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Elbow Joint

Quick Reference​

PropertyDetails
Joint TypeHinge joint (humeroulnar) + Pivot joint (radioulnar)
BonesHumerus, Radius, Ulna
Degrees of Freedom2 (flexion/extension, pronation/supination)
Key LigamentsUlnar Collateral Ligament (UCL), Radial Collateral Ligament (RCL), Annular Ligament
Key StructuresMedial epicondyle, Lateral epicondyle, Olecranon, Trochlea, Capitulum
Primary ActionsFlexion, Extension, Pronation, Supination
Common IssuesTennis elbow, Golfer's elbow, UCL tears, Cubital tunnel syndrome

Anatomy​

The elbow is a complex joint comprised of three distinct articulations within a single joint capsule, allowing for both hinging and rotational movements of the forearm.

The Three Joints​

Humeroulnar Joint: The primary hinge joint between the trochlea of the humerus and the trochlear notch of the ulna. This articulation is responsible for flexion and extension movements and provides the majority of elbow stability due to its deep bony congruency.

Humeroradial Joint: A secondary articulation between the capitulum of the humerus and the head of the radius. This joint contributes to both flexion/extension and allows the radius to rotate during pronation and supination.

Proximal Radioulnar Joint: A pivot joint between the radial head and the radial notch of the ulna. The annular ligament wraps around the radial head, holding it against the ulna while allowing rotation. This joint is crucial for forearm rotation.

Ligamentous Support​

The Ulnar Collateral Ligament (UCL) complex on the medial side consists of anterior, posterior, and transverse bands. The anterior bundle is the primary restraint to valgus stress and is commonly injured in throwing athletes.

The Radial Collateral Ligament (RCL) complex on the lateral side provides resistance to varus stress and includes the lateral ulnar collateral ligament (LUCL), which prevents posterolateral rotatory instability.

The Annular Ligament encircles the radial head, maintaining the radioulnar relationship while permitting rotation.

Clinical Landmarks​

The medial and lateral epicondyles serve as attachment points for forearm flexor and extensor muscles, respectively. The olecranon process of the ulna forms the bony point of the elbow posteriorly and provides the attachment for the triceps tendon.

Range of Motion​

MovementNormal RangeFunctional RangeNotes
Flexion0-145°30-130°End feel: soft tissue approximation
Extension0°Full extensionSome people have 5-10° hyperextension
Pronation0-90°50-75°Measured with elbow at 90° flexion
Supination0-90°50-75°Measured with elbow at 90° flexion

Functional Arc: Most daily activities occur within 30-130° of flexion and 50° of pronation and supination from neutral.

Carrying Angle: Normal valgus angle of 5-10° in males and 10-15° in females when the arm is fully extended and supinated.

Joint Actions​

Elbow Flexion​

Flexion brings the forearm toward the upper arm, decreasing the angle at the elbow joint.

Prime Movers:

  • Biceps Brachii: Most powerful flexor when forearm is supinated
  • Brachialis: Primary flexor in all forearm positions
  • Brachioradialis: Most effective when forearm is in neutral/pronated position

Assistance: Pronator teres, forearm flexors (when performing grip activities)

Range: 0-145°

Muscles Acting On It​

Flexors​

Biceps Brachii

  • Origin: Short head from coracoid process; long head from supraglenoid tubercle
  • Insertion: Radial tuberosity and bicipital aponeurosis
  • Actions: Elbow flexion (especially when supinated), forearm supination, weak shoulder flexion
  • Note: Most effective flexor when the forearm is supinated

Brachialis

  • Origin: Distal half of anterior humerus
  • Insertion: Coronoid process and ulnar tuberosity
  • Actions: Pure elbow flexion (unaffected by forearm position)
  • Note: The "workhorse" of elbow flexion

Brachioradialis

  • Origin: Proximal lateral supracondylar ridge of humerus
  • Insertion: Lateral styloid process of radius
  • Actions: Elbow flexion (most effective in neutral/pronated position), returns forearm to neutral
  • Note: Only forearm muscle that crosses the elbow joint

Extensors​

Triceps Brachii

  • Origin: Long head from infraglenoid tubercle; lateral and medial heads from humerus
  • Insertion: Olecranon process of ulna
  • Actions: Elbow extension; long head assists with shoulder extension and adduction
  • Note: Comprises approximately 2/3 of upper arm mass

Anconeus

  • Origin: Lateral epicondyle of humerus
  • Insertion: Lateral olecranon and proximal ulna
  • Actions: Assists with elbow extension, stabilizes elbow joint
  • Note: Small triangular muscle, sometimes considered part of triceps

Pronators​

Pronator Teres

  • Origin: Medial epicondyle of humerus and coronoid process of ulna
  • Insertion: Middle of lateral radius
  • Actions: Forearm pronation, assists with elbow flexion
  • Note: Forms medial border of cubital fossa

Pronator Quadratus

  • Origin: Distal anterior ulna
  • Insertion: Distal anterior radius
  • Actions: Primary pronator for fine motor control
  • Note: Deepest muscle of anterior forearm

Supinators​

Supinator

  • Origin: Lateral epicondyle, supinator crest of ulna
  • Insertion: Proximal lateral radius
  • Actions: Forearm supination
  • Note: Wraps around proximal radius; posterior interosseous nerve passes through it

Biceps Brachii

  • Also functions as a powerful supinator (see Flexors section above)

Mobility Work​

Stretches​

Wrist Flexor Stretch (for Golfer's Elbow)

  1. Extend arm forward with palm facing up
  2. Use opposite hand to gently pull fingers back toward body
  3. Keep elbow straight
  4. Hold 30 seconds, repeat 3 times

Wrist Extensor Stretch (for Tennis Elbow)

  1. Extend arm forward with palm facing down
  2. Use opposite hand to gently push fingers down and toward body
  3. Keep elbow straight
  4. Hold 30 seconds, repeat 3 times

Biceps Stretch

  1. Stand in doorway with arm extended behind, thumb pointing down
  2. Place palm against doorframe at shoulder height
  3. Gently rotate body away from extended arm
  4. Hold 30 seconds, repeat 3 times

Triceps Stretch

  1. Raise one arm overhead and bend elbow
  2. Use opposite hand to gently pull elbow behind head
  3. Hold 30 seconds, repeat 3 times

Joint Mobilizations​

Elbow Flexion/Extension Mobilization

  1. Sit or stand with elbow supported
  2. Use opposite hand to gently assist end-range flexion
  3. Apply gentle overpressure for 2-3 seconds
  4. Repeat 10 times, then perform with extension

Forearm Rotation Mobilization

  1. Sit with elbow bent to 90° and supported
  2. Hold forearm near wrist with opposite hand
  3. Gently rotate into pronation and supination
  4. Apply gentle overpressure at end range
  5. Perform 10 repetitions each direction

Soft Tissue Work

  • Foam rolling for triceps and biceps
  • Massage ball work for forearm flexors and extensors
  • Cross-friction massage for tendinopathy

Common Issues​

Lateral Epicondylitis (Tennis Elbow)​

Description: Tendinopathy of the common extensor tendon, primarily affecting the extensor carpi radialis brevis.

Symptoms: Pain on the lateral elbow, especially with gripping, lifting, or wrist extension activities.

Common Causes: Repetitive wrist extension, gripping activities, poor technique in racquet sports.

Management:

  • Rest and activity modification
  • Eccentric strengthening exercises
  • Forearm stretching
  • Proper ergonomics and technique correction
  • Counterforce bracing

Medial Epicondylitis (Golfer's Elbow)​

Description: Tendinopathy of the common flexor tendon, affecting the pronator teres and flexor carpi radialis.

Symptoms: Pain on the medial elbow, worsened by wrist flexion, gripping, and pronation.

Common Causes: Repetitive wrist flexion, gripping, throwing activities, golf (especially with poor technique).

Management:

  • Activity modification
  • Eccentric strengthening
  • Flexor stretching
  • Technique modification
  • Gradual return to activities

Ulnar Collateral Ligament (UCL) Injury​

Description: Sprain or tear of the UCL, most commonly the anterior bundle.

Symptoms: Medial elbow pain, instability sensation, loss of throwing velocity, sometimes with ulnar nerve symptoms.

Common Causes: Repetitive overhead throwing, acute valgus stress to the elbow.

Management:

  • Partial tears: Rest, strengthening, gradual return to throwing
  • Complete tears: Often require surgical reconstruction (Tommy John surgery)
  • Prevention through proper mechanics and arm care programs

Cubital Tunnel Syndrome​

Description: Compression or irritation of the ulnar nerve at the cubital tunnel (medial elbow).

Symptoms: Numbness and tingling in ring and small fingers, weak grip, elbow pain.

Common Causes: Prolonged elbow flexion, leaning on elbows, repetitive elbow motion, direct trauma.

Management:

  • Avoid aggravating positions
  • Nerve gliding exercises
  • Night splinting to prevent full flexion
  • Activity modification
  • Surgical decompression if conservative treatment fails

Olecranon Bursitis​

Description: Inflammation of the bursa over the olecranon process.

Symptoms: Swelling at the tip of the elbow, possible pain, warmth, and redness if infected.

Common Causes: Repetitive pressure on elbow, direct trauma, infection, inflammatory conditions.

Management:

  • Avoid pressure on elbow
  • Ice and compression
  • Aspiration if large
  • Antibiotics if infected
  • Surgical removal if chronic

Elbow Hyperextension Injury​

Description: Injury to anterior capsule, brachialis muscle, or collateral ligaments from forced extension beyond normal range.

Symptoms: Anterior elbow pain, swelling, limited extension, possible instability.

Common Causes: Fall on outstretched hand, contact sports, gymnastics.

Management:

  • Immobilization in slight flexion initially
  • Gradual ROM exercises
  • Strengthening program
  • Bracing during return to activity

Shoulder​

The shoulder and elbow work in coordination to position the hand in space. Shoulder dysfunction or limited mobility can increase stress on the elbow joint, particularly in overhead athletes. Scapular stability is crucial for optimal elbow function.

Key Relationships:

  • Long head of biceps and triceps cross both joints
  • Throwing mechanics require synchronized shoulder-elbow action
  • Shoulder ROM restrictions can increase elbow compensations

Wrist​

The wrist and elbow are mechanically linked through the forearm bones and muscles that cross both joints. Many forearm muscles originate at the elbow and insert at the wrist, creating a functional kinetic chain.

Key Relationships:

  • Common flexor and extensor origins at the elbow affect wrist function
  • Forearm rotation affects wrist position and hand orientation
  • Grip strength activities load both the wrist and elbow simultaneously

Radioulnar Joints​

The proximal radioulnar joint at the elbow works in conjunction with the distal radioulnar joint at the wrist to produce forearm rotation.

Key Relationships:

  • Both joints must be mobile for full pronation/supination
  • Restriction at one joint increases stress on the other
  • Interosseous membrane connects radius and ulna along their length

Sources​

  1. Neumann DA. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 3rd ed. Elsevier; 2017.

  2. Magee DJ. Orthopedic Physical Assessment. 7th ed. Elsevier; 2021.

  3. Morrey BF, Sanchez-Sotelo J. The Elbow and Its Disorders. 4th ed. Saunders; 2008.

  4. American Academy of Orthopaedic Surgeons. Joint Motion: Method of Measuring and Recording. AAOS; 1965.

  5. Safran MR. Elbow injuries in athletes: a review. Clin Orthop Relat Res. 2004;419:130-143.

  6. Ahmad CS, ElAttrache NS. Elbow valgus instability in the throwing athlete. J Am Acad Orthop Surg. 2006;14(12):693-700.

  7. Nirschl RP, Ashman ES. Elbow tendinopathy: tennis elbow. Clin Sports Med. 2003;22(4):813-836.

  8. Purcell SB, Channell BT, Schoch BS, et al. Clinical examination of the elbow. Curr Rev Musculoskelet Med. 2017;10(4):449-458.