 | Term | Definition |
| |
humeroulnar joint |
trochlea of humerus and trochlear notch of ulna; resting position= 70 deg. flexion and 10 deg. supination; closed-packed= full ext. and supination |
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humeroradial joint |
capitulum of humerus and head of radius |
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proximal radioulnar joint |
head of radius and radial notch of ulna |
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distal radioulnar joint |
head of ulna and ulnar notch of radius |
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the relationship between humeroular and humeroradial joints |
function as a loose hinge joint, allowing 150 deg. flexion and 0 deg. extension |
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the relationship between proximal and distal radioulnar joints |
pivot joints that function together for 90 deg. supination and 90 deg. pronation |
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what happens during pronation |
the radial head spins and the radius crosses over the ulna |
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what happens during supination |
the radius and ulna lie parallel to each other |
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annular ligament |
wraps around the head of radius to stabilize the proximal radioulnar joint |
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medial collateral/ ulnar collateral ligament |
resist valgus forces |
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lateral collateral/ radial collateral ligament |
resist varus forces |
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interosseous membrane |
connects the shafts of the radius and ulna to add stability to the proximal and distal radioulnar joints, provide surface area for muscle attachment, and transmit WBing forces from the radius to the ulna |
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cubitus valgus |
carrying angle |
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Biceps brachii |
O= short head: coracoid process of scapula; long head: supraglenoid tubercle of scapula. I= radial tuberosity. F=elbow flexion and forearm supination, the long head helps with glenohumeral stabilization and flexion |
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musculocutaneous nerve (C5-6) innervates |
biceps brachii and brachialis |
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Brachialis |
O= anterior distal half of humerus. I= coronoid process and ulnar tuberosity. F= elbow flexion |
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brachioradialis |
O= lateral supracondylar ridge of humerus (just above the epicondyle). I= styloid process of radius. F= elbow flexion |
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radial nerve (C5-6) innervates |
brachioradialis |
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triceps brachii |
O= long head: infraglenoid tubercle of scapula; lateral head: posterior humerus, superior to the radial groove; medial head: posterior humerus, inferior to the radial groove. I= olecranon process of ulna. F= elbow extension; long head helps with shldr extension |
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radial nerve (C7-8) innervates |
triceps brachii and anconeus |
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anconeus |
O= lateral epicondyle of humerus. I= lateral olecranon and proximal posterior ulna. F= elbow extension ; stabilizes humeroulnar joint and assist the triceps with elbow extension |
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supinator |
O= lateral epicondyle of humerus and posterior ulna. I= proximal lateral radius. F= forearm supination |
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radial nerve (C6) innervates |
supinator |
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pronator teres |
O= medial epicondyle of humerus and coronoid process of ulna. I= lateral radius, midshaft. F= forearm pronation |
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median nerve (C6-7) innervates |
pronator teres |
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pronator quadratus |
O= anterior distal ulna. I= anterior distal radius. F= forearm pronation |
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median nerve (C8-T1) innervates |
pronator quadratus |
