The muscles of the arm
M. Biceps brachii (the two-headed upper arm muscle)
Origin: Long head: supraglenoid tubercle and glenoid labrum
Short head: tip of the coracoid process
Insertion: radialtuberosity and forearm fascia
Function: flexion and supination of the elbow, flexion of the shoulder joint
M. Triceps brachii (the three-headed upper arm muscle)
Origin: Caput longum: infraglenoid tubercle
Caput mediale: Distal two-thirds of the humerus
Caput laterale: Proximal third of the humerus, proximal to the radial nerve groove
Insertion: olecranon and joint capsule
Function: Elbow extension, adduction, and shoulder joint extension
The flexor muscles of the forearm
Origin: anterior aspect of the medial humeral condyle, anterior aspect of the radius and ulna
Insertion: palmar aspect of the bones of the hand
Function: flexion of the wrist and fingers
Extensor muscles of the forearm (forearm extensors)
Origin: posterior surfaces ofthe radius and ulna
Insertion: dorsal surfaces of the bonesof the hand
Function: extension of the wrist and fingers
M. Coracobrachialis
Origin: Processus coracoideus
Insertion: Medial , middle portion of the humerus
Function: Flexion of the shoulder joint (forward movement of the arm) and, to some extent, adduction of the shoulder joint due to its medial insertion on the humerus.
Brachialis
Origin: Processus coracoideus
Insertion: Medial , middle portion of the humerus
Function: Flexion of the shoulder joint (forward movement of the arm) and, to some extent, adduction of the shoulder joint due to its medial insertion on the humerus.
Brachioradialis
Origin: Distal humerus; superior to the lateral humeral epicondyle
Attachment: Distal radius at the styloid process of the radius.
Function: Elbow joint flexion, particularly in a slightly pronated position with the thumb facing upward.
Images above: On the left is a cross-section of the forearm, with the brachioradialis muscle located at the top left. On the right is the anterior side of the forearm, with the brachioradialis muscle marked in blue.