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					Hand
           Bony, soft landmarks

• 1. dorsum:
  – a. knuckles = metacarpal bone heads
  – b. skin - thinner than palm, has hair follicles,
    sebaceous & sweat glands
  – c. dorsal venous network
            Bony, soft landmarks

• palm:
  – a. skin - much thicker than dorsum, many sweat
    glands, no hair follicles or sebaceous
  – b. transverse flexion creases: when
    metacarpophalangeal joints flex - proximal, distal
  – c. longitudinal flexion creases - when thumb is
    opposed - radial & midpalmar
  – d. thenar eminence - ball / heel of thumb
  – e. hypothenar eminence - heel of hand at little finger
Trisomy 21
                      Fingers
• Also have digital transverse flexion creases -
  proximal, middle, distal (thumb has only 2)
• Fingerprints - improve gripping ability
• Synovial sheaths
  – a. radial bursa - encloses tendon of flexor pollicis
    longus
  – b. ulnar bursa - encloses four tendons each of flexors
    digitorum superficialis & profundus
    & medially, extends distally to surround the two flexor
    tendons to pinkie
  – c. Three separate distal sheaths - surround flexor
    tendons to index, middle, ring fingers
    - from metacarpophalangeal joints to base of distal
    phalanx
                   Fingers
• Fibrous digital sheaths - dense fibrous
  connective tissue
  – annular bands - surround phalanges
  – cruciform bands - cross over between joints
  – form osteofibrous canals - through which
    flexor tendons travel (in their synovial
    sheaths)
• Flexor retinaculum
  – Fibrous connective fascia that covers and
    holds most of the flexors of the forearm in
    wrist.
      Carpal Tunnel Syndrome
• Because the median is enclosed with the
  tendons in this tunnel, anything that decrease
  the size of the tunnel (infection, arthritis,
  degeneration etc.) will compress the median
  nerve causing carpal tunnel syndrome. Its
  symptom includes tingling sensation
  (paresthenia), absence of tactile sensation
  (anethesia), or diminished sensation
  (hypothenia), loss strength of thumb (abductor
  pollicis brevis, flexor pollicis brevis and
  opponents pollicis), lumbricals (lateral two) can
  also be affected.
                  Blood vessels
• Ulnar artery
  – a. deep branch - joins radial to form deep palmar arch
  – b. superficial palmar arterial arch, formed by
    superficial palmar branch from ulnar artery (more like
    the terminal branch of ulnar, which mainly forms the
    arch) + superficial palmar branch of radial artery. It
    gives off three branches and joint with palmar
    metacarpal branches from deep palmar arch to form:
     • i) three common palmar digital artery - in the three medial
       intermetacarpal spaces; each then divides
     • proper palmar digital artery - to medial side of index finger,
       radial side of little finger
       and both sides of middle & ring fingers
     • proper palmar digital artery - little finger, ulnar side, a branch
       directly from the superficial palmar arch (or a branch off the
       ulnar artery)
              Blood vessels
• radial a. - (sits in floor of anatomical snuff
  box)
  – a. superficial palmar branch - to thenar
    muscles, joins superficial palmar arch (ulnar)
  – b. princeps pollicis - to thumb, then splits into
    two proper digital arteries to both sides of the
    thumb
  – c. radialis indicis - to lateral index finger
  – d. deep palmar arterial arch - formed by Radial
    artery (mainly). + deep branch of the ulnar a.
    - three palmar metacarpal arteries - between
    metacarpals - join common palmar digitals
     Deep palmar arterial arch
• three palmar metacarpal arteries
• three perforating arteries to dorsal arch
            Dorsal arterial arch
• a. formed by dorsal carpal branch from radial and
  ulnar arteries, and terminal branches of the
  anterior and posterior interosseus arteries. It is
  also joined by the perorating arteries from deep
  palmar arch.
• b. Dorsal arch gives off three dorsal metacarpal
  arteries, each then splits into dorsal proper digital
  arteries
• c. Dorsalis pollicis and dorsalis indicis can be
  considered as direct branches from radial dorsal
  carpal artery
• d. dorsal proper digital artery - to the medial side
  of little finger, direct branch from the dorsal arch
  (or branch from the dorsal carpal branch from
  ulnar artery).
                  Nerves
• 1. ulnar nerve - superficial branch of the
  ulnar nerve - enters palm on ulnar side of
  center; divides:
  - three palmar digital branches - to skin of
  little finger (both sides), medial side ring
  finger
• 2. ulnar nerve - deep branch - to muscles
  of fine movements of hand
  - hypothenar muscles, interosseous,
  medial lumbricals, adductor pollicis
                   Median nerve
• Enters palm to radial side of center; divides to 3
  common palmar digital branches:
   – a. 1st common to abductor pollicis brevis, flexor
     pollicis brevis, opponens pollicis, and 1st lumbrical
     muscle
      • then it divides: - 3 proper palmar digital nerve - to skin, both
        sides of thumb; & lateral side of index
   – b. 2nd common - to 2nd lumbrical muscle
      • divides - to 2 proper palmar digital nerve - to skin of medial
        index, lateral middle finger
   – c. 3rd common palmar digital branch divides to 2
     proper palmar digital nerve. - to skin on medial
     middle, lateral ring finger
             Radial nerve
• all sensory innervation in hand (dorsal &
  lateral skin & fascia)
               Muscles
• Thenar / short thumb muscles
         ABDUCTOR POLLICIS BREVIS
• ORIGIN
  Flexor retinaculum, tubercle of trapezium bone,
  and tubercle of scaphoid bone
• INSERTION
  Base of proximal phalanx of thumb, radial side,
  and extensor expansion
• ACTION
  Abducts the carpometacarpal and
  metacarpophalangeal joints of the thumb in a
  vertical direction perpendicular to the place of
  the palm. By virtue of its attachment into the
  dorsal extensor expansion, extends the
  interphalangeal joint of the thumb. Assists in
  opposition, and may assist in flexion and medial
  rotation of the metacarpophalangeal joint.
• NERVE
  median nerve - C6, C7, C8, T1
               FLEXOR POLLICIS BREVIS
• ORIGIN
   – Superficial head: flexor retinaculum and
     trapezium bone
   – Deep head: trapezoid and capitate bones
• INSERTION
  Base of proximal phalanx of thumb, radial
  side, and extensor expansion
• ACTION
  Flexes the metacarpophalangeal and
  carpometacarpal joints of the thumb, and
  assists in opposition of the thumb toward
  the little finger. By virtue of its attachment
  into the dorsal extensor expansion, may
  extend the interphalangeal joint
• NERVE
   – superficial head: median nerve. - C6, C7, C8,
     T1
   – deep head: C8, T1
                   OPPONEN POLLICIS
• ORIGIN
  Flexor retinaculum and tubercle of trapezium
  bone
• INSERTION
  Entire length of first metacarpal bone, radial
  side
• ACTION
  Opposes (i.e., flexes and abducts with slight
  medial rotation) the carpometacarpal joint of
  the thumb, placing the thumb in a position so
  that, by flexion of the metacarpophalangeal
  joint, it can oppose the fingers. For true
  opposition of the thumb and little finger, the
  pads of these digits come in contact. Bringing
  the tips of these digits together can be donw
  without opponens action
• NERVE
  median nerve - C6, C7, C8, T1
                   ADDUCTOR POLLICIS
• ORIGIN
    – oblique head: capitate bone, and bases of
      second and third metacarpal bones
    – transverse head: palmar surface of third
      metacarpal bone
• INSERTION
  Transverse head into ulnar side of base of
  proximal phalanx of thumb, and oblique head
  into extensor expansion
• ACTION
  Adducts the carpometacarpal joint, and
  adducts and assists in flexion of the
  metacarpophalangeal joint, so that the thumb
  moves toward the plane of the palm. Aids in
  opposition of the thumb toward the little finger.
  By virtue of the attachment of the obilique
  fibers into the extensor expansion, may assist
  in extending the interphalangeal joint.
• NERVE
  ulnar never - C8, T1
                 Muscles
• Hypothenar / short muscles of little finger
             ABDUCTOR DIGITI MINIMI
• ORIGIN
  Tendon of flexor carpi ulnaris and pisiform
  bone
• INSERTION
  By two slips: one into base of proximal
  phalanx of little finger, ulnar side; the
  second, into the ulnar border of the
  extensor expansion
• ACTION
  Abducts, assists in opposition, and may
  assist in flexion of the
  metacarpophalangeal joint of the little
  finger; by virtue of insertion into the
  extensor expansion, may assist in
  extension of interphalangeal joints
• NERVE
  ulnar nerve - C(7), C8, T1
     FLEXOR DIGITI MINIMI BREVIS

• ORIGIN
  hook of hamate bone, and flexor
  retinaculum
• INSERTION
  base of proximal phalanx of little
  finger, ulnar side
• ACTION
  Flexes the metacarpophalangeal
  joint of the little finger and assists in
  opposition of the little finger toward
  the thumb
• NERVE
  ulnar never, C(7), C8, T1
       OPPONEN DIGITI MINIMI HAND
• ORIGIN
  hook of hamate bone, and flexor
  retinaculum
• INSERTION
  entire length of fifth metacarpal, ulnar
  side
• ACTION
  opposes (i.e., flexes with slight rotation)
  the carpometacarpal joint of the little
  finger, lifting the ulnar border of the
  hand into a position so that the
  metacarpophalangeal flexors can
  oppose the little finger to the thumb.
  Helps to cup the palm of the hand
• NERVE
  ulnar nerve - C(7), C8, T1
              Muscles
• Short Hand muscles
                   LUMBRICALS

• ORIGIN
  – #1 and #2: radial surface of flexor
    profundus tendons of index and
    middle fingers, respectively.
  – #3: adjacent sides of tendon of
    flexor digitorum profundus tendons
    of middle and ring fingers
  – #4: adjacent sides of tendon of
    flexor digitorum profundus of ring
    and little fingers
• INSERTION
  Into the radial border of the
  extensor expansion on the
  dorsum of the respective digits
                         LUMBRICALS
• ACTION
  Extend the interphalangeal joints and
  simutaneously flex the metacarpophalangeal
  joints of the second through fifth digits. The
  lumbricales also extend the interphalangeal
  joints when the metacarpophalangeal joints are
  extended. As the fingers are extended at all
  joints, the flexor digitorum profundus tendons
  offer a form of passive resistance to this
  movement. Since the lumbricales are attached
  to the flexor profundus tendons, they can
  diminish this resistive tension by contracting
  and pulling these tendons distally, and this
  release of tension decreases the contractile
  force needed by the muscles that extend the
  finger joints.
• NERVE
  I, II: median nerve, C(6), 7, C8, T1 III, IV: ulnar
  nerve – C(7), C8, T1
                        DORSAL INTEROSSEI
•   ORIGIN
     – First, lateral head: Proximal one half of ulnar border of
       first metacarpal bone
     – First, medial head: radial border of second metacarpal
       bone
     – second, third, and fourth: adjacent sides of metacarpal
       bones in each interspace
•   INSERTION
    into extensor expansions and to base of proximal
    phalanges as follows:
     – First: radial side of index finger, chiefly to base of
       proxiaml phalanx
     – Second: radial side of middle finger
     – Third: ulnar side of middle finger, chiefly into extensor
       expansion
     – Fourth: ulnar side of ring finger
•   ACTION
    Abducts the index, middle, and ring fingers from the
    axial line through the third digit. Assists in flexion of
    metacarpophalangeal joints and extension of
    interphalangeal joints of the same fingers. The first
    assists in addition of the thumb
•   NERVE
    ulnar nerve - C8, T1
                       PALMAR INTEROSSEI
• ORIGIN
    – First: base of first metacarpal bone, ulnar side
    – Second: length of second metacarpal bone, ulnar
      side
    – Third: length of fourth metacarpal bone, radial side
    – Fourth: length of fifth metacarpal bone, radial side
• INSERTION
  Chiefly, into the extensor expansion of the
  respective digit, with possible attachement to base
  of proximal phalanx as follows
    –   First: ulnar side of thumb
    –   Second: ulnar side of index finger
    –   Third: radial side of ring finger
    –   Fourth: radial side of little finger
• ACTION
  Adduction of thumb, index , ring, and little finger
  toward the axial line through the third digit. Assist in
  flexion of metacarpophalangeal joints, and
  extension of interphalangeal joints of the three
  fingers
• NERVE
  ulnar nerev C8, T1

				
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