Photographic and Descriptive Musculoskeletal Atlas of Bonobos by unknow

Author:unknow
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

Comparison with common chimpanzees: In P. troglodytes it runs from the interosseous membrane and/or ulna and/or radius, to MI and trapezium; sometimes the muscle inserts also/instead onto the scaphoid and/or sesamoid bone adjacent to the trapezium, and occasionally the muscle extends to the proximal phalanx of digit 1. Apart from modern humans, in all of the primate specimens dissected by us only in hylobatids is there a distinct extensor pollicis brevis that is only partially blended, proximally, with the belly of the abductor pollicis longus (e.g., Diogo and Wood 2011, 2012). It should be noted that some authors have described an ‘extensor pollicis brevis’ and an ‘abductor pollicis longus’ in primate taxa other than hylobatids and modern humans, including common chimpanzees (see Synonymy below). For example, in gorillas the name ‘extensor pollicis brevis’ has been used (e.g., Hepburn 1892; Straus 1941a, b) to refer to a tendon of the abductor pollicis longus (sensu the present study) that inserts onto the proximal phalanx of the thumb (i.e., to the typical insertion point of the extensor pollicis brevis of modern humans). However, as stressed by authors such as Kaneff (1979, 1980a, b) and Aziz and Dunlap (1986) and corroborated by our dissections in gorillas, there is usually a single fleshy belly of the abductor pollicis longus that then gives rise to the so-called tendons of the extensor pollicis brevis and of the abductor pollicis longus; this configuration is usually also found in Pongo and Pan. Thus, contrary to the condition in Homo and hylobatids, in Pongo, Pan and Gorilla the extensor pollicis brevis is usually not present as a separate muscle. However, these two tendons present consistently in great apes clearly seem to be the precursors of the tendons of the abductor pollicis longus and of the extensor pollicis brevis of modern humans. In P. troglodytes the insertion of the abductor pollicis longus is onto the MI, the adjacent sesamoid bone and trapezium according to Hepburn (1892), Dwight (1895), and Sonntag (1923), to the scaphoid and MI according to Humphry (1867), to the sesamoid, scaphoid and MI according to Ziegler (1964), and to MI and trapezium according to Vrolik (1841), Wyman (1855), Wilder (1862), Huxley (1864), Champneys (1872), Hartmann (1886), Beddard (1893), Sutton (1883), Gratiolet and Alix (1866), Macalister (1871), MacDowell (1910), Ogihara et al. (2005), and according to our dissections. An insertion onto MI and trapezium is the common condition in Pan according to Gibbs (1999), and in the review of the literature done by Keith (1899) an extension to the proximal phalanx of the thumb was only found in 1 out of 20 Pan, while Sarmiento (1994) did not find such an extension in any of the two Pan specimens dissected by him, and in the review of the literature done by Sarmiento (1994) there was no such extension in 10 out of 10 Pan.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.