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Pamela BL
 The
wrist is located at the junction of the
forearm and hand.
 The hand, which is the manual part(used for
grasping and holding) of the upper limb is
located distal to the forearm, and consists
of:
1. Wrist
2. Hand proper(palm)
3. The digits(fingers)
 Movements
of the hand occurs at the wrist
joint.
 The skeleton of the hand consists of carpals
in the wrist, metacarpals in the hand proper,
and phalanges in the digits.
 The
skeleton of the wrist/carpus, is
composed of eight carpal bones(carpals)
arranged in two rows of four each.
 These bones give flexibility to the wrist.
 The carpus is markedly convex from side to
side posteriorly and concave anteriorly.
 The carpals are attached to each other by
interosseous ligaments.
 From
lateral to medial, the four bones in the
proximal row are:
 Scaphoid- a boat shaped bone that
articulates proximally with the radius and
has a prominent tubercle.
 Lunate- a moon shaped bone that articulates
proximally with the radius and is broader
anteriorly than posteriorly.
 Triquetrum-
a three cornered pyramidal bone
that articulates proximally with the articular
disc of the distal radioulnar joint.
 Pisiform- a small, pea shaped bone that lies
on the palmar surface of the triquetrum.
 From
lateral to medial, the bones in the
distal row of the carpus are:
 Trapezium- which is four sided
 Trapezoid- which is wedge shaped
 Capitate- which has a rounded head
 Hamate- which is wedge shaped and has a
hooked process, the hook of hamate.
Red part represents hook(hamulus) of hamate bone
 The
proximal surfaces of the distal rows of
carpal bones articulate with the proximal
row of carpals, and their distal surfaces
articulate with the metacarpals.
 The
skeleton of the hand between the carpus
and phalanges is composed of five
metacarpal bones(metacarpals).
 Each bone consists of a body, a proximal end
and distal end.
 The distal ends or heads of the metacarpals
articulate with the proximal phalanges and
form the knuckles of the fist.
 The proximal ends or bases of the
metacarpals articulate with the carpal
bones.
 The
1st metacarpal(of the thumb) is the
thickest and shortest of the metacarpals.
 The 3rd metacarpal is distinguished by a
styloid process on the lateral side of its base.
 Each digit has three phalanges except the
1st(thumb) which has only two.
 Each phalanx has a base proximally, a head
distally and a body btwn the base and the
head.
 The
proximal phalanges are the largest, the
middle ones are intermediate in size and the
distal ones are the smallest.
 Each terminal phalanx is flattened and
expanded at its distal end to form the nail
bed.
 Fracture
of the scaphoid- the scaphoid is the
most frequently fractured carpal
bone(common injury of the wrist) especially
as a result of fall onto the palm when the
hand is abducted.
 Pain occurs primarily on the lateral side of
the wrist especially during dorsiflexion and
abduction of the hand.
 Initial
radiographs may not reveal a fracture
of the scaphoid.
 An apparently severely sprained wrist is
subsequently diagnosed as a fractured
scaphoid after repeated radiographs 2-3
weeks alter revealing a fractured site
because bone resorption has occurred there.
 Because
of poor blood supply to the proximal
part of the scaphoid, union of the fractured
parts may take several months.
 Avascular necrosis of the proximal fragment
of the scaphoid(pathological death of bone
resulting from inadequate blood supply) may
occur and produce degenerative joint disease
of the wrist.
 Fracture
of the hamate may result in non
union of the fractured bony parts because of
the traction produced by the attached
muscles.
 Ulnar nerve may be injured by a hamate
fracture because of its close proximity to the
hook of hamate, causing decreased grip
strength of the hand.
 Fracture
of the metacarpals- fracture of the
necks of the 1st and 2nd metacarpals are
often referred to as “boxer’s fractures”.
 In unskilled street fighters, the neck of the
more mobile 5th metacarpal is commonly
fractured when they strike a blow with the
fist clenched.
 Severe crushing injuries of the hand mat
produce multiple metacarpal fractures
resulting in instability of the hand.
 The
hand is involved in the following
activities:
 Power grasping
 Precision handling
 Pinching
 The power grip(palm grip) refers to forcible
motions of the digits acting against the palm,
the fingers are wrapped around an object
with counter pressure from the thumb, e.g.
when grasping a cylindrical structure.
 The
precision handling grip involves a change
in position of a handled object that requires
fine control of the movements of the fingers
and thumb(e.g. holding a pen or winding a
watch).
 In precision grip, the wrist and the fingers
are held firmly by the long flexors and
extensor muscles, and the intrinsic hand
muscles perform fine movements of the
digits e.g. when treading a needle or
buttoning a shirt/blouse.
 Pinching
refers to compression of something
btwn the thumb and index finger(e.g.
handling a teacup), or btwn the thumb and
adjacent two fingers(e.g. when snapping the
fingers).
 The
fascia of the palm is continuous with the
antebrachial fascia of the dorsum of the
hand.
 The palmar fascia is thin over the thenar and
hypothenar eminences but it is thick
centrally where it forms the fibrous palmar
aponeurosis and in the digits where it forms
the digital sheaths
 The
palmar aponeurosis a strong well defined
part of the deep fascia covers the soft tissues
and overlies the long flexor tendons.
 The proximal end/apex of the triangular
palmar aponeurosis is continuous with the
flexor retinaculum and the Palmaris longus
tendon.
 When
the muscle is present, the palmar
aponeurosis is the expanded tendon of the
Palmaris longus.
 Distal to the apex, the palmar aponeurosis
forms four longitudinal digital bands that
radiate from the apex and attach distally to
the bases of the proximal phalanges and
become continuous with the fibrous digital
sheaths.
1.Deep antebrachial fascia
2.Superficial fascia and dorsal venous network
7.Cephalic vein
8.Basilic vein
3.Palmar aponeurosis
4.Thenar muscles
5.Hypothenar muscles
6.Palmaris brevis.
 Bwtn
the flexor tendons and the fascia
covering the deep palmar muscles are two
potential spaces, the thenar space and
midpalmar space.
 The spaces are bounded by fibrous septa
passing from the edges of the palmar
aponeurosis to the metacarpals.
 Btwn the two spaces is the specially strong
lateral fibrous septum that is attached to the
3rd metacarpal.
Hand infections
 Because the palmar fascia is thick and
strong, swellings resulting from hand
infections usually appear on the dorsum of
the hand where the fascia is thinner.
 The potential fascial spaces of the palm are
important because they may be infected.
 The fascial spaces determine the extent and
direction of the spread of pus formed by
these infections.
1.
 Depending
on the sites of infection, pus will
accumulate in the thenar, hypothenar or
adductor compartments.
 An untreated infection can spread proximally
through the carpal tunnel into the forearm,
anterior to the pronator quadratus and its
fascia.
 2.
Dupuytren’s contracture of palmar fasciais a progressive shortening, thickening and
fibrosis of the palmar fascia and aponeurosis.
 The fibrous degeneration of longitudinal
bands of the palmar aponeurosis on the
medial side of the hand pulls the ring and
little finger into partial flexion at the
metacarpophalangeal and proximal
interphalangeal joints.
 The
contracture is frequently bilateral and is
common in men older than 50 yrs.
 Its cause is unknown but evidence points to a
hereditary predisposition.
 First the disease manifests itself as painless
nodular thickenings of the palmar
aponeurosis that adhere to the skin.
 Gradually,
progressive contracture of the
longitudinal bands produces raised ridges in
the palmar skin that extend from the
proximal part of the hand to the base of the
ring and little fingers.
 Treatment of Dupuytren’s contracture usually
involves surgical excision of all fibrotic parts
of the palmar fascia to free the fingers.
 The
intrinsic muscles of the hand are in 4
compartments:
 Thenar muscles in the thenar compartmentabductor pollicis brevis, flexor pollicis brevis
and opponens pollicis.
 Adductor pollicis in adductor compartment
 Hypothenar
muscles in the hypothenar
compartment- abductor digiti minimi, flexor
digiti minimi and opponens digiti minimi.
 Short muscles of the hand ,the lumbricals in
the central compartment and the interossei
are btwn the metacarpals.
 The
thenar muscles form the thenar
eminence on the lateral surface of the palm
and are chiefly responsible for opposition of
the thumb.
 The movement begins with the thumb in
extended position and initially involves a
medial rotation of the 1st metacarpal
produced by the action of the opponens
pollicis muscle at the carpometacarpal joint
and then abduction, flexion and usually
adduction.
 The
reinforcing action of the adductor
pollicis and flexor pollicis longus increases
the pressure that the opposed thumb can
exert on the fingertips.
 Abductor pollicis brevis-short abductor of the
thumb, forms the anterolateral part of the
thenar eminence.
 It
abducts the thumb at the carpometacarpal
joint and assists the opponens pollicis during
the early stages of opposition by rotating its
proximal phalanx slightly medially.
 To test the abductor pollicis brevis, abduct
the thumb against resistance.
 Opponens
pollicis- a quadrangular muscle
lying deep to abductor pollicis brevis and
lateral to flexor pollicis brevis.
 It opposes the thumb, most important thumb
movement, that is flexes and rotates the 1st
metacarpal medially at the carpometacarpal
joint during opposition.
 This movement occurs when picking up an
object.
 Flexor
pollicis brevis- short flexor of the
thumb located medial to the abductor
pollicis brevis.
 Its tendon usually contains a sesamoid bone.
 It flexes the thumb at the carpometacarpal
and metacarpophalangeal joints and aids in
opposition of the thumb.
 To test flexor pollicis brevis, flex the thumb
against resistance.
 Adductor
pollicis-a fan shaped adductor of
the thumb that is located in the adductor
compartment.
 Has two heads of origin that are separated by
the radial artery as it enters the palm to
form the deep palmar arch.
 Its
tendon usually contains a sesamoid bone.
 The adductor pollicis adducts the thumb,
moves the thumb to the palm of the hand
thereby giving power to the grip.
 Produce
the hypothenar eminence on the
medial side of the palm and move the little
finger.
 They are in the hypothenar compartment.
 Abductor digiti minimi-most superficial of
the three muscles.
 Abducts the 5th digit and helps flex its
proximal phalanx.
 Flexor
digiti minimi brevis-short flexor of the
little finger lying lateral to the abductor
digiti minimi.
 Flexes the proximal phalanx of the 5th digit
at the metacarpophalangeal joint.
 Opponens digiti minimi-quadrangular muscle
lying deep to the abductor and flexor
muscles of the 5th digit.
 Draws
the 5th metacarpophalangeal joint
anteriorly and rotates it laterally deepening
the hollow of the palm and bringing the 5th
digit into opposition with the thumb.
 Palmaris brevis- a small, thin muscle in the
subcutaneous tissue of the hypothenar
eminence.
 It
wrinkles the skin of the hypothenar
eminence and deepens the hollow of the
palm thereby aiding the palmar grip.
 The Palmaris brevis covers and protects the
ulnar nerve and artery.
 It is attached proximally to the medial
border of the palmar aponeurosis and to the
skin on the medial border of the hand.
 The
short muscles of the hand are the
lumbricals and interossei.
 Lumbricals-four slender muscles named so
because of their wormlike form.
 Flex the digits at the metacarpophalangeal
joints and extend the interphalangeal joints.
 Interossei-
four dorsal interossei muscles are
located btwn the metacarpals, three palmar
interosseous muscles are on the palmar
surfaces of the metacarpal bones.
 The 1st dorsal interosseous muscle is easy to
palpate, oppose the thumb firmly against the
index finger and it can be easily felt.
 The
4 dorsal interossei abduct the digits and
three palmar interossei adduct them.
 Dorsal ABduct(DAB)
 Palmar ADduct(PAD).
 Acting together, the dorsal and palmar
interossei and lumbricals produce flexion at
the metacarpophalangeal joints and
extension in the interphalangeal joints(the so
called Z movement).
 The
ulnar and radial arteries and their
branches provide blood supply to the hand.
 Ulnar artery- enters the hand anterior to the
flexor retinaculum btwn the pisiform bone
and the hook of the hamate(Guyon’s canal).
 Lies lateral to the ulnar nerve.
 Divides into two terminal branches, the
superficial palmar arch and deep palmar
arch.
 The
superficial palmar arch, the main
termination of the ulnar artery give rise to
three common palmar digital arteries that
anastomose with palmar metacarpal arteries
from the deep palmar arch.
 Each common palmar digital artery divided
into a pair of proper palmar digital arteries
that run along the adjacent sides of the 2nd4th digits.
 Radial
artery-curves dorsally around the
scaphoid and trapezium in the floor of the
anatomic snuff box and enters the palm by
passing btwn the heads of the 1st dorsal
interossei muscle.
 It then runs medially and passes btwn the
heads of adductor pollicis.
 The radial artery anastomoses with the deep
branch of the ulnar artery to form deep
palmar arch.
 The
deep palmar arch, formed mainly by the
radial artery, lies across the metacarpals just
distal to their base.
 The deep arch gives rise to three palmar
metacarpal arteries and the princeps pollicis
arteries which supply the palmar surfaces
and sides of the thumb.
 The
superficial and deep palmar arterial
arches are accompanied by superficial and
deep palmar venous arches respectively.
 The dorsal digital vein drains into three
dorsal metacarpal veins, which unite to form
a dorsal venous network
 Superficial
to the metacarpus, this network
is prolonged proximally on the lateral side as
the cephalic vein.
 The basilic vein arises from the medial side
of the dorsal venous network.
 The
median, ulnar and radial nerves supply
the hand.
 Branches or communications from the lateral
and posterior cutaneous nerves may
contribute some fibers to supply the dorsum
of the hand.
 Enters
the hand through the carpal tunnel,
deep to the flexor retinaculum along with
nine tendons of the flexor digitorum
superficialis and profundus and the flexor
pollicis longus.
 The carpal tunnel is the passageway deep to
the flexor retinaculum bwtn the tubercles of
the scaphoid and trapezoid bones on the
lateral side and the pisiform and hook of
hamate on the medial side.
 Distal
to the carpal tunnel, the median nerve
supplies the three thenar muscles and the 1st
and 2nd lumbricals.
 It also sends sensory fibers to the skin on the
entire palmar surface, the sides of the 1st
three digits, the lateral half of the 4th digit,
and the dorsum of the distal halves of these
digits.
 Results
from any lesion(e.g. inflammation of
synovial sheaths) that significantly reduces
the size of the carpal tunnel.
 Fluid retention, infection and excessive
exercise of the fingers may cause swelling of
the tendons or their synovial sheaths.
 The median nerve is the most sensitive in
the carpal tunnel and is therefore most
affected.
 This
nerve has two terminal sensory branches
that supply the skin of the hand hence par
aesthesia, hypoesthesia or anesthesia may
occur in the lateral three and half digits.
 The nerve also has one terminal motor
branch, the thenar or reccurrent branch
which supply three thenar muscles.
 Progressive
loss of coordination and strength
in the thumb(owing to weakness of the
abductor pollicis brevis and opponens
pollicis) may occur if the cause of the
median nerve compression is not alleviated.
 People with median nerve compression are
unable to oppose the thumb.
 As
the condition progresses, sensory changes
radiate into the forearm and axilla.
 People with carpal tunnel syndrome have
difficulty performing fine movements such as
buttoning a blouse/shirt as well as gripping
things such as a hairbrush.
 Partial or complete surgical division of flexor
retinaculum(carpal tunnel release) may be
necessary to relieve the symptoms.