, 37 formalin-fixed forearms were used to demonstrate the muscular branching patterns from the main ulnar nerve to the flexor carpi ulnaris muscle (FCU) and ulnar part of the flexor digitorum profundus muscle (FDP). Eight branching patterns were found and classified into four groups according to the number of the muscular branches leaving the main ulnar nerve. Two (Group I) and three (Group II) branches left the main ulnar nerve in 18 and 17 forearms respectively. The remaining two specimens had four (Group III) and five (Group IV) branches each. Usually one or two branches were associated with the innervation of the FCU. However, in 2 cases, three and in one, four branches to FCU were observed. The FDP received a single branch in all cases, except in four, all of which had two branches. In six forearms, a common trunk was observed arising from the ulnar nerve to supply the FCU and FDP. The distribution of the muscular branches to the revealed muscles was outlined in figures and the distance of the origin of these branches from the interepicondylar line was measured in millimeters. The first muscular branch leaving the main ulnar nerve was the FCU-branch in all specimens. The terminal muscular branch of the ulnar nerve to the forearm muscles arose at the proximal 1/3 of the forearm in all specimens. In 7 forearms, Martin-Gruber anastomosis in form of median to ulnar was observed.     

Intramuscular communicating branches in the flexor digitorum profundus: dissection and Sihler’s staining

Purpose  

This study was designed to clarify the anatomy of the intramuscular communicating branch (ICb) between the median and ulnar nerves in the flexor digitorum profundus (FDP), and morphologically demonstrate the location of connection.     

人指屈肌和指伸肌的肌纤维型构成及年龄差异

用尸检取材(死后24小时内),肌球蛋白ATP酶染色法,检测了不同年龄组(共18例,3～69岁)指浅屈肌、指深屈肌和指伸肌的肌纤维型构成.结果表明:中青年组各肌的Ⅰ型纤维比例分别为指浅屈肌47.2%,指深屈肌44.7%,指伸肌47.7%,各肌之间无明显差异.肌纤维型构成随年龄增加而明显变化,各肌Ⅰ型纤维比例均表现为少儿组较高,中青年组较低,而老年组又明显增高,三组之间具有显著差异.文中还讨论了肌纤维型构成与年龄的关系.     

Histomorphometry of the ulnar nerve and of its branches

A morphometric study has shown that 10% of the fibers of the ulnar nerve should suffice to reinnervate the biceps muscle in brachial plexus palsies. The aim of this study was to evaluate, by a morphometric study using computerized microanalysis, the cross-sectional surface areas of the different collateral and terminal branches of the ulnar nerve. This was expressed in terms of percentage of the cross-sectional surface area of the main trunk of the ulnar nerve. The study revealed that the branch to the flexor digitorum profundus bellies to the ring and little fingers formed 9.5% of the cross-sectional area of the ulnar nerve. Thus use of these fascicles destined for the flexor digitorum profundus, identified by intra-operative nerve stimulation, at the level of the arm would be sufficient for neurotisation of the nerve to the biceps. This has been confirmed by the initial clinical results in patients operated upon using this technique.     

Evolutionary adaptations in the flexor digitorum profundus muscle in Tamandua mexicana (Xenarthra,Myrmecophagidae)

The northern tamandua (Tamandua mexicana) is a neotropical mammal of the order Pilosa, suborder Vermilingua, and family Myrmecophagidae. This species has anatomical and functional adaptations in its forelimb for semiarboreal quadrupedal locomotion. Several studies have reported that the medial head of the triceps brachii and flexor digitorum profundus muscles are fused in species belonging to the family Myrmecophagidae. However, there is no reference to the innervation in these. The triceps brachii muscle is commonly innervated by the radial nerve and the flexor digitorum profundus muscle by the ulnar and median nerves. This study aims to describe the gross anatomy of the flexor digitorum profundus muscle in Tamandua mexicana with respect to the shape, origin, insertion, innervation, and arterial supply. Both forelimbs of nine specimens were used, which were dissected from superficial to deep layers. The formalin-fixed caudomedial forearm muscles were weighed, and the weight percentages of individual forearm muscle specimens were calculated. The flexor digitorum profundus had the highest weight among the forearm muscles and consisted of five heads (three humerals, one radial, and one ulnar). These heads were innervated by median and ulnar nerves; therefore, based on the innervation pattern, we concluded that the medial head of the triceps brachii muscle is not fused with the flexor digitorum profundus. Therefore, the flexor digitorum profundus muscle is highly developed in Tamandua and occupies the caudal part of the arm and forearm, which is an evolutionary adaptation that could have occurred during evolution from the common ancestor of Tamandua and Myrmecophaga.     

An anomalous accessory flexor digiti minimi profundus muscle: A case study

A well-developed anomalous muscle within the forearm flexor compartment was discovered during a routine cadaveric dissection. The identified muscle originated from the intercompartmental septum on the medial side of the forearm just proximal to the wrist joint and inserted on the proximal phalanx of the fifth digit. When stressed, the tendon of the muscle produced flexion of the metacarpophalangeal joint of the fifth digit. Contiguous muscles, including the flexor digitorum profundus, displayed normal morphology. The muscle appeared to be an accessory belly of flexor digitorum profundus. The combination of an accessory flexor digitorum profundus muscle belly acting on the metacarpophalangeal joint of the little finger has not been previously reported. Based on its origin, insertion, and action we have named this variant accessory flexor digiti minimi profundus. This muscular variant could have clinical relevance, possibly affecting ulnar nerve function and circulation in the hand. Clin. Anat. 11:55–59, 1998. © 1998 Wiley-Liss, Inc.     

The fourth lumbrical muscle in the hand: a variation of insertion on the fifth finger

Usually the four lumbrical muscles arise from the tendons of flexor digitorum profundus and insert into the extensor expansions on the radial side of the corresponding fingers. This special case showed a very rare variation of a unipennate fourth lumbrical muscle of the right hand; the muscle fibre bundles originated on the radial side of the flexor digitorum profundus and coursed horizontal on its radial side, deep to the palmar aponeurosis and in front of the deep transverse metacarpal ligament over the fifth metacarpophalangeal joint. At the level of this joint, its tendon divided into one radial and one ulnar slips. Both heads surrounded the tendons of the flexor digitorum superficialis and profundus muscles, and found their insertion into the flexor digitorum superficialis tendon, as well as their bony attachment into the proximal and even more into the middle phalanx.     

Clinical anatomy of the chiasma tendlinum (camper) in the fingers

Sixty human hands from adult cadavers were used to study the chiasma tendinum (Camper) of the flexor digitorum superficialis tendon in the finger. Two hundred forty fingers were microdissected and examined morphometrically. The formation of the chiasma tendinum could be divided into nine types. The most common type shows that the flexor digitorum superficialis tendon divides into four bundles, the two inner of which cross each other. The length and width of the chiasma tendinum in the middle finger is the longest and widest, while in the little finger it is the shortest and narrowest. The relationship of the chiasma tendinum and the long vinculum of the flexor digitorum profundus tendon was also observed in the present study. In the most common type the long vinculum lies distal to the chiasma lying between the two terminal tendons of the flexor digitorum superficialis. The authors suggest three functions for the chiasma tendinum: (1) it provides a pathway for the flexor digitorum profundus tendon; (2) it increases the stability and balance of the proximal interphalangeal joint; and (3) it prevents hyperextension of the proximal interphalangeal joint. © 1994 Wiley-Liss, Inc.     

Electromyographic evidence of two functional subdivisions in the rhesus monkey's flexor digitorum profundus

The main belly of the macaque's flexor digitorum profundus (FDP) is divided by a dissectible plane into radial and ulnar regions. The present report describes three findings which suggest that the radial and ulnar regions represent separate functional subdivisions of the FDP. First, electromyographic (EMG) recordings during individuated finger movements performed by rhesus monkeys demonstrated different patterns of activation in the radial versus the ulnar region of the FDP. Second, studies of single motor units discriminated from the parent EMG activity also suggested at least two differentially activated motoneuronal pools in the radial versus ulnar region. Third, the finger movements evoked by intramuscular stimulation, delivered through the recording electrodes, indicated that contraction of the radial versus ulnar region produces different patterns of tension on the finger tendons. Together these findings suggest that the radial and ulnar regions of the FDP provide differential tension on the finger tendons to individuate finger movements.     

Stratification of the flexor retinaculum and the course and distribution of the ulnar, median, and palmar digital nerves: an anatomical study

A gross anatomic study of 169 hands from 94 human adult cadavers was carried out to define the morphology of the flexor retinaculum and the relationship of the flexor retinaculum to the course of the median and ulnar nerves and branching of the palmar digital nerves. The following results were obtained. Three parts of the flexor retinaculum were arranged like overlapping tiles on a roof, and in all cases, the median nerve passed deep to the flexor retinaculum, whereas the ulnar nerve passed through various parts of the flexor retinaculum in 19% of cases irrespective of its proximal form and branching of the palmar digital nerves.     

Tendineal arteries of the flexor tendons in the human hand

Two hundred upper extremities of fresh human cadavers were used to study the anatomy of the tendinous apparatus of the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) muscles. This study describes the different types of mesotendons revealed by layered dissection, and the complex arterial network of the structures and their various sources of blood supply as revealed by the injection of colored latex or India ink solution in gelatin.     

成人前臂前群肌的神经入肌点定位及意义

目的 准确定位成人前臂前群肌神经入肌点（NEP）的体表位置和深度。 方法 成人尸体12具,仰卧。紧贴皮肤连接肱骨外上髁和内上髁间的曲线为横向参考线(H),肱骨外上髁和桡骨茎突间的曲线为纵向参考线(L)。解剖暴露NEP,硫酸钡标记,螺旋CT扫描与三维重建。将NEP在体表上的投影点记为P点,P点通过NEP后投射至前臂后体表上的点为P'点。P点投射到H线与L线上的位置分别记为PH和PL。Syngo系统下确定PH和PL在H和L线上的位置及NEP的深度。 结果 旋前圆肌、桡侧腕屈肌、掌长肌、尺侧腕屈肌、指浅屈肌、拇长屈肌、指深屈肌（正中神经支）、指深屈肌（尺神经支）、旋前方肌NEP的PH分别位于H线上的58.08%、64.17%、75.14%、61.14%、62.26%、52.07%、50.81%、63.38%和51.37%处;PL分别位于L线上的9.79%、3.97%、16.37%、4.42%、17.88%、34.17%、30.27%、11.48%和75.32%处;穿刺深度分别位于PP'线的26.80%、25.06%、27.68%、28.13%、37.30%、39.85%、49.26%、70.86%和44.25% 处。以上数据均为平均值。 结论 这些NEP的体表穿刺位置与深度的界定可为提高前臂前群肌痉挛肌外神经溶解术靶点阻滞的效率、手术切断神经肌支治疗肌痉挛的微创切口设计、作为供肌的功能评估、以及肌移植术中对神经的保护等提供形态学指导。     

Anomalous flexor of the little finger

We report an anomalous palmar muscle belly of the flexor digitorum superficialis muscle (FDS) in the right hand of an 80-year-old female cadaver. The muscle originated from the center of the volar surface of the flexor retinaculum and inserted onto the palmar aspect of the base of the middle phalanx of the little finger. Its tendon of insertion divided into two bands, a pattern typical of the FDS tendon, between which the tendon of flexor digitorum profundus muscle to the little finger passed. The tendon of the usual antebrachial FDS to the little finger was absent. The anomalous muscle belly was innervated by a branch from the median nerve.     

Biometry of the muscular branches of the median nerve to the forearm

The aim of this study was to determine the biometry of the muscular branches of the median nerve to the forearm in ten embalmed upper limbs. We measured the length of the forearm and the level of origin of each muscular branch of the median nerve to the forearm from the middle of a line between the medial and lateral epicondyles. The level of origin of each branch was then calculated as a percentage of the length of the forearm. Mean length of the forearm was 25 ± 2.36 cm (range: 22-29 cm). Although the levels of origin of the proximal and distal nerves to pronator teres, and of the nerves to palmaris longus, flexor carpi radialis and flexor digitorum superficialis, were quite variable (coefficient of variation: CV > 48.61%), the level of origin of the anterior interosseous nerve (CV = 31.24%) and its branches (nerves to flexor pollicis longus and flexor digitorum profundus, CV = 20.06%) was less variable. These results suggest that the anterior interosseous nerve of the forearm is probably the nerve to connect in muscular free transfers in order to restore flexion of the fingers after damage to the flexor tendons to the forearm. We observed Martin-Gruber communications in six out of ten dissections. Clin. Anat. 11:239–245, 1998. © 1998 Wiley-Liss, Inc.     

The cubital tunnel: anatomical study of its distal part

Different levels of ulnar nerve compression have been reported (the medial intermuscular septum, the posterior compartment of the arm, soft tissue or bony abnormalities of the cubital tunnel). In some rare cases, compression can lie in a 10-cm long tunnel, distal to Osborne's ligament, between the humeral head of the ulnar flexor muscle of wrist (FCU) and the medial epicondylar muscles. Only few publications mention this fact as a factor of residual or recurrent symptoms after common surgical procedures. However, a distal pathology of the cubital tunnel has proved to be the only factor of nerve entrapment in our clinical practice. Specific anatomical dissection of this area was carried out to find and classify the anatomical structures that may play a role in ulnar nerve distal compression. Twenty-four embalmed limbs from 13 cadavers were dissected. The purpose of this study was to find anatomical fibrous structures at an average of 10 cm from the medial epicondyle. Anatomical structures were classified into five types: no aponeurosis between the FCU and the medial epicondylar muscles (54.2% of cases), a fibrous band taut between the FCU and the fourth- and fifth-finger ulnar insertions of the flexor digitorum superficialis (FDS) (8.3%), a thin (20.8%) or thick (4.2%) partial aponeurosis between the FCU and the medial epicondylar muscles, and total aponeurosis (12.5%). Anatomical variations of the distal cubital tunnel were divided in five types, but their clinical significance remains unclear.     

肘部及前臂上段正中神经卡压综合征的临床解剖学研究

目的 探讨肘部正中神经卡压综合征的解剖学基础。方法 解剖观察５０侧上肢标本,结果 肱二头肌腱膜与正中神经的关系有非覆盖４０例（８０％）,部分覆盖型６侧（１２％）和完全覆盖型４侧（８％）。旋前圆肌纤维桥斜过正中神经前方３２侧（６４％）。旋前圆肌肱骨头肌内有腱束８例（成人,占１８．６％）,尺骨头汪岙较厚筋膜４７侧（９４％）。指浅屈肌起始结构有联合腱弓型４４侧（８８％）,纤维情怀２侧型（４％）和腱束型（