The biceps brachii (biceps flexor cubiti) is a two-headed arm muscle that consists of the long head (caput longum), and the short head (caput breve). The long head originates from the supraglenoid tuberosity of the scapula and the short head originates from the coracoid process. The muscle extends from the shoulder to the elbow where the biceps tapers into a flat, strong tendon that inserts in the tuberosity on the upper end of the radius. It is innervated by the musculocutaneous nerves (5th and 6th crevical nerves) and is supplied by branches of the brachial artery. This muscle is the main flexor of the elbow joint. When working with other nearby muscles, it can also move the shoulder, since its upper ends are attached to the scapula. In addition it can twist the lower arm so that the palm faces outward, a movement called supination. The biceps and the triceps work together to control the up and down movement of the forearm. Research Biceps Brachii
The coracobrachialis or 'Casser's perforated muscle' is the smallest muscle in the upper arm region. It originates from the coracoid process of the scapula and inserts in the medial border of the humerus. The coracobrachialis is innervated by the musculocutaneous nerve and supplied by the brachial artery. This muscle is a somewhat superficial muscle and can be partially seen on the inside of the upper arm near the arm pit when the arm is raised. It runs alongside, but separate from, the short head of the biceps brachii. It flexes and adducts the arm at the shoulder joint. Research Coracobrachialis
The triceps brachii (three-headed muscle) lies at the upper portion of the inside of the arm. It is the main extensor of the arm and is made up of three teardrop shaped heads: the long head, the lateral head, and the medial head. When working with other nearby muscles it can also move the shoulder, since its upper ends are attached to the scapula. The long head (caput longum), the largest of the three heads, originates from the scapula just below the rounded socket of the shoulder joint, and extends almost three-fourths of the way toward the front of the arm. The lateral head (caput laterale) originates below the greater tubercle of the humerus and lies on the back and side of the upper arm. The medial head (caput mediale) originates below the radial groove and curves around the back of the humerus and is mostly covered by the long head. The lower end of the muscle inserts in the flattened end of the ulna (olecranon). This muscle is innervated by the radial nerve and supplied by muscular branches of the brachial artery. The triceps brachii extend the forearm at the elbow joint. It works with the biceps brachii to control the up and down movement of the forearm. Research Triceps
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Biceps Brachii
