Arm, Elbow, and Cubital Region

Supination occurs _______

As the radial head spins on the capitulum

Epicondyles

Bumpy areas on the distal end of the humerus that are the primary sites of muscle attachment; medial and lateral

The olecranon process is in close approximation to the distal humerus in the olecranon fossa in what position of the elbow?

Extension

The elbow is most stable in which position?

Extension (the olecranon is locked right into the distal humerus, so there is lots of bony stability)

The olecranon process pulls away from the distal humerus in what position of the elbow?

Flexion

Which three elbow joints share a joint cavity?

Humeroulnar, humeroradial, and proximal radioulnar

Four joints in the elbow region

Humeroulnar, humeroradial, proximal radioulnar, distal radioulnar

Trochlea

Lateral region of the condyle that articulates with the ulna

Annular Ligament

Ligament that encircles the head of the radius and holds it against the ulna; provides stability at the humeroradial joint and protects against distal dislocation of the radius

Medial (Ulnar) Collateral Ligament

Ligament that runs from the epicondyle of the humerus to the coronoid process and olecranon process; protects against valves (lateral) deviation of the forearm

Lateral (Radial) Collateral Ligament

Ligament that runs from the lateral epicondyle to the annular ligament of the radius; protects against virus (medial) deviation of the forearm

Capitulum

Medial region of the condyle that articulates with the radius

Humeroradial Joint

Modified hinge joint that is responsible for flexion/extension and some rotation of the elbow

Supination/pronation occurs:

Primarily at the proximal and distal radioulnar joints; there is associated rotation at the humeroradial joint

Three fossae in the distal humerus

Radial and coronoid (anterior), olecranon (posterior)

Boundaries of the cubital fossa:

Superior: an imaginary line connecting the medial and lateral epicondyles Medial: pronator teres Lateral: brachioradialis

Cubital Fossa

The triangular hollow area on the anterior aspect of the elbow

Why does the radius spin and the ulna does not?

The ulna is locked into the olecranon fossa while the radius has a flat head that can spin

Condyle

articulating surface with two regions: capitulum and trochlea; at the distal end of the humerus; smooth and covered with cartilage

Proximal Radioulnar Joint

Uniaxial joint in the elbow region responsible for supination/pronation of the hand (turning palm up/turning palm down)

Distal Radioulnar Joint

Uniaxial joint responsible for supination/pronation of the hand

Humeroulnar Joint

Uniaxial joint that is responsible for flexion/extension of the elbow