Chapter 7 the Wrist and Hand Joints

• Many sports require precise functioning of wrist & hand • Archery, bowling, golf, baseball, tennis, etc. Chapter 7 require combined use of wrist & hand joints • Relate functional anatomy to joint actions The Wrist and Hand Joints – flexion, extension, abduction, & adduction of wrist & hand Manual of Structural Kinesiology – 29 bones – More than 25 joints R.T. Floyd, EdD, ATC, CSCS – More than 30 muscles • 18 are intrinsic

Bones Bones

• 29 bones, including radius & ulna Eight carpal bones – 8 carpal bones in 2 rows of 4 bones form wrist • Proximal row from radial – 5 metacarpal bones, numbered 1 to 5 from to ulnar side thumb to little finger, join the wrist bones – scaphoid (boat-shaped) or – 14 phalanges (digits), 3 for each phalange navicular except the thumb, which has only 2 – lunate (moon-shaped) • Proximal, middle, & distal – triquetrum (three-cornered) – Thumb has a sesamoid bone in its flexor – pisiform (pea-shaped) tendon – Other sesamoids may occur in joints of fingers From Anthony CP, Kolthoff NJ: Textbook of anatomy and physiology , ed 9, St Louis, 1975, Mosby.

Bones Bones

Eight carpal bones • Scaphoid most often injured • Distal row, from the radial – From falling on outstretched hand to ulnar side – Often dismissed as a sprain – trapezium (greater – Significant problem if not recognized & multangular) treated properly – trapezoid (lesser multangular) – Usually long period of precise – capitate (head-shaped) immobilization or surgery – hamate (hooked)

1 Bones Bones

• Carpal bones form a three-sided arch • Medial epicondyle, – concave on palmar side medial condyloid ridge, – bony arch is spanned by transverse carpal & volar & coranoid process - carpal ligaments origin for many wrist & – creates the carpal finger flexors tunnel • Lateral epicondyle & – frequently a source of lateral supracondylar problems known ridge - origin for many as carpal tunnel wrist & finger extensors syndrome

Bones Joints

• Key distal bony landmarks for • Wrist joint muscles involved in wrist – condyloid-type joint motion – allows flexion, – base of 2 nd , 3 rd , & 5 th metacarpals, pisiform, & extension, abduction, & hamate adduction • Key bony landmarks for – motion occurs primarily finger muscles between distal radius & – base of proximal, middle, & proximal carpal row distal phalanxes (scaphoid, lunate, & – base of 1 st metacarpal, proximal triquetrum) & distal phalanxes of thumb

Joints Joints • Wrist joint • Each finger has 3 joints – 70 to 90 degrees of flexion – Metacarpophalangeal (MCP) joints – 65 to 85 degrees of extension – Proximal interphalangeal (PIP) joints – 15 to 25 degrees of abduction – Distal interphalangeal (DIP) joints – 25 to 40 degrees of adduction

2 Joints Joints

• Each finger has 3 joints • Each finger has 3 joints – Metacarpophalangeal (MCP) joints – Proximal interphalangeal (PIP) joints • Condyloid • Ginglymus • 0 to 40 degrees of extension • Full extension to 90 to 120 degrees of • 85 to 100 degrees of flexion flexion

Joints Joints

• Each finger has 3 joints • Thumb has 2 joints – Distal interphalangeal (DIP) joints – Metacarpophalangeal (MCP) joint • Ginglymus • Full extension into 40 to 90 degrees of • Flex 80 to 90 degrees from full extension flexion • Ginglymus

Joints Joints

• Thumb has 2 joints • Thumb has 2 joints – Interphalangeal (IP) joint – Carpometacarpal (CMC) joint of thumb • Flex 80 to 90 degrees • Unique saddle-type joint • Ginglymus • 50 to 70 degrees of abduction • Flex 15 to 45 degrees & extend 0 to 20 degrees

3 Movements Movements

• Wrist • Middle phalange is reference point to – Flexion & extension differentiate abduction & adduction – Thumb, index & middle fingers abduct when – Abduction & adduction they move laterally toward radial side of hand • Fingers – Ring & little fingers adduction when they move – Flex & extend medially toward ulnar side of hand – Medial movement of thumb, index & middle – MCP joints also abduct & adduct fingers toward ulnar side of hand is adduction – Lateral movement of ring & little finger toward radial side of hand is abduction

Movements Movements

• Flexion • Extension – movement of palm of – movement of back of hand hand and/or phalanges and/or phalanges toward toward anterior or volar posterior or dorsal aspect aspect of forearm of forearm

Movements Movements

• Abduction (radial • Adduction (ulnar flexion) flexion) – movement of little finger – movement of thumb side of hand toward side of hand toward medial aspect or ulnar lateral aspect or side of forearm radial side of forearm – Also, movement of – Also, movement of fingers toward middle fingers away from finger middle finger

4 Movements Muscles

• Opposition Extrinsic muscles of wrist & hand grouped according to function & location – movement of thumb across palmar aspect to • 6 muscles move wrist but not fingers & thumb oppose any or all of the – 3 wrist flexors phalanges • flexor carpi radialis • Reposition • flexor carpi ulnaris • palmaris longus – movement of thumb as it returns to anatomical – 3 wrist extensors position from opposition • extensor carpi radialis longus with hand and/or fingers • extensor carpi radialis brevis • extensor carpi ulnaris

Muscles Muscles

• 9 muscles primary movers of phalanges – Extensors – Also involved in wrist joint actions • Extensor digitorum – Generally weaker in their wrist actions • Extensor indicis – Flexors • Extensor digiti minimi • Extensor pollicis longus (thumb • Flexor digitorum superficialis extensor) • Flexor digitorum profundus • Extensor pollicis brevis (thumb extensor) • Flexor pollicis longus (thumb flexor) – Abductor of thumb & wrist – Abductor pollicis longus

Muscles Muscles

• All wrist flexors generally have their origins on • Carpal tunnel syndrome anteromedial aspect of proximal forearm and – Swelling & inflammation can cause increased medial epicondyle of humerus with insertions pressure in carpal tunnel resulting in decreased function of median nerve leading to reduced motor on anterior aspect of wrist & hand & sensation function in its distribution • Median nerve & all flexor tendons except – particularly common with repetitive use of the flexor carpi ulnaris & palmaris longus pass hand and wrist in manual labor and clerical work through carpal tunnel such as typing and keyboarding – Often, slight modifications in work habits and hand & wrist positions during these activities can be preventative – Flexibility exercises for the wrist & finger flexors may be helpful

5 Muscles Muscles

• Wrist extensors generally have their origins • Wrist abductors on posterolateral aspect of proximal forearm – Generally cross wrist joint anterolaterally & & lateral humeral epicondyle with insertions posterolaterally to insert on radial side of located on posterior aspect of wrist & hand hand • Flexor & extensor tendons immediately • Flexor carpi radialis proximal to wrist are held in place on palmar • Extensor carpi radialis longus & dorsal aspects by transverse bands of • Extensor carpi radialis brevis tissue known as flexor & extensor retinaculum • Abductor pollicis longus to prevent the tendons from bowstringing • Extensor pollicis longus during flexion & extension • Extensor pollicis brevis

Muscles Muscles

• Wrist adductors • Intrinsic hand muscles have origins & insertions on bones of hand – cross wrist joint anteromedially & – Radial side - four muscles of thumb posteromedially to insert on ulnar side of • opponens pollicis hand • abductor pollicis brevis • Flexor carpi ulnaris • flexor pollicis brevis • Extensor carpi ulnaris • adductor pollicis – Ulnar side - three muscles of little finger • opponens digiti minimi • abductor digiti minimi • flexor digiti minimi brevis

Muscles Muscles

• Intrinsic hand muscles • Anteromedially at elbow & – Remainder of hand - 11 different muscles forearm and anterior at • 4 lumbricals hand • 3 palmar interossei – Primarily wrist flexion • 4 dorsal interossei • Flexor carpi radialis • Flexor carpi ulnaris • Palmaris longus

6 Muscles Muscles

• Anteromedially at • Posterolaterally at elbow & elbow & forearm and forearm and posterior at anterior at hand hand – Primarily wrist & – Primarily wrist extension phalangeal flexion • Extensor carpi radialis • Flexor digitorum longus superficialis • Flexor digitorum • Extensor carpi radialis profundus brevis • Flexor pollicis longus • Extensor carpi ulnaris

Muscles Nerves

• Posterolaterally at elbow & • All wrist & hand muscles are innervated from forearm and posterior at hand the radial, median, & ulnar nerves of the – Primarily wrist & phalangeal brachial plexus extension • Extensor digitorum • Extensor indicis • Extensor digiti minimi • Extensor pollicis longus • Extensor pollicis brevis • Abductor pollicis longus

Nerves Nerves

• Radial nerve from C6, C7, & C8 • Median nerve - arising from C6, C7, C8, & T1 – Extensor carpi radialis brevis – Flexor carpi radialis – Extensor carpi radialis longus – Palmaris longus • Posterior interosseous nerve from radial nerve – Flexor digitorum superficialis – Extensor carpi ulnaris • Anterior interossseous nerve from median nerve – Extensor digitorum – Flexor digitorum profundus for index & long finger – Extensor digiti minimi – Flexor pollicis longus – Abductor pollicis longus – Intrinsic muscles – Extensor pollicis longus • abductor pollicis brevis, flexor pollicis brevis – Extensor pollicis brevis (superficial head), opponens pollicis, and 1 st & nd – Extensor indicis 2 lumbrical

7 Nerves Nerves

• Ulnar nerve - branching • Ulnar nerve - branching from C8 & from C8 & T1 T1 – Remaining intrinsic muscles – Flexor digitorum profundus • flexor pollicis brevis (deep head), for 4 th & 5 th fingers adductor pollicis, palmar interossei, rd th – Flexor carpi ulnaris dorsal interossei, 3 & 4 lumbrical, opponens digiti minimi, abductor digiti minimi, & flexor digiti minimi brevis – Sensation to ulnar side of hand, ulnar one-half of ring finger & entire little finger

Flexor Carpi Radialis Muscle Palmaris Longus Muscle

Flexion of wrist Flexion of wrist Abduction of wrist Weak flexion Weak flexion of of elbow elbow Weak pronation of forearm

Flexor Carpi Ulnaris Muscle Extensor Carpi Ulnaris Muscle Flexion of wrist Adduction of wrist, Extension of together with wrist extensor carpi ulnaris muscle Adduction of wrist Weak flexion of together with flexor elbow carpi ulnaris muscle Weak extension of elbow

8 Extensor Carpi Radialis Brevis Muscle Extensor Carpi Radialis Longus Muscle

Extension of Extension of wrist wrist Abduction of wrist Abduction of wrist Weak flexion of Weak flexion of elbow elbow Weak pronation to neutral from a fully supinated position

Flexor Digitorum Superficialis Muscle Flexor Digitorum Profundus Muscle

Flexion of fingers at Flexion of 4 fingers at metacarpophalangeal metacarpophalangeal, & proximal proximal interphalangeal joints interphalangeal, & distal interphalangeal Flexion of wrist joints

Weak flexion Flexion of wrist of elbow

Flexor Pollicis Longus Muscle Extensor Digitorum Muscle

Flexion of thumb Extension of 2 nd , 3 rd , 4 th , carpometacarpal, & 5 th phalanges at metacarpophalangeal, metacarpophalangeal & interphalangeal joints joints Extension of wrist Flexion of wrist

Abduction of Weak extension wrist of elbow

9 Extensor Indicis Muscle Extensor Digiti Minimi Muscle Extension of index finger at metacarpophalangeal joint Weak wrist extension

Extension of little finger at metacarpophalangeal Weak supination of joint forearm from a pronated position Weak wrist extension Weak elbow extension

Extensor Pollicis Longus Muscle Extensor Pollicis Brevis Muscle Extension of thumb at Extension of thumb at carpometacarpal, carpometacarpal & metacarpophalangeal, & metacarpophalangeal interphalangeal joint joints Extension of wrist Weak wrist extension Abduction of wrist Wrist abduction Weak supination of forearm from a pronated position

Abductor Pollicis Longus Muscle Intrinsic Muscles of the Hand

Abduction of thumb at carpometacarpal joint Abduction of wrist Extension of thumb at carpometacarpal joint Weak supination of forearm from a pronated position Weak flexion of wrist

Modified from Van De Graaff KM: Human anatomy, ed 4, New York, 1995, McGraw-Hill. © 2007 McGraw-Hill Higher Education. All rights reserved. 7-59 © 2007 McGraw-Hill Higher Education. All rights reserved. 7-60

10 Intrinsic Muscles of the Hand Intrinsic Muscles of the Hand • Thenar eminence - muscular pad on • Hypothenar eminence - muscular pad palmar surface of 1 st metacarpal that forms ulnar border on palmar surface – abductor pollicis brevis – abductor digiti minimi – opponens pollicis – flexor digiti minimi brevis – flexor pollicis brevis – opponens digiti minimi – adductor pollicis • Intermediate muscles – three palmar interossei – four dorsal interossei – four lumbrical muscles

Intrinsic Muscles of the Hand Intrinsic Muscles of the Hand • Four muscles act on CMC of thumb • Three palmar interossei – opponens pollicis - opposition in thumb – adduct the 2 nd , 4 th , & 5 th phalanges metacarpal • Four dorsal interossei – abductor pollicis brevis & flexor pollicis brevis – flex & abduct index, middle, & ring proximal abduct thumb metacarpal phalanxes – flexor pollicis brevis flexes thumb metacarpal – assist with extension of middle & distal – adductor pollicis adducts thumb metacarpal phalanxes of index, middle, & ring fingers – flexor pollicis brevis & adductor pollicis flex • Third dorsal interossei proximal phalanx of thumb – adducts middle finger

Intrinsic Muscles of the Hand Wrist Flexion • Four lumbricales • Agonists – flex index, middle, ring, & little proximal – Flexor carpi phalanxes radialis – Flexor carpi – extend middle & distal phalanxes of index, ulnaris middle, ring, & little fingers. – Palmaris longus • Three muscles act on little finger – Flexor digitorum – opponens digiti minimi causes opposition of superficialis little finger metacarpal – Flexor digitorum profundus th – abductor digiti minimi abducts 5 metacarpal – Flexor pollicis – flexor digiti minimi brevis flexes 5 th longus metacarpal

11 Wrist Flexion Wrist Extension • Agonists • Agonists – Extensor carpi – Flexor carpi radialis longus radialis – Extensor carpi – Flexor carpi radialis brevis ulnaris – Extensor carpi – Palmaris longus ulnaris – Flexor digitorum – Extensor digitorum superficialis – Extensor indicis – Flexor digitorum – Extensor digiti minimi profundus – Extensor pollicis – Flexor pollicis longus longus – Extensor pollicis brevis

Wrist Extension Wrist Extension • Agonists • Agonists – Extensor carpi – Extensor carpi radialis longus radialis longus – Extensor carpi – Extensor carpi radialis brevis radialis brevis – Extensor carpi – Extensor carpi ulnaris ulnaris – Extensor digitorum – Extensor digitorum – Extensor indicis – Extensor indicis – Extensor digiti minimi – Extensor digiti minimi – Extensor pollicis – Extensor pollicis longus longus – Extensor pollicis – Extensor pollicis brevis brevis

Wrist Abduction Wrist Abduction

• Agonists • Agonists – Flexor carpi – Flexor carpi radialis radialis – Extensor carpi – Extensor carpi radialis longus radialis longus – Extensor carpi – Extensor carpi radialis brevis radialis brevis – Abductor pollicis – Abductor pollicis longus longus – Extensor pollicis – Extensor pollicis longus longus – Extensor pollicis – Extensor pollicis brevis brevis

12 Wrist Adduction Phalangeal Flexion

• Agonists • Agonists • Flexor carpi – Flexor ulnaris digitorum • Extensor carpi superficialis ulnaris – Flexor digitorum profundus – Flexor pollicis longus

Phalangeal Extension Phalangeal Extension

• Agonists • Agonists – Extensor – Extensor digitorum digitorum – Extensor indicis – Extensor indicis – Extensor digiti minimi – Extensor digiti – Extensor pollicis minimi longus – Extensor pollicis – Extensor pollicis longus brevis – Extensor pollicis brevis

Web Sites Web Sites

Radiologic Anatomy Browser Arthroscopy.Com http://radlinux1.usuf1.usuhs.mil/rad/iong/index.html www.arthroscopy.com/sports.htm – This site has numerous radiological views of the – Patient information on various musculoskeletal problems of musculoskeletal system. the upper and lower extremity University of Arkansas Medical School Gross Anatomy for Premiere Medical Search Engine Medical Students http://www.medsite.com/Default.asp?bhcp=1 http://anatomy.uams.edu/anatomyhtml/grossresources.html – This site allows the reader to enter any medical condition and – Dissections, anatomy tables, atlas images, links, etc. it will search the net to find relevant articles. Loyola University Medical Center: Structure of the Human Body Virtual Hospital www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/GA.html www.vh.org – An excellent site with many slides, dissections, tutorials, etc., – Numerous slides, patient information, etc. for the study of human anatomy Medical Multimedia Group Wheeless’ Textbook of Orthopaedics www.healthpages.org/AHP/LIBRARY/HLTHTOP/CTD/ www.wheelessonline.com/ – A Patient's Guide to Cumulative Trauma Disorder(CTD) – This site has an extensive index of links to the fractures, joints, muscles, nerves, trauma, medications, medical topics, lab tests, and links to orthopedic journals and other orthopedic and medical news. © 2007 McGraw-Hill Higher Education. All rights reserved. 7-77 © 2007 McGraw-Hill Higher Education. All rights reserved. 7-78

13 Web Sites Web Sites

Medical Multimedia Group American Society for Surgery of the Hand www.healthpages.org/AHP/LIBRARY/HLTHTOP/CTS/ctsndx.htm http://www.assh.org/Content/NavigationMenu/PatientsPublic/ – A Patient's Guide to Carpal Tunnel Syndrome HandConditions/ExtensorTendonInjuries/Extensor_Tendon_In Physioroom.com j.htm www.physioroom.com/injuries/arm/index.shtml – Extensor Tendon Injuries – Articles on hand and wrist injuries Dartmouth Medical School www.dartmouth.edu/~anatomy/wrist-hand/muscles/ – Muscles of the wrist and hand American Academy of Orthopaedic Surgeons http://orthoinfo.aaos.org/category.cfm?topcategory=Arm – Patient Education Library on the Hand MayoClinic.com www.mayoclinic.com/invoke.cfm?id=AR00030 – Hand exercises for people with arthritis