The costoclavicular ligament (rhomboid ligament) is the anatomic name of a ligament that is short, flat, strong, and rhomboid in form.


Attached below to the upper and medial part of the cartilage of the first rib, the costoclavicular ligament ascends obliquely backward and lateralward, and is fixed above to the costal tuberosity on the under surface of the clavicle.


It is in relation, in front, with the tendon of origin of the subclavius; behind, with the subclavian vein.