Bone and Muscles of the Hand

COLLEGE OF ALLIED COLLEGE OF ALLIED HEALTH AND SCIENCESHEALTH AND SCIENCES

ANATOMY ANATOMY MUSKULOSKELETALMUSKULOSKELETAL

UPPER LIMB (PART 5) UPPER LIMB (PART 5)

Carpals, Metacarpals and Carpals, Metacarpals and PhalangesPhalanges

By : HERMIZAN BIN HALIHANAFIAH

HANDHAND

Introduction Introduction

Gross motor skills and fine motor skills.Gross motor skills and fine motor skills.

5 Digits / fingers5 Digits / fingers

Thumb – pollexThumb – pollex

Index finger – digitus indicisIndex finger – digitus indicis

Middle finger – digitus tertiusMiddle finger – digitus tertius

Ring finger – digitus annulusRing finger – digitus annulus

Little finger – digitus minimiLittle finger – digitus minimi

HandHand Hand composed by a bony Hand composed by a bony

framework :framework : 8 carpals bones8 carpals bones 5 metacarpals5 metacarpals 14 phalanges14 phalanges

Carpal BonesCarpal Bones

The names reflect on their shapeThe names reflect on their shape

Divide in two rows; proximal and distal rowDivide in two rows; proximal and distal row

Proximal row:Proximal row:

From lateral to medialFrom lateral to medial

Scaphoid, lunate, triquetrum and pisiformScaphoid, lunate, triquetrum and pisiform

Distal rowDistal row

From lateral to medialFrom lateral to medial

Trapezium, trapezoid, capitate and hamateTrapezium, trapezoid, capitate and hamate

8 bones of Carpals8 bones of Carpals

A – Scaphoid (boatlike)A – Scaphoid (boatlike) B – Lunate (moon-shaped)B – Lunate (moon-shaped) C – Triquatrum (three-cornered)C – Triquatrum (three-cornered) D – Pisiform (pea-shaped)D – Pisiform (pea-shaped) E – Trapezium (four sided figure)E – Trapezium (four sided figure) F – Trapezoid F – Trapezoid G – Capitate (head-shaped)G – Capitate (head-shaped) H – Hamate (hooked)H – Hamate (hooked)

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CapitateCapitate

Largest carpal boneLargest carpal bone

Rounded projectionRounded projection

Head articulate with lunate boneHead articulate with lunate bone

LunateLunate

Large hook-projection on its anterior Large hook-projection on its anterior

surfacesurface

ScaphoidScaphoid 70 % fractures involve the 70 % fractures involve the

scaphoidscaphoid Fall on outstretched hand – force Fall on outstretched hand – force

is transmitted from the capitate is transmitted from the capitate

through the scaphoid to the radiusthrough the scaphoid to the radius

Carpal TunnelCarpal Tunnel

Concave space formed by the pisiform and hamate (on Concave space formed by the pisiform and hamate (on

the ulnar side), and the scaphoid and trapezium ( on the ulnar side), and the scaphoid and trapezium ( on

the radial side) plus the flexor retinaculum (deep the radial side) plus the flexor retinaculum (deep

fascia)fascia)

Long flexor tendons of the digits and thumb (flexor Long flexor tendons of the digits and thumb (flexor

digitorum superficialis, flexor digitorum profundus, digitorum superficialis, flexor digitorum profundus,

flexor pollicis longus) and the median nerve pass flexor pollicis longus) and the median nerve pass

through the carpel tunnelthrough the carpel tunnel

Narrowing of the carpel tunnel may give rise to a Narrowing of the carpel tunnel may give rise to a

condition called condition called carpal tunnel syndromecarpal tunnel syndrome..

Anatomy of Carpal Tunnel

Carpal Turnel SyndromeCarpal Turnel Syndrome

Flexor RetinaculumFlexor Retinaculum

The The flexor retinaculumflexor retinaculum ( (transverse transverse

carpal ligamentcarpal ligament, or , or anterior annular anterior annular

ligamentligament) is a strong, fibrous band, which ) is a strong, fibrous band, which

arches over the carpus. arches over the carpus. Converting the deep groove on the front of Converting the deep groove on the front of

the carpal bones into a tunnel, the the carpal bones into a tunnel, the carpal carpal

tunneltunnel Flexor tendons of the digits and the Flexor tendons of the digits and the

median nerve pass.median nerve pass.

Flexor Retinaculum

Extensor RetinaculumExtensor Retinaculum

The The extensor retinaculumextensor retinaculum ( (dorsal dorsal

carpal ligamentcarpal ligament) is an anatomical term ) is an anatomical term

for the fascia that holds the tendons of the for the fascia that holds the tendons of the

extensor muscles in place. extensor muscles in place.

It is located on the back of the forearm, It is located on the back of the forearm,

just proximal to the hand.just proximal to the hand.

Extensor Retinaculum

Joints of the Carpal BonesJoints of the Carpal Bones

Intercarpal Intercarpal

/midcarpal joint/midcarpal joint

Articulation between Articulation between

carpals bone.carpals bone.

Planar jointPlanar joint

Biaxial movement – Biaxial movement –

gliding gliding

movement( back – movement( back –

forth , side – side)forth , side – side)

MetacarpalsMetacarpals

Divide into:Divide into:

Proximal baseProximal base

Intermediate shaftIntermediate shaft

Distal headDistal head

It consists of five cylindrical bones which are It consists of five cylindrical bones which are

numbered from the radial (lateral ) to the numbered from the radial (lateral ) to the

ulnar (medial) side.ulnar (medial) side.

1.1. First metacarpal bone First metacarpal bone

2.2. Second metacarpal bone Second metacarpal bone

3.3. Third metacarpal bone Third metacarpal bone

4.4. Fourth metacarpal bone Fourth metacarpal bone

5.5. Fifth metacarpal bone Fifth metacarpal bone



Proximal base

Intermediate Shaft

Distal Head

Joints of the MetacarpalsJoints of the Metacarpals Carpometacarpal jointsCarpometacarpal joints

Proximal based of metacarpals articulate with Proximal based of metacarpals articulate with distal row of carpal bones.distal row of carpal bones.

11stst metacarpal articulate with trapezium bones metacarpal articulate with trapezium bones The second metacarpal articulates primarily The second metacarpal articulates primarily

with the trapezoid and secondarily with the with the trapezoid and secondarily with the trapezium and capitate. trapezium and capitate.

The third metacarpal articulates primarily with The third metacarpal articulates primarily with the capitate, the capitate,

The fourth metacarpal articulates with the The fourth metacarpal articulates with the capitate and hamate. capitate and hamate.

The fifth metacarpal articulates with the The fifth metacarpal articulates with the hamate. hamate.

CarpometacarpalCarpometacarpal The 1The 1stst CMC (between trapezium and 1 CMC (between trapezium and 1stst

metacarpal) is a saddle jointmetacarpal) is a saddle joint

Also known as a trapeziometacarpal joint Also known as a trapeziometacarpal joint

(TMC)(TMC)

Produce triaxial diarthrosisProduce triaxial diarthrosis

The rest CMC – condyloid jointThe rest CMC – condyloid joint

Produce biaxial diarthrosisProduce biaxial diarthrosis

Joints of the MetacarpalsJoints of the Metacarpals

Metacarpophalangeal jointMetacarpophalangeal joint

Distal head of metacarpals articulate Distal head of metacarpals articulate

with proximal phalanges.with proximal phalanges.

Condyloid jointCondyloid joint

Produce biaxial diarthrosis ; flexion – Produce biaxial diarthrosis ; flexion –

extension / abduction - adductionextension / abduction - adduction

Joints of the MetacarpalsJoints of the Metacarpals

PhalangesPhalanges

14 bones14 bones Numbered 1-5 same with metacarpalsNumbered 1-5 same with metacarpals Each phalanx consist:Each phalanx consist:

Proximal baseProximal base Intermediate shaftIntermediate shaft Distal headDistal head

2 phalanges in thumb, 3 the other 2 phalanges in thumb, 3 the other

fingers.fingers.

Phalanges can divide into:Phalanges can divide into:

Proximal phalanxProximal phalanx

Middle phalanxMiddle phalanx

Distal phalanxDistal phalanx

Except thumb; only proximal and distal Except thumb; only proximal and distal

part.part.

PhalangesPhalanges

Joint of the PhalangesJoint of the Phalanges

Interphalangeal jointInterphalangeal joint Joint between phalangesJoint between phalanges

Proximal and distal IP Proximal and distal IP

except thumbexcept thumb

Hinge jointHinge joint

Permits monoaxial Permits monoaxial

diarthrosis ; flexion and diarthrosis ; flexion and

extensionextension

Movement of Hand and DigitsMovement of Hand and Digits

ulnar and radial deviation at RCulnar and radial deviation at RC Wrist flexion and extension at RCWrist flexion and extension at RC Flexion and extension digit at MCPFlexion and extension digit at MCP Abduction and adduction digits at MCPAbduction and adduction digits at MCP Abduction and adduction thumb at 1Abduction and adduction thumb at 1stst CMC CMC Opposition and reposition thumb at 1Opposition and reposition thumb at 1stst

CMCCMC Flexion and extension digits at IPFlexion and extension digits at IP

Wrist MovementWrist Movement

Thumb MovementThumb Movement

Thumb opposition Thumb adductionThumb abduction

Adduction / abduction digits at MCPAdduction / abduction digits at MCP

Thumb extension / flexion at Thumb extension / flexion at MCP / CMCMCP / CMC

Flexion Digit at PIP / DIPFlexion Digit at PIP / DIP

Muscles of the Forearm Move the Muscles of the Forearm Move the Wrist, Hand, Thumb and FingersWrist, Hand, Thumb and Fingers

Group of muscles that act on the digits are known Group of muscles that act on the digits are known

as as extrinsic hand musclesextrinsic hand muscles because originate because originate

outside the hand and insert within it.outside the hand and insert within it.

There is 2 groups of forearm muscles:There is 2 groups of forearm muscles:

Anterior compartment (flexor muscles)Anterior compartment (flexor muscles)

Posterior compartment (extensor muscles)Posterior compartment (extensor muscles)

Extrinsic Hand MusclesExtrinsic Hand Muscles

Anterior compartment of Anterior compartment of Forearm MusclesForearm Muscles

Muscle of the forearm originate on Muscle of the forearm originate on

the humerusthe humerus Insert on the carpals, metarcarpals, Insert on the carpals, metarcarpals,

and phalangesand phalanges Act as flexorAct as flexor Divide into superficial or deep Divide into superficial or deep

muscles.muscles.

Posterior compartment of Posterior compartment of Forearm MusclesForearm Muscles

Muscle of the forearm originate on Muscle of the forearm originate on

the humerusthe humerus Insert on the carpals, metarcarpals, Insert on the carpals, metarcarpals,

and phalangesand phalanges Act as extensorAct as extensor Divide into superficial or deep Divide into superficial or deep

muscles.muscles.

Forearm MusclesForearm Muscles

Superficial anterior compartment Superficial anterior compartment

musclesmuscles

Deep anterior compartment musclesDeep anterior compartment muscles

Superficial posterior compartment Superficial posterior compartment

musclesmuscles

Deep posterior compartment musclesDeep posterior compartment muscles

Superficial Anterior Compartment Superficial Anterior Compartment MusclesMuscles

Arrange in following order from lateral to Arrange in following order from lateral to

medial:medial:

1.1. Flexor carpi radialisFlexor carpi radialis

2.2. Palmaris longusPalmaris longus

3.3. Flexor carpi ulnarisFlexor carpi ulnaris

4.4. Flexor digitorum superficialis – deep to the Flexor digitorum superficialis – deep to the

other 3 muscles and is a largest superficial other 3 muscles and is a largest superficial

muscle in the forearm.muscle in the forearm.

From lateral – medial : Flexor Carpi Radialis, Palmaris Longus, Flexor Carpi Ulnaris, Flexor Digitorum Superficialis

Deep Anterior Compartment Deep Anterior Compartment MusclesMuscles

Arrange in following order from Arrange in following order from lateral to medial:lateral to medial:

1.1. Flexor pollicis longusFlexor pollicis longus

2.2. Flexor digitorum profundusFlexor digitorum profundus

Deep Flexor Muscles: From lateral to Medial : Flexor Pollicis Longus, Flexor Digitorum Profundus (deep to flexor digitorum

superficialis)

Superficial Posterior Compartment Superficial Posterior Compartment MusclesMuscles

Arrange in following order from lateral Arrange in following order from lateral

to medial:to medial:

1.1. Extensor carpi radialis longusExtensor carpi radialis longus

2.2. Extensor carpi radialis brevisExtensor carpi radialis brevis

3.3. Extensor digitorumExtensor digitorum

4.4. Extensor digiti minimiExtensor digiti minimi

5.5. Extensor carpi ulnarisExtensor carpi ulnaris

From lateral – medial : extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris

Deep Posterior Compartment Deep Posterior Compartment MusclesMuscles

Arrange in following order from Arrange in following order from

lateral to medial:lateral to medial:

1.1. Abductor pollicis longusAbductor pollicis longus

2.2. Extensor pollicis brevisExtensor pollicis brevis

3.3. Extensor pollicis longus Extensor pollicis longus

4.4. Extensor indicisExtensor indicis

From lateral to medial : abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis.

Flexor Carpi RadialisFlexor Carpi Radialis Origin – medial epicodyle of Origin – medial epicodyle of

humerushumerus

Insertion –base of Second Insertion –base of Second

and third metacarpalsand third metacarpals

ActionAction

Flexion and abduction Flexion and abduction

hand (radial deviation) at hand (radial deviation) at

wrist jointwrist joint

Nerve innervations – Nerve innervations –

median nervemedian nerve

Palmaris longusPalmaris longus

Origin – medial epicondyle of Origin – medial epicondyle of

humerushumerus

Insertion – flexor retinaculum Insertion – flexor retinaculum

and palmar aponeurosis (deep and palmar aponeurosis (deep

fascia in center of palm)fascia in center of palm)

ActionAction

Weakly flexes hand at wrist Weakly flexes hand at wrist

jointjoint

Nerve innervations – median Nerve innervations – median

nervenerve

Flexor Carpi UlnarisFlexor Carpi Ulnaris Origin – medial epicondyle of Origin – medial epicondyle of

humerus, proximal posterior of humerus, proximal posterior of

ulnaulna

Insertion – pisiform, hamate, Insertion – pisiform, hamate,

and base of fifth metacarpal.and base of fifth metacarpal.

Action – flexion and adduction Action – flexion and adduction

hand (ulnar deviation) at wrist hand (ulnar deviation) at wrist

joint.joint.

Nerve innervations – ulnar Nerve innervations – ulnar

nervenerve

Flexor digitorum superficialisFlexor digitorum superficialis

Origin – medial epicondyle of humerus, coronoid process Origin – medial epicondyle of humerus, coronoid process

of ulna, ridge along lateral margin of anterior surface of of ulna, ridge along lateral margin of anterior surface of

radius.radius.

Insertion – middle phalanx of each fingers (2Insertion – middle phalanx of each fingers (2ndnd – 5 – 5thth digits) digits)

Action Action

Flexion the proximal interphalangeal joints of 2Flexion the proximal interphalangeal joints of 2ndnd

through 5through 5thth digits digits

Assist flexion metacarpophalangealAssist flexion metacarpophalangeal

Assist wrist flexionAssist wrist flexion

Nerve innervations – Medial nerveNerve innervations – Medial nerve

Flexor digitorum superficialisFlexor digitorum superficialis

Flexor Pollicis LongusFlexor Pollicis Longus Origin – anterior surface of Origin – anterior surface of

radius and interosseous radius and interosseous

membrane, medial epicondyle membrane, medial epicondyle

of humerusof humerus

Insertion – base of distal Insertion – base of distal

phalanx of thumbphalanx of thumb

Action – flexes distal phalanx of Action – flexes distal phalanx of

thumb at interphalangeal joint.thumb at interphalangeal joint.

Nerve innervations – Median Nerve innervations – Median

nervenerve

Flexor Digitorum ProfundusFlexor Digitorum Profundus

Origin - anterior medial surface of proximal body of Origin - anterior medial surface of proximal body of

ulnaulna Insertion – base of distal phalanx of each finger (2Insertion – base of distal phalanx of each finger (2ndnd – –

55thth)) ActionAction

Flexion distal interphalangeal joint of 2Flexion distal interphalangeal joint of 2ndnd – 5 – 5thth

digitsdigits Assist flexion proximal interphalangeal and MCPAssist flexion proximal interphalangeal and MCP Assist wrist flexionAssist wrist flexion

Nerve innervations – index and middle (median Nerve innervations – index and middle (median

nerve), ring and digiti minimi (ulnar nerve)nerve), ring and digiti minimi (ulnar nerve)

Flexor Digitorum ProfundusFlexor Digitorum Profundus

Flexor Digitorum Profundus (FDP) & Superficialis (FDS)

Flexor digitorum superficialis (FDS) insert into middle phalanx.

Flexor digitorum profundus (FDP) runs deep to the FDS until the level of the MP joint where FDS bifurcates.

FDP inserts at the base of the distal phalanx and acts primarily to flex the DIP joint as well as all other joints flexed by FDS.

Extensor Carpi Radialis LongusExtensor Carpi Radialis Longus

Origin – lateral Origin – lateral

supracondylar ridge of supracondylar ridge of

humerushumerus

Insertion – dorsal surface Insertion – dorsal surface

of base second of base second

metacarpal metacarpal

Action – extend and Action – extend and

abduct hand at wrist jointabduct hand at wrist joint


Radial nerveRadial nerve

Extensor Carpi Radialis BrevisExtensor Carpi Radialis Brevis

Origin – lateral epicondyle Origin – lateral epicondyle

of humerusof humerus

Insertion – dorsal surface Insertion – dorsal surface

of base third metacarpalof base third metacarpal

Action - Extend and Action - Extend and

adduct hand at wrist jointadduct hand at wrist joint



Extensor digitorumExtensor digitorum Origin – lateral epicondyle of humerusOrigin – lateral epicondyle of humerus Insertion – dorsum of distal and middle phalanges of Insertion – dorsum of distal and middle phalanges of

each fingers (2each fingers (2ndnd - 5 - 5thth digits). digits). Action Action

Extends proximal of each finger at Extends proximal of each finger at metacarpophalangeal jointmetacarpophalangeal joint

Extends distal and middle phalanges of each Extends distal and middle phalanges of each fingers at interphalangeal joint.fingers at interphalangeal joint.

Assists in Extends hand at wrist jointAssists in Extends hand at wrist joint Nerve innervation – Radial nerveNerve innervation – Radial nerve

Extensor digitorumExtensor digitorum

Extensor digiti minimiExtensor digiti minimi

Origin – lateral epicondyle of Origin – lateral epicondyle of

humerushumerus Insertion – tendon of extensor Insertion – tendon of extensor

digitorum on fifth phalanx.digitorum on fifth phalanx. ActionAction

Extends proximal phalanx of Extends proximal phalanx of

little finger at little finger at

metacarpophalangealmetacarpophalangeal Extend the interphalangeal of Extend the interphalangeal of

little finger.little finger. Nerve supply – Radial nerveNerve supply – Radial nerve

Extensor Carpi UlnarisExtensor Carpi Ulnaris

Origin – lateral epicondyle Origin – lateral epicondyle

of humerus and posterior of humerus and posterior

border of ulnaborder of ulna Insertion –base of fifth Insertion –base of fifth

metacarpalmetacarpal Action – extends and Action – extends and

adducts hand at wrist adducts hand at wrist

joint.joint. Nerve innervations – Nerve innervations –


Abductor Pollicis LongusAbductor Pollicis Longus

Origin – posterior surface of Origin – posterior surface of middle of radius and ulna and middle of radius and ulna and interosseous membraneinterosseous membrane

Insertion – base of first Insertion – base of first metacarpalsmetacarpals

ActionAction Abducts and extends thumb Abducts and extends thumb

at carpometacarpal jointat carpometacarpal joint Abducts hands at wrist jointAbducts hands at wrist joint

Nerve innervations – Radial Nerve innervations – Radial nervenerve

Extensor pollicis brevisExtensor pollicis brevis

Origin – posterior surface of middle of radius and Origin – posterior surface of middle of radius and interosseous membrane.interosseous membrane.

Insertion – base of proximal phalanx of thumbInsertion – base of proximal phalanx of thumb ActionAction

Extends proximal phalanx of thumb at Extends proximal phalanx of thumb at metacarpophalangeal jointmetacarpophalangeal joint

Extends1Extends1stst metacarpal of thumb at metacarpal of thumb at carpometacarpal jointcarpometacarpal joint

Assists in radial deviation at wrist jointAssists in radial deviation at wrist joint Nerve innervations – Radial nerveNerve innervations – Radial nerve

Extensor pollicis brevisExtensor pollicis brevis

Extensor Pollicis LongusExtensor Pollicis Longus Origin – posterior surface of middle of ulna and Origin – posterior surface of middle of ulna and

interosseous membraneinterosseous membrane Insertion – base of distal phalanx of thumbInsertion – base of distal phalanx of thumb Action Action

extend distal phalanx of the thumb at interphalangeal extend distal phalanx of the thumb at interphalangeal

jointjoint Assist in extension of thumb at metacarpophalangeal Assist in extension of thumb at metacarpophalangeal

and carpometacarpal joint.and carpometacarpal joint. Assist radial deviation and extension hand at wrist Assist radial deviation and extension hand at wrist

joint.joint. Nerve innervations - Radial nerveNerve innervations - Radial nerve

Extensor pollicis longusExtensor pollicis longus

Extensor IndicisExtensor Indicis

Origin – posterior surface of Origin – posterior surface of

ulna, interosseous membraneulna, interosseous membrane

Insertion – tendon of entensor Insertion – tendon of entensor

digitorum of index fingerdigitorum of index finger

Action – extend distal and Action – extend distal and

middle phalanx at IP joint, middle phalanx at IP joint,

extend proximal phalanx at extend proximal phalanx at

MCPMCP

Deep radial nerveDeep radial nerve

Surface anatomy of hand

The tendons that are

palpated with thumb

abducted and

extended form an

anatomic snuff-box

Surface anatomy of hand

Flexor Tendons: Flexor carpi

radialis, flexor carpi ulnaris, and palmaris longus primarily flex the wrist

Intrinsic Hand MusclesIntrinsic Hand Muscles

Has a origins and Has a origins and insertions within insertions within the handthe hand

Produce weak but Produce weak but intricate and intricate and precise precise movements of the movements of the digits (Fine motor digits (Fine motor skills)skills)

Intrinsic Hand MusclesIntrinsic Hand Muscles

The intrinsic muscle of the hand divided The intrinsic muscle of the hand divided

into 3 groups:into 3 groups:

Thenar musclesThenar muscles

Hypothenar musclesHypothenar muscles

Intermediate musclesIntermediate muscles

Thenar MusclesThenar Muscles

Thenar (lateral aspect of palm)

Abductor pollicis brevis

Opponens pollicis

Flexor pollicis brevis

Adductor pollicis

Move the thumb (pollex)

This 4 muscles form the thenar eminence, lateral

rounded contour on the palm. (ball of the thumb)

Abductor Pollicis Abductor Pollicis BrevisBrevis

OriginOrigin Flexor retinaculumFlexor retinaculum ScaphoidScaphoid TrapeziumTrapezium

InsertionInsertion Lateral side of proximal Lateral side of proximal

phalanx of thumbphalanx of thumb Action Action

Abduct of thumb at CMC Abduct of thumb at CMC

joint.joint. Median NerveMedian Nerve

Opponens PollicisOpponens Pollicis OriginOrigin

Flexor retinaculumFlexor retinaculum TrapeziumTrapezium

InsertionInsertion Lateral side of 1Lateral side of 1stst

metacarpal (thumb)metacarpal (thumb)

ActionAction Opposition thumb at CMC Opposition thumb at CMC

joint.joint.

Median nerveMedian nerve

Flexor Pollicis BrevisFlexor Pollicis Brevis OriginOrigin

Flexor retinaculumFlexor retinaculum TrapezoidTrapezoid TrapeziumTrapezium CapitateCapitate

InsertionInsertion Lateral side of proximal phalanx of Lateral side of proximal phalanx of

thumb.thumb. ActionAction

Flexion thumb at CMC and MCP joint.Flexion thumb at CMC and MCP joint. Median and ulnar nervesMedian and ulnar nerves

Adductor PollicisAdductor Pollicis OriginOrigin

Oblique head – Capitate and 2Oblique head – Capitate and 2ndnd

and 3and 3rdrd metacarpals metacarpals

Transverse head – 3Transverse head – 3rdrd metacarpal metacarpal

InsertionInsertion

Medial side of proximal phalanx of Medial side of proximal phalanx of

thumbthumb

Action – adduct thumb at CMC and Action – adduct thumb at CMC and

MCPMCP

Ulnar NerveUlnar Nerve

Hypothenar Muscles

Medial aspect of palm

Abductor digiti minimi

Flexor digiti minimi brevis

Opponens digiti minimi

Move the digiti minimi

This 3 muscles form the

hypothenar muscles (medial

rounded contour in the palm)

– ball of the little finger

Abductor digiti minimiAbductor digiti minimi OriginOrigin

Tendon flexor carpi ulnarisTendon flexor carpi ulnaris

PisiformPisiform

InsertionInsertion

Medial side of proximal phalanx of Medial side of proximal phalanx of

little fingers.little fingers.

ActionAction

Abduction little finger at MCPAbduction little finger at MCP

Assist flexion little finger at MCPAssist flexion little finger at MCP

Ulnar nerveUlnar nerve

Flexor digiti minimi Flexor digiti minimi brevisbrevis

OriginOrigin

Flexor retinaculumFlexor retinaculum

HamateHamate

InsertionInsertion

Medial side of proximal phalanx Medial side of proximal phalanx

of little fingersof little fingers

Action – flexion little finger at MCP, Action – flexion little finger at MCP,

assist opposition little finger at assist opposition little finger at

CMC CMC


Opponens Digiti Opponens Digiti MinimiMinimi

Origin Origin

Flexor retinaculumFlexor retinaculum

HamateHamate

InsertionInsertion

Medial side of entire length Medial side of entire length

fifth metacarpals (little fifth metacarpals (little

finger)finger)

ActionAction

Opposition little finger at Opposition little finger at

CMCCMC


Intermediate MuscleIntermediate Muscle

Midpalmar / intermediate (11 muscles)

Lumbricals

Palmar interossei

Dorsal interossei

Acts on all the digits

Important muscles for movements in skilled

activities (playing piano , writing, typing,

precision handling etc)

Lumbricals Consists of 4 musclesConsists of 4 muscles OriginOrigin

Lateral and adjacent side of tendons of flexor digitorum Lateral and adjacent side of tendons of flexor digitorum

profundus of each fingers (2profundus of each fingers (2ndnd – 5 – 5thth)) InsertionInsertion

Lateral side of tendon of extensor digitorum on Lateral side of tendon of extensor digitorum on

proximal phalanges of each fingers (2proximal phalanges of each fingers (2ndnd – 5 – 5thth)) ActionAction

Flexion each finger at MCP and extend each finger at IPFlexion each finger at MCP and extend each finger at IP Median and ulnar nerveMedian and ulnar nerve

Lumbricals

Flexor Digitorum

Profundus

1st lumbricals

Insertion to tendon of

Extensor digitorum

4th lumbricals

Palmar interosseiPalmar interossei 4 muscles Origin

Sides of shafts of metacarpals of all digits (except the middle one)

Insertion Side of bases of proximal

phalanges of all digits (except the middle finger)

Action Adduction each finger at

MCP assists in Flexion each finger at MCP

Ulnar nerves

Dorsal InterosseiDorsal Interossei

4 muscles4 muscles OriginOrigin

Adjacent side of metacarpalsAdjacent side of metacarpals InsertionInsertion

Proximal phalanx of each Proximal phalanx of each fingerfinger

ActionAction Abduction Finger 2-4 at MCPAbduction Finger 2-4 at MCP Assist Flexion Finger 2-4 at Assist Flexion Finger 2-4 at

MCP and extension at IP at MCP and extension at IP at the same fingerthe same finger



Concave space located at the palmar Concave space located at the palmar

surface of the wrist.surface of the wrist. Formed by medially by pisiform and Formed by medially by pisiform and

hamate and laterally by scaphoid hamate and laterally by scaphoid

and trapezium.and trapezium. Cover by flexor retinaculum on the Cover by flexor retinaculum on the

roof side.roof side.


10 structures passed through this 10 structures passed through this

passageway.passageway. 4 flexor digitorum superficialis4 flexor digitorum superficialis 4 flexor digitorum profundus4 flexor digitorum profundus 1 flexor pollicis longus1 flexor pollicis longus Median nerve Median nerve

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Health & Medicine

Bone and Muscles of the Hand