Muscles of Arm

Anterior Compartment

Biceps Brachii

Muscle	Origin	Insertion	Nerve Supply	Action
Biceps Brachii	Long head: §  A long tendon from supraglenoid tubercle within the shoulder joint Short head: §  A thick tendon from the tip of coracoids process of scapula	§  A strong tendon into rough part of radial tuberosity §  Bicipital apponeurosis with deep fascia of forearm	§  Musculo-cutaneous nerve	Both head: §  Strong supinator when the elbow is flexed §  Flexor of elbow Short head: §  Weak flexor of shoulder joint Long head: §  Help stabilize the head of humerus in the glenoid cavity

Coracobrachialis

Muscle	Origin	Insertion	Nerve Supply	Action
Coraco-brachialis	§  Coracoids process of scapula	§  Middle of medial border of humerus	§  Musculo-cutaneous nerve	§  Flexor of the arm §  Weak adductor of the arm

Brachialis

Muscle	Origin	Insertion	Nerve Supply	Action
Brachialis	§  Lower half of anteromedial & anterolateral surface of humerus	§  Ulna tuberosity & rough impression on the anterior surface of coronoid process of ulna	Medial part: §  Musculo-cutaneous nerve Lateral part: §  Radial nerve	§  Flexor of the elbow joint

Posterior Compartment

Triceps Brachii

Muscle	Origin	Insertion	Nerve Supply	Action
Triceps Brachii	Long head: §  Infraglenoid tubercle (extracapsular & extrasynovial) Lateral head: §  Upper third of humerus above the spiral groove Medial head: §  Posterior surface of lower half of humerus shaft below spiral groove	§  The 3 head fuse together in a common tendon & inserted into the posterior part of upper surface of olecranon process of ulna	§  Each head receives a separate branch from the radial nerve	§  It is a powerful extensor of elbow joint Long head: §  Stabilized of the shoulder joint