Arm Muscles

Triceps brachii: Action

1. Extension of forearm 2. Extension of arm

Aconeus: Action

1. Extension of forearm 2. Stabilize elbow joint against flexion or pronation-supination

Coracobrachialis: Action

1. Flexion of arm 2. Adduction of arm

Biceps brachii: Action

1. Flexion of arm 2. Flexion of forearm 3. Supination of forearm

Brachialis: Action

Flexion of forearm

Biceps brachii: Innervation

Musculocutaneous nerve

Brachialis: Innervation

Musculocutaneous nerve

Coracobrachialis: Innervation

Musculocutaneous nerve

Brachialis: Origin & Insertion

Origin: 1. Lower half of anterior surface of humerus 2. Intermuscular septa Insertion: 1. Ulnar tuberosity

Coracobrachialis: Origin & Insertion

Origin: 1. Coracoid process of scapula Insertion: 1. Anteromedial surface of midshaft of humerus

Anconeus: Origin & Insertion

Origin: 1. Lateral epicondyle of humerus Insertion: 1. Lateral side of olecranon of ulna

Triceps brachii: Origin & Insertion

Origin: 1. Long head- infraglenoid tubercle of scapula 2. Lateral head- posterior surface of humerus above/lateral to radial nerve & lateral intermuscular septum 3. Medial head- posterior surface of humerus below/medial to radial nerve & both intermuscular septa Insertion: 1. Proximal end of olecranon of ulna

Biceps brachii: Origin & Insertion

Origin: 1. Short head- tip of coracoid process of scapula 2. Long head- supraglenoid tubercle of scapula Insertion: 1. Radial tuberosity 2. Bicipital aponeurosis into fascia of forearm

Aconeus: Innervation

Radial nerve

Triceps brachii: Innervation

Radial nerve