The anatomy of the wrist

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The anatomy of the wrist hand

• Done by
• Mohad mubarak
• Sameer esawi

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A- Bones

• 8 bones form the wrist or carpus
• 5 bones form the metacarpus or palm.
• The remaining 14 are digital bones.

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• These eight bones of the wrist are arranged in
  two rows of four ( proximal and distal rows).
• The proximal raw pisiform tiquetrum-lunate-scap
  hoid
• The distal raw hamate capitate-trapezoid-trapez
  ium

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• 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

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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 .

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• 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 .

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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.

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Extrinsic extensors

• They can be divided into
• A - primary action is wrist extension
• Extend abduct the hand _at_ wrist joint
• Extend adduct the hand _at_ the wrist joint

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• 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

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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

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Intrinsic muscles

• Situated totally within the hand.
• Divided into 4 groups
• 1 -Thenar
• 2- Hypothenar
• 3- Lumbrical
• 4- Interossei

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1- Thenar

• The thenar group consists of
• .
• Abducts the CMC and MCP joints of the thumb.
  Pull the thumb medially dorward
• 
  
  across the palm

Opponens pollicis
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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 .

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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

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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 1st part
• By Mohad Mubarak

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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.

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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)

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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
• _at_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_At the hand, the superficial branch forms the
  digital nerves.
• Provide sensation at the small finger and ulnar
  aspect of the ring finger

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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.

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BLOOD SUPPLY

• The radial and ulnar arteries, which are branches
  of the brachial artery, provide the blood supply
  to the hand.

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• 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.

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• 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
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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.

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• 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 .

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• 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 .

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End of the 2nd part by Sameer Esawi