first rib I

(redirected from costa prima I)

first rib [I]

[TA]
atypical rib having a single facet on its head, for articulation with the T1 vertebra, and the broadest, shortest and most sharply curved shaft; it also bears two transverse grooves on its superior surface for the subclavian vessels, separated by the scalene tubercle and ridge.
Synonym(s): costa prima [I] [TA]