Elbow, Forearm, Wrist PDF

Elbow, Forearm, Wrist John Damiao, PhD, MS, OTR/L Adapted from Corinne Piren, MS, OTR/L, CHT What are the bones of the elbow and forearm? u The elbow/forearm complex consist of three bones and 4 joints: u Distal humerus, Ulna, Radius u Humero-ulnar joint u Humeror...

Elbow, Forearm, Wrist John Damiao, PhD, MS, OTR/L Adapted from Corinne Piren, MS, OTR/L, CHT What are the bones of the elbow and forearm? u The elbow/forearm complex consist of three bones and 4 joints: u Distal humerus, Ulna, Radius u Humero-ulnar joint u Humeroradial Joint u Proximal Radio-ulnar joint u Distal Radio-ulnar joint Mid-Distal Humerus u Anterior View: u Trochlea u Coronoid Fossa u Capitulum u Radial Fossa u Medial Epicondyle u Lateral Epicondyle Mid-Distal Humerus u Posterior View: u Trochlea (D) u Olecrenon Fossa (H) u Medial Epicondyle (C) u Lateral Epicondyle Proximal Ulna u Trochlear Notch u Radial Notch u Coronoid Process u Olecrenon Process Proximal Radius u Head (Fovea) u Neck u Radial Tuberosity How it Fits u Humero-ulnar Joint u Humeroradial Joint u Proximal Radio-ulnar Joint How it Fits Radius and Ulna Joints of the Elbow and Forearm u Elbow: u Consists of humero-ulnar and humeroradial joints u Modified hinge joint (Ulna rotates slightly during flexion and extension) u Two joints, 1 degree of freedom u Flexes and extends u Tight fit between trochlea and trochlea notch makes the elbow a very stable joint Carrying Angle u Normal: 15 degrees u Excessive: 25 degrees u Varus deformity: medially deviated Women will have greater carrying angles than men, why? Joint Stabilizers u Articular Capsule u Lateral Collateral Ligament u Radial Collateral Ligament u Ulnar Collateral Ligament u Medial Collateral Ligament u Anterior u Posterior u Transverse u Annular Ligament Joint Stabilizers u Medial Collateral Ligament-taught with excessive valgus force u Lateral Collateral Ligament-taught with varus force u Annular Ligament- distraction of the radius Movements of the Humero-ulnar, Humeroradial, and Proximal Radio-ulnar joint u Humeroulnar/humeroradial joints: Flexion and Extension u Functional Range: 30-130 u Normal Range: 0-145 u Proximal Radioulnar joint: Pronation/Supination u Functional range: 50/50 u Normal Range: 90/90 Arthrokinematics of the Elbow u Convex-Concave orientation (Trochlea-Trochlear notch; capitulum-fovea of radial head) u Rolls and Slides in the same direction u True for Humero-ulnar and humeroradial joints u Very stable joint-stability provided by the articular congruency of humerus and ulna Function u Motions of the elbow adjust the functional length of the limb u Feeding, reaching, throwing, personal hygiene u Lifting, pulling, pushing u Loss of the extremes of elbow ROM usually result in minimal impairment u Functional range of 30-130 Arthrokinematics of the Forearm u Radius moves over a fixed ulna u Proximal Radio-ulnar joint: spins in the annular ligament on the radial notch u Annular ligament covers the radial head and keeps the radius in place u Distal Radio-ulnar joint: radius rolls and slides over the ulna (Convex ulna head-ulnar notch) u Distal RU joint follows convex-concave arthrokinematics u Very shallow joint-stability provided by muscles and connective tissue Forearm Arthrokinematics u 1 Degree of Freedom u Supination: 0-80 u Pronation: 0-90 u Functional range: 50/50 u Forearm rotation places the hand with palm up/palm down-hand and wrist are attached firmly at the radius with space between distal ulna and carpals  Forearm Function u Bringing hand to face-feeding, washing, shaving while supinating u Pronation: pushing up from a chair, picking up objects on a table Interosseous Membrane u Radius and ulna are bound together by the interosseous membrane of the forearm u Serves as a stable attachment for extrinsic muscles of the hand u Transmits force proximally to the upper limb u 80% of compression force crosses the wrist through the radius-very common to fx radius during a fall on outstretched hand) u Interosseous Membrane transfers much force across to the ulna and to the humero-ulnar joint u Additionally protects wear and tear of humeroradial joint- most elbow flexors insert on the radius-pull radius into humerus with high compression force u Tears of interosseous membrane causes proximal migration of radius and degeneration of joints Interosseous Membrane u Taught with compression forces u Is slackened with distracting forces u Contraction of brachioradialis and wrist extensors can help stabilize in distraction Triangular Fibrocartilage Complex (TFCC) u Occupies most of the space between the ulna and the carpal bones u Primary stabilizer of the distal RU joint u If disrupted, motions of the wrist and forearm are painful and difficult to perform Nerve Innervation u Musculocutaneous: Biceps Brachii, Coracobrachialis, Brachialis u Injury greatly impacts elbow flexion u Radial Nerve: Triceps, Anconeous, Wrist Extensors u Median Nerve: Hand Flexors and forearm Pronators u Ulnar Nerve: Wrist flexors, hand intrinsics Muscles that Move the Elbow u Flexors: Biceps Brachii, Brachialis (Musculocutaneous Nerve); Brachioradialis (Radial Nerve) u Biceps: Originates on Scapula, inserts onto radial tuberosity-supinates forearm/flexes elbow u Brachialis: Deep, originates on humerus attaches distally to ulna-more pronounced with forearm pronated u Brachioradialis: Originates lateral supracondylar ridge, inserts onto distal radius-places forearm in neutral Elbow Extensors u Triceps Brachii and Anconeous (Radial Nerve) u Long, Lateral, Medial Heads u Anconeous: Lateral Epicondyle to Proximal Ulna-provides medial- lateral stability across the HU joint Forearm Supinators u Supinator (Radial Nerve) and Biceps Brachii u Supinator for less forearm motions involving just forearm rotation u Biceps for forceful Supination actions and combined elbow flexion (Deltoid and triceps would need to stabilize-not efficient) Forearm Pronators u Pronator Teres and Pronator Quadratus (Median Nerve) u Pronator Quadratus stabilizes Distal RU joint and guides arthrokinematics Any Questions? The Wrist Joint u John Damiao PhD, MS, OTR/L u Adapted from: Corinne Piren, MS, OTR/L, CHT What bones make up the wrist? u Distal Radius u Head of the Ulna u Carpal Bones Distal Radius u Lister’s Tubercle (Separates EPL ulnarly from ECRB) u Styloid Process u Ulnar Notch Distal Radius u BiConcave u 25 degrees of ulnar tilt u 10 degrees palmar tilt u Great ulnar deviation and flexion Distal Ulna u Concave u Prominent Head u Styloid Process (ECU) Carpal Bones u SLTPTTCH u 8 total u Proximal Row: loosely joined: Scaphoid, lunate, triquetrum, pisiform u Distal Row: Trapezium, Trapezoid, Capitate, Hamate (bound tightly with strong ligaments) Carpal Bones u Scaphoid: u Most commonly fractured u Proximal pole (poorly vascularized), Distal pole, Neck u Lunate u Most commonly dislocated u Triquetrum u Pisiform: Sesamoid, moveable and palpable Carpal Bones u Capitate: u Central Column u Trapezium u Articulates with 1st Metacarpal u Trapezoid u Stable base-articulates with 2nd Metacarpal u Hamate: Joints of the Wrist u Radiocarpal joint u Midcarpal Joint u Intercarpal joints Radiocarpal Joint u Proximal: Concave Radius and articular disc u Distal: Convex scaphoid, lunate, triquetrum u Condyloid u Bi-Concave, Bi-Convex u Two degrees of freedom Midcarpal Joint u Between proximal and distal carpal rows u Biaxial synovial joint u Concave-convex relationship of movement applies u The distal row of carpal bones moves in the same direction as the hand, but in opposite direction of the proximal carpal bones Other structures of the wrist u The Ligaments u Stabilize u Permit and Guide Motion u Limit joint motion u Transmit forces from hand to forearm u Prevent dislocation u Intrinsic vs extrinsic Triagular Fibrocartilage Complex (TFCC) u Consists of articular disc, ECU sheath, meniscus homologue, ulnotriquetral ligament, ulnolunate ligament, volar radioulnar ligament, dorsal radioulnar ligament u Stabilizes the Distal RU joint u Reinforces the ulnar side of the wrist u Forms part of the concavity in the radiocarpal joint u Helps transfer part of the compression forces that cross the wrist u Radius bears 60%, TFCC bears 40% The Carpal Tunnel Floor: Concave carpal bones Roof: Transverse carpal ligament (Prevents bowstringing) Running through: Flexor Pollicis Longus (FPL), Flexor Digitorum Profundus (FDP), Flexor Digitorum Superficialis (FDS) and Median Nerve Arthrokinematics u 2 Degrees of Freedom u Flexion/Extension, Radial/Ulnar Deviation u In what planes? u Convex-on-Concave at both Radiocarpal and Midcarpal joints u Central column: Radius, Lunate, Capitate, 3rd metacarpal Muscles of the Wrist u Primary Set (Act at Wrist only) u Secondary Set (Act on Wrist and Hand) Primary Wrist Flexors and Extensors u Wrist Extensors: u Extensor carpi radialis longus (ECRL), Extensor carpi radialis brevis (ECRB), Extensor carpi ulnaris u Innervated by the radial nerve u Wrist Flexors: u Flexor carpi radilias, Palmaris Longus (Median Nerve) u Flexor carpi ulnaris (Ulnar Nerve) u What about radial and ulnar deviation? Wrist Extensor Muscles u Secondary Set includes extensor digitorum, extensor indicis, extensor digiti-minimi, and extensor pollicis longus u Originate at or near lateral epicondyle u ECRL inserts at base of 2nd metacarpal, ECRB at base of 3rd metacarpal, ECU at base of 5th metacarpal u Pass through extensor retinaculum Extensor Retinaculum u Prevents bowstringing of wrist/hand extensors u Comprised of 6 Dorsal compartments u Common site of tenosynovitis u Dorsal Compartments: u I: EPB, APL u II: ECRL, ECRB u III: EPL u IV: ED, EI u V: EDM u VI: ECU Role During Grasping/Gripping u Wrist extensors stabilize the wrist during finger flexion u Counterbalance the flexion torque on the wrist from the finger flexors u Grip strength is significantly reduced when the wrist is fully flexed u Why? u Wrist flexors and wrist extensors Wrist Flexors u Primary set: Flexor carpi radialis, palmaris longus, flexor carpi ulnaris u Secondary Set: Flexor Digitorum Profundus, Flexor digitorum superficialis, Flexor pollicis longus, abductor pollicis longus, extensor pollicis brevis u Originate at or near medial epicondyle u Flexor Carpi Radialis inserts: base of 2nd metacarpal u Palmaris Longus: Palmar aponeourosis u Flexor Carpi Ulnaris: Pisiform, base of 5th metacarpal u Strong gripping and pulling requires activation of wrist flexors Ulnar and Radial Deviation u Radial Deviators: u ECRL, ECRB, EPL, EPB, Flexor Carpi Radialis, APL, FPL u Ulnar Deviators: u ECU, Flexor Carpi Ulnaris, FDP, FDS, ED Pathologies De Quervain’s Tenosynovitis u Radial styloid tenosynovitis – swelling of the tendons of extensor pollicis longus and brevis that attach to the base of digit 1. u First Dorsal Compartment Inflammation u Repetitive Strain Injury u Repeated forceful grasping, pinching, pulling, ulnar deviation and extension Radial Nerve Palsy u Saturday Night Palsy u Compression of radial nerve at the spiral groove u Results in wrist drop Cubital Tunnel Syndrome u Ulnar nerve impingement u Between medial epicondyle and olecranon u Chronic compression, repetitive trauma u Tingling, numbness u Weakness, atrophy Conditions Resource: Elbow and Forearm Pathology u Contusions u Fractures u Bursitis u Overstretch Injuries u Sprains/Strains u Lateral Epicondylitis u Medial Epicondylitis u Myositis Ossificans u Pulled Elbow Conditions Resource: Wrist Pathology u Fractures u Rheumatoid Arthritis u Strains u Dislocation u Sprains/Tears u Hyperpronation/Hypersupination u Carpal Tunnel Syndrome u Extensor Intersection Syndrome u Ulnar Nerve Entrapment Any Questions?