A rare quadruplicate arrangement of abductor pollicis longus tendons: anatomical and clinical relevance

The anatomy of the tendon of abductor pollicis longus and its morphological variations: An anatomical approach emphasizing the clinical relevance

PURPOSE

The anatomical literature describes the abductor pollicis longus as a muscle with a single tendon inserting on the base of the first metacarpal bone, but investigations have shown that it often exhibits morphological variations. However, methodological approaches used to describe these variations have not been useful in a clinical context. Therefore, the purpose of this investigation was to study and relate such anatomical variations in a clinical context.

BASIC PROCEDURES

Thirty upper limbs from the body donation program were dissected using standard procedures to identify the number of abductor pollicis longus (APL) tendons, their position, site of insertion, length, width and thickness. The presence or absence of the extensor pollicis brevis muscle was also noted. Inter and intra-observer reliability was analysed.

MAIN FINDINGS

A total number of 71 tendons from the APL muscle were found in the thirty limbs. The most frequent distribution pattern was a main tendon inserted on the base of the first metacarpal and an accessory tendon inserted into the abductor pollicis brevis muscle. These tendons could divide into various tendinous slips that could insert in different locations. Also, clustering algorithms and classical statistical tests showed tendons inserting on the first metacarpal were longer than tendons not inserting on the first metacarpal (p = 0.03), while medial tendons and tendons from an APL muscle with supernumerary tendons were narrower (p < 0.001). The absence of the extensor pollicis brevis muscle was not related to the presence of supernumerary APL tendons.

CONCLUSIONS

Radiological and surgical implications of these results are important when examining this region of the hand and wrist. The pathophysiology and treatment of de Quervain's tenosynovitis, trapeziometacarpal arthritis and trapeziometacarpal subluxation or laxity could be influenced by the results of our findings.

Anatomical variations in the first extensor compartment: a cadaver study

BACKGROUND

Anatomical variations in the first extensor compartment are associated with the pathogenesis of de Quervain's disease. Here, we report two novel anatomical variations of the first extensor compartment.

METHODS

The wrists of two adult cadavers were dissected to reveal the anatomical variations in the first extensor compartment.

RESULTS

In one of the cadavers, no septum was present in the first extensor compartment. However, the extensor pollicis brevis tendon and its proximal muscle belly were absent. The abductor pollicis longus (APL) tendon had multiple slips, and one of them inserted on the dorsal base of the proximal thumb phalanx. In another cadaver, a septum was present in the first extensor compartment. One of the multiple APL tendon slips ran into the septum alongside the extensor pollicis brevis tendon for 4 mm, which then exited the septum and inserted into the base of the first phalanx together with the APL tendon.

CONCLUSION

Our findings may help to improve the awareness of the anatomical variations in the first extensor compartment.

Anomalous bilateral contribution of extensor pollicis longus and muscle fusion of the first compartment of the wrist

Knowledge of the anatomical variations of the muscles of the first dorsal compartments of the wrist is clinically relevant to De Quervain's tenosynovitis and to reconstructive surgeries. In the literature, there are many reports of the presence of multiple insertion tendons in the first dorsal compartment of the wrist, but few reports describe occurrences of fusion and muscle contributions. This case report describes an anomalous bilateral contribution of the extensor pollicis longus. This anomalous contribution was found through a slender auxiliary tendon that crossed laterally under the extensor retinaculum, entered the first dorsal compartment of the wrist and merged with the tendon of the extensor pollicis brevis muscle. In the same cadaver in which this contribution was present, there was atypical muscle fusion of the abductor pollicis longus muscle and extensor pollicis brevis muscle. In conclusion, anomalous bilateral contribution of the extensor pollicis longus muscle and atypical muscle fusion, concomitant with a variant insertion pattern, are the highlight of this case report. Furthermore, it is concluded that additional tendons may be effectively used in reconstructive surgeries, but that there is a need for knowledge of the possible numerical and positional variations of these tendons, with a view to making more effective surgical plans.

Anatomical variation of abductor pollicis longus in Indian population: A cadaveric study

BACKGROUND

Many authors have reported the anatomical variation of abductor pollicis longus (APL) around the wrist and its association with de Quervain tenosynovitis (DQT), first carpo-metacarpal arthritis, and trapezio-metacarpal subluxation. From Indian subcontinent, there is only one original article and a few case reports on the variability of APL tendon insertion.

MATERIALS AND METHODS

Fifty formaldehyde preserved cadaveric wrists were dissected to look for the anatomical variation of APL in the Indian population.

RESULTS

The APL was found with single tendon in 2, double in 31, triple in 8, and quadruple in 8 extremities. A maximum of 6 tendon-slips were found in one cadaveric wrist. In all hands, the APL had at least one attachment to first metacarpal bone and in 46 hands (92%), there was second insertion to the trapezium bone. Of all tendon-slips of APL (n = 126), 44% of tendons (68 tendons) were inserted into the base of the first metacarpal bone. This was followed by the insertion into the trapezium in 42% tendons (52 tendons).

CONCLUSION

Bi-tendinous APL is commonly observed on the dorsal compartment of the wrist in Indian population and these tendon-slips are commonly attached to the first metacarpal base and trapezium. This variation must be understood by the Indian Orthopedic surgeons as the response to treatment of DQT and reason for first carpo-metacarpal arthritis can be dependent on this anatomical variation.

Multiple variations of the tendons of the anatomical snuffbox

INTRODUCTION

Multiple tendons of the abductor pollicis longus (APL) in the anatomical snuffbox of the wrist can lead to the development of de Quervain's syndrome, which is caused by stenosing tenosynovitis. A cadaveric study was performed to establish the variations present in the tendons of the anatomical snuffbox in a Malaysian population, in the hope that this knowledge would aid clinical investigation and surgical treatment of de Quervain's tenosynovitis.

METHODS

Routine dissection of ten upper limbs was performed to determine the variations in the tendons of the anatomical snuffbox of the wrist.

RESULTS

In all the dissected upper limbs, the APL tendon of the first extensor compartment was found to have several (3-14) tendon slips. The insertion of the APL tendon slips in all upper limbs were at the base of the first metacarpal bone, trapezium and fascia of the opponens pollicis muscle; however, in seven specimens, they were also found to be attached to the fleshy belly of the abductor pollicis brevis muscle. In two specimens, double tendons of the extensor pollicis longus located in the third extensor compartment were inserted into the capsule of the proximal interphalangeal joints before being joined to the extensor expansion. In two other specimens, the first extensor compartment had two osseofibrous tunnels divided by a septum that separated the APL tendon from the extensor pollicis brevis tendon.

CONCLUSION

Multiple variations were found in the anatomical snuffbox region of the dissected upper limbs. Knowledge of these variations would be useful in interventional radiology and orthopaedic surgery.

Estudo de publicações em periódicos gerais de artigos sobre ortopedia e aparelho locomotor

Os autores estudam o perfil de publicação de artigos sobre ortopedia e área de interesse em aparelho locomotor em revistas gerais, não específicas de ortopedia, com registro no PUBMED, em um período de dois anos. Selecionados 67 artigos com distribuição heterogênea entre as revistas estudadas foi constatada presença de 26,47% de artigos com desenho de intervenção e 38% com desenho observacional. Os dados são comentados.