The coracoid tubercle is an anatomical feature of the
pectoral skeleton in
archosaur
Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avian d ...
s, including
maniraptora
Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to ''Ornithomimus velox''. It contains the major subgroups Avialae, Deinonychosauria, Oviraptoros ...
n
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s. It is sometimes called the
biceps tubercle. It is also sometimes called the coracoid tuber or biceps tuber.
The coracoid tubercle is a prominent area on the anterior surface of the
coracoid, just
ventral to the shoulder socket (
glenoid
The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word ''glenoid'' is pronounced or (both are common) and is from el, gléne, "socket", reflecting the shoulder joint's ball-and-socket form. It is a sha ...
). The coracoid tubercle forms the pointed portion in those coracoids described as "flexed". It was previously called the biceps tubercle because it was thought to be the origin of the M.
biceps
The biceps or biceps brachii ( la, musculus biceps brachii, "two-headed muscle of the arm") is a large muscle that lies on the front of the upper arm between the shoulder and the elbow. Both heads of the muscle arise on the scapula and join ...
muscle. Makovicky & Sues (1998)
[ Makovicky, peter, Sues, Hans-Dieter. (1998) "Anatomy and Phylogenetic Relationships of the Theropod Dinosaur ''Microvenator celer'' from the Lower Cretaceous of Montana" "American Museum Novitates" no. 3420 27pp. 27 August 1998. ] followed Alick Walker (1990)
[Walker, A.D. (1990) "A revision of ''Sphenosuchus acutus'' Haughton, a crocodylomorph reptile from the Elliot Formation (Late Triassic or Early Jurassic) of South Africa." "Philosophical Transactions of the Royal Society of London B., Biological Sciences" 330:1-120] in asserting that it is, instead, probably the origin of the M.
coracobrachialis muscle. Thus, they preferred the term "coracoid tubercle". Norell and Makovicky (1999) followed this precedent and credited Osmolska (1972)
[ Osmolska, Halszka, Roniewicz, E., Barsbold, R. (1972) "Results of the Polish-Mongolian Palaeontological Expeditions-PartIV. A new dinosaur, ''Gallimimus bullatus'' n. gen. n. sp. (Ornithomimidae) from the Upper Cretaceous of Mongolia". "Palaontologica Polonica" 27:103-143] with their precise definition of "coracoid tubercle".
[ "Important Features of the Dromaeosaurid Skeleton II: Information from Newly Collected Specimens of ''Velociraptor mongoliensis''". "American Museum Novitates" 3282, pp.27 8 December 1999]
References
{{reflist
Dinosaur anatomy