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Hand
-Bones
-Articulation
-Musculature
-Vasculature
-innervation
Bones of hand
Matecarpals: 5, base, shaft and head
Phalanges: 3 rows from 2ndto 5th, thumb 2 bones
Fractures are common
Articulation
carpometacarpal joints
1stjoint ( thumb)b/w trapezium and 1stmtacarpal bone
Movement:
flexion / extension ( 75)
Abduction / adduction
Opposition ( flexion and abduction)
Reposition ( extension and abduction)
Support by carpometacarpal ligament
Others:
allow, slight flexion, extension, abduction and adduction
metacarpophalangeal joint
Flexion / extension (100)Abduction/adduction ( up to 30)Rotation is possibleProximal and distal -3interphalangeal
joint ( PIP , DIP)1stfinger has only IPOnly flexion and extension
Dorsum of the hand
Fascia:forearm fascia condense at dorsum of wrist to form extensor retinaculumTendons lie in synovial sheath, to distal to
retinaculumDorsal subcutaneous space: b/w skin and fascia with tendons of extensor digitorumSkin is mobile, thin can pickup, little fatArea
rich in blood supply, cutaneous nerves and rich lymphatic networkInfection of palm spread to dorsal spaceSynovial sheath: facilitate
movement
Innervation:3½ : 1 ½ branches of radial : ulnar ( superfacial branch of radial and posterior cut, branch of ulnar )At nail bed up to middle phalanx same but
by median : ulnar
Extensor tendon and expantion
•for each finger, extensor tendon passes over the MPJ and blend with triangular fibrous expansion over proximal phalanx
margins thickened by attachement with tendons of interosseus and lumbrical muscles
•then divide into 3 bands, central over PIP into base of middle phalanx, ,
•2 lateral bands over PIP and DIP to base of distal phalanx
Extrensic muscles
•The extensor of the wrist inserted to 1st and 5th metacarpal bones
•Extensors of the fingers lie superficially to deep fascia and interconnected near metacarpal heads
•EI joins the tendon of index finger
•EDM joins the tendon of little finger
Extrensic muscles:Arranged in 2 layers in the forearmSuperficial group: act on fingers: ( extensor digitorum and ext digiti minimi)Deep
group: on index and thumb ( extensor indicis, abd pol longus, ext pol brevis, ext pol longus)Ext digitorum in hand divide into 4 slips into apeneorosis of 2nd
to 5th fingersabd pol longus and ext pol brevis: inserted into base of 1st metacarpal and proximal phalanx Ext pol longus: distal phalanx
Palm of the handflexure creases, papillary ridges ( finger prints)
Skin:
More sweat glands, no sebaceous glands, no hair
The sensory nerve supply to the skin of the palm
•palmar cutaneous branch of the median nerve ,which crosses in front of the flexor retinaculum and supplies the lateral part of
the palm,
•the palmar cutaneous branch of the ulnar nerve ;the latter nerve also crosses in front of the flexor retinaculum and supplies the
medial part of the palm.
•The skin over the base of the thenar eminence is supplied by the lateral cutaneous nerve of the forearm or the superficial
branch of the radial nerve
Palm of the hand
•Fascia
•1-subcutaneaus fascia: connect palmar skin with aponeuroses so limit movement
•2-flexor retinaculum
3-palmar apeneurosis
•Deep fascia in the central area of the palm, triangular in shape
•Continuous proximally (apex) with flexor retinaculum
•Distally ( base) divided into 4 slips, one for each finger
Medially and laterally with fascia covering the thinnar and hypothinnar areas in which fibrous septa formedFunction: firm
attachments to skin to improve grip and protect tendons
Dupuyterene contractureLocalized thickness and contracture of P.A.USUALLY BIGENS IN RING FINGER AND FLEX IT AT
MPJOTHER FINGERS INVOLVED IN MPJ AND PIPDIJ ARE NOT INVOLVED
Flexor retinaculum
•2-3 cm , in front of concaved curved carpus fporming carpal tunnel
•Attached to hamate and pisiform medially
•Scaphoid and trapezium laterally
•Flexor tendons of fingers and thumb and median nerve
•Tendons of FDS lie in 2 row , middle and ring in front
•Tendon of FDP lie in same plane
•All 8 tendons share common flexor sheath
•FPL
•FCR
•MEDIAN NERVE
•The ulnar nerve and artery lie in front of retinaculum, palmar cutaneous branch of median nerve
•Palmaris longus tendon
Carpal tunnal syndrome
•When the median nerve compression occur due to arthritic changes in the wrist joint, synovial sheath thickening or odema
•Impaired sensation over median nerve innervation areas ( altered sensation over 3 ½ fingers, weakness of thenar muscles)
•Sensation over thenar area supplied by palmar branch of median nerve passes over retinaculum
Synovial flexor sheath
•Invest the flexor tendons in the wrist for about 2.5 cm, in 2 layers, one covering the long tendons other covering the fibrous sheath
•Tendon of FPL sheath extend till insertion
•Tendons of flexor digitorum has common sheath, extend to the mid palm , for all length, to little finger only
•Others separated then covered the tendons in the fingers, so short area of bar tendon for 3 fingers at level of proximal and distal creases
•The common sheath known as ulnar bursa and FPL sheath known as radial bursa, which communicate together in 50%
•Function: allow long tendons to move smoothly
•Tenosynovitis
Muscles of the hand1-Extrinsic palmar muscles:digital attachments
•A-flexors
•Tendons lie in carpal tunnel
•Superficial layer: palmaris longus ( sup to retinaculum)
•Intermediate: flexor digitorum superficialis into 4 tendons at wrist inserted by divided into 2 halves at level of proximal phalanx
to borders of middle phalanx
•Deep: flexor digitorum profundus 4 tendons to anterior surface of g the base of distal phalanx , passes in b/w of FDS tendon
•flexor pollicis longus : to distal phalanx of the thumb
Muscles of the hand
•Intermediate: flexor digitorum superficialis into 4 tendons at wrist inserted by divided into 2 halves at level of proximal phalanx
to borders of middle phalanx
Muscles of the hand
•Deep: flexor digitorum profundus 4 tendons to anterior surface of g the base of distal phalanx , passes in b/w of FDS tendon
•flexor pollicis longus: to distal phalanx of the thumb
Intrinsic palmar musculature1-Thenar eminence
•Made up of 3 short thumb muscles
•Origin from flexor retinaculum
•1-abductor pollicis brevis: to base of proximal phalanx
•2-flexor pollicis brevis: to proximal phalanx
•3-opponens pollicis: to metacarpal bone of thumb
•Nerve supply: median nerve
Intrinsic palmar musculature
•2-Hypothenar eminence
•1-abductor digiti minimi
•2-flexor digiti minimi
•3-opponens digiti minimi
•Nerve supply ; deep branch of ulnar nerve
•To cup the palm and assist the grip of a large object
Intrinsic palmar musculature:4-adductor pollicisLie deep, has 2 heads, metacarpalThe two head has same insertionDeep branch of Ulnar nerve
palmar muscles
•A-dorsal interosseus
•muscle: 4 bipennate muscles
•originateby 2 heads ,1st from 1st and 2nd metacarpal bone, 2nd from 2nd and 3rd , 3rd from 3rd and 4th, and 4th from 4th and 5th
metacarpal bones .
•inserted to: 1st to lateral side of PP of index, 2nd to lateral side of PP of middle, 3rd to medial side of PP of middle, 4th to medial side of PP
of ring finger
•Also in extensor expansion
•No thumb and little finger so attach to 3 digits
•B-palmar interosseus muscle: 4 unipennate muscles ,
•1st is originate from the medial side of 1st metacarpal bone, 2nd, 3rd and 4th from 2nd , 4th and 5th metacarpal bone
•Insertion: 1st to medial side of PP of thumb, 2ND medial side of PP of index
•3rd and 4th into lateral side of ring and little fingers
•Also in extensor expantions for each
•index no palmar muscles
•Nerve: “ deep branch of ulnar
•Action: PAD= palmar adduct , flexion ( MPJ), extension ( IPJ)
•DAB = dorsal abduct , flexion ( MPJ), extension ( IPJ)
Intrinsic palmar musculature:C-lumbrical muscles: from tendons of flexor digitorum profundusInserted into the lateral side of
extensor expansion on the dorsum of the proximal phalanx for same digitLumbricals I & II: unipennate, innervated by median nerve arise
from 1 tendonLumbricals III & IV: bipennate : innervated by ulnar nerve arise from 2 tendonsFlex MPJ , extend IPJ
:Group actionAbduction at MPJ: by dorsal interosseus musclesAbduct 2nd, 4thand 5thaway midline, 3rdinto radial and ulnar sidesAdduction
at MPJ: by palmar interosseus muscles adduct 2nd, 4thand 5thNo palmar muscles at middle fingerFlexion at MPJ: by oth palmar and dorsal
interosseus muscles and lumbricals which are stronger flexor than other musclesExtension at MPJ: interosseus muscles and lumbricals
Group action;FLEXION of digitsFlexion at MPJ : by interosseiFlexion at PIP: FDSFlexion at DIP:
FDP
of thumb: Group actionFlexion: by FPL ( IPJ) & FPB ( MPJ)Extension: by EPL AND EPBAbduction: by AbPL ( carpometacarpal) & AbPB (
MPJ)Adduction: by AdP ( carpometacarpal)Opposition: involve medial rotation by OP & FPB , This complex movement involves a flexion
of the carpometacarpal and metacarpophalangeal joints and a small amount of abduction and medial rotation of the metacarpal
bone at the carpometacarpal joint. Reposition: lateral rotation by AbPB, EPL& EPBGroup innervation: Median nerve: AbPB, OP & FPB(
superficial head)Ulnar nerve: AdP & FPB ( deep head)
: at little finger Group actionAbduction: by AbDM Flexion: by FDMB and ODMOpposition : by ODMInnervatedby ulnar nerve
The gripPower grip: depends on long flexors of the fingers with opposition of the thumbSynergistic contraction of wrist extensorsHook grip:
long flexors, but oppositions and wrist extensors not nessasary in actionPrecision grip:Small hand muscles, opposition are important with
wrist extensors