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Bones and Joints of the
 Proximal Row of Carpal Bones
 Review- testable
 Scaphoid:
    Most lateral.
    Forms floor of anatomical snuff box.
    Most commonly fractured wrist bone.
    Fractures may compromise radial artery in
    snuff box.
    Articulates with radius.
Proximal Row of Carpal Bones
   Lunate:
       Articulates with radius
   Triquetral:
       Articulates with ulna (via articular (ulnar)
       disc) during extreme ulnar deviation.
   Pisiform:
       Sesamoid bone
       Forms in tendon of the flexor carpi ulnaris
    Distal Row of Carpal Bones:
   Trapezium:
      Most lateral
 Trapezoid
 Capitate
 Hamate
    Distal Row of Carpal Bones:
 Entire complex enclosed in a common
  synovial membrane.
 Articulations are plane joints that perform
  gliding motions.
              Radiocarpal Joint
   Condyloid (ellipsoidal) synovial joint.
   Two degrees of freedom.
   Articular surfaces:
       Scaphoid (convex)
       Lunate (convex)
       Distal radius:
               Two concave fossae (lateral and medial)
       Triquetral (convex)
               Only during extreme ulnar deviation
    Radiocarpal Joint Ligaments
   Lateral (radial) collateral ligament.
   Medial (ulnar) collateral ligament.
   Dorsal radiocarpal ligament.
   Palmar radiocarpal ligament.

   Strengthen capsule
    Radiocarpal Joint Functions
 Some flexion and extension
 Ulnar deviation
    Radiocarpal Joint Arteries
 Articular arteries
 Arise from dorsal and palmar carpal
    Radiocarpal Joint Nerves
 Anterior interosseous branch of median
 Posterior interosseous branch of radial
 Dorsal and deep branches of the ulnar
    Radiocarpal Joint Injuries
 Colle’s fracture
 Scaphoid fracture
    Usually at “waist”
    Compromises radial artery in snuffbox
              Midcarpal Joint
   Made up of intercarpal joints:
       Between proximal and distal rows of carpals
       and between carpals.
   Movements:
       Some flexion and extension.
       Radial deviation (abduction).
       Especially due to movement of head of
       capitate in its socket.
   Enclosed within synovial capsule.
              Midcarpal Joint
   Ligaments:
       Dorsal ligaments.
       Palmar ligaments.
       Interosseous ligaments.
   Nerves and arteries:
       Same as for radiocarpal.
     Palmar Structure Sequence
          (radial to ulnar)
 Radius
 Radial artery
 Flexor carpi radialis tendon
 Median nerve:
     Under palmaris longus tendon
     Palmar Structure Sequence
          (radial to ulnar)
 Flexor digitorum superficialis tendons
 Ulnar artery
 Ulnar nerve
 Flexor carpi ulnaris tendon
      Carpometacarpal Joints
 Plane synovial joints:
 Motion:
     None for digits 2-3
     Limited for 4
     More mobile for 5
     Carpometacarpal Joints
 Saddle (sellaris) joint between metacarpus
  and trapezium:
 Movements:
    Metacarpophalangeal Joints
 Condyloid synovial joints
 Movements:
       Some opposition at MCP 5
   Capsular ligaments:
       Palmar ligaments (pads)
       Interphalangeal Joints
 Synovial hinge joints
 Only flexion/extension allowed
 Ligaments:
     Strong collaterals
 Proximal interphalangeal joints (PIPs)
 Distal interphalangeal joints (DIPs)
     Dorsal Venous Drainage
 Dorsal venous arch drains hand dorsum.
 Medially drains into basilic.
 Laterally drains into cephalic.
          Lymphatic Drainage
   Medial via lymph vessels accompanying
    basilic vein to:
      Supratrochlear nodes to:
      Lateral axillary nodes.
   Lateral via lymph vessels accompanying
    cephalic vein to:
      Infraclavicular nodes to:
      Lateral axillary nodes.
      Arterial Supply to Dorsum
   Via dorsal arterial arch from:
       Radial and ulnar arteries.
 Dorsal metacarpals.
 Dorsal digitals.
    Muscles of Dorsum of Hand
 Long extensor tendons.
 Dorsal interosseous muscles (4):
          Middle finger is reference
          Middle finger has two
          First and fifth digits have none.
Long Extensors
          Superficial Palm
 Palmar aponeurosis
 Flexor retinaculum
 Palmaris brevis
         Palmar Aponeurosis
 Triangular layer of deep fascia located
  between two eminences.
 Provides protection for superficial vessels,
  nerves, and tendons.
 Anchored to skin and flexor retinaculum.
 Splits into four slips that blend with fibrous
  flexor sheaths of four medial digits (II – V).
         Flexor Retinaculum
 = Transverse carpal ligament.
 Laterally attaches to tubercles of scaphoid
  and trapezium.
 Medially attaches to hook of hamate and
         Palmaris Brevis Muscle
   O:     Flexor retinaculum and palmar
 I:       Skin on medial side of palm.
 A:       Tenses skin on palm.
        Carpal Tunnel Contents
   Long flexor tendons of:
       Flexor digitorum superficialis
       Flexor digitorum profundus
       Flexor pollicis longus
   Median nerve

   Note: ulnar nerve and artery pass through
    Guyon’s canal.
Long Flexors
    Intrinsic Muscles of the Thumb
 Thenar eminence:
 Adductor pollicis:
           Deep branch of ulnar nerve (C8, T1).
      Thenar Eminence Muscles
 Abductor pollicis brevis
 Flexor pollicis brevis
 Opponens pollicis

   Innervation:
       Recurrent branch of median nerve (C8, T1).
Thenar Muscles
         Hypothenar Eminence
   Intrinsic muscles for digit V.

 Abductor digiti minimi
 Flexor digiti minimi brevis
 Opponens digiti minimi

   Innervation:
       Ulnar nerve
Hypothenar Muscles
         Long Digital Flexors
 Flexor digitorum superficialis
 Flexor digitorum profundus
    Flexor Digitorum Superficialis
 Flexes PIP (and MCP and wrist).
 Each tendon passes through fibrous flexor
 Each tendon bifurcates opposite proximal
 Each tendon inserts on middle phalanx.
    Flexor Digitorum Profundus
 Flexes DIP (and PIP and MCP).
 More active than superficialis.
 Each tendon inserts on distal phalanx.
 Small vascular bundles connecting palmar
  surface of phalanges with long flexor
 Long and short
Long Flexors
          Dorsal Interossei
 Four bipennate muscles.
 Each arises via two heads from adjacent
  sides of two metacapals.
             Dorsal Interossei
   Insertion:
       Onto extensor expansions and:
       Radial sides of proximal phalanges 2 and 3;
       Ulnar sides of proximal phalanges 3 and 4.
       Note: digit has two dorsal interossei.
   Abducts MP joints of digits 2-4:
       Reference is line through middle finger.
Interossei Muscles
             Palmar Interossei
   Four unipennate muscles:
       First is sometimes considered part of flexor
       pollicis brevis.
       Supply each digit except third:
             Reference is middle finger.
   Innervation for all interossei (incl. dorsal):
       Ulnar nerve
   Four small, narrow, elongated muscles.
   Each arises from the radial side of a flexor
    digitorum profundus tendon.
   Innervation:
        Two on radial side:
             Median nerve
       Two on ulnar side:
             Ulnar nerve
   Flex MCP joints and extend IP joints.
        Arterial Supply to Hand
   Superficial palmar arch:
       Continuation of ulnar artery.
   Deep palmar arch:
       Continuation of radial artery.
       Route of Radial Artery
 Smallest terminal branch of brachial
 Passes proximally deep to brachioradialis
 Distally the artery lies against the radius
  lateral to the tendon of the flexor carpi
  radialis, where it can be felt (radial pulse).
 Passes across scaphoid in anatomical
  snuff box.
         Route of Radial Artery
   Wraps around the dorsum of first
       Gives off arteries to the thumb and index
 Pierces the first dorsal interosseous
  muscle and reappears in the palm of the
 Gives rise to the deep palmar arch.
Deep Palmar Arch
            Boundaries of the
           Anatomical Snuff Box
   Lateral (anterior):
       Tendons of the:
             Abductor pollicis longus.
             Extensor pollicis brevis.
   Medial (posterior):
       Tendon of the:
             Extensor pollicis longus.
     Ulnar Nerve in the Hand
 Enters hand superficial to flexor
 Superficial branch:
     Muscular branch to palmaris brevis

     Cutaneous to palmar aspect of ulnar side of
     little finger and adjacent sides of little and
     ring fingers, including tips and dorsum.
       Ulnar Nerve in the Hand
   Deep branch:
      Supplies hypothenar muscles, all interossei,
      two ulnar side lumbricals, and adductor
Nerve Supply to Hand
    Median Nerve in the Hand
 Enters palm deep to flexor retinaculum.
 Divides into lateral and medial branches:
     Lateral branch:
          To thenar muscles and first lumbrical.
          Cutaneous to anterior surface of thumb and
          radial side of index finger.
     Medial branch:
          To second lumbrical.
          Cutaneous to adjacent sides of digits 2-4,
          including nail-bed and finger tips.
          Spaces in the Hand
   Thenar space:
      Located between the palmar side of the
      adductor pollicis muscle and the long flexor
      tendons to the index finger and the thumb.
   Midpalmar space:
      Located between metacarpals 4-5 and the
      long flexor tendons to digits 4-5.
               Clinical Notes
   Mallet finger:
       Avulsion by long flexor tendon.
       Results in hyperflexion of DIP.
   Dupuytren’s contracture:
       Progressive fibrosis of palmar aponeurosis.
       Results in marked flexion of fingers at MP
 Colle’s fracture.
 Fracture of scaphoid.
                Clinical Notes
   Median nerve injury:
       Loss of thumb opposition.
       Atrophy of thenar muscles.
       Ape hand.
   Ulnar nerve injury:
       Paralysis and atrophy of interossei.
       Loss of thumb adduction.
 Hood
 Lateral bands:
       To bases of distal phalanges.
   Central band:
       To base of middle phalanx.
   Function:
       Flexion at MCP joint.
       Extension at PIP, DIP joints.
          Functional Notes
 Extension of the PIP is always
  accompanied by the simultaneous
  extension of the DIP.
 When the PIP is flexed, the DIP may be
  extended or flexed
                Clinical Notes
   If lateral bands detach:
       Lateral bands will flex the PIP and
       hyperextend the DIP.

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