brachiocephalic muscle

The brachiocephalicus is a long and flat, complex of muscles that extends from the lower half of the humeral shaft to the head and neck. The muscle divides into two parts at the clavicular intersection. This is also the point of origin for all the muscles that make up the brachiocephalicus. This point is situated just cranial to the shoulder. The two main sections are the cleidobrachialis which is distal to the clavicular intersection and the cleidocephalicus which extends proximally to the clavivular intersection. The cleidocephalicus can also be divided into the pars cervicalis, which inserts on the broad aponeurosis, over the fibrous raphe of the cranial half of the neck. The other part, the pars mastoideus inserts on the mastoid process of the temporal bone via a strong tendon. The cleidobrachialis extends distally from the clavicular intersection and inserts on the cranial edge of the distal half of the humerus. The tendon that inserts the cleidobrachialis lies between the brachialis muscle and the biceps brachii. As a result of the brachiocephalicus spanning a large region it has the ability to provide a number of actions. These include extending the shoulder joint, protracts the limb, provides lateral movement of the head and allows the neck to be depressed.