part of part of Homo sapiens rib 1 surface groove groove for subclavian artery of first rib 2026-03-19T00:00:00Z A surface groove on the superior surface of the first rib, located posterior to the scalene tubercle, that lodges the subclavian artery as it passes over the rib between the anterior and middle scalene muscles. This groove is a distinctive feature of the first rib and is absent on all other ribs. David Osumi-Sutherland