Anatomy of Elbow joint

Elbow anatomy includes the elbow joint which is a complex joint and structures surrounding it.

The bones of Elbow Joint

• the lower end of humerus (arm bone)
• the upper end of radius (forearm bone)
• the upper end of ulna (forearm bone)

Elbow consists of three joints

• between humerus and ulna (ulno-humeral)
• between humerus and radius (radio-humeral)
• between ulna and radius (radio-ulnar joint)

Part of the ulna that articulates with the humerus includes the olecranon process and the coronoid process. Corresponding part of humerus that articulates with these processes is called trochlea.

The head of the radius articulates with the capitulum of the humerus.

Ligaments of elbow joint

Two ligaments are present in the elbow joint.

1. the ulnar collateral ligament and
2. the radial collateral ligament

The ulnar collateral ligament is a strong fan shaped condensation of the fibrous joint capsule. It is located on the medial side of the joint, extending from the medial epicondyle of the humerus to the proximal portion of the ulna. This ligament prevents excessive abduction of the elbow joint.

The radial collateral ligament is also a strong fan shaped condensation of the fibrous joint capsule. It is located on the lateral side of the joint, extending from the lateral epicondyle of the humerus to the head of the radius. This ligament prevents excessive adduction of the elbow joint.

The different movements of elbow joint

• Flexion (touch the shoulder with the finger tips of the same side)
• Extension (straighten your upper limb)
• Supination (palm facing upwards)
• Pronation (palm facing downwards)

Flexion and extension occur mainly at the ulno-humeral joint. Supination pronation occurs at the radio-ulnar joint.

Muscles acting across the elbow joint

• biceps brachii (responsible for supination and flexion)
• brachialis (causes flexion)
• triceps (causes extension)
• pronator teres (causes pronation)

Different important nerves pass close to the elbow joint.

1. The ulnar nerve passes just behind the medial epicondyle.
2. The radial nerve passes anterior to the lateral epicondyle. Median nerve and brachial artery pass in front of the elbow.
3. Median nerve, ulnar nerve and brachial artery are at risk of injury in

• elbow dislocation
• supracondylar fracture of humerus

Sports and associated injuries of elbow joint

• Golf: Medial epicondylitis of trailing arm and lateral epicondylitis of leading arm
• Racquet sports: Lateral epicondylitis with backhand
• Bowling: Medial epicondylitis
• Baseball and volleyball: Valgus stress of medial structures and compression of lateral structures
• Weight training: Ulnar collateral ligament strain and ulnar neuritis
• Canoeing and kayaking: Distal bicipital tendinitis
• Archery: Lateral epicondylitis of bow arm
• Rock climbing: Distal bicipital and brachialis tendinitis
• Football: Valgus stress with throwing a pass