KINE 3200 - Chp. 7

Intrinsic muscles of the hand

- 4 intrinsic muscles act on carpometacarpal joint of thumb - opponens pollici -> causes opposition in thumb metacarpal - abductor pollicis brevis abducts thumb metacarpal & assisted in this action by flexor pollicis brevis, also flexes thumb metacarpal - metacarpal of thumb adducted by adductor pollicis - flexor pollicis brevis & adductor pollicis flex proximal phalanx of thumb - 3 palmar interossei are adductors of 2nd, 4th & 5th phalanges - 4 dorsal interossei flex & abduct the index, middle & ring proximal phalanxes of these fingers - 3rd interossei adducts middle finger - 4 lumbricals flex index, middle, ring, & little proximal phalanxes & extend middle & distal phalanxes of these fingers

Muscles of the wrist & hand

- all innervated from the radial, median & ulnar nerves of the brachial plexus Radial nerve: - originates from C6-C8 - provides innervation for extensor carpi radials breves & extensor carpi radials longus - branches to become the posterior interosseous nerve - supplies the extensor carpi ulnaris, extensor digitorum, extensor digit minimizing, abductor pollicis longus, extensor pollicis longus, extensor pollicis brevis & extensor indicis Median nerve: - arising from C6-C8 & T1 - innervates flexor carpi radialis, palmares longus & flexor digitorum superficialis - branches to become anterior interosseous nerve, which innervates flexor digitorum profundus for the index & long fingers as well as flexor pollicis longus - regarding intrinsic muscles of the hand, median nerve innervates abductor pollicis breves, flexor pollicis breves, opponens pollicis & 1st & 2nd lumbrical Ulnar nerve: - branches from C8 & T1 - supplies the flexor digitorum profundus for the 4th & 5th fingers & flexor carpi ulnaris - innervates the remaining intrinsic muscles of the hand (deep head of flexor pollicis breves, adductor pollicis, palmar interossei, dorsal interossei, 3rd & 4th lumbrical, opponens digit minimizing, abductor digits minimize, flexor digits mini brevis) - provides sensation to ulnar side of the hand, ulnar half of ring finger & entire little finger

Carpal tunnel syndrome

- bony arch is spanned by transverse carpal & volvar carpal ligaments creating carpal tunnel, which is frequently a source of problems - conditions leading to swelling & inflammation in this area can result in incr. pressure in carpal tunnel, which interferes with normal function of median nerve, leading to reduced motor & sensory function of its distribution - condition is particularly common with repetitive use of the hand & wrist in manual labor & clerical work e.g.) typing & keyboarding

Wrist joint

- classified as condyloid-type joint - bi-axial for 2 planes of movement - elliptical/rounded & depression articulation - radiocarpal (wrist) - metacarpalphalangeal - allowing flexion, extension, abduction (radial deviation) & adduction (ulnar deviation) - flexion & extension -> sagittal plane - abduction & adduction -> frontal plane - wrist motion occurs primarily between distal radius &b proximal carpal row, consisting of scaphoid, lunate & triquetum

Wrist & hand

- contains 29 bones, including radius & ulna - 8 carpal bones in 2 rows od 4 bones form -> wrist

Flexion (palmar flexion)

- movement of palm of the hand and/or the phalanges toward the anterior or volvar aspect of the forearm

Extension (dorsiflexion)

- movement of the back of the hand and/or the phalanges toward the posterior or dorsal aspect of the forearm; sometimes referred to as hyperextension

Adduction (ulnar deviation, ulnar flexion)

- movement of the little finger side of the hand toward the medial aspect or ulnar side of the forearm; also, movement of the fingers back together toward the middle finger

Opposition

- movement of the thumb across the palmar aspect to oppose any or all of the phalanges

Reposition

- movement of the thumb as it return to the anatomical position from opposition with the hand and/or fingers

Abduction (radial deviation, radial flexion)

- movement of the thumb side of the hand toward the lateral aspect or radial side of the forearm; also, movement of the fingers away from the middle finger

5 metacarpal bones

- numbered 1-5 from thumb to little finger - 14 phalanxes (digits) -> 3 for each phalange except thumb - 5 proximal phalanges - 4 middle phalanges - 5 distal phalanges

Proximal row

- scaphoid (boat-shaped) or called navicular - lunate (moon-shaped) - triquetum (3-cornered) - pisiform (pea-shaped)

Distal row

- trapezium - trapezoid - capitate - hamate

Extensor indicis muscle

Origin: - between middle & distal one-third of posterior ulna Insertion: - base of middle & distal phalanxes of 2nd phalange Action: - extension of index finger at metacarpophalangeal joint - weak wrist extension - weak supination of forearm from a pronated position Innervation: - radial nerve, posterior interosseous branch Application, Strengthening, & Flexibility: - the pointing muscle - responsible for extending index finger, particularly when other fingers are flexed - provides weak assistance to wrist extension - developed through exercises similar to extensor digitorum - stretched by -> passively taking index finger into maximal flexion at metacarpophalangeal, proximal interphalangeal & distal interphalangeal joints while fully flexing wrist

Extensor carpi radialis longus muscle

Origin: - distal 3rd of lateral supracondylar ridge of humerus & lateral epicondyle of humerus Insertion: - base of 2nd metacarpal Action: - extension of wrist - abduction of wrist - weak flexion of elbow - weak pronation to neutral from a fully supinated position Innervation: - radial nerve Application, Strengthening, & Flexibility: - important in any sports activity that requires powerful wrist extension - extensor carpi radialis lingus & extensor carpi radialis brevis are involved in abduction of wrist - may be developed with same wrist extension exercises (like extensor carpi radialis ulnaris) - stretched by -> same manner as extensor carpi radialis brevis

Extensor digitiorum muscle

Origin: - lateral epicondyle of humerus Insertion: - 4 tendons of bases of middle & distal phalanxes of 4 fingers Action: - extension of 2nd, 3rd, 4th, & 5th phalanges at metacarpophalangeal joints - extension of wrist - weak extension of elbow Innervation: - radial nerve, posterior interosseous branch Application, Strengthening, & Flexibility: - also known as digitorum communis - only muscle involved in extension of all 4 fingers - divides into 4 tendons on dorsum of wrist to insert on each finger - assists with wrist extension movements - developed by -> applying manual resistance to dorsal aspect of flexed fingers & extending fingers fully - performing with wrist in flexion, increases workload on extensor digitorum - stretched by -> fingers must be maximally flexed at metacarpophalangeal, proximal interphalangeal & distal interphalangeal joints while wrist is fully flexed

Extensor carpi radialis brevis muscle

Origin: - lateral epicondyle of humerus Insertion: - base of 3rd metacarpal Action: - extension of wrist - adduction of wrist - weak flexion of elbow Innervation: - radial nerve Application, Strengthening, & Flexibility: - important in any sports activity that requires powerful wrist extension e.g.) tennis or golf - development of extensor carpi radialis brevis -> wrist extension exercises - stretching of extensor carpi radialis brevis & longus requires elbow to be extended with forearm pronated while wrist is passively fixed & slightly adducted

Extensor digiti minimi muscle

Origin: - lateral epicondyle of humerus Insertion: - base of middle & distal phalanxes of 5th phalange Action: - extension of little finger at metacarpophalangeal joint - weak wrist extension - weak elbow extension Innervation: - radial nerve, posterior interosseous branch Application, Strengthening, & Flexibility: - primary function is to assist extensor digitorum in extending little finger - dorsal relationship to wrist, it provides weak assistance in wrist extension - strengthened with same exercises like extensor digitorum - stretched by -> passively taking little finger into maximal flexion at metacarpalphalangeal, proximal interphalangeal, & distal interphalangeal joints while fully flexing wrist & elbow

Extensor carpi ulnaris muscle

Origin: - lateral epicondyle of humerus - middle two-fourths of posterior border of ulna Insertion: - base of 5th metacarpal (dorsal surface) Action: - extension of wrist - adduction of wrist together with flexor carpi ulnaris muscle - weak extension of elbow Innervation: - radial nerve, posterior interosseous branch Application, Strengthening, & Flexibility: - powerful wrist extensor - only muscle than flexor carpi ulnaris involved in wrist adduction/ulnar deviation - most powerful of wrist extensors: - extensor carpi ulnaris - extensor carpi radialis brevis - extensor carpi radialis longus - may be developed by performing wrist extension against handheld resistance - accomplished with pronated forearm being supported by table with hand hanging over edge to allow full range of motion - wrist moved from fully flexed to fully extended position against resistance - stretched by -> the elbow to be extended with forearm pronated while wrist is passively flexed & slightly abducted

Flexor carpi radialis muscle

Origin: - medial epicondyle of humerus Insertion: - base of 2nd & 3rd metacarpals, anterior (palmar surface) Action: - flexion of wrist - abduction of wrist - weak flexion of elbow - weak pronation of forearm Innervation: - median nerve Application, Strengthening, & Flexibility: - most powerful of wrist flexors & brought into plat during any activity that requires wrist curling or stabilization of wrist against resistance, if the forearm is supinated - flexor carpi radialis - flexor carpi ulnaris - palmaris longus - flexor carpi radialis developed by performing wrist curls against handheld resistance - accomplished when supinated forearm is supported by table, with hand & wrist hanging over the edge to allow a full range of motion - strengthened by -> extended wrist (flexed or curled up) - stretched by -> elbow must be fully extended with forearm supinated while a partner passively extends & adducts the wrist

Palmaris longus muscle

Origin: - medial epicondyle of humerus Insertion: - palmar aponeurosis of 2nd, 3rd, 4th, & 5th metacarpals Action: - flexion of wrist - weak flexion of elbow Innervation: - median nerve Application, Strengthening, & Flexibility: - online flexor carpi radials & flexor carpi ulnaris, not only wrist flexors but also abductors & adductors - palmaris longus only involved in wrist flexion from anatomical position b/c of central location on anterior forearm & wrist - assists in abducting wrist from an extremely adducted position back to neutral & assist in adducting wrist from an extremely abduction position back to neutral - assists slightly in forearm pronation b/c of slightly lateral insertion in relation to its origin on medial epicondyle - strengthened by -> any type of wrist curling activities e.g.) described for flexor carpi radialis - stretched by -> maximal elbow & wrist extension

Flexor digitorum superficialis muscle

Origin: - medial epicondyle of humerus - ulnar head: medial coronoid process - radial head: upper two-thirds of anterior border of radius just distal to radial tuberosity Insertion: - each tendon splits & attaches to the sides of the middle phalanx of 4 fingers Action: - flexion of humerus at metacarpophalangeal & proximal interphalageal joints - flexion of wrist - weak flexion of elbow Innervation: - median nerve Application, Strengthening, & Flexibility: - also known as flexor digitorum sublimis - divides into 4 tendons on palmar aspect of wrist & hand to insert on each of 4 fingers - flexor digitorum superficialis & flexor digitorum profundus are the only muscles involved in flexion of all 4 fingers - vital in any type of gripping activity - squeezing a sponge rubber ball in palm of hand, along with other gripping & squeezing activities -> develop these muscles - stretched by -> passively extending elbow, wrist, metacarpophalangeal & proximal interphalangeal joints while maintaining forearm in full supination

Flexor carpi ulnaris muscle

Origin: - medial epicondyle of humerus - posterior aspect of proximal ulna Insertion: - pisiform, hamate, & base of 5th metacarpal (palmar surface) Action: - flexion of wrist - adduction of wrist, together with extensor carpi ulnaris muscle Innervation: - ulnar nerve Application, Strengthening, & Flexibility: - very important in wrist flexion/curling activities - one of only 2 muscles involved in wrist adduction of ulnar flexion - strengthen by -> any type of wrist-curling activity against resistance - stretched by -> elbow must be fully extended with forearm supinated while partner passively extends & adducts the wrist

Flexor pollicis longus muscle

Origin: - middle anterior surface of radius & anterior medial border of ulna just distal to coracoid process; occasionally a small head is present attaching on medial epicondyle of humerus Insertion: - base of distal phalanx of thumb Action: - flexion of thumb carpometacarpal, metacarpophalangeal, & interphalangeal joints - flexion of wrist - abduction of wrist Innervation: - median nerve, anterior interosseous branch Application, Strengthening, & Flexibility: - primary function is the flexion of the thumb, which is vital in gripping & grasping activities of the hand - palmar relationship to wrist -> provides some assistance in wrist flexion - strengthened by -> pressing a sponge rubber ball into hand with thumb & by many other gripping/squeezing activities - stretched by -> passively extending entire thumb while simultaneously maintaining maximal wrist extension

Abductor pollicis longus muscle

Origin: - posterior aspect of radius & mid shaft of ulna Insertion: - base of 1st metacarpal Action: - abduction of thumb at carpometacarpal joint - abduction of wrist - extension of thumb at carpometacarpal joint - weak supination of forearm from pronated position - weak extension of wrist joint Innervation: - radial nerve, posterior interosseous branch Application, Strengthening, & Flexibility: - primary function -> abduction of thumb, although it does provide some assistance in abduction of wrist - developed by abutting thumb from adducted position against manual resistance - stretched by -> fully flexing & adducting the entire thumb across the palm with the wrist fully adducted in slight flexion

Extensor pollicis longus muscle

Origin: - posterior lateral surface of the lower middle ulna Insertion: - base of the distal phalanx of thumb Action: - extension of thumb at carpometacarpal, metacarpophalangeal & interphalangeal joints - extension of wrist - abduction of wrist - weak supination of forearm from a pronated position Innervation: - radial nerve, posterior interosseous branch Application, Strengthening, & Flexibility: - primary function -> extension of thumb, although it does provide weak assistance in wrist extension - strengthened by -> extending flexed thumb against manual resistance - stretched by -> passively taking entire little thumb into maximal flexion at carpometacarpal, metacarpophalangeal, & interphalangeal joints while fully flexing wrist with forearm in pronation

Extensor pollicis brevis muscle

Origin: - posterior surface of the lower middle radius Insertion: - base of proximal phalanx of thumb Action: - extension of thumb at carpometacarpo & metacarpophalangeal joints - wrist abduction - weak wrist extension Innervation: - radial nerve, posterior interosseous branch Application, Strengthening, & Flexibility: - extensor pollicis brevis assists the extensor pollicis longus in extending the thumb - dorsal relationship to wrist, provides weak assistance in wrist extension - strengthened through same exercises described fro extensor pollicis longus - stretched by -> passively taking 1st carpometacarpo & metacarpophalangeal joint of the thumb into maximal flexion while fully flexing & adducting the wrist - due to its lateral orientation at the wrist it assists in wrist abduction

Flexor digitorum profundus muscle

Origin: - proximal three-fourths of anterior & medial ulna Insertion: - base of distal phalanxes of 4 fingers Action: - flexion of 4 fingers at metacarpophalangeal, proximal interphalangeal & distal interphalangeal joints - flexion of wrist Innervation: - median nerve, anterior interosseous branch to the 2nd & 3rd fingers - ulnar nerve to the 4th & 5th fingers Application, Strengthening, & Flexibility: - both flexor digitorum profundus & flexor digitorum superficialis muscles assist in wrist flexion b/c of palmar relationship to wrist - flexor digitorum profundus used in any type of gripping, squeezing, or handclenching activity e.g.) gripping a racket or climbing a rope - only muscle that flexes finger dips joints & disruption of tendon at or near its insertion is known as a "jersey or sweater finger" - may be developed through these activities, in addition to strengthening exercises for flexor digitorum superficialis - stretched by -> similar to flexor digitorum superficialis, except that distal interphalangeal joints must be passively extended in addition to wrist, metacarpophalangeal & proximal interphalangeal joints while maintaining forearm in full supination