An unusually distal and complete additional flexor profundus muscle to the index finger

Abstract

Anomalous muscles in the first flexor compartment of the forearm are quite common. Flexor digitorum superficialis (FDS) is a well known example (Kernohan et al. 1984; Ametewee et al. 1985; Elias et al. 1985; Tonkin & Lister, 1985). However, the anatomical variations of muscles, for example flexor digitorum profundus (FDP) in the second flexor compartment, are not rare (Hollinshead, 1969; Williams & Warwick, 1980; Honing et al. 1995; Williams et al. 1995). These muscles are usually asymptomatic and discovered incidentally during anatomical dissection or at operation. However, they may be symptomatic, presenting as an enlarging tumour-like mass simulating a ganglion (Vichare, 1970; Hayes, 1974; Murakami & Todani, 1982) or may cause a compression neuropathy (Hutton & Kernohan, 1981; Simodynes & Cochran, 1981).