muscles of upper arm Flashcards
2 fascial compartments
anterior and posterior
muscles of anterior compartment (3)
biceps brachii
coracobrachialis
brachialis
muscles of posterior compartment (2)
triceps brachii
aconeus
origin / insertion / innervation / action of biceps brachii
origin: coracoid process of scapula (short head) AND supraglenoid tubercle of scapula (long head)
insertion: radial tuberosity and forearm fascia (via bicipital aponeurosis)
innervation: musculocutaneous nerve (C5, C6!, C7)
action: supinates forearm AND if forearm = supinated, flexes forearm (short head stabilises GH joint)
origin / insertion / innervation / action of coracobrachialis
origin: coracoid process of scapula
insertion: middle third of medial humeral surface
innervation: musculocutaneous nerve (C5, C6!, C7)
action: helps flex and adduct arm (stabilises CH joint)
origin / insertion / innervation / action of brachialis
origin: distal half of anterior humeral surface
insertion: coronoid process of ulna
innervation: musculocutaneous nerve (C5, C6) and radial nerve (C6, C7)
action: flexes forearm in all positions
origin / insertion / innervation / action of triceps brachii
origin: infraglenoid tubercle of scapula (LONG head), superior to radial groove on the posterior humeral surface (LATERAL head), inferior to radial groove on posterior humeral surface (MEDIAL head)
insertion: proximal end of olecranon of ulna AND fascia of forearm
innervation: radial nerve (C6, C7!, C8!)
action: main extensor of forearm AND long head resists humeral dislocation during adduction
origin / insertion / innervation / action of aconeus
origin: lateral epicondyle of the humerus
insertion: lateral surface of olecranon AND superior part of posterior ulnar surface
innervation: radial nerve (C7, C8, T1)
action: assists triceps in extending forearm, stabilises elbow joint (MAY abduct ulna during pronation)