Anomalous extensor tendons to the long finger: a cadaveric study of incidence

Abstract

Purpose: To evaluate the incidence and anatomic insertion sites of extensor medii proprius and extensor indicis medii communis tendons to the long finger in cadaveric dissection and to describe the insertion of the extensor medii proprius.

Methods: Thirty randomly selected adult cadavers, 44 upper extremities, were examined for the presence or absence of an anomalous extensor tendon to the long finger. If present, tendon origin and insertion sites were documented, and the width of the tendon was evaluated.

Results: The extensor medii proprius was observed in 4 of 44 extremities, an incidence of 9%. The extensor indicis medii communis was observed in 7 of 44 extremities, an incidence of 16%. Tendon widths for both the extensor medii proprius and extensor indicis medii communis specimens ranged from 1.5 to 3.0 mm.

Conclusions: The incidence of an anomalous slip of tendon to the long finger might be higher than previously reported, with a combined incidence of 25% in this cadaveric study. This anomalous slip can be a resource for surgical reconstruction.

Clinical relevance: The presence of anomalous tendinous slips to the long finger can be easily overlooked. Understanding the anatomical relationships, incidence, and donor tendon availability of these anomalous tendons might aid with surgical planning.