Elbow Joint Elbow Joint Type Synovial hinge joint

Elbow Joint

Elbow Joint Type: Synovial hinge joint

Trochlea of the humerus capitulum of the humerus Trochlea Capitulum head of radius Trochlear notch of the ulna v It actually includes two articulations (a) Humero-ulnar articulation, between trochlea of humerus and trochlear notch of ulna (b) Humero-radial articulation, between capitulum of humerus and head of radius v Articular surfaces of elbow joint; Trochlear notch a- Proximal; trochlea and capitulum of the humerus. Head of radius b- Distal; Trochlear notch of the ulna. - Upper surface of the head of the radius.

upper margins of the coronoid and radial fossae lateral epicondyle Anteriorly Capsule ** Capsule: surrounds the articular surfaces of the joint. ** Synovial membrane: lines the inner surface of the capsule and non-articular parts. - Inferiorly, it is Continuous with the synovial membrane of the superior radioulnar joint. Annular ligament of radius anterior and medial margins of the coronoid process of the ulna

margins of the olecranon fossa of the humerus upper , medial and lateral margins of the olecranon process of the ulna Capsule Posteriorly annular ligament

Ligaments of Elbow joint

Radial collateral ligament Ulnar collateral ligament v Ligaments I) Radial collateral (lateral) ligament: a strong band between the lateral epicondyle of the humerus and upper border of the annular ligament. 2) Ulnar collateral (Medial) ligament: a thick triangular ligament and formed of 3 bands a- Anterior band: between the medial epicondyle and medial border of the coronoid process. b- Posterior band: between the medial epicodyle and the medial border of the olecranon process. c- Middle band: between the medial borders of the coronoid and olecranon processes.

Carrying angle 1650～ 1700 ** Carrying angle; - It is the angle between the long axis of arm and extended supinated forearm. - It is opened laterally and measure about 170 degree. - It is more in female than male. - It disappears in pronation of the extended forearm and in full flexion of the forearm. - It is caused by Projection of the medial edge of the trochlea more than the lateral. Movements: 1) Flexion: by brachialis (main), biceps and brachioradialis. • Flexion is limited by contact of anterior surfaces of forearm & arm. 2) Extension: by triceps and anconeus.

Relations of elbow joint Ulnar nerve Brachial artery Bicipital aponeurosis Med. Cut N forearm Median nerve Median cubital vein Basilic vein Cephalic vein Intermediate vein

v Relations of the elbow joint 1 - Cephalic vein (laterally) ﺍﻟﻮﺭﻳﺪ ﺍﻟﺮﺃﺴﻰ 2 - Basilic vein (medially) ﺍﻟﻮﺭﻳﺪ ﺍﻟﻤﻠﻜﻰ 3 - Median cubital vein directs upward from cephalic vein to the basilic vein 4 - Intermediate vein ends in the median cubital vein. But, commonly it divides into a lateral branch to the cephalic vein and a medial branch to the basilic vein. 5 - Bicipital aponeurosis separates the median cubital vein from brachial artery 6 - Brachial artery passes from medial side to the cubital fossa where the Bicipital aponeurosis separates it from the median cubital vein 7 - Median nerve passes deep to bicipital aponeurosis that separate it from the median cubital vein. - It enters the forearm between the two heads of pronator teres. The deep head separates it from the ulnar artery. 8 - Ulnar nerve descends to the back of the medial epicondyle of the humerus (dangerous position).

v Applied anatomy (injury of the ulnar nerve) 1 - Dislocation of the elbow joint. 2 - Fracture medial epicondyle of the humerus. v Deformity (partial claw hand) - Hyperextension of the metacarpo-phalangeal joints and flexion of the inter-phalangeal joints of the ring and little lingers due to paralysis of Lumbrical Muscles. (Writing position by Lumbrical Muscles 1 st & 2 nd by median N while 3 rd & 4 th by ulnar N). - Positive Formant's test: When the sheet of paper between the thumb and index is pulled against a holding resistance, the thumb is fully flexed at distal phalanx due to Paralysis of the adductor pollicis - Sensory effects; Loss of sensations in the medial third of the hand medial one and half fingers. v Cubital tunnel syndrome: Compression of the ulnar nerve behind the medial epicondyle. • Burning sensation, numbness in the medial third of the hand medial one and half fingers. • These symptoms increase during flexion of the elbow. v Pronator teres syndrome § Compression of the median nerve at the elbow joint leading to pain and numbness in the lateral two third of palm of the hand lateral three and half fingers and weakness of flexor muscles

Radioulnar joints

Radioulnar joints Pronation • Superior Radioulnar Joint ** Type; a pivot (uniaxial) synovial joint. ** Articular surfaces: 1 - Articular circumference of the head of the radius. 2 - Radial notch of the ulna and annular ligament. • Inferior Radioulnar Joint ** Type; a pivot (uniaxial) synovial joint. ** Articular surfaces; head of the ulna and ulnar notch of the radius. • Middle Radioulnar Joint ** Type; fibrous joint. - It is formed by oblique cord and interosseous membrane between the radius and ulna. - Directions of fibers, obliquely downwards and medially from the radius to the ulna. Supination Superior Middle Inferior

Pronation and Supination 1 - Definition: - Pronation: medial rotation of the forearm and the palm of the hand face posteriorly. - Supination: lateral rotation of the forearm and the palm of the hand face anteriorly. 2 - Joints: superior and inferior radioulnar joints. ** The axis extends from the head of the radius to the head of the ulna. 3 - Muscles of Pronation and their nerve supply a- It is initiated by brachioradialis = supplied by radial nerve. b- It is completed by - Pronator teres = supplied by median nerve. - Pronator quadratus = supplied by anterior interosseous nerve. 4 - Muscles of Supination and their nerve supply a- It is initiated by the brachioradialis = supplied by radial nerve. b- It is completed by - Supinator supplied by posterior interosseous nerve. - Biceps brachii supplied by musculocutaneous nerve. N. B Supination is much more powerful than pronation. Because, in the usual working position with elbow flexed (e. g. Turning a screw-driver, a doorknob) are designed to be fixed by the use of the power of supination. • In a semiflexed elbow the palm is turned upwards in supination and downward in pronation (kings pronate and beggars supinate)

Brachialis Pronator Teres Brachioradialis Pronator quadratus

Supinator Biceps brachii Triceps brachii

Th ank Qu you est ion s I/Azzam - 2004