14. Elbow joint (Flexion/Extension) Flashcards
Brachialis
Location
Origin
Insertion
Action
L- Strong muscle that is immediately deep to biceps brachii on distal humerus
O- anterior surface of distal humerus; embraces insertion of deltoid muscle
I- coronoid process of ulna and capsule of elbow joint
A- Flexes forearm (lifts ulna as biceps lifts the radius)
Triceps Brachii
Location
Origin
Insertion
Action
L- large fleshy muscle; the only muscle of posterior compartment of arm; three-headed origin; long and lateral heads lie superficial to medial head
O- long head; infraglenoid tubercle of scapula; lateral head; posterior shaft of humerus; medial head; posterior shaft of humerus distal to radial groove
I- by common tendon into olecranon of ulna
A- powerful forearm extensor (prime mover, particularly medial head). antagonist of forearm flexors;
Brachioradialis
Location
Origin
Insertion
Action
L-Superficial muscle of lateral forearm; forms lateral boundary of cubital fossa; extends from distal humerus to distal forearm; develops from extensor muscle grou
O- lateral supracondylar ridge at distal end of humerus
I- base of styloid process of radius
A- Synergist in forearm flexion; acts to best advantage when forearm is partially flexed and semipronated - carrying luggage, stabilizes elbow during rapid flexion and extension
Biceps barachii
Location
Origin
Insertion
Action
L- Two-headed fusiform muscle; bellies unite as insertion point is approached; tendon of long head helps stabilize shoulder joint
O- short head; coracoid process; long head;
I-
A-
