the elbow - anatomy and common pathologies

• What type of joint is the elbow classified as?

  Synovial uniaxial hinge joint
• What bones make up the elbow joint?


  The distal end of the humerus and the upper ends of the radius and ulna
• What are the articulations of the elbow joint?

  • The trochlea and capitulum at the distal end of the humerus
  • The proximal ends of the radius and ulna
• What are the two joined articular regions at the distal end of the humerus?


  The grooved trochlea (medially) and rounded capitulum (laterally)
• With which part of the ulna does the trochlea articulate?


  The trochlear notch of the ulna
• With which part of the radius does the capitulum articulate?


  The head of the radius
• What type of cartilage covers the whole surface of the elbow joint?

  Hyaline cartilage
• What movements are available at the elbow joint?


  • Flexion
  • Extension
• What movements occur about the radioulnar joint associated with the elbow?


  • Supination
  • Pronation
• How does the elbow joint enable the hand and fingers to be placed in space?


  By allowing flexion and extension of the upper limb
• What is one function of the elbow joint related to carrying food to the mouth?


  It allows for shortening and lengthening of the upper limb
• What type of joint is the elbow in relation to the superior radioulnar joint?


  It is a synovial joint (hinge variety) that shares the same joint capsule
• What promotes a large range of flexion at the elbow?


  The projection of the two articular surfaces (distal ends of the humerus and trochlear notch of the ulna)
• What provides stability to the elbow joint?

  • The shape of articular surfaces
  • Collateral ligaments
  • Muscles crossing the joint
• carrying angle


  The forearm axis deviates laterally from that of the humerus, this deviation is referred to as the carrying angle

  Approximately 10-15 degrees in men and 20-25 degrees in women

  Disappears when the elbow joint is flexed

  Permits the forearm to clear the hips in swinging movements during walking and is important when carrying objects
• radial collateral ligament (aka lateral collateral ligament)


  Runs along the outside of the elbow

  Resists varus forces

  Proximal attachment:

  Lateral epicondyle-2 bands

  Distal attachment:

  Ant. band and post band both to annular ligament and radial notch
• ulnar collateral ligament (aka medial collateral ligament)


  Runs along the inside of the elbow

  Resists valgus forces

  Proximal attachment:

  Medial epicondyle-3 bands

  Distal attachment:

  Ant. band: Coronoid process and CFO

  Post. Band: Olecranon process

  Int. band: Between 2 other bands
• capsule

  • The joint capsule resembles a sac-like envelope that forms a sleeve around the synovial joint and encloses its cavity. It is a dense fibrous connective tissue that is attached to the bones via specialized attachment zones at the end of each involved bone.
  • Capsule attaches to edges of articular surfaces
  • Encloses superior radio-ulnar joint
  • Collateral ligaments blend with and strengthen capsule at the sides
  • Weak anteriorly and posteriorly
• What is the primary action of flexion in the elbow joint?

  Flexion decreases the angle between the forearm and the upper arm.
• Which nerve innervates the biceps brachii?

  Musculocutaneous nerve C5 and C6
• What is the role of the biceps brachii during elbow flexion?


  It provides full power of elbow flexion and supination at 90 degrees elbow flexion.
• How does the biceps brachii's function change at full elbow extension?


  Strong supination power is lost in full elbow extension.
• What is the function of the long head of the biceps brachii?

  It flexes and stabilizes the shoulder joint.
• Which nerve innervates the brachialis muscle?


  Musculocutaneous nerve and radial nerve.
• What is the primary role of the brachialis muscle?


  It is the main elbow flexor.
• What additional role does the brachialis play during elbow movement?


  It is important in eccentric elbow extension.
• Which nerve innervates the brachioradialis muscle?


  Radial nerve C5, C6, C7, C8, T1.
• Where is the brachioradialis located in relation to the cubital fossa?


  It forms the lateral border of the cubital fossa.
• When does the brachioradialis primarily flex the elbow?


  Particularly at mid-pronation/supination.
• Which nerve innervates the pronator teres muscle?


  Median nerve C6, C7, C8, T1.
• What is the role of the pronator teres in elbow movement?


  It supports elbow flexion.
• What is the primary action of flexion in the context of the elbow?


  Flexion decreases the angle between the forearm and the upper arm.
• Which nerve innervates the biceps brachii?

  Musculocutaneous nerve C5 and C6
• extention

  • Triceps brachii – innervated by radial nerve (C6, C7 and C8); extends the elbow joint; long head can adduct the shoulder and extend it from a flexed position.
  • Anconeus – innervated by the motor branch of the radial nerve (C6-C8); small triangular muscle behind the elbow; assists in elbow extension
• What is the role of the biceps brachii during elbow flexion?


  It provides full power of elbow flexion and supination at 90 degrees elbow flexion.
• How does the biceps brachii's function change at full elbow extension?


  Strong supination power is lost in full elbow extension.
• What is the function of the long head of the biceps brachii?


  It flexes and stabilizes the shoulder joint.
• Which nerves innervate the brachialis muscle?


  Medially by the musculocutaneous nerve and laterally by the radial nerve.
• What is the primary role of the brachialis muscle?


  It is the main elbow flexor.
• What additional role does the brachialis play during elbow movement?


  It is important in eccentric elbow extension.