Download Paronychia:

The anatomy of the wrist
& hand
Done by:
Mohad mubarak
Sameer esawi
A- Bones
8 bones form the wrist or
carpus;
5 bones form the metacarpus
or palm.
The remaining 14 are digital
bones.
These eight bones of the wrist
are arranged in two rows of
four ( proximal and distal
rows).
The proximal raw : pisiform –
tiquetrum-lunate-scaphoid
The distal raw: hamate –
capitate-trapezoid-trapezium
metacarpal bone & phalangeal bone divide into :
Base- shaft – head
the 14 phalnges are divided to
Proximal-Middle – distal .
Exept the the thumb which contain only the proximal &
the distal
B- The joints of the hand.
1- wrist :
the distal end of the radius articulates
with two bones of the proximal raw of
the carbal bone which are the lunate &
the scaopoid & triquetrum to form the
wrist joint
2- Intercarpal joints :
Articulation between the carpal bones .
3- carpometacarpal joints :
The base of metacarpals articulate with
the distal raw of the carpal bones .
1st metacarpal ….. Trapezium
2nd metacarpal ….trapezoid , trapezium
., capitate .
3rd metacarpal …….capitate.
4th metacarpal ……hamate , capitate .
5th metacarpal …..hamate.
4- metacarpophalangeal joint :
The head of the metacarpals articulate
with the base of thr proximal phalnges
5- interphalangeal joint :
Which are 9 joints articulate between
the phalnges .
Ther is distal & proximal phalangeal
joints .exept the thumb .
C- Muscles and tendons
The muscles of the hand subdivided
into :
1- The intrinsic muscles are located
within the hand itself.
1- thenar .
2- hypothenar .
3- lumbrical.
4- Interossei.
2- The extrinsic muscles are located
proximally in the forearm and insert
to the hand skeleton by long
tendons.
1- extensor .
2- flexor.
Extrinsic extensors
They can be divided into:
A - primary action is wrist extension
Extend & abduct the hand @ wrist joint
Extend & adduct the hand @ the wrist joint
2- primary action is at the digits
Extends the MCP of the thumb
Extends the IP joint of the thumb
Abducts and extends the CMC of the thumb
Extends the fingers from II –V @ the MCJ,
Extend little finger @ the MCP
p.S : all of the extrinsic extnsor group innerated by the radial nerve .
Extrinsic flexors
There are 3 layers of extrinsic flexors:
1- the superficial muscle: their primary action at the wrist or palm.
Adduct
& flex &
abduct
2- the intermediate muscle : Flexes PIP joints of 2-5 digits, assists in flexion of the MCP
joints and in wrist flexion.
3- the deep muscles : primary action at the digits.
. Flexes DIP joint of digits 2-5; assists in flexion of proximal
PIP and MCP joints of digits 2-5; may assist in flexion of wrist
Flexes IP joint of thumb
p.S : all the extrinsic flexor are innervated b the median nerve exept the FCU by ulnar nerve .
Intrinsic muscles
Situated totally within the hand.
Divided into 4 groups:
1 -Thenar
2- Hypothenar
3- Lumbrical
4- Interossei
1- Thenar
The thenar group consists of :
Opponens
pollicis
.
Abducts the CMC and MCP joints of the thumb.
Pull the thumb medially & dorward
across the palm
Flexes the MCP
Adducts of the thumb
p.S : all the muscle of the thenar are innervated by median nerve except (AP) by deep
branch of the ulnar nerve .
2-Hypothenar
The hypothenar group consists of:
Flexes the MCP joint of the little finger
Abducts, assists in opposition
pull the 5th metacarpal forward & medially
p.S : all the muscle of this group innervated by the deep branch of the ulnar .
Lumbricals
The lumbrical muscles contribute to:
Flexion of the MCP joints & Extension of the interphalangeal joints.
 p.s Nerve to Lumbricals I, II, Median
 Nerve to Lumbricals III, IV: deep branch of the Ulnar
Interossei
The interossei group consists of :
3 palmar muscles
4 dorsal muscles
Innervated by thedeep branch of the
ulnar nerve
Dorsal interossei abduct the fingers
Palmar interossei adduct the fingers to
the hand axis.
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End of the part
By Mohad Mubarak
Nerves
The hand is innervated by 3 nerves:
1- median nerve.
2- ulnar nerve.
3- radial nerve.
Each one has a sensory and motor
components.
Median nerve
#Originates from the lateral and medial
cords of the brachial plexus (C5-T1).
#Palmar cutaneous branch provides
sensation at the thenar eminence.
#Recurrent motor branch innervates the
thenar and lumbrical muscles.
Sensory digital branches provide
sensation to:
1-Thumb
2-Index
3-Ring finger (radial side)
Ulnar nerve
Innervates the muscles involved in the power grasping function
of the hand.
It originates at the medial cord of the brachial plexus (C8-T1).
Motor branches innervate:
Flexor carpi ulnaris
Flexor digitorum profundus
@Palmar cutaneous branch provides sensation at the
hypothenar eminence.
The dorsal branch provides sensation to:
1-Ulnar portion of the dorsum of the hand and small finger.
2-Part of the ring finger.
@At the hand, the superficial branch forms the digital nerves.
Provide sensation at the small finger and ulnar aspect of the ring finger
Radial Nerve
Innervating the wrist extensors
Originates from the posterior cord of
the brachial plexus (C6-8).
At the elbow, motor branches innervate
the brachioradialis and extensor carpi
radialis longus muscles.
BLOOD SUPPLY
The radial and ulnar arteries, which are branches of the
brachial artery, provide the blood supply to the hand.
The radial artery runs distally in the
forearm between the brachioradialis
and flexor carpi radialis muscles.
The ulnar artery runs distally in the
forearm under the flexor carpi
ulnaris muscle.
The superficial palmar arch : is formed
mainly by the ulnar artery with a
contribution of the radial artery, the arch gives raise to common palmar digital arteries
wich supply the palm & each divide into a pair of proper palmar digital arteries which
supply the finger
Deep palmer arch :
Is formed mainly by the
radial artery with a
contribution from a
branch of the ulnar artery
. It give raise to palmar
metacarpal arteries which
supply the palm and
anastomose with the
common palmar digital
arteries to the superficial
palmar arch
Veins
Veins generally follow the deep
arterial system as venae comitantes.
A superficial venous system also
exists at the dorsum of the hand
Contributes to the cephalic and
basilic vein in the upper extremity.
Dorsal digital veins : pass along the sides of the fingers and are joined to one
another by oblique communicating branches. Those from the adjacent sides of the fingers
unite to form three dorsal metacarpal veins
Dorsal metacarpal veins: which end in Dorsal venous network of hand
opposite the middle of the metacarpus.
Dorsal venous network of hand It is
found on the back of the hand and
gives rise to veins such as
the cephalic and the basilic veins .
Palmar metacarpal veins :
drains the metacarpal region of the palm, eventually draining into the deep palmar
venous arch. & then to the radial veins which drain the lateral aspect of the arm
Proper palmar digital : which drain into the common palmar digital veins then
drain to the superficial palmar venous arch and eventually draining to the ulnar
veins which drain the medial aspect of the arm .