STERNECLAVICULAR JOINT

Type & variety: synovial, saddle. Articular surfaces: clavicle (sternal end) & sternum (clavicular notch). Capsule: attached to margins of articular surfaces. Intracapsular structures: cartilaginous articular disc Synovial Membrane: • Lines the capsule. • Covers intracapsular non articular structures. Ligaments: • Costaclavicular. • Interclavicular.

ACROMIOCLAVICULAR JOINT Type: synovial, plane. Articular surfaces: clavicle (acromial end), acromion (clavicular facet). Capsule: • Attached to the margin of articular surfaces. Synovial membrane: • Lines the capsule. • Covers intracapsular non articular structures. Ligaments: Coracoclavicular ligament - 2 parts: conoid & trapezoid. - Strong ligament transmits upper limb weight to the clavicle & axial skeleton.

SHOULDER GRIDLE

Definition: Movement of scapula and clavicle through sternoclavicular and acromioclavicular joints. Movement & muscles: • Elevation: trapezius (upper fibers), levator scapulae, rhomboids minor & major. • Depression: trapezius (lower fibers) & pectoralis minor. • Protraction: serratus ant & pectoralis minor. • Retraction: trapezius, levator scapulae, rhomboids minor & major. • Up (lat) rotation (elevation of arm ˃ 90°): trapezius & serratus ant. • Down (med) rotation: pectoralis minor, rhomboids minor & major.

SHOULDER JOINT

Type and variety: synovial (ball& socket). Articular surfaces: scapula (glenoid cavity) & humerus (head). Capsule: Attachements: at the margins of articular surfaces except inferiorly where it reaches surgical neck. Intracapsular structures: Labrum glenoidal: fibrocartilage ring attached to the margin of glenoid cavity to deepen it. Long head of biceps Synovial membrane: • Lines the capsule. • Covers the intracapsular non articular structures (labrum glenoidal & long head of biceps). Ligaments: Coracohumeral ligament: from coracoid process to greater tuberosity. Glenohumeral ligament: from glenoid cavity to lesser tuberosity. Coracoacromial ligament: from coracoid to acromial processes. The 2 processes & the ligament form coracoacromial arch. Transverse humeral ligament: between greater & lesser tuberosities.

Movements and muscles: Flexion: pectoralis major, deltoid (ant fibers), biceps & coracobrachialis. Extension: deltoid (post fibers), teres major & latismus dorsi. Adduction: pectoralis major, latismus dorsi & teres major (TLP). Abduction: • 0-15°: supraspinatus. • 15-90°: shoulder joint deltoid. N.B.: elevation of arm ˃ 90°: trapezius & serratus ant (shoulder girdle). Med rotation: pectoralis major, latismus dorsi, teres major (TLP), deltoid (ant fibers) & subscapularis. Lat rotation: infraspinatus, teres minor & deltoid (post fibers). Circumduction Stability: • Weak joint due to shallow articular surfaces & weak ligaments. • Mainly supported by rotator cuff muscles; supraspinatus (sup), infraspinatus and teres minor (post) & subscapularis (ant). It is also supported by coracoacromial arch (sup). • Frequently dislocated inferiorly, usually with abducted arm.

ELBOW JOINT

Types & variety: synovial, hinge. Articular surfaces: • Trochlea of humerus with trochlear notch of ulna. • Capitulum of humerus with head of radius. Capsule: attached to margins of articular surfaces. Synovial membrane: • Lines the capsule. • Covers intracapsular nonarticular structures. Ligaments: Med (ulnar) collateral ligament: between med epicondyle & med margin of coronoid & olecranon processes. Lat (radial) collateral ligament: between lat epicondyle & annular ligament. Movements and muscles: Flexion: biceps, brachialis & brachioradialis. Extension: triceps & anconeus.

SUPERIOR RADIOULNAR JOINT

Type & variety: synovial, pivot. Articular surfaces: head of radius & radial notch of ulna. Capsule: attached to margins of articular surfaces. Synovial membrane: • Lines the capsule. • Covers intracapsular non articular structures. Ligaments: Annular ligament: attached to margins of radial notch & surrounds head of radius. Quadrate ligament: between neck of radius & ulna. Movement: supination & pronation.

MIDDLE RADIOULNAR JOINT (INTEROSSEOUS MEMBRANE) Type & variety: fibrous, syndesmosis. Attachment: interosseous borders of radius & ulna. Direction of fibers: med (from radius to ulna) & downwards. INFERIOR RADIOULNAR JOINT Type & variety: synovial, pivot. Articular surfaces: head of ulna and ulnar notch of radius. Capsule: attached to the margins of articular surfaces. Synovial membrane: • Lines the capsule. • Covers intracapsular non articular structures. Movement: supination and pronation.

N.B.: triangular articular disc: attached between lower end of radius & styloid process of ulna. It separates ulna from the carpal bones. SUPINATION AND PRONATION Definition: Supination: is lat rotation of forearm so that the palm faces anteriorly & the thumb is directed laterally. Pronation: is med rotation of forearm so that the palm faces posteriorly & the thumb is directed medially. • In both movements the radius moves while the ulna is fixed. Joints concerned: radio ulnar joints. Muscles: Supination: biceps (with flexed elbow) & supinator. Pronation: pronator teres and pronator quadratus. N.B.: Brachioradialis initiates both movements.

WRIST (RADIOCARPAL) JOINT

Type & variety: synovial, ellipsoid. Articular surfaces: Proximal: lower end of radius & triangular articular disc. Distal: scaphoid, lunate & triquetrum. Capsule: attached to the margins of articular surfaces. Synovial membrane: • Lines the capsule. • Covers intracapsular non articular structures. Ligaments: Ant radiocarpal: between lower ends of radius & ulna & carpals (ant). Post radiocarpal: between lower ends of radius & ulna & carpals (post). Med (ulnar) collateral ligament: between styloid process of ulna & pisiform & triquetrum. Lat (radial) collateral ligament: between styloid process of radius & scaphoid & trapezium.

Movements and muscles: Flexion: flexor carpi radialis, flexor carpi ulnaris, palmaris longus, flexor digitorum superficialis & profundus & flexor pollicis longus. Extension: extensor carpi radialis longus and brevis, extensor carpi ulnaris, extensor digitorum, extensor digitiminimi, extensor pollicis longus & extensor indicis. Adduction: flexior carpi ulnaris, extensor carpi ulnaris. Abduction: flexor carpi radialis, extensor carpi radialis longus & brevis. Circumduction.