Fourth Intermetacarpal Space Research Articles

Pedicled palmar intermetacarpal perforator flap for skin-graftless syndactyly release: Anatomical study and clinical application.

Dorsal hand skin flaps have been described in order to avoid digit skin grafting in syndactyly release. Although these skin-graftless techniques present a lower rate of long term complications, they result in unsightly dorsal scarring and worse patient satisfaction. We describe a novel technique using an intermetacarpal palmar flap by performing an anatomic study and clinical application. Ten colored-latex-injected fresh upper limbs were used to study the palmar cutaneous perforators to second to fourth intermetacarpal space skin flaps designed elliptical, its width extending from the center of each involved ray and measuring 40%-50% the length of the palm. The anatomical study revealed a mean 2.77 (range 1 to 4) cutaneous perforators originating from either the common or proper digital vessels for every intermetacarpal space and measuring 0.4 mm (range 0.3 to 0.5 mm) in diameter. This flap, measuring a mean of 21.5 mm (range 20 to 23 mm) in length and 9.5 mm (range 9 to 10 mm) in width, was used to release simple syndactylies in three patients of mean age 24 months (range=18-30 months). After skin incision, cutaneous septa to the digital canal were released to permit flap advancement to the web space. Cutaneous perforators were not dissected. Intra-operative palmar-flap advancement provided commissure coverage in all children with no skin grafts needed. Over a mean follow-up of 15 months, no complications occurred, mean palm scar VSS was 2.4 (range 2 to 3) while it was 3 (range 3 to 3) for the commissure scars. Skin-graftless syndactyly release using a palmar intermetacarpal flap seems both reliable and easy-to-perform. Therapeutic IV.

Multi-dorsal metacarpal artery perforator adipofascial turnover flap for index to little finger reconstruction: Anatomical study and clinical application

Reconstruction of the dorsum of the hand and fingers is one of the main challenges in hand surgery. Regional flaps from the forearm, free flaps, or pocket procedures are options when multiple digits are injured with tendon damage and bone exposure. These procedures can be technically demanding and are often plagued by a texture mismatch. We conducted an anatomical study of 20 fresh frozen hands. The second, third and fourth intermetacarpal spaces were analyzed with the aim of defining the vascular foundation of dorsal hand adipofascial-turnover flaps based on dorsal metacarpal artery (DMA) perforators, analyzing their potential for reconstruction procedures on the dorsum of the hand. In three cases, the 4th intermetacarpal space lacked the DMA. A mean of 3.5 arterial communications were found between the DMA and palmar arterial system. Each hand had 11 ± 2 dorsal skin perforators, which were equally distributed among different intermetacarpal spaces. At least one perforator was present in each one-third of the space. The most distal perforators were the largest in all spaces but missing in two hands. A clinical case of multiple index finger to little finger reconstruction with this new multi-dorsal metacarpal artery perforator (mDMAP) adipofascial turnover flap is presented. Our anatomical study confirmed previous descriptions of the anatomy of the dorsum of the hand. It supports the safety of the mDMAP adipofascial turnover flap based on all distal arterial perforator for the simultaneous reconstruction of index to little finger injuries. Similarly, adipofascial turnover flaps can be raised from more proximal perforators arising from DMAs if more than one intermetacarpal space is included.

Prevalence of the extensor digitorum, extensor digiti minimi and extensor indicis tendons and their variations

We aimed to investigate tendon variations of the extensor digitorum (ED), extensor digiti minimi (EDM), and extensor indicis proprius (EIP) muscles. Our study was performed on 43 fetal cadavers (86 extremities), aged between 17 and 40 weeks of gestation. The number of ED tendons varied from three to six, proximal to the extensor retinaculum (ER), and from three to eight, distal to the ER. The ED most often had four tendons, both proximally and distally from the ER. The ED tendons of the fourth finger were observed to be most frequently duplicated. The most common juncturae tendinum (JT) was type 1 in the second intermetacarpal space (IMCS), type 2 in the third IMCS, and type 3r in the fourth IMCS according to von Schroeder classification. The number of EIP and EDM tendons varied from one to two and from one to five, respectively. The EIP double tendons inserted both into the ulnar and palmar sides of the extensor digitorum of the second finger, which had not been reported in the literature. In our study, 7% of hands had variant muscles. In 4.7% of hands, the extensor indicis et medii communis was observed, while the extensor medii proprius and the extensor digitorum brevis manus were observed in 1.2% and 1.2% of hands, respectively. Knowing the prevalence of the ED, EDM and EIP tendons and their variations in the fetal period should help to treat partial loss of hand function or injury after birth and to correct congenital hand deformities.

A Cadaveric Study of the Juncturae Tendinum

Abstract Introduction The superficial extensor tendons of the fingers are connected by juncturae tendinum (JT). JTs are of three types namely JT-1, JT-2, and JT-3. JT-3 are very thick with maximum occurrence in fourth intermetacarpal space (IMCS), where it is associated with agenesis of extensor digitorum communis to small finger (EDCs). Awareness of frequency and morphology of JT is essential in surgical repair of tendon injury. Methods JTs were dissected in 80 free adult cadaveric upper limbs and 32 fetal upper limbs of 16 stillborn and embalmed fetuses present in the department. The pattern and frequency of JT was studied. Frequency of JT-3 in association with agenesis of EDCs was looked into. The length and width of JT were measured and analyzed using ANOVA and post hoc analysis. Results JT-1 and JT-2 were commonly observed in the second and third IMCS, respectively. JT-3 had a maximum frequency in the fourth space and was observed in 78.37% of cases of agenesis of EDCs. A gradual increase in length and a decrease in the width of JT were observed from JT-1 to JT-2, JT-3r, and JT-3y. Conclusion JTs are absent in the first IMCS and in 6.25% of second IMCS. The commonest pattern of distribution of JT in the second, third and fourth IMCS is JT-1, JT-2, and JT-3, respectively. JT-3 is the longest and thickest JT, and partially compensates for agenesis of EDCs. The structural resemblance to tendons enables JT-3 utilization for a tendon graft.

The best vein to be accessed based on descriptive study of dorsal metacarpal vein.

It is well known that the most common sites for venous access are the superficial veins of the upper limb, particularly dorsal metacarpal veins and median cubital vein. Although dorsal metacarpal veins are the first choice for venous cannulation, there is scarce information about their anatomic variation. Hence, detailed anatomical information about these veins will improve the anatomic knowledge of the health care providers. Subsequently, this study was designed to study the dorsal metacarpal veins and to determine the most prominent dorsal metacarpal vein. A cross sectional study of 402 subjects (804 hands), was prepared to study the superficial veins on the dorsum of the hand among Jordanian students and staff of one of the major governmental medical colleges in Jordan, by using infrared illumination system. The obtained data was analyzed according to sex, sidedness, and handedness. Six locations of the most prominent dorsal metacarpal veins were identified. There was a significant relation between both females and males and the most prominent dorsal metacarpal vein (P=0.01). For the first time this study identified the most common location of the most prominent dorsal metacarpal vein in the fourth intermetacarpal space.

Stress Lymphoscintigraphy for Early Detection and Management of Secondary Limb Lymphedema.

Stress lymphoscintigraphy was performed within 1 year after surgery and the completion of chemotherapy and radiation treatments. All patients were classified by the International Society of Lymphology clinical stages from 0 to 3. A dose of 50 MBq of 99mTc-HSA-nanocolloidal in 0.4mL was injected intradermally at the first and fourth intermetacarpal spaces on the hand, for the upper limb with edema, or at the first intermetatarsal space and at the lateral malleolus for lower extremities. Two planar static scans at rest were acquired immediately after tracer injection. Stress scans were acquired after weight lifting for upper extremity or stepping for 2 minutes for lower-extremity edema. After that, the patients underwent prolonged muscular exercise limited by symptoms, and later scans were acquired at 60 minutes to visualize regional lymph nodes and the effects of sustained muscular exercise. Transport Index was evaluated. Five patterns of lymphoscintigraphy were observed. In our experience, patients with types I to III pattern benefit from an exercise program as a first-line treatment. Patterns IVand V seem to be predictive of lymphedema. The abnormal patterns found may provide the basis for earlier complex physical therapy or microsurgical treatment of lymphatic disorders in patients resulting in improved outcomes.

A rare cause of ulnar nerve entrapment at the elbow area illustrated by six cases: The anconeus epitrochlearis muscle

Ulnar nerve entrapment is the second most common compressive neuropathy after carpal tunnel syndrome. The accessory anconeus epitrochlearis muscle – present in 4% to 34% of the general population – is a known, but rare cause of ulnar nerve entrapment at the elbow. The aim of this article was to expand our knowledge about this condition based on six cases that we encountered at our hospital between 2011 and 2015. Every patient had a typical clinical presentation: hypoesthesia or sensory deficit in the fourth and fifth fingers; potential intrinsics atrophy of the fourth intermetacarpal space; loss of strength and difficulty with fifth finger abduction. Although it can be useful to have the patient undergo ultrasonography or MRI to aid in the diagnosis, only electromyography (EMG) was performed in our patients. EMG revealed clear compression in the ulnar groove, with conduction block and a large drop in nerve conduction velocity. Treatment typically consists of conservative treatment first (splint, analgesics). Surgical treatment should be considered when conservative treatment has failed or the patient presents severe neurological deficits. In all of our patients, the ulnar nerve was surgically released but not transposed. Five of the six patients had completely recovered after 0.5 to 4years follow-up. Ulnar nerve entrapment at the elbow by the anconeus epitrochlearis muscle is not common, but it must not be ignored. Only ultrasonography, MRI or, preferably, surgical exploration can establish the diagnosis. EMG findings such as reduced motor nerve conduction velocity in a short segment of the ulnar nerve provides evidence of anconeus epitrochlearis-induced neuropathy.

Anatomical similarity between tendons and Type 3 intertendinous connections: suitability as local donor tissue.

The aim of this study was to investigate the effects of the freeze drying and solvent dehydration allograft preservation methods on the mechanical properties of the graft material. Bone blocks obtained from bovine humeri were divided into three groups. Samples in the first group were freeze dried, samples in the second group were dehydrated by solvents and samples in the third group were used as controls. All samples underwent three point bending test to investigate bending strength and were evaluated for calcium content. Bending strength of both the freeze-dried and solvent-dehydrated samples were found to have decreased significantly compared to that of the control group. The calcium content of the solvent dehydrated group was also significantly lower than that of the control group. Our results suggested that both preservation techniques, used to dehydrate bone, have negative effects on the bending strength of bone as they decrease the mechanical properties of the graft material.

An anatomic study on the junctura tendinum in the 4th intermetacarpal space and its clinical implication

We report results of anatomic study in the fourth intermetacarpal space, focusing on the pattern of junctura tendinum and variations of extensor tendons of the little finger with its clinical implication on snapping of the little finger. Fifty unpaired cadaveric hands were dissected from the wrist to the middle phalanx of the ring and little fingers. The type of junctura tendinum was judged based on Von Schroder's classification and the relationship with EDC were recorded. EDC to the little finger and EDM were dissected and the numbers were recorded. Forty six hands (92%) exhibited a junctura tendinum in the fourth intermetacarpal space and it was Type III in 42 hands (84%). The EDC-little finger was absent in 76% (38 of 50 hands). When present, EDC-little finger originated most commonly as single thin tendon. The absence of an EDC-little finger was associated with increased incidence of Type III junctura tendinum (37 of 38 hands). An EDM was present in all 50 hands running from the fifth dorsal compartment. Based on these clinical and anatomic studies, we considered that the snapping of the little finger is more likely subluxation of junctura tendinum rather than subluxation/dislocation of EDC of the little finger.

“Stabilized Arthroplasty” for Old Fracture Dislocations of the Fifth Carpometacarpal Joint

The procedure of stabilized arthroplasty we present in this paper aims at a global functional restoration of old fracture dislocations of the fifth carpometacarpal joint. The conflict is eliminated by resecting the base of the metacarpal, whereas length of the fifth digit ray is restored by fusion to the adjacent fourth metacarpal. Fifth metacarpal mobility is maintained via transfer to the fourth carpometacarpal joint. The base of the fifth metacarpal is resected through a dorso-lateral approach to the fourth-fifth intermetacarpal space. The preferred plane of resection is not perpendicular to the shaft of the metacarpal but parallel to the distal articular surface of the hamatum which faces 30 degrees anteriorly. A 5 to 10 mm resection is possible without compromising the insertion of extensor carpi ulnaris. The fifth metacarpal must then be temporarily fixed by 1 or 2 intermetacarpal K-wires in the preferred position. The cortical bones on both sides of the proximal fourth intermetacarpal space must then be refreshed over 1 to 1.5 cm and the space filled with cancellous bone graft. The osteosynthesis of the lateral fusion is secured by 2 transverse screws including the 4 cortices. A temporary distal metaphyseal wire relieves forces until bone fusion. Compared with the more commonly used operative procedures, stabilized arthroplasty provides a better mobility than arthrodesis and restores metacarpal length better than nonstabilized resectional arthroplasty. Nevertheless, it can only be done given the fourth carpometacarpal joint is intact.

Snapping Junctura Tendinum to the Small Finger Simulating Radial Sagittal Band Rupture

Snapping of the extensor tendon over the metacarpophalangeal joint usually involves a longitudinal or oblique tear of the radial sagittal band1, with subsequent displacement of the extensor tendon in an ulnar direction2. Most reports have dealt with pathologic snapping secondary to inflammatory joint disease and posttraumatic subluxation of the extensor tendons, which usually occurs in either the long or ring finger. Because of its rarity, little attention has been given to snapping at the metacarpophalangeal level of the small finger2,3. We report two cases of snapping of junctura tendinum in the fourth intermetacarpal space over the radial side of the fifth metacarpal head, which could be misdiagnosed as extensor tendon subluxation due to sagittal band injury. Surgical treatments together with anatomic variations in this area are also discussed. The patients were informed that data concerning their cases would be submitted for publication, and they consented. Case 1. A twenty-year-old woman was referred because of a three-month history of painful snapping of the left small finger. She had started to play the drums three weeks before the symptoms had developed, and she noted constant and painful snapping with flexion of the metacarpophalangeal joint. On examination, the extensor tendon of the small finger dislocated radially at the level of the metacarpophalangeal joint with flexion of >30°. There was an obvious snapping sound at the time of dislocation (Fig. 1, A ). This finding was not related to wrist or elbow motion. A diagnosis of extensor tendon dislocation of the small finger was made, and surgical reconstruction of the sagittal band was planned. Fig. 1 Case 1. A: The extensor tendon of the small finger dislocated to the radial side of the metacarpophalangeal joint with flexion. B: Surgical exploration revealed a thick cord-like structure (arrows) crossing obliquely …

The anatomical variations of the extensor tendons to the dorsum of the hand

To lead a quality life, tendon repair must be performed in a trauma causing damage to the extensor tendon of the hand. The aim of this study is to study the structures that can be used as donor tendons. Fifty-four dissected adult hands were examined to study the pattern of the extensor tendons on the dorsum of the hand. The most common distribution patterns of the extensor tendons of the fingers were as follows: a single extensor indicis proprius (EIP) tendon which inserted ulnar to the extensor digitorum (ED)-index; a single ED-index; a single ED-middle; a single ED-ring; an absent ED-little; a double extensor digiti minimi (EDM), and a single ED-ring to the little finger. The frequency of the number of tendons is as follows: a single (87.03%) EIP, a single ED-index (100%), a single (92.6%) ED-middle, a single (75.9%) ED-ring, and an absent (68.5%) or a single (24.1%) ED-little. A double (88.9%) EDM tendons were seen. The thickest type of juncturae tendinum (JT) is found primarily between the ring and little fingers (90%). Suitable excessive tendon and the thickest JT as donor tendon were found in the fourth intermetacarpal space. The present findings, especially the fourth intermetacarpal space, may explain why incisions on the dorsum of the hand should be large and performed with particular care. It is necessary to have a thorough understanding of the arrangements of the multiple extensor muscles and their junctural connections of the hand when tenoplasty or tendon transfer is required.

Arterial anatomical basis of the dorsal digito-metacarpal flap for long fingers

Several flaps have been described to treat severe soft tissue defects of the finger dorsal side. Many authors studied vascular organization of the hand on its dorsal side; most of them insisted on deep vascularization into the intermetacarpal spaces, which is formed by the dorsal metacarpal arteries. Those dorsal metacarpal arteries are the anatomical support of many flaps, which do not preserve the dorsal interosseous muscles fascias. Only few authors described dorsal vascular organization at the level of the proximal phalanx; however, using a rotation point of a flap distally to the metacarpal head with a donor site on the dorsal aspect of the hand could cover all distal soft tissue defect of long finger. In order to determine the technical limitations of dorsal digito-metacarpal flap procedures, we studied number and location of arterial anastomoses between the reticular subcutaneous dorsal network and the rest of the vascularization at this level, which was formed by the deeper dorsal metacarpal arteries, common palmar digital arteries and proper palmar digital arteries, and between the dorsal digital arteries. Twenty-four long fingers from embalmed cadavers were studied after a reverse flow injection of colored latex and dissected layer-by-layer preserving the digital-metacarpal arterial network. At the level of the hand, the dorsal metacarpal arteries of the third and fourth intermetacarpal spaces were inconstant. When present, two or three arteries anastomosed in star shape with the reticular network. No such arterial anastomosis was observed proximally to the level of the intertendinous connections (junctura tendinorum) that bridge the extensor digitorum communis tendons. When no dorsal metacarpal artery was present, some communicant arteries arose from the common palmar digital arteries. Moreover, all the nutrient branches were more numerous distally to the intertendinous connections (junctura tendinorum). At the level of the metacarpophalangeal joints, the hand cutaneous network was always anastomosed with the dorsal cutaneous network. At the level of fingers, the dorsal cutaneous network was always supplied by four branches arising from the proper digital artery. Our study supported the reliability of dorsal digitometacarpal flaps, supplied by numerous palmodorsal digital anastomoses and by a rich plexiforme network joining the hand skin supply and that of the dorsal finger skin. During the procedure, we recommend limiting the surgical dissection of the flap at the level of the middle phalanx.

The Anatomic Basis of the Fourth Dorsal Metacarpal Flap: A Cadaveric Dissection

To study the vascularization of the fourth dorsal intermetacarpal space and to determine the contribution of the dorsal metacarpal artery and the interosseous muscle fascia to flap viability. The fourth dorsal intermetacarpal space is considered to be less reliable as a donor site because of previously reported vascular variations. We performed 15 cadaver dissections. The vascular tree was injected with black latex through the radial and ulnar arteries at the forearm. The skin paddle was designed within the fourth intermetacarpal space. The proximal border was placed at the wrist joint line. The distal border was located 1 cm proximal to the head of the fourth and fifth metacarpal. The width of the skin paddle was based on whether the donor site could be closed directly. A zigzag incision was performed from the distal end of the skin paddle to the volar edge of the interdigital web. The borders of the skin paddle were outlined down to the fascia of the dorsal interosseous muscle. Once the fourth dorsal metacarpal artery was identified each vascular connection was dissected and recorded. The fourth dorsal metacarpal artery was identified in all specimens under the dorsal interosseous muscle fascia. The distal recurrent branch consistently entered the base of the flap superficial to the extensor digitorum communis tendon of the small finger and the dorsal interosseous muscle fascia. Cutaneous perforators branching off the dorsal metacarpal artery were not found consistently. Reliable flaps can be raised from the fourth dorsal intermetacarpal space based solely on the distal recurrent branch, excluding the dorsal metacarpal artery and interosseous muscle fascia.

The retrograde neurocutaneous island flap of the dorsal branch of the ulnar nerve: anatomical basis and clinical application.

It is well known that a cutaneous artery is constantly located near a cutaneous peripheral nerve, forming a vascular plexus around it. This vascular axis can be either a true artery or an interlacing network, ensuring the vascularization of the nerve and giving off several neurocutaneous perforators to the skin. The anatomy of the accompanying arteries of the dorsal branch of the ulnar nerve (DBUN) and their relationships with the dorsal branch of the ulnar artery (DBUA) were investigated in 22 fresh upper limbs injected with colored neoprene latex. A constant perineural vascularization of the terminal branch of the DBUN was observed in the fourth web space, connected distally with the corresponding dorsal metacarpal or palmar digital arteries. Our findings therefore provide anatomical bases for a new neurocutaneous island flap. Moreover, they allow us to describe a precise surgical technique in order to raise this flap over the larger branch of the DBUN, in the fourth intermetacarpal space. The flap is harvested on the medial aspect of the dorsum of the hand, and its point of rotation is located in the fourth web space, 1 cm proximal to the metacarpophalangeal joint. It is supplied by a reversed flow originating from distal anastomoses of the perineural vessel with the dorsal metacarpal and digital palmar arteries in the fourth web space. This flap does not involve in its pedicle the distal course of the DBUA. It represents a pure neurocutaneous flap.

Pseudorotation of the little finger metacarpal

Fractures of the little finger metacarpal are common, and are often associated with significant soft-tissue swelling and the appearance of rotational malalignment when the fingers are flexed. Our hypothesis is that soft-tissue swelling causes this apparent rotational deformity of the flexed little finger. The fourth intermetacarpal spaces of three of the authors’ non-dominant hands were injected with saline. Following injection, all the hands exhibited the appearance of internal rotation of the little finger. The mean change in rotation was 16° and the maximum was 25°. There was no change in the plane of the nail plate in extension in any hand. We conclude that soft-tissue swelling can cause the appearance of internal rotation of the flexed little finger in the absence of fracture.

Dorsal ulnar cutaneous nerve conduction: reference values.

We investigated the reference values of the dorsal ulnar cutaneous nerve (DUC) sensory nerve conduction (SNC) in 66 healthy individuals. Measurements were processed using stimulating electrodes positioned between the ulnar bone and the flexor carpi ulnaris muscle, 11-13 cm proximal to the active electrode recording. Superficial recording electrodes were placed on the fourth intermetacarpal space. The mean sensory conduction velocity (SCV) in males was 63.7 - 0.16 x age +/- 3.36 m/s and in females was 57.7 +/- 3.37 m/s. The mean sensory nerve action potential (SNAP) amplitude in males was 19.5 +/- 10.7 microV and in females was 24.6 +/- 5.8 microV. The mean SNAP duration was 0.96 +/- 0.13 ms. No significant differences regarding the DUC-SCV, distal latency, and SNAP duration or amplitude were found between both sides of the same subject. The amplitude of the SNAP was higher in females than males. The effects of age on DUC-SCV were distinct for each gender.

An anatomic study of the extensor tendons of the human hand.

A total of 548 upper limbs (276 right and 272 left hands) from Japanese cadavers were dissected. The arrangements of extensor indicis proprius, extensor digitorum communis (EDC), and extensor digiti minimi tendons and the intertendinous connections were studied. The most common pattern of extensor tendons was as follows: the index finger had a single EDC tendon, the middle finger had a single EDC tendon, the ring finger had a single EDC tendon, and the small finger had a single EDC tendon or a single common EDC tendon distributed to the ring and small finger. A single extensor indicis proprius tendon ran along the ulnar side of the EDC, and the extensor digiti minimi tendon consisted of 2 slips. Intertendinous connections were classified into 3 types: type 1 with a filamentous band, type 2 with a fibrous band, and type 3 with a tendinous band subdivided to r-shaped and y-shaped. The most common patterns were type 1 in the second intermetacarpal space (IMCS), type 3r in the third IMCS, and type 3y in the fourth IMCS.

Ramification Pattern of Intermetacarpal Branches of the Deep Branch (Ramus profundus) of the Ulnar Nerve in the Human Hand

The branching pattern of the deep branch (ramus profundus) of the ulnar nerve and its relation with the target were analyzed in the human hand by an improved dissection method. After sending off branches to the hypothenar muscles, the r. profundus branched off an ulnar stem and a radial stem to the fourth, to the third and to the second intermetacarpal spaces, respectively, in this order, and an ulnar stem to the first to become terminal branches. The ulnar stems included an ulnar interosseous branch and a superficial articular branch in addition to a lumbrical branch in the third and fourth intermetacarpal spaces. The radial stems included only a radial interosseous branch. The branching pattern of the ulnar stems as well as its topographical relationship with the radial stems indicated a fundamental spatial arrangement of the branches in the intermetacarpal spaces: the lumbrical, superficial articular, ulnar interosseous and radial interosseous branches were arranged fundamentally in this order from ulnar to radial in each space; the first three branches may form a common trunk. The present observations demonstrate that individual nerves in the extremities may have a regular branching pattern, contrary to most of the previous observations.

Anatomy of the juncturae tendinum of the hand

Three distinct morphologic types of juncturae tendinum of the extensor tendons were identified in the dissection of 40 cadaver hands. Type 1 juncturae consists of filamentous regions within the intertendinous fascia that attached to the extensor tendons on either side of the intermetacarpal space in a transverse or oblique direction. The second type, consists of much thicker and well-defined connecting bands. Type 3 juncturae consist of tendon slips from the extensor tendons and were subclassified into "y" or "r" subtypes depending on shape. Type 1 juncturae were present in 88% of the second intermetacarpal spaces and in 28% of the third intermetacarpal spaces. Type 2 juncturae were present in 40% of the third intermetacarpal spaces and in 23% of the fourth intermetacarpal spaces. Type 3 juncturae were present in 33% of the third intermetacarpal spaces and in 80% of the fourth intermetacarpal spaces. Juncturae were absent in all of the first intermetacarpal spaces and in 12% of the second intermetacarpal spaces; they were present in all other spaces. The extensor indicis proprius did not receive a junctural connection, whereas extensor digiti quinti tendons did receive junctural connections. Intertendinous fascia was present between all extensor digitorum communis tendons regardless of presence of juncturae.