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Upper Limb, part II Cubital fossa, Forearm, and Hand Objectives: 1. Bones and joints of the upper limb 2. Fascial compartments of arm, forearm and hand 3. Special areas of upper limb - cubital fossa, wrist, carpal tunnel, anatomical snuffbox 4. Arteries and veins of upper limb 5. Nerves innervating upper limb humerus radius ulna carpal bones metacarpal bones { phalanges Radiolulnar joints Which carpal bone is the most commonly fractured? scaphoid Wrist (radiocarpal joint) Intercarpal joints Carpometacarpal and intermetacarpal joints Carpometacarpal joint of the thumb Metacarpophalangeal joints Interphalangeal joints -Why is the scaphoid the most commonly fractured carpal bone? -- due to palming a floor after a fall Responsible for wrist rotation Carpal bones: Proximal row of carpals (from lateral to medial): 1. scaphoid bone S 2. lunate bone L 3. triquetrum bone T 4. pisiform bone P Distal row of carpals (from lateral to medial): 1. trapezium bone T 2. trapezoid bone T 3. capitate bone C 4. hamate bone H Hand movements Flexion - Extension Abduction - Adduction *Be sure to reference the anatomical position* Compartmentalization = Functionally related groups of muscles are enclosed within compartments defined by thick layers of deep fascia and intermuscular septa that attach to the bone. Compartments contain muscles sharing a common function (action) and a common innervation. FLEXORS ARM compartment anterior } biceps brachii, musculocutaneous n. coracobrachialis brachial a. brachialis EXTENSORS triceps brachii } radial n. profunda brachii a. posterior FOREARM compartment FLEXORS median and ulnar nn. ulnar and radial aa. anterior } flexors, pronators, palmaris longus brachioradialis radial n. radial a. EXTENSORS extensors, supinator, abductor radial n. posterior interosseus a. } posterior Forearm muscles - anterior/flexor-pronator compartment Three functional groups: 1. Muscles which pronate the forearm and hand *pronator teres *pronator quadratus 2. Muscles that flex the hand *flexor carpi radialis/abduct *flexor carpi ulnaris/adduct *palmaris longus 3. Muscles that flex the digits *flexor digitorum superficialis (FDS) *flexor digitorum profundus (FDP) *flexor pollicis longus Superficial group (5): *pronator teres *flexor carpi ulnaris *flexor carpi radialis *palmaris longus *flexor digitorum spf. (FDS) Deep group (3): Flexor carpi ulnaris and medial half of FDS are innervated by ulnar nerve First two lumbricals, thenar muscles and … are innervated by the median nerve .: pronator quadratus .: flexor digitorum prof. (FDP) .: flexor pollicis longus Teres: round 5 superficial muscles 1. Pronator teres 2. Flexor carpi radiales 3. Flexor carpi ulnaris 4. Palmaris longus muscle 5. Flexor digitum superficialis Flexor digitorum superficialis Flexor carpi ulnaris Palmaris longus Radial artery Tendon of flexor carpi radialis Forearm muscles - posterior/extensor-supinator compartment Three functional groups: 1. Muscles that extend the hand *extensor carpi radialis longus/abduct *extensor carpi radialis brevis/abduct *extensor carpi ulnaris/adduct 2. Muscles that extend the digits *extensor digitorum *extensor digiti minimi *extensor indicis 3. Muscles that extend the thumb *extensor pollicis longus EPL *extensor pollicis brevis EPB *abductor pollicis longus ABL/abduct Superficial group: *extensor carpi radialis brevis extensor carpi radialis longus *extensor carpi ulnaris *extensor digitorum *extensor digiti minimi brachioradialis Deep group: supinator EPL EPB APL extensor indicis 5 4 8 1. 2. 3. 4. 5. 6. 7. 8. 3 7 Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Abductor policis longus Extensor pollicis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris 2 6 1 Lateral epicondyle Cubital fossa - borders and contents Borders: (4; it’s a “cube) * medially - pronator teres m. * laterally – brachioradialis m. * the roof – deep fascia, subcutaneous tissue, and skin * the floor – supinator m. laterally and brachialis m. medially. Contents from medial to lateral side: (5) * median n. * bifurcation of the brachial a. * (deep) accompanying veins of the arteries * tendon of biceps brachii m. * radial n. and its branches (within the floor of the fossa) Superficially, in the subcutaneous tissue overlying the fossa: *median cubital vein (connects cephalic vein to basilar vein) *medial and lateral antebrachial (forearm) cutaneous nerves Superficial branch of radial nerve Brachial artery Tendon of biceps brachii Biceps brachii Brachioradialis Median nerve Medial epicondyle Pronator Muscles of the hand – 4 compartments 1. Thenar compartment: * abductor pollicis brevis * flexor pollicis brevis * opponens pollicis Thenar: a raised fleshy area on the palm of the hand near the base of the thumb median n. – recurrent branch 2. Adductor compartment: * adductor pollicis ulnar n. – deep branch, 3. Hypothenar compartment: * abductor digiti minimi * flexor digiti minimi * opponens digiti minimi ulnar n. – deep branch 4. Central compartment: 1st and 2nd median n. – digital branches 3rd and 4th ulnar n. – deep branch * interossei- 3 PAD and 4 DAB ulnar n. – deep branch * lumbricals : Palmar aponeurosis{ Hypothenar fascia Palmaris brevis Flexor pollicis brevis Abductor pollicis brevis Thenar fascia 1st lumbrical 1st dorsal interosseous Superficial palmar branch Adductor pollicis Abductor digiti minimi Palmaris brevis Ulnar artery Pisiform bone Flexor pollicis brevis Abductor pollicis brevis Superficial branch of radial artery Radial artery Short muscles of the Hand Flex the digits at the metacarpophalangeal joints and extend the interphalangeal joints. Abduct the digits (4 DAB) Adduct the digits (3 PAD) Lumbricals: .: What do they do? They flex the digits at the metacarpophalangeal joints and extend the interphalangeal joints Abductor: Dorsal interossei muscles How many are there? 4 Hence, 4 DAB Adductor: Palmar interossei How many are there? 3 Hence, 3 PAD Metacarpophalangeal joints are the knuckle joints Carpal tunnel is the space between the carpal bones and the flexor retinaculum. The flexor retinaculum (transverse carpal ligament) is a thick connective tissue ligament that bridges the space between the medial and lateral side of carpal arch. Structures that pass anterior to the flexor retinaculum (from medial to lateral side): * ulnar n. * ulnar a. *tendon of palmaris longus m. Structures that pass beneath to the flexor retinaculum pass the carpal tunnel (from medial to lateral side): * tendons of flexor digitorum superficialis and profundus *median n. *tendon of flexor pollicis longus m. Anatomical snuffbox (visible, when the thumb is fully extended): Anteriorly (laterally) bounded by 2 muscles: • extensor pollicis brevis (EPB) • abductor pollicis longus (APL) Posteriorly (medially) bounded by 1 muscle: • extensor pollicis longus (EPL) The radial artery lies in the floor of the snuff box. Anatomical snuffbox EPB APL EPL AXILLARY A. (SHOULDER REGION) DEEP BRACHIAL A. = profunda brachi (POSTERIOR COMPARTMENT) BRACHIAL A (ANTERIOR COMPARTMENT) CUBITAL FOSSA INTEROSSEOUS AA (ANTERIOR AND POSTERIOR RADIAL A (ANTERIOR COMPARTMENT) COMPARTMENTS) ULNAR A (ANTERIOR COMPARTMENT) ARTERIAL ARCHES (HAND) Which artery in the forearm is often used to palpate an arterial pulse? Radial artery (remember the thumb point) Superficial palmar arch is formed mainly by the ULNAR ARTERY Deep palmar arch is formed mainly by the RADIAL ARTERY CEPHALIC VEIN BASILIC VEIN MEDIAN CUBITAL VEIN Where is the common place for venipuncture? Cutaneous innervation of the upper limb Branch of median nerve = Dinner fork deformity Questions of the day! 1. Which muscle of the forearm has a double innervation? 1. Flexor digitorum profundus 2. Loss of pronation of the hand suggests a lesion of which nerve? 2. Median 3. Numbness to the skin on the lateral half of the palm of the hand would be caused by a lesion to which nerve? - Median