Lab3 - Module 2 - Anatomy of the Arm and Forearm: Page 3 of 11

The Elbow Joint

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Add the Bones of the Elbow. This is a hinge type of synovial joint formed by the distal end of the humerus with the proximal ends of the radius and ulna. The elbow is uniaxial and its movements consist of flexion and extension. The elbow joint consists of three different articulations:

Rotate to view the Humeroradial articulation. The articulation between the capitulum of the humerus and the head of the radius.

• Allows flexion and extension. The humeroradial joint is considered a hinge joint.

• Anatomically is a ball-and-socket joint.

• The radial head butts up against the capitellum.

• The capitellum acts as a buttress for lateral compression.

• Absorbs lateral compression and other rotational forces during throwing or other rapid forearm movements

Rotate to view the Humeroulnar articulation. The articulation between the trochlea of the humerus and trochlear notch of the ulna.

• Allows flexion and extension of the elbow joint. It is considered a hinge joint.

• The trochlear notch offers good structural stability.

• The trochlea is asymmetrical in shape.

• In the extended position, this asymmetry creates an angulation of the ulna laterally, resulting in a valgus position. This angulation is termed the carrying angle. 10-15° in males and 15-20° in females.

Rotate to view the Proximal Radioulnar articulation. The articulation between the head of the radius and the radial notch of the ulna.

• Pivot Joint that allows pronation and supination of the forearm.