Elbow Joint Anatomy & Function: A Complete Guide for Students

1. Introduction

  • The elbow joint is a hinge type of synovial joint.
  • It connects the arm (humerus) with the forearm (radius and ulna).
  • Allows mainly flexion and extension.

2. Articular Surfaces

  • Between:
    • Lower end of humerus:
      • Trochlea → articulates with ulna
      • Capitulum → articulates with head of radius
    • Upper end of radius and ulna:
      • Trochlear notch of ulna fits the trochlea
      • Head of radius fits the capitulum

3. Ligaments

  • Capsule – Encloses the joint
  • Ulnar collateral ligament (medial side)
  • Radial collateral ligament (lateral side)
  • Annular ligament – Encircles head of radius (helps in supination-pronation)

4. Relations

Anterior

  • Brachialis muscle
  • Median nerve
  • Brachial artery

Posterior

  • Triceps muscle
  • Olecranon process
  • Ulnar nerve (runs behind medial epicondyle)

Medial

  • Ulnar nerve
  • Medial epicondyle of humerus

Lateral

  • Radial nerve
  • Lateral epicondyle of humerus

Superior

  • Lower end of humerus

Inferior

  • Upper ends of radius and ulna
  • Biceps tendon and brachialis muscle

5. Blood Supply

  • Anastomosis around elbow formed by:
    • Brachial artery
    • Radial artery
    • Ulnar artery
    • Profunda brachii

6. Nerve Supply

  • Supplied by:
    • Median nerve
    • Radial nerve
    • Ulnar nerve
    • Musculocutaneous nerve

7. Movements of the Elbow Joint

  • Flexion – by Biceps brachii, Brachialis, Brachioradialis
  • Extension – by Triceps brachii, Anconeus

8. Clinical Anatomy

  • Dislocation – Common in children
  • Tennis elbow – Pain on lateral side due to overuse (lateral epicondylitis)
  • Golfer’s elbow – Pain on medial side (medial epicondylitis)
  • Fracture of olecranon – Affects triceps extension
  • Ulnar nerve injury – “Funny bone” pain when struck


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