Intrinsic flaps in the hand

Advances in anatomical research have created the base for a vast variety of flaps that can be raised in the hand. They are either based on the palmar arterial system or on the dorsal vascular system, which is fed by either perforating vessels from the palmar side or the dorsal arterial system nourished by dorsal carpal arterial network. The majority of small to moderate size defects in the hand can be reconstructed with these types of flaps.     

The carpal synovial sheaths and their vascularization]

The synovial sheaths of the flexor digitorum of 70 pieces of fresh cadavers have been studied on the whole of their length as far as the basis of the fingers: 20 have been injected with a latex or a physiologic solution, after the ablation of the palmar aponeurosis and of the superficial palmar arch. The arteries of the 50 other pieces have been injected with coloured latex solution from humeral artery. The proximal limit of the superficial sheaths is located 5 centimetres above the radiocarpal articular line and this of the deep sheaths 7 centimetres. In the metacarpal area, the superficialis central sheath presents peritendinous expansions, which realise an uninterrupted connection with each digital sheath. It is the aponeurotic and vascular extrinsic compressions, which simulate the interruption of these expansions. The proximal synovial arteries have a muscular origin. The antibrachial collateral arteries, 3 pairs in number, arise from the radial and the ulnar arteries. The distal synovial arteries come from the palmar arches and from their branches: superficial branches for the superficial sheaths and deep branches for the deep sheaths. There is many anastomoses between the different synovial arteries. Two are particularly developed and connect the proximal arteries to the palmar arches: the superficial longitudinal anastomotic artery; which runs close along the medial edge of the median nerve; the deep longitudinal anastomotic artery, which gives the nutritious branches for the tendons of the flexor digitorum. This disposition allows to create two synovial flaps of gliding and vascular help, centred on the anastomotic longitudinal arteries, pediculated on the volar archs and distal-ward rotated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lumbrical muscle with an additional origin in the forearm

Background : Although variations in the attachments of the lumbrical muscles have been commonly reported, these have been seen mainly in the Caucasian population. The present study is the first reported case of such an anomaly in a Chinese cadaver in the literature. Methods : The upper extremities of 26 Chinese (23 male and three female) cadavers were examined. Results : Dissection of a male 66‐year‐old Chinese cadaver has revealed the rare case of a bipennate first lumbrical muscle with an additional origin extending from the distal part of the forearm. Its first origin arose from the flexor digitorum profundus in the hand distal to the flexor retinaculum. The intrinsic muscles in the hands of all the other cadavers were normal. Conclusions : An anomalous origin of the lumbrical from muscles in the forearm has the potential to cause compression of the median nerve in the carpal tunnel.     

Vascular anatomy of plantar muscles

Many reports on the plantar arteries and the deep plantar arch exist, but none of them focus on the arterial pedicles of the plantar muscles. They mainly discuss the deep plantar arch, its variations, and location. This study plans to determine the location and origin of arterial pedicles of all the plantar muscles as a preliminary study for designing new flaps. The study was carried out on 20 feet from 10 cadavers aged from 35 to 67 years. After an injection of latex via popliteal arteries, dissection of the arteries was carried out under a microscope. Abductor hallucis and flexor hallucis brevis muscles receive their main blood supply from the medial plantar artery; abductor digiti minimi and flexor digiti minimi brevis muscles receive their main blood supply from the lateral plantar artery. The flexor digitorum brevis muscle receives branches from both arteries. Adductor hallucis and plantar interosseous muscles receive branches from plantar metatarsal arteries. Quadratus plantae is directly nourished from a branch of the posterior tibial artery. No distal anastomoses between the medial and lateral plantar arteries were identified, except 1 specimen in which the medial plantar artery made anastomosis with the deep plantar arch. As a result, the arterial pedicles of all the plantar muscles were defined, and based on these findings, new flaps can be planned or existing flaps can be modified.     

The versatile metacarpal and reverse metacarpal artery flaps in hand surgery.

Vascular anatomy of dorsal metacarpal arteries was investigated in fresh cadaver dissections and by injection of methylene blue. Origin and termination of the vessels were studied, as well as their connection to the palmar vasculature. Vascular territories and elevation of flaps based on these vessels are also discussed. The second dorsal metacarpal artery was found to be the most consistent. This vessel has a large distal connection to the palmar vessels which allows both proximal and reverse elevation. Representative cases and surgical technique are described.     

The anatomical basis for reverse first to fifth dorsal metacarpal arterial flaps

This study discusses the anatomical basis for reverse first to fifth dorsal metacarpal arterial flaps. The arterial pattern and size of the first to fifth dorsal metacarpal arteries were examined in 20 fresh cadaver hands. Their connections to the palmar arterial system at the metacarpal head were observed, and the location, number and diameter of skin perforators from each dorsal metacarpal artery were measured. The first to fourth dorsal metacarpal arteries were found in all specimens; the fifth dorsal metacarpal artery was found in 19 of our 20 specimens. The mean diameters of the first to fifth arteries at their bifurcation site were 0.6, 0.8, 0.5, 0.4 and 0.2 mm, respectively. Each artery gave off four to eight skin perforators (diameter: 0.1-0.3 mm) between the metacarpal head and base. The first to third dorsal metacarpal arteries consistently connected to the palmar arterial system, and connections between the fourth and fifth dorsal metacarpal arteries and the palmar system were found in 65% and 40% of specimens.     

A bilateral and symmetric anatomic variation of a lombrical muscle causing a trigger finger

Trigger finger is a very common disease. The vast majority of trigger fingers are primary idiopathic trigger ?ngers. We report the case of a bilateral and symmetric triggering of the fifth finger secondary to an anatomical variation of the lumbrical muscle. This lumbrical muscle arose from the flexor digitorum superficialis instead of the flexor digitorum profundus as is usual. To our knowledge, this is the third published case of trigger finger caused by an anatomical abnormality of a lumbrical muscle.     

Dorsal metacarpal reverse flaps. Anatomical basis and clinical application.

The presence of distal intermetacarpal anastomoses between dorsal and palmar vascular networks makes it possible to raise distally-based cutaneous island flaps oriented along the axis of the dorsal metacarpal arteries. These flaps receive a reverse-flow vascularisation. Distal intermetacarpal anastomoses were found consistently in 35 hands from adult cadavers. The exact location of these anastomoses varied with the course of the dorsal metacarpal artery. Thus, island flaps can be raised consistently from the dorsal aspect of the hand and rotated around a distal intermetacarpal pivot. These flaps are suitable for covering the dorsal aspect of the proximal phalanx and the proximal interphalangeal joint.     

Architectural design of the human intrinsic hand muscles.

The architectural features of twenty different muscles (18 intrinsics and 2 thumb extrinsics, n = 180 total muscles) were studied. Muscle length, mass, fiber pennation angle, fiber length, and sarcomere length were determined. From these values, physiologic cross-sectional area and fiber length/muscle length ratio were calculated. Intrinsic muscle lengths were relatively similar to one another, which we interpreted as representing a space constraint within the hand. However, several specialized architectural designs were observed: lumbrical muscles had an extremely high fiber length/muscle length ratio, implying a design toward high excursion. The first dorsal interosseous and adductor pollicis had physiologic cross-sectional areas comparable to those of extrinsic muscles and much greater than those of the other intrinsic muscles. The interosseous muscles had relatively high physiologic cross-sectional areas with low fiber length/muscle length ratios, suggesting their adaptation for high force production and low excursion. Taken together, these observations illustrate the underlying structural basis for the functional capacities of the intrinsic muscles.     

第三骨间掌侧肌及其肌支的解剖观察

目的观察第三骨间掌侧肌及其肌支的解剖学特点，探讨腕尺管综合征中小指内收恢复困难的解剖学基础。方法在2．5倍手术放大镜下对20具新鲜无外伤、无畸形成人手标本进行解剖，观察第三骨间掌侧肌及其肌支及邻近结构，测量了第三骨间掌侧肌的大小和第三骨间掌侧肌支的长度、宽度、厚度，并对所得数据进行统计学处理。结果第三骨间掌侧肌及第三骨间掌侧肌支分别是骨间掌侧肌和骨间掌侧肌支中最细小的，部分第三骨间掌侧肌浅层存在明显的腱束，对第三骨间掌侧肌支形成潜在的卡压。结论第三骨间掌侧肌及其肌支是骨间掌侧肌和肌支中最细小的，部分由第三骨间掌侧肌桡侧绕至尺侧入肌，而第三骨间掌侧肌掌侧存在明显的腱束，对第三骨间掌侧肌支形成潜在卡压，可以解释小指内收恢复困难的原因。     

Micro-CT扫描下舟月骨间韧带的显微解剖学研究

目的研究舟月骨间韧带(SLIL)的形态和血供分布,并从解剖学角度探讨临床上SLIL损伤对其血供的影响及重建的方法。方法2018年10月至2018年12月,选取12例新鲜成人前臂标本,从尺动脉或桡动脉灌注明胶-氧化铅溶液,于Micro-CT下扫描,通过Mimics软件三维重建图像,观察SLIL在中立位的形态和韧带内滋养血管分布,测量韧带掌侧、背侧和近端的宽度、长度、厚度,测量SLIL内滋养血管入口处的解剖参数,并分析其与舟、月骨的血供关系。结果①数字化技术三维重建SLIL的大体形态并测量其解剖参数,近端长度均值最大,掌侧、背侧长度相近;韧带掌侧最宽,厚度最小,而背侧与近端在厚度与宽度上相近。②SLIL的近端无滋养血管分布,掌侧与背侧均有丰富的滋养血管分布,其血供分布差异无统计学意义(P>0.05)。③SLIL的掌侧与背侧内滋养血管从SLIL附着处进入舟、月骨内形成吻合。结论SLIL掌侧较宽且厚度小,从解剖学角度分析其较其它亚区更易损伤;其掌侧与背侧亚区均有丰富的血供且与舟、月骨内相吻合,而近端无血管分布,因此,掌、背侧韧带早期轻度损伤有一定的自我修复能力,而近端损伤则较难修复,韧带掌侧与背侧损伤对舟、月骨血供会产生一定影响。     

Surgical anatomy of the dorsal face of the hand and the wrist

The anatomical knowledge of the dorsal aspect of the hand has been enriched these last years by a more surgically applied approach, especially of that of its integument and blood supply. The vascularization of the superficial nerves, the anastomoses between the dorsal and palmar arterial networks has allowed designing new flaps, ante- and retrograde, usable in the coverage of more and more distal defects. The extensor apparatus shows many anatomic variations, often asymptomatic, except the extensor digitorum brevis manus muscle, which can mimic a mass at the dorsal aspect of the hand.     

The vascular anatomy of the abductor digiti minimi and the flexor digiti minimi brevis muscles

PURPOSE: The abductor digiti minimi (ADM) and the flexor digiti minimi (FDM) brevis muscles could be used as flaps with their low functional morbidity, especially in severe crushed injuries of the hand. The vascular anatomy of both of the muscles were investigated to classify the muscles according to the Mathes-Nahai classification. METHODS: Nine cadavers embalmed with formaline were dissected under loupe magnification (x4) from the wrist proximally to the proximal phalanx of the small finger distally, delineating the branches of the ulnar artery along the ADM and FDM muscles. RESULTS: The dissections and the microangiography of the muscles revealed 1 major and 2 minor pedicles. Both of the muscles could be classified as type II muscles according to the Mathes-Nahai classification. CONCLUSIONS: The vascular pattern of the ADM muscle has been described previously, this study explored the vascular anatomy of the FDM muscle. The information regarding the vascular supplies of these muscles could be of help to the clinician when manipulating the muscles. The FDM muscle could be a suitable alternative for the ADM muscle in opponensplasty. When the pedicles are preserved the muscles could be used--based proximally or distally.     

Lumbrical function: interaction of lumbrical contraction with the elasticity of the extrinsic finger muscles and its effect on metacarpophalangeal equilibrium

Since conflicting statements have been made in the literature regarding the influence of lumbrical contraction on the metacarpophalangeal (MP) joint, a study was undertaken to determine the length-tension curve for the index flexor profundus. Four fresh cadaver hands were used. Measurements for the flexor superficialis and for the common extensor were determined in there. The measurements were correlated with measured displacement of these tendons in six finger positions. Isolated lumbrical contraction was then mechanically simulated, acting against spring homologues of the index extrinsic muscles. The finger moved from the rest position toward the intrinsic position with loads of less than 5 N. This demonstrated that in addition to its effect on interphalangeal joint extension, the lumbrical acting alone can cause flexion of the metacarpophalangeal joint.     

Extensive skin losses of the upper limb

The development of microsurgical techniques and of pedicled local flaps has improved the prognosis of major injuries of the upper limb. Pedicled muscle-skin flaps from the latissimus dorsi muscle allow repairing losses of substance in the arm-pit and arm while restoring the function of the elbow. In the forearm, the same flap, transferred by microsurgery, ensures the rehabilitation of the wrist and hand. In the hand, the Chinese and posterior interosseous flaps allow covering the losses of substance on both the palmar and the dorsal aspects. Here, the free flaps are used only if the palmar vascular arches of these interosseous anastomoses are affected. Lastly, remote flaps are required only for the contraindications of microsurgery. Thus, using this array of donor sites, the emergent replacement of the most complex losses of sin substance can be performed, thus fostering the repair and protection of fony, neurovascular and tendon lesions.     

Vascular anatomy of the metacarpal bones and the interosseous muscles

The utilization of the metacarpal bones and interosseous muscles in the reconstruction of the hand should be based on the vascular anatomy of the metacarpal bones and the interosseous muscles. The authors studied the vascular anatomy of the metacarpal bones and the interosseous muscles to design a split metacarpal musculoosseous flap. Eighteen cadaveric hands from 9 cadavers were included in the study. The dorsal metacarpal arteries arise from the arch and course along the metacarpal bones closer to the ulnar borders of the bones supplying their periosteum through the muscular branches. Despite the indistinct pattern of muscular supply and anastomotic branches to the palmar surface, in all hands the arteries extend constantly along the metacarpal bone closer to the ulnar border. For defects or any pathology of the carpal bones, the metacarpal bones could be split at the ulnar border distally and a split metacarpal musculoosseous flap (based proximally depending on the dorsal metacarpal artery) could be performed (or based distally along with a distal intermetacarpal anastomosis).     

Surgical correction of crossover deformity of the second toe: a technique for tenodesis

Twenty-seven patients with 30 crossover toe (COT) deformities of the second toe were evaluated. This deformity in the transverse and sagittal planes at the second metatarsophalangeal joint may be caused by hindfoot pronation. Compression of the lateral plantar nerve may produce incompetence of the second dorsal interosseous muscle and an increased extension-adduction pull by the lumbrical and first dorsal interosseous muscles. A surgical procedure for tenodesis is described to correct these deformities and restore the extrinsic-intrinsic musculotendinous balance at the second MTP joint. Our results are encouraging, with 83% good or excellent results. There was one recurrence.     

A High Bifurcation of the Dorsal Branch with Dominant Superficial Palmar Branch of the Radial Artery: A Case Report of an Aberrant Radial Artery with Traumatic Aneurysm

Anatomical abnormalities such as unusual bifurcations or aberrant arteries of the radial artery are extremely rare and due to malformation or disruption of the vascular net. We present a case of a 64 year old woman with a high bifurcated dorsal branch of the left radial artery, consulting us for a pulsatile mass in the anatomical snuffbox after a fall. The mass measured 3–4 mm in diameter and was located on the dorsal aspect of the wrist over the anatomical snuffbox. Primary imaging studies using Duplex Ultrasound suggested an aneurysm of the radial artery, further imaging with arteriogram revealed a high bifurcation of the dorsal branch of the radial artery, presenting with an aneurysm. The deep palmar branch of the ulnar artery was the dominating vessel, allowing ligation and excision of the aneurysm. Histological evaluation revealed intimal wall hyperplasia within the aneurysm, suggesting an injury as initiating factor. A review of the literature showed that this abnormality of high bifurcation of the dorsal palmar branch of the radial artery has not been previously reported. Management of aneurysms at the wrist is discussed.     

Muscle perforator flaps: the name game

The creation of a consistent nomenclature for muscle perforator flaps is essential not only to eliminate confusion in the literature, but also to facilitate their surgical application. Universal acceptance demands that the chosen system be as simple as possible, yet remain comprehensive and flexible enough to anticipate future adaptations. Flaps named by anatomical region alone can be ambiguous due to the frequent variations in perforator origin and sometimes multiple or overlapping "mother" vessels, which unfortunately is an inherent characteristic of muscle perforator flaps. One sensible solution is an appellation that includes both the involved muscle and its source vessel, in any order, eg. "source vessel(MUSCLE)" or "muscle(SOURCE VESSEL)" perforator flap. Such a combination immediately readily identifies the precise anatomical location of the flap, as well as stating exactly which vascular pedicle must be dissected.     

Anomalous flexor digitorum superficialis muscle transposition for vascular coverage of the median nerve in recurrent carpal tunnel syndrome

Recurrent carpal tunnel syndrome is uncommon yet troublesome. Significant adhesions and scarring around the median nerve can render it relatively ischemic. A number of vascular flaps have been described to provide vascular coverage in attempts to decrease further cicatricial adhesions and to improve local blood supply around the median nerve. A rare case of an anomalous muscle in the distal forearm used as tissue to provide good vascularized coverage of the median nerve that was severely scarred in its bed is reported. The anomalous muscle was distal to the flexor digitorum superficialis tendon and inserted in the palmar fascia on the ulnar aspect of the hand. Referring branches from the ulnar artery provided vascular supply to the anomalous muscle. The muscle on these vascular pedicles was transposed over the median nerve, providing good, stable, unscarred coverage. The patient had an excellent result with resolution of the carpal tunnel symptoms. The redundant anomalous muscle provided a unique vascularized source for coverage of the median nerve in recurrent carpal tunnel syndrome.