0 a short muscle under the collarbone (= the bone that goes from the top of the arms to the bottom of the neck) --
Nerve to subclavius labeled at top center.
Medially, it blends with the fascia covering the first two intercostal spaces, and is attached also to the first rib medial to the origin of the subclavius.
At the lateral side of inferior surface, there is a subclavian groove for insertion of the subclavius muscle.
Just as with supplying the subclavius muscle, it anastomoses with the thoracoacromial artery in supplying skin areas.
It is in relation, in front, with the tendon of origin of the subclavius; behind, with the subclavian vein.
It occupies the interval between the pectoralis minor and subclavius, and protects the axillary vessels and nerves.
At the nerve trunk, branches of suprascapular nerves and the nerve to the subclavius also merge.
Most often it is a branch of the nerve to the subclavius and may contain numerous phrenic nerve fibers.
