elbow joint (cubital joint)

• 1.Joint Classification:

  Synovial hinge joint (with two articulations)
• 2. Axis of movement:

  One degree of freedom available (about a transverse axis)
• 3. Articular Surfaces:

  Humero-ulnar joint (medially)

  • Trochlea of humerus

  Almost circular pulley-shaped trochlea with oblique groove and tilted inferiorly on the medial side which creates the carrying angle

  Concave in frontal plane

  Convex in the sagittal plane

  • Trochlear notch of ulna

  Deep trochlear notch with ridge running from tip of olecranon to tip of coronoid process

  Congruent fit to groove on trochlea
• 3. Articular Surfaces:

  Humero-radial joint (laterally)

  • Capitulum of humerus

  Incomplete hemispherical shape with variable radius of curvature

  Covered in hyaline cartilage, thickest centrally

  • Superior concave surface head of radius

  All surfaces covered with hyaline cartilage

  Head of Radius

  Superior concave surface for articulation with captitulum

  Raised edge for capitulotrochlear groove
• 4. Joint Capsule:

  • Single fibrous capsule

  • Lined with synovial membrane

  • Shared with the superior radioulnar joint

  • No direct attachment to radius

  • Blends with collateral ligaments, which increase its strength

  • Weaker anteriorly and posteriorly
• 5. Ligaments:

  Ulnar Collateral Ligaments

  • Anterior band: From: Medial epicondyle (anteriorly) To: Coronoid process
  • Posterior band: From: Medial epicondyle (posteriorly) To: Olecranon
  • Transverse band: From: Coronoid process To: Olecranon
  • Intermediate band: From: Medial epicondyle To: Transverse band
  • Action: Limits abduction, Anterior band also helps limit extension
• 5. Ligaments:

  Radial Collateral Ligament - Strong triangular band (not as strong as ulnar collateral ligament)

  • From: Lateral epicondyle (deep to common extensor tendon)

  • To: Blends with annular ligament of the radius and margins of radial notch of ulna

  • Action: Limits Adduction
• Elbow Flexion:

  ROM: approx. 145 (active) 160 (passive)

  Created by: Brachialis, Biceps brachi, Brachioradialis

  Limited by: Soft tissue apposition, tension in the triceps, posterior joint capsule
• Elbow Extension:

  ROM: 0

  Created by: Triceps and anconeus (Actively)

  Limited by: Tension in the flexor muscles, anterior joint capsule, and possibly bony apposition (olecranon in olecranon fossa)