Hand and Wrist Anatomy😍

Anatomical Snuff Box

  • Small triangular area between 1st and 3rd compartments.

Boundaries:

  • lateral
    • Extensor pollicis brevis tendon
    • Abductor pollicis longus tendon
  • medial
    • Extensor pollicis longus tendon
        • notion image

De Quervains synovitis

  • Extensor pollicis brevis tendon
  • Abductor pollicis longus tendon

Content & Roof

  • Radial artery.
  • Cephalic vein.
      • notion image

Floor

  • 1st compartment tendons: ECRL, ECRB.
  • Styloid process of Radius
  • Trapezium.
  • Scaphoid.
  • Base of 1st Metacarpal.

Applied Aspect

  • Fracture of scaphoid
    • Pain and tenderness in anatomical snuff box.
        • notion image

NOTE:

  • Epiphysis location
    • First metacarpal: Base
      • if at head = aberrant epiphysis
    • All other metacarpals: Head

Extensor compartment of the wrist — Extensor retinaculum

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Layers of Forearm (Lateral to Medial)

Compartment
Muscles
I
• Extensor pollicis brevis
• Abductor pollicis longus
II
• Extensor carpi radialis longus
• Extensor carpi radialis brevis
III
• Extensor pollicis longus
IV
• 4 tendons of extensor digitorum
• Extensor indicis
V
• Extensor digiti minimi
VI
• Extensor carpi ulnaris

Hand muscles

  • Total: 20 muscles
  • Categories:
    • 4 thenar muscles
    • 4 hypothenar muscles
    • 4 lumbricals
    • 4 palmar interossei
    • 4 dorsal interossei
        • notion image

Thenar Muscles 💪

  • Thenar muscles originate from:
    • Scaphoid
    • Trapezium
  • Muscles
    • Flexor pollicis brevis
    • Abductor pollicis brevis
    • Opponens pollicis
    • Adductor pollicis
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HyPothenar Muscles

  • Hypothenar muscles originate from:
    • Pisiform
    • Hamate
  • Muscles
    • Abductor digiti minimi
    • Flexor digiti minimi
    • Opponens digiti minimi
    • Palmaris brevis

Lumbricals

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Origin

  • Tendon to tendon muscle
  • From FDP tendon
    • LumBar → Laterally bend
  • 1st and 2nd
    • unipinnate
  • 3rd and 4th
    • bipinnate
        • notion image

Insertion

  • Dorsal digital expansion
    • Common extensor tendon

Nerve Supply

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  • 1st and 2nd
    • Median nerve
  • 3rd and 4th
    • Ulnar nerve

Actions

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  • Flex metacarpophalangeal joints
  • Extend interphalangeal joints

Interossei Muscles

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Nerve Supply

  • All interossei supplied by Ulnar nerve

Palmar Interossei

  • Unipinnate
  • Function: Adduction of fingers (PAD)
  • Clinical test: Card test
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Dorsal Interossei

  • Bipinnate
  • Function: Abduction of fingers (DAB)
  • Clinical test: Egawa test
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  • Pad (PAD) vangamo → UNi (unipinnate) Card (CARD test) tharam → “Illa” 🖕 (Not in middle finger) → all insertions away from middle finger
  • DAB → Ego (Egawa) ullavar do Big (bipinnate) DAB → all fingers towards middle finger → all insertions towards middle finger

Special Points

  • Middle finger
    • No palmar interossei
    • 2 dorsal interossei
      • one on each side
  • Little finger and Thumb
    • No dorsal interossei inserted

Note

  • 1st palmar interossei often absent
  • Can be mistaken for Opponens Pollicis
      • notion image

Nerve Supply

Muscle Group
Nerve Supply
Anterior compartment of arm
Musculocutaneous nerve
Posterior compartment of arm & forearm
Radial nerve
Anterior compartment of forearm
Ulnar and median nerve
Muscles of hand
Ulnar and median nerve

Sensory Supply of Hand 🌟

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Muscle Insertions 📍

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  • Thenar muscles
    • All muscles insert to proximal phalanx of thumb
    • Except
      • Opponens pollicis:
        • Inserts into shaft of 1st metacarpal
      • Abductor pollicis longus:
        • Inserts into base of 1st metacarpal
    • Adductor pollicis:
      • Fibers originate from 3rd metacarpal and capitate
  • Hypothenar muscles:
    • All Hypothenar muscles insert to proximal phalanx of thumb
    • Except Opponens digiti minimi:
      • Inserts into shaft of 5th metacarpal (inside)
    • Palmaris brevis:
      • Subcutaneous muscle

Wrist Joint

She looks too pretty Try to catch her
She looks too pretty Try to catch her
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  • Formed by articulation of:
    • Scaphoid
    • Lunate
    • Triquetrum
    • radius.
    • She Looks too Ridiculous

Points to Remember

  • Scaphoid:
    • M/c bone fractured.
  • Lunate:
    • M/c bone dislocated.
    • Lunate change Location
  • Capitate:
    • Largest carpal bone.
    • First carpal bone to ossify.
  • Pisiform:
    • Smallest carpal bone.
    • Last carpal bone to ossify.
      • notion image
      • Sesamoid bone
        • Bone within a tendon
        • Examples
          • Patella: quadriceps tendon
          • Pisiform: Flexor carpi ulnaris

Note

Flexor carpi radialis and palmaris longus
Flexor carpi radialis and palmaris longus
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Pulp Space

Boundaries

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  • Superficially
    • Skin, superficial fascia.
  • Deep:
    • distal phalanx

Whitlow:

  • Infection of pulp space.