An unusual elbow muscle in the red howler monkey: does it deserve invention of a new name musculus contrahens cubiti?статья
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 23 ноября 2017 г.
Аннотация:During dissection of a juvenile specimen of howler monkey (Alouatta seniculus),
we discovered a supernumerary muscle. This muscle originates from the lateral
epicondyle of the humerus, distal to the m. brahioradialis and beneath the m. extensor
carpi radialis longus, and runs deeply to insert on the proximal part of the radius
adjacent to the m. supinator.
To determine homology of the unusual muscle, we compared it with the known
abnormal extra muscles in the group of preaxial forearm extensors in humans and
other primates, as well as other mammals. The only similar muscle is the so-called
m. brachioradialis accessorius, which is very rarely found in humans medial to the
n. radialis r. superficialis. Both in howlers and humans, its unique topological interrelations
with the n. radialis suggest that this muscle is fundamentally different from all
surrounding forearm extensors including the proper m. brachioradialis. At the same
time, its innervation by the n. radialis confirms that it is a true extensor, contrary to
the reptilian m. tractor radii.
The general problem of identifying homology of anomalies and novelties is
considered. As the enigmatic muscle departs from rules of myological architecture
of the tetrapod forelimb, we failed to establish its general homology and, instead,
suggest naming it as m. contrahens cubiti. This means that the muscle acts as the
elbow flexor although it intimately belongs to extensors.