A new classification of the brachial extensors in Tarsius
Matsumoto, S.; Yamada, T.K.; Ikeda, A.
Acta Anatomica 142(3): 267-271
1991
ISSN/ISBN: 0001-5180 PMID: 1796743 Document Number: 384870
The muscular system of the tarsier was first described by Burmeister (1846), who noted that brachial extensors (triceps complex) have six heads. The first three heads, respectively, correspond to the long, lateral and medial heads of the triceps brachii muscle in man. The fourth head is the anconaeus and the fifth is the dorsoepitrochlearis. Schultz (1984) divided the sixth head into two different parts (preaxial and postaxial) from the viewpoint of nerve supply. The present study found that the whole sixth head in innervated by the ulnar nerve, and we propose that it is recognized as the proximal and distal heads of the (preaxial) epitrochleoanconaeus muscle. The proximal head may have developed specially in the tarsier in addition to the distal head observed in other prosimians. It is thought to support the extension of the elbow joint and contribute to the tarsier's effective locomotion.