subclavian groove subclavian groove on the medial part of the clavicle is a broad rough surface, the costal tuberosity (rhomboid impression), rather more than 2 cm. in length, for the attachment of the costoclavicular ligament. the rest of this surface is occupied by a groove, which gives attachment to the subclavius; the coracoclavicular fascia, which splits to enclose the muscle, is attached to the margins of the groove. not infrequently this groove is subdivided longitudinally by a line which gives attachment to the intermuscular septum of the subclavius. subclavian grooveleft clavicle. inferior surface. (subclavian groove visible at center.)detailsidentifierslatinsulcus musculi subclaviita98a02.4.02.006ta21173fma23343anatomical terms of bone