Elbow or Cubital joint

Elbow or Cubital joint is a composite joint consisting of –

1. Humero-radio-unlar articulation
2. Radio-ulnar articulation

Humero-radio-unlar articulation

Ox

• It is a ginglymus formed between the distal extremity of Humerus and the proximal ends of radius and ulna. The articular surfaces are the condyles of the Humerus and concavities on the proximal extremity of radius and the semilunar notch of the ulna.
  • Ligaments
    1. Capsular ligament forms a pouch over the olecranon fossa
    2. Medial and Lateral collateral ligaments attached above on the respective faces of the distal extremity of the humerus and the medial and lateral tuberosities of the upper extremity to the radius.
    3. The medial ligament consists of a superficial part attached to the medial border of the radius below the radial tuberosity and a deep part attached to the medial tuberosity.
  • Motion
    1. Extension and flexion.

Horse

• No difference.

Dog

• The capsule is strengthened by two bands.
• One is in front, which is oblique and arising in front of the lateral condyle of humerus above the joint surface joins the terminal part of biceps and brachialis below:
• The other is on the postero medial aspect from the medial side of olecranon fossa (or the lateral aspect of medial epicondyle) to the ulna just above the anconeus process and the lateral ligaments are attached below to the radius and ulna. 

Radio-ulnar articulation

Ox

• It is a diarthrosis and an amphiarthrosis formed between the radius and ulna.
• The diarthrosis is formed between the facets on the ulna and corresponding facets of the radius.
• Ligaments
  1. Capsular ligament-continuous with that of the humero-radio articulation.
  2. The amphiarthrosis is formed between the shafts of the radius and ulna. One above the proximal radio ulnar arch, second between the two radio ulnar arches and the third below the distal radio ulnar arch.
  3. Three interosseous ligaments, which ossify in the adult.
  4. In addition, there are two arciform ligaments, lateral and medial which are attached to lateral aspect of the olecranon process of the ulna.
• Motion
  • Is inappreciable, the forearm being fixed in the position of pronation.

Horse

• There is only one inter-osseous ligament.
• Two bones above the proximal ulnar arch are not ossified till late in life.

Dog

• The joints between the radius and ulna at either end are trochoid. The proximal joint has in addition to the capsular ligament, an annular ligament that arises from the lateral condyle of the humerus and joins the terminal part of the brachialis and the biceps brachii.
• The distal joint has a tight capsular ligament.
• The shafts are united by interosseous ligaments.
  • Motion
    1. Limited supination is possible with the lateral rotation of the radius carrying the paw with it.