Accessory extensor pollicis longus

An unusual configuration of two anomalies in the extensor digitorum profundus complex in a human

The extensor digitorum profundus complex underwent degeneration of the ulnar segments during primate adaptation and evolution. This process resulted in the preservation of only the extensor pollicis longus and extensor indicis in some apes, including humans. Consequently, anatomical variations within the digitorum profundus complex in modern humans have been well-documented, with detailed reports on their frequency and patterns in previous studies. Here, we report an unusual arrangement involving two anomalies in the extensor digitorum profundus complex, identified in a 66-year-old Japanese male cadaver. In this cadaver, two accessory muscles differentiated from both the extensor pollicis longus and extensor indicis. Notably, the latter muscle featured a tendon bifurcating towards both the thumb and index fingers, referred to as the extensor pollicis et indicis communis. Under the extensor retinaculum, the tendon of the accessory extensor pollicis longus passed through an independent compartment, whereas that of the extensor pollicis et indicis communis traversed a compartment shared by the extensor indicis and the extensor digitorum communis. Both muscles were innervated by the posterior interosseous nerve. Previous studies have reported that the accessory slip of the extensor pollicis longus and extensor pollicis et indicis communis appear at frequencies of 0.6% and 0.4-1.4%, respectively. However, to the best of our knowledge, a configuration in which both appear simultaneously has not been reported. The data from this case could provide essential insights into the variations in the extensor digitorum profundus complex in humans and non-human primates.

Accessory Extensor Pollicis Longus Tendon Classification Modification

Supernumerary extensor pollicis longus (EPL) and extensor indicis proprius tendons are infrequently reported. There are few case reports on more than one accessory tendon in one individual. As a result, they are not represented in previously described classifications for variations in extensors to the thumb. Elective surgery was performed on a 57-year-old right-handed female. Within the fourth compartment, two anomalous accessory tendons were present. These tendons were identified as an accessory EPL tendon and an accessory extensor indicis proprius tendon. The normal EPL tendon occupied the third compartment ulnar to Lister's tubercle, as usual. The previous classification system for anomalous EPL tendons is useful in the organization and description of thumb extensor tendon variations. However, it is not a complete representation of the anomalies identified, including the one in this report. We have proposed an additional category for this classification system to better encompass the variation in anomalous tendon anatomy.

Solitary extensor tendon in the third compartment has a companion: variant course of extensor pollicis brevis in third extensor compartment

Anomalous variants of the extensor tendons in the first and third compartments of the wrist have been described following cadaveric study. Being aware of such variants during either an elective or emergency hand surgery will prove beneficial in the execution of the extensor tendon repairs. A very few clinical reports are available in the literature. We report a rare finding of extensor pollicis brevis tendon accompanying the solitary extensor pollicis longus tendon in the third compartment observed during an emergency trauma surgery.Level of evidence V.

Supernumerary extensor pollicis longus tendon masking an extensor pollicis longus rupture following non-surgical treatment of a distal radius fracture

Extensor pollicis longus tendon pathology is a recognised complication following non-surgical treatment of non-displaced distal radius fractures. Tendon entrapment typically presents with pain, but preservation of thumb retropulsion during complete rupture results in loss of active thumb retropulsion and tenodesis effect. We present the case of a 52-year-old woman who developed extensor pollicis longus tendon entrapment with full active thumb extension following a non-displaced distal radius fracture. During her elective third dorsal compartment release, the extensor pollicis longus tendon was found to be completely ruptured and a rare supernumerary extensor pollicis longus tendon was found emerging from the fourth dorsal compartment. Gentle traction of this tendon resulted in thumb interphalangeal joint extension and simultaneous index finger metacarpophalangeal joint extension. An extensor indicis proprius to extensor pollicis longus tendon transfer was performed. At her final 6-month follow-up, she had painless full active thumb motion comparable to her contralateral side.

Accessory extensor pollicis longus tendon in emergency surgery

Background

A true accessory extensor tendon of the thumb seems to be rare. We found a variation of the accessory extensor pollicis longus (EPL) tendon while performing an emergency surgical procedure. Identification of this accessory tendon during emergency surgery has not been previously reported.

Case presentation: A 43-year-old man presented to our hospital after sustaining a work-related injury involving a saw. During the operation, the tendons of the EPL, accessory EPL, and extensor pollicis brevis were severed. The lacerated tendon and tendon sheath were repaired, and the wrist and thumb were positioned in extension. The patient’s postoperative activity returned to normal without the need for a second tendon release operation.

Conclusions

Surgeons should be aware of this anatomic anomaly of the EPL tendon. Presentation of our case increases clinicians’ chances of preoperatively detecting this anomaly, which can improve surgical outcomes.

Accessory extensor pollicis longus: A rare tendon anomaly

This report provides a complete review of a rare anatomical variation, the accessory extensor pollicis longus (EPL) tendon and its clinical significance. We will describe a case of an asymptomatic accessory EPL that was found incidentally during surgery with a tendon located in the fourth extensor compartment. Pulling on it induced extension of the thumb interphalangeal joint. Very few cases of accessory EPL have been previously reported with various muscle origins and tendon insertions. In the literature, three symptomatic cases of accessory EPL were reported with a tendon running in a compartment other than the fourth. Although this variation is asymptomatic in most cases, knowledge of its existence might be useful in routine procedures to avoid inadvertent tendon damage, or during tendon repair.

A classification system for anomalies of the extensor pollicis longus

INTRODUCTION

Variations of the long extensor tendon to the thumb are very rare.

MATERIALS AND METHODS

We present three cases in which there was a supernumerary long extensor tendon to the thumb. In all three cases, the supernumerary tendon emerged from the fourth dorsal compartment and had a parallel course to the extensor pollicis longus.

RESULTS

Details of the anomalies are described along with a meta-analysis of relevant literature. A classification system of these anomalies is also proposed.

Double extensor pollicis longus tendon in independent extensor compartments: a case report of an anatomical variation requiring alteration of surgical strategy

The authors report the case of an anatomical variation with a double extensor pollicis longus tendon found during a dorsal approach to the wrist for rheumatoid arthritis. The accessory tendon was located in an additional separate wrist dorsal compartment, which is an extremely rare arrangement.