Internal anatomy of the communicating branch between the ulnar and median nerves in the hand and its relevance to volar digital sensibility.

We studied the microanatomy of the communicating branch between the ulnar and median nerves in 26 adult cadaver hands to explain diminished sensibility in the fourth and fifth fingers we had observed in 2 patients after complete transection of the median nerve. Two new variations of the communicating branch were observed. In the first variation the communicating branch originated proximally from the third common digital nerve to distally join the ring finger ulnar digital nerve and the small finger radial digital nerve. In the second variation the ramus communicans traversed perpendicularly between the third and fourth common digital nerves with a crossover of nerve fibers.     

The surgical anatomy of ulnar and median nerve communications in the palmar surface of the hand

OBJECT: Sensation in the palmar surface of the digits is supplied by the median and ulnar nerves, with the boundary classically being the midline of the ring finger. Overlap and variations of this division exist, and a communicating branch between the ulnar and median nerve could potentially explain further variations in digital sensory innervations. The aim of this study was to examine the origin and distribution of the communicating branch between the ulnar and median nerves and to apply such findings to the risk involved in surgical procedures in the hand. METHODS: The authors grossly and endoscopically examined 200 formalin-fixed adult human hands obtained in 100 cadavers, and a communicating branch was found to be present in 170 hands (85%). Of the specimens with communicating branches, the authors were able to identify four notable types representing different points of connections of the branches. The most common, Type I (143 hands, 84.1%), featured a communicating branch that originated proximally from the ulnar nerve and proceeded distally to join the median nerve. Type II (12 hands, 7.1%) designated a communicating branch that originated proximally from the median nerve and proceeded distally to join the ulnar nerve. Type III (six hands, 3.5%) designated a communicating branch that traversed perpendicularly between the median and ulnar nerves in such a way that it was not possible to determine which nerve served as the point of origin. Type IV (nine hands, 5.3%) designated a mixed type in which multiple communicating branches existed, arising from both ulnar and median nerves. CONCLUSIONS: According to the origin and distribution of these branching patterns, the investigators were able to define a risk area in which the communicating branch(es) may be subject to iatrogenic injury during common hand procedures.     

Sensory communication of the median and ulnar nerves in the palm

A communicating branch between the median and superficial ulnar nerve in the palm of the hand has been described, but its relationship to the cutaneous anatomy of the hand has had little emphasis. Fifty preserved cadaveric hands were dissected. A communicating branch was found in 37 of 50 specimens. In 34 specimens, the connecting branch proceeded from the ulnar nerve to enter the median nerve distally; in three specimens it proceeded from the median nerve to reach the ulnar nerve distally. This study describes the communicating branch in relation to the distal crease of the wrist with the axis of the third webspace and fifth ray as the radial and ulnar borders, respectively. This study may aid surgeons in determining the likelihood of injury in trauma or during various surgical procedures.     

游离足底内侧皮瓣修复腕掌尺侧皮肤神经缺损

目的 探讨修复腕掌尺侧皮肤神经同时缺损的新方法.方法 2000年4月至2009年8月,应用游离足底内侧皮瓣修复腕掌尺侧皮肤并神经缺损5例.足拇趾胫侧趾底固有神经修复小指尺掌侧固有神经缺损1例;桡神经浅支修复尺神经及其深浅支缺损2例,修复尺神经浅支、第4指掌侧总神经及小指尺掌侧固有神经缺损1例;尺神经手背支修复尺神经浅支、第4指掌侧总神经及小指尺掌侧固有神经缺损1例.足底内侧血管与尺血管吻合.供区取同侧大腿皮片移植修复.结果 术后皮瓣及移植皮片全部成活.5例获得6个月至4年的随访,皮瓣质地好、外观满意,无手内肌萎缩和爪形手畸形,皮瓣和手指感觉恢复达S3～S3+,皮瓣两点辨距觉为7～10 mm.尺神经深浅支缺损病例术后综合评价均为优.结论 游离足底内侧皮瓣是修复腕掌尺侧皮肤神经缺损的有效方法.     

游离足底内侧皮瓣修复腕掌尺侧皮肤神经缺损

目的 探讨修复腕掌尺侧皮肤神经同时缺损的新方法.方法 2000年4月至2009年8月,应用游离足底内侧皮瓣修复腕掌尺侧皮肤并神经缺损5例.足拇趾胫侧趾底固有神经修复小指尺掌侧固有神经缺损1例;桡神经浅支修复尺神经及其深浅支缺损2例,修复尺神经浅支、第4指掌侧总神经及小指尺掌侧固有神经缺损1例;尺神经手背支修复尺神经浅支、第4指掌侧总神经及小指尺掌侧固有神经缺损1例.足底内侧血管与尺血管吻合.供区取同侧大腿皮片移植修复.结果 术后皮瓣及移植皮片全部成活.5例获得6个月至4年的随访,皮瓣质地好、外观满意,无手内肌萎缩和爪形手畸形,皮瓣和手指感觉恢复达S3～S3+,皮瓣两点辨距觉为7～10 mm.尺神经深浅支缺损病例术后综合评价均为优.结论 游离足底内侧皮瓣是修复腕掌尺侧皮肤神经缺损的有效方法.     

游离足底内侧皮瓣修复腕掌尺侧皮肤神经缺损

目的 探讨修复腕掌尺侧皮肤神经同时缺损的新方法.方法 2000年4月至2009年8月,应用游离足底内侧皮瓣修复腕掌尺侧皮肤并神经缺损5例.足拇趾胫侧趾底固有神经修复小指尺掌侧固有神经缺损1例;桡神经浅支修复尺神经及其深浅支缺损2例,修复尺神经浅支、第4指掌侧总神经及小指尺掌侧固有神经缺损1例;尺神经手背支修复尺神经浅支、第4指掌侧总神经及小指尺掌侧固有神经缺损1例.足底内侧血管与尺血管吻合.供区取同侧大腿皮片移植修复.结果 术后皮瓣及移植皮片全部成活.5例获得6个月至4年的随访,皮瓣质地好、外观满意,无手内肌萎缩和爪形手畸形,皮瓣和手指感觉恢复达S3～S3+,皮瓣两点辨距觉为7～10 mm.尺神经深浅支缺损病例术后综合评价均为优.结论 游离足底内侧皮瓣是修复腕掌尺侧皮肤神经缺损的有效方法.

Abstract：

Objective To explore a new method for repair of concurrent skin and nerve defect at palm and carpal on ulnar side. Methods From April 2000 to August 2009, five cases with concurrent skin and nerve defect at palm and carpal on ulnar side were reconstructed with free medial plantar flaps.Palmar nervous proprii defect at ulnar side of little finger was repaired by the first toe tibia nervous proprii in one case. The superficial branch of radial nerve was applied to repair the defect of ulnar nerve, as well as its deep or superficial branch in two cases. The superficial branch of radial nerve was also used to repair the defect of superficial branch of ulnar nerve, common palmar digital nerve of the fourth finger, Little finger ulnar palmar nervous proprii in one case. The dorsal branch of ulnar nerve was applied to repair the defect of superficial branch of ulnar nerve, common palmar digital nerve of the fourth finger, little finger ulnar palmar nervous proprii in one case. The vascular bundle of medial plantar flap was anastomozised with ulnar vascular bundle. The wounds at donor sites were covered with free skin grafts which were obtained from upper leg. Results All the flaps and skin grafts were survived completely. The five patients were followed up for six months to four years with no muscular atrophy or claw hand deformity. The esthetic result was satisfied. The Sensory of flaps and fingers recovered to S3 to S3+. The two-point discrimination distance on flaps was range from 7 mm to 10 mm. The postoperative comprehensive evaluation was excellent in the cases whose superficial and deep branches of ulnar nerve were repaired.Conclusions Free medial plantar flap is an effective method to repair concurrent skin and nerve defect at palm and carpal on the ulnar side.     

Anatomic study of the ramus communicans between the ulnar and median nerves

The communicating branch between the fourth and third common digital nerves in the palm of the hand was studied. The incidence and branching pattern were studied in 53 dissected cadaveric hands. The "danger zone" in which the nerve is at risk during surgery was established using morphometric data. A communicating branch was found in 50 hands. It originated proximally from the fourth common digital nerve to join the third common digital nerve distally in 44 hands and traversed perpendicularly between the third and fourth common digital nerves in 4 hands. In the 2 remaining hands the branch left the third common digital nerve proximally to join the fourth digital common nerve distally. In 90% of the hands the ramus communicans crossed over in the middle third of the palm of the hand. As a cautious measure, hand surgeons should take into account that this structure could cross over anywhere in the middle three fifths of the palm.     

指固有神经背侧支的应用解剖学研究

目的 为指固有神经背侧支的临床应用提供解剖学基础。方法 观测12只新鲜成人手标本48个手指指固有神经背侧支出的出现率、直径、走向及分支。结果 示、中、环指及小指桡侧指固有神经发出的单一分支形成背侧支者占92．86％（78．84）,背侧支缺如者占7．14％（6．84侧）。各指背侧支均在近节手指近、中1／3平面发出,并从指侧面斜向指背远端走行。在近指间关节桡背（或尺背）侧向背面及中节指背发出2－5条分支。除小指外,2－4指指桡、尺侧背侧支的直径粗细均有显著性差异（P＜0．05）,桡侧＞尺侧。小指飞侧无指固有神经背侧支。结论 示、中、环及小指的桡侧指固有神经背侧支走向恒定,可包含在同指逆行岛状皮瓣内,适用于修复指腹软组织缺损。     

Anatomic variations in sensory innervation of the hand and digits

Anatomic dissections under microscopic magnification were performed on 30 fresh cadaveric hands to depict the course and interconnections of the sensory nerves to the digits. The dissections included the median nerve, the ulnar nerve, the superficial branch of the radial nerve, the dorsal branch of the ulnar nerve, and the dorsal branch of the proper digital nerve. The communicating branches between the median and ulnar nerves in the palm were found in 20 of the 30 (67%) specimens. The dorsal branch of the proper digital nerve was found to arise at or proximal to the A1 pulley zone in 62% of the long digits, more proximally than previously reported. The dorsal sensory nerves (the terminal branch of radial or ulnar sensory nerves) extending to the nail bed area were found in 46% of the digits, thus confirming that sensory supply to the dorsum of the distal phalanx and nail bed also arises from the dorsal sensory nerves. Four types of palmar-dorsal interconnections, located in the middle of the proximal phalanx, were found in the digits but not in the thumb. The presence of these branches indicates dual innervation of the dorsal and palmar side of the distal areas of the digits. These anatomic findings may help hand surgeons interpret discrepancies in sensory loss after either dorsal or palmar injuries.     

Digital innervation patterns following median or ulnar nerve laceration and their correlation to anatomic variations of the communicating branch between these nerves

The midline of the ring finger is classically considered as the neural watershed between the median and ulnar nerve sensory territories on the palmar surfaces of the fingers. Variations of this division exist and may be explained by a communicating branch between the third and fourth common digital nerves. The palmar sensibility patterns of fingers were assessed with Semmes Weinstein filaments after either a complete median or an ulnar nerve transection in 43 patients. Eight out of nine observed sensibility patterns could be explained by known anatomic types and subtypes of the communicating branch. The type of communicating branch, but not its subtype, could be established in the one remaining pattern.     

The anatomy of the Berrettini branch: implications for carpal tunnel release

OBJECT: Dissections were performed in 100 fresh cadaver palms to determine the frequency with which superficial palmar communication between the median and ulnar nerves occurs and to what extent it might incur iatrogenic injury during endoscopic carpal tunnel release. METHODS: Superficial palmar communication between the median and ulnar nerves was present in 81% of the dissected hands. Superficial palmar communication, also known as the Berrettini branch, has been classified into four distinct types by Ferrari and Gilbert. Twelve hands were classified as Group 1 (communication in an oblique course from the ulnar to the median nerve originating >4 mm above the distal margin of the transverse carpal ligament [TCL]), 16 hands were classified as Group 2 (communication parallel to the distal margin of the TCL), and 53 hands were classified as Group 3 (communication in an oblique course from the ulnar nerve to the third common digital nerve, originating below the distal margin of the TCL). No hand fit the Group 4 classification (atypical communication). CONCLUSIONS: The Berrettini branch can be considered a normal anatomical finding. In 28% of the hands in this study, the branch was proximal to the edge of the distal ligament and, therefore, prone to iatrogenic injury in both one-portal and two-portal endoscopic surgery.     

Median nerve compression in the palm of the hand by an anomalously enlarged ulnar artery

Median nerve compression in the carpal tunnel by a thrombosed persistent median artery and a large aberrant artery substituting for the radial artery has been described but there have been no reports of median nerve compression in the palm of the hand by an anomalously enlarged ulnar artery. A 46 year old man is described who presented with clinical and electrophysiological features consistent with a median neuropathy at the wrist but surgical exploration revealed median nerve compression in the palm of the hand by an anomalously enlarged palmar branch of the ulnar artery. This case highlights another treatable cause of median nerve compression and illustrates that symptoms suggestive of carpal tunnel syndrome may be produced by median nerve compression in the palm of the hand.     

Palmar cutaneous branch of the median nerve

The palmar cutaneous branch of the median nerve was dissected in 25 fresh cadavers. The origin from the median nerve, the course, termination, and variability of the palmar cutaneous nerve are described in relation to two reference lines. In no case did a branch of the palmar cutaneous nerve extend ulnar to the axial line of the ring finger. The planning of incisions around the palmar aspect of the palm and wrist should be based on this anatomical knowledge.     

游离尺动脉腕上皮支皮瓣修复手指创面

目的探讨尺动脉腕上皮支皮瓣修复手指创面的手术方法及效果。方法对11例手指皮肤软组织缺损合并肌腱或骨外露者,采用游离尺动脉腕上皮支皮瓣进行修复。其中8例面积为2．5cm×1．0cm-5．2cm×2．2cm的皮瓣．在腕上皮支下行支轴线上切取：3例面积为5．5cm×3．0cm×6．2cm×3．8cm的皮瓣,在腕上皮支下行支及上行支轴线上切取。皮瓣切取后,8例下行支皮瓣内腕上皮支主干均直接与受区指动脉吻合,3例合并有上行支的皮瓣均移植了前臂静脉与受区的指动脉吻合,皮瓣内的皮下静脉或伴行静脉分别与近端指掌侧或指背侧2-3根静脉吻合,将皮瓣内携带的1条尺神经手背支与指固有神经接合。结果术后11例皮瓣全部成活．并获得4～17个月随访。皮肤弹性、色泽、质地良好,外形满意。两点辨别觉9-12mm。结论游离尺动脉腕上皮支皮瓣供区隐蔽,血管穿支位置恒定,不损伤主干血管,供区损伤小,切取简单。修复手指缺损外观满意,可携带神经恢复皮瓣感觉,是修复手指创面的一种理想选择。     

Prevalence of anatomic variations encountered in elective carpal tunnel release

PURPOSE: To determine the prevalence of aberrant or unexpected anatomic structures within one surgeon's elective experience of carpal tunnel releases and their association with pathologic compression. METHODS: A total of 31 anomalies of median nerve, muscle, and tendon, median artery persistence, and ulnar nerve were documented in 30 hands during the course of 526 elective carpal tunnel releases in one surgeon's practice. The data collected were reviewed retrospectively. All carpal tunnel releases were performed open, exposing the median nerve from the palmar arch to the proximal wrist crease. Anomalies were categorized into those involving the median nerve and its motor and sensory branches, the ulnar nerve, a persistent median artery, and anomalies of muscle/tendon units traversing the carpal tunnel area. RESULTS: Seven hands were noted to have aberrant muscle/tendon variations within the carpal tunnel region (1.3%). Anomalies of the median nerve or its palmar cutaneous or motor branches were observed in 5 hands (1.0%). An anomaly of the ulnar nerve with an aberrant branch crossing the carpal tunnel incision occurred in one hand. A persistent median artery (>or=1 mm) was noted in 18 hands (3.4%). One hand had 2 anomalies present. One anomaly was high bifurcation of the median nerve and the second anomaly was an anomalous muscle to the long finger superficialis. CONCLUSIONS: The specific anatomic variations described may be anticipated and more readily recognized by hand surgeons during such open surgery, thus increasing the efficacy and safety of this common procedure.     

A variant of Kaplan's accessory branch of the dorsal cutaneous branch of the ulnar nerve: a case report and review of the literature

Kaplan's accessory branch is an aberrant branch of the dorsal cutaneous branch of the ulnar nerve that arises proximal to the styloid process of the ulna and courses ulnar to the pisiform. Variations of this anomaly have been described as having an end point of connection to the sensory branch of the ulnar nerve, to the motor branch of the ulnar nerve (rare), to the digital nerve at the level of the midhypothenar eminence, or to the proximal interphalangeal joint of the small finger or as running as an independent branch to the volar aspect of the small finger. We report a variant of Kaplan's accessory branch that coursed through the insertion of the flexor carpi ulnaris, a groove on the ulnar aspect of the pisiform, and connected to the ulnar nerve trunk proximal to its bifurcation into its motor and sensory branch. Based on the findings of the case presented and a review of the literature we offer a classification system for this anomaly.     

End-to-side repair of thenar motor branch of median nerve to the ulnar nerve after excision of the median nerve neurofibroma

A 13-year-old male patient suffering for the past 5 years with a gradually swelling and occasionally painful volar side of right forearm, presented to our clinic without any trauma. An end-to-side nerve repair performed between the ulnar nerve and thenar motor branch, and second common digital nerve to the digital nerve of the first finger for mend the sensorial, digital, and motor impairments related to the median nerve associated plexiform neurofibroma that occured after the excision of the tumor.     

Aberrant course of a communicating branch of the ulnar nerve to the median nerve contributing to hypothenar Hammer syndrome

This presentation represents a unique anatomic predisposition to the development of hypothenar hammer syndrome (HHS). In this case, a communicating branch of the ulnar nerve to the median common digital nerve of the ring finger was identified crossing volar to the superficial palmar arch. This relationship caused thrombosis of the superficial palmar arch proximal to this crossing nerve branch. The aberrant course of this nerve created a structural anomaly contributing to HHS, which ultimately mandated surgical intervention.     

应用环指感觉神经传导速度测定诊断腕管综合征

目的探讨应用环指感觉神经传导速度(sensory nerve conduction velocity, SCV)诊断腕管综合征的方法。方法对18例(26手)腕部感觉动作电位潜伏期正常的患者，行顺向感觉神经传导速度测定，测定环指正中神经和尺神经SCV，中指正中神经SCV，对其结果进行比较，并与15例正常人(30手)作对照。结果中指正中神经SCV的异常率为50％，环指正中神经与尺神经SCV差值的异常率为84．6％。刺激6例(9手)患者环指后在正中神经腕部可记录到双峰波，对照组则未见。结论在腕管综合征肌电图的诊断中，比较正中神经和尺神经SCV的差值是早期诊断腕管综合征的敏感指标之一。     

Éminence hypothénar

The hypothenar eminence is of great surgical interest yet its complex anatomy is yet to be fully discovered. This review focuses on: the osteoligamentous floor and topography of the Guyon's canal and the carpal ulnar neurovascular space. The canal under the Pisohamate ligament must be individualized. It corresponds to the zone 2 of Shea and McClain where the deep branch of the ulnar nerve is particularly vulnerable. Usually described as a hole, it is a real canal that circumvents the hamulus; the hypothenar muscles are extremely variable. The short abductor of the little finger may be harvested for opposition transfer but its absence penalizes abduction of the little finger if an independent flexor digiti minimi brevis inserts on the head of the fifth metacarpal; the termination of the ulnar nerve distribution to the hypothenar muscles and medio-ulnar anastomoses. The ulnar artery, its close relationship with the hook of the hamate and its variable course that may put it at risk during endoscopic carpal tunnel release. Finally, blood supply of fat pads and skin and their use as flaps to cover the palm and fingers.