[TA] a small spine on the inner edge of the first rib, giving attachment to the scalenus anterior muscle, lying between and thus demarcating the grooves for the subclavian artery (anteriorly) and vein (posteriorly). SYN: tuberculum musculi scaleni anterioris [TA], Lisfranc tubercle, scalene tubercle of Lisfranc, tubercle of anterior scalene muscle.
