Chapter 7 - Upper Extremity Injuries Impair peoples’ ability to manipulate the environment. Upper extremity design for motion not for the support of large loads

Shoulder Anatomy Shoulder complex: Sternoclavicular joint: Shoulder girdle: scapula and clavicle Shoulder joint joint Sternoclavicular joint: Modified Ball & Socket disk Acromioclavicular joint AC ligaments Coracoclavicular joint Glenohumeral joint: Scapulothoracic joint

Shoulder Anatomy Glenohumeral Joint Muscular support Most mobile joint Shallow joint cavity Glenoid labrum Glenohumeral ligaments Coracohumeral ligament Muscular support Rotator cuff muscles

Shoulder Anatomy Rotator cuff subscapularis infraspinatus supraspinatus teres minor Primary source of stability to the shoulder

Shoulder Anatomy

Shoulder Injuries AC sprain or separated shoulder Indirect or direct forces direct force to acromion with shoulder in adducted position fall on a outstretched arm traction to arm Classification Type I-III Type IV > rare severe forces

Shoulder Injuries Shoulder instability poor joint cavity poor ligament musculature Intracapsular pressure Concavity compression scapulohumeral balance

Shoulder Injuries Anterior Luxation Posterior luxation mostly anterior when arm is abducted, extended and ext. rotated posterior forces Posterior luxation same mechanism reverse Inferior luxation

Shoulder Injuries Impingement Categories glenohumeral joint: abduction supraspinatus and bursae Categories Under 35 year: sports or jobs with overhead movement Older: degeneration Microtrauma-instability-subluxation-aggravation

Shoulder Injuries Mechanism Rotator cuff impingements Intrinsic Extrinsic: structural factors hook acromion hypertrophy of supraspinatus Intrinsic inflammation of the tissue Mechanism work of sports requiring overhead movements Wheelchair (abductor dominance)

Shoulder Injuries Rupture Rotator cuff Chain of events: inflammation microtears partial or total rupture movement adaptations Supraspinatus rupture most common Eccentric actions acceleration phase decceleratiom phase

Shoulder Injuries Upper arm Humeral fractures two compartments anterior posterior Humeral fractures 7% of fractures Direct or indirect Low & high energy falls, car crashes, direct loading, violent muscle contraction (throwing)

Shoulder Injuries Biceps tendon injuries tenosynovitis (repetition) dislocation (medial) abduction/ext. rotation falls outstretched arm lateral impact hyperextension anterior GH dislocation bicipital grove angulation rupture: tissue degeneration SLAP

Elbow Anatomy Hinge joint Ligament support Muscles MCL:valgus loading LCL: varus loading Annular ligament Muscles Flexors: biceps, brachialis and brachioradialis Extensor: Triceps & anconeus

Elbow Injuries Epicondylitis: repeated loading causing microtrauma and tissue degeneration leading to inflammation and tissue weakness Lateral epicondylitis tennis players 30-50 years old, poor stroke mechanics, excessive muscle contraction Overuse of extensor mechanics, pinching and grasping

Elbow Injuries Medial epicondylitis excessive loading forehand and serve Advanced players Wrist motions

Elbow Injuries Valgus Extension Loading Mechanism large varus torque elbow extension huge internal rotation torque transmitted to elbow

Elbow Injuries Dislocations more stable, less incidence of dislocation Axial force to extended or hyper Avulsion of collateral ligaments

Elbow Injuries Fractures humeral Ulnar Radial olecranon:impact or hyperextension Radial axial loading of radius from a fall or dislocation

Forearm Anatomy Two bones Two compartments of muscles radius & ulna Two compartments of muscles anterior: flexor-pronator posterior:extensor-supinator Proximal radioulnar joint Distal radioulnar joint

Forearm injuries Diaphyseal fractures of ulna & Radius Galeazi: distal 1/3 radius, outstretched arm, blow to dorsum of wrist Nightstick Montegia lesion: classification for ulnar fractures Distal radius: Colles etc.

Forearm injuries Ulnar variance: relative length of ulna and radius Determined genetics elbow pathology mechanical loading Ulnar variance in gymnast-premature closure of radial growth plate Gymnastic: huge loads to the wrist- cartilage degeneration/fractures

Wrist & Hand Anatomy Wrist joints Hand joints CM: MP: condyloid distal radio ulnar radiocarpal intercarpal Hand joints CM: MP: condyloid IP: hinge

Wrist & Hand Anatomy Strong ligaments Muscles control wrist & finger motion carpal tunnels Flexor & extensor retinacula

Wrist & Hand Injuries Carpal tunnel (CTS) result from repetitive stress to tissue 64% of work injuries Compressive neuropathy Wrist flexion/ext and finger movements Risk factors exertion repetitive stress posture localized contact cold

Wrist & Hand Injuries Carpal fractures compressive loads to hyperextended wrist hyper flexion rotation loading against a fixed wrist Scaphoid 60-70% Lunate

Wrist & Hand Injuries Thumb: essential to prehension Sprain: skiers thumb fall with thumb in abducted position tensile loads on MCL Hyperextension Bennets fracture (fighting) Bowler’s thumb: ulnar digital nerve trauma tingling, sensitivity

Wrist & Hand Injuries Metacarpal & phalangeal injuries Fractures Boxers Dislocations