Elbow joint.

It is the hinge variety of synovial joint. It is situation between the lower end of humerus and upper end of radius and ulna bone. 

Bones involved - 

1. Humerus

2. Radius

3. Ulna

Articular surface - 

a. Upper articular surface 

1. Trochlea and capitulum of humerus.

b. Lower articular surface

1. Upper surface of head of radius with capitulum.

2. Trochlear notch of ulna with trochlea of humerus. 

Ligaments of elbow joint

1. Capsular ligament.

2. Ulnar collateral ligament.

3. Radial collateral ligament.

Relations 

1. Anterior 

Brachialis, median nerve, brachial artery and tendon of biceps brachii.

2. Posterior

Triceps brachii and anconeus.

3. Medially 

Ulnar nerve, flexor carpi ulnaris and common flexors.

4. Laterally 

Supinator, extensor carpi radialis brevis and other extensor muscles.

Blood supply 

Anastomoses around elbow joint.

Nerve supply 

1. Ulnar nerve

2. Median nerve 

3. Radial nerve

4. Musculocutaneous nerve

Movements

1. Flexion 

2. Extension

Muscles producing movements

1. Flexion 

a. Brachialis

b. Biceps brachii

c. Brachioradialis

2. Extension 

a. Triceps brachii

b. Anconeus

Note - Carrying angle 

When the forearm is in extension position then the transverse axis of the elbow joint is directed medially and downwards. Because forearm is not in the straight line with the arm. So it makes an angle of 13 degrees which is known as carrying angle. This carrying angle becomes null when the elbow is in full flexion condition.

Clinical anatomy 

1. Dislocation of the elbow 

(Usually posteriorly because of the weak capsule).

2. Pulled elbow or subluxation of the head of the radius which happens when forearm is suddenly pulled in pronated state.

3. Tennis elbow 

It happens in tennis players and there is abrupt pronation with the fully extended elbow. It leads to pain and tenderness over lateral epicondyl.

4. Student's elbow

Bursae on olecranon process gets inflammed.

5. Golfer's elbow 

Pain in common flexor origin