Objectives

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Objectives

• I. Enumerate the bony components of the hand
• II. Demonstrate and memorize the muscles of
  the palmar surface of the hand
• III. Describe the course of the vasculature and
  nerve supply of the hand

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Landmarks

• A. thenar eminence - the swelling at the base
  of the thumb
• B. hypothenar eminence - the swelling at the
  base of the little finger
• C. review the landmarks at the wrist

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Landmarks

• cubital fossa, a triangularly shaped space in
  front of the elbow
• Boundaries
• a. medial - pronator teres muscle
• b. lateral - brachioradialis muscle
• c. base - line between epicondyles of humerus
• d floor - brachialis muscle
• e. roof - deep fascia

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Osteology
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Deep Fascia

• A. deep fascia of the palm of the hand is
  continuous with the antebrachial fascia at the
  wrist via the palmar carpal ligament
• B. deep fascia and the septa radiating from it
  form the compartments in the palm
• 1. deep fascia
• a. thenar fascia - covers thumb muscles and
  forms the thenar compartment
• b. hypothenar fascia - covers short muscles of
  the little finger and forms the hypothenar
  compartment
• c. palmar aponeurosis - directly covers the
  central compartment which overlies the
  adductor- interosseous compartment

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Osteofascial Compartment

• Thenar compartment
• Hypothenar compartment
• Central compartment
• Adductor - interosseous compartment

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Thenar Compartment

• Three muscles have origin from the lateral end of
  the flexor retinaculum
• a. abductor pollicis brevis muscle - inserts on
  lateral side of base of proximal phalanx
• b. opponens pollicis muscle inserts - along
  shaft of first metacarpal
• c. flexor pollicis brevis muscle - inserts - with
  abductor pollicis brevis
• d. recurrent branch of median nerve innervates
  all three
• e. vascular supply from superficial palmar branch
  of the radial artery

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Hypothenar Compartment

• Three muscles have origin from the medial end of
  the flexor retinaculum
• abductor digiti minimi (quinti) muscle - inserts
  - on medial side of base of proximal phalanx
• opponens digiti minimi (quinti) muscle - inserts
  - on medial side of entire fifth metacarpal
• flexor digiti minimi brevis muscle inserts - with
  abductor digiti minimi muscle
• innervation by deep branch of ulnar nerve
• vascular supply by superficial and deep branches
  of ulnar artery

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Central Compartment

• a. flexor tendons and their synovial sheaths
• b. four lumbrical muscles
• (1) origin - from tendons of flexor digitorum
  profundus muscle and pass to lateral side of
  digit they serve
• (2) inserts - on radial side of extensor tendons
• (3) helps to flex the metacarpophalangeal
  joints and extend the interphalangeal joints
• (4) lateral two lumbricals innervated by median
  nerve and medial two lumbricals innervated by
  ulnar nerve
• superficial palmar arch
• digital and muscular branches of superficial
  palmar arch and ulnar and median nerves

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Adductor - Interosseous Compartment

• adductor pollicis muscle
• (1) origin - by transverse (from second, third
  and fourth
• metacarpal bones) and oblique heads (from
  capitate)
• (2) inserts - on medial side of first phalanx of
  thumb
• three palmar interossei muscles - all are
  adductors
• (1) origin - from metacarpal bone
• (2) inserts - on base of proximal phalanx and
  extensor tendon of digit acted upon
• four dorsal interossei muscles - all are
  abductors
• (1) origin - from adjacent metacarpal bones
• (2) inserts - on base of proximal phalanx and
  extensor tendon
• deep palmar arterial arch and its branches
• all muscles innervated by the deep branch of
  the ulnar nerve

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Synovial Sheaths

• As the flexor tendons pass under the flexor
  retinaculum, they are enclosed in synovial
  sheaths to reduce friction
• 1. ulnar bursa
• a. complex synovial sheath for the 8 tendons of
  the two flexor muscles of the fingers
• b. continues into the little finger, but not
  into the second, third, and fourth fingers
• 2. radial bursa
• a. synovial sheath for the tendon of the flexor
  pollicis longus muscle
• b. continues into thumb
• 3. synovial sheaths for the distal tendons to
  the index, middle, and ring fingers are
  separate from the ulnar bursa

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Fascial Clefts (Spaces)

• 1. potential spaces which act as planes of
  cleavage between fascial membranes
• 2. should not be confused with fascial
  compartments
• 3. may occur inside compartments or lie between
  compartments
• 4. major fascial cleft in the palm is situated
  between the central and adductor-interosseous
  compartments
• a. divided by an oblique septum extending from
  the palmar aponeurosis to the shaft of the
  middle metacarpal bone to form
• (1) midpalmar cleft (space) medially
• (2) thenar cleft (space) laterally

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Arteries

• radial artery branches in the hand
• 1. princeps pollicis artery
• 2. radialis indicis artery
• 3. deep palmar arch - connection between deep
  radial and ulnar arteries
• 4. palmar metacarpal arteries
• 5. perforating and recurrent branches

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• ulnar artery branches in the hand
• 1. deep branch
• 2. superficial palmar arch
• 3. common and proper palmar digital arteries
• a. three common palmar digital arteries arise
  from the
• superficial palmar arch
• b. common palmar digital arteries divide into
  the proper palmar digital arteries which supply
  the sides of the digits

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Nerves

• median nerve 3 ½ fingers with cutaneous
• palmar cutaneous branch - given off in forearm
• recurrent muscular branch - motor nerve to
  muscles in thenar compartment
• common and proper palmar digital nerves - sensory
  to lateral 3 1/2 digits and motor to lateral two
  lumbrical muscles
• a. median nerve gives off 3 common palmar
  digital nerves as it emerges from beneath the
  flexor reticulum into the hand
• b. each common palmar digital nerve divides into
  proper digital nerves which supply the cutaneous
  innervation to the sides of the digits and the
  lateral two lumbrical muscles

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• ulnar nerve
• 1. palmar cutaneous branch - given off in
  forearm
• 2. superficial palmar branch - sensory to
  medial 1 1/2 fingers
• 3. deep palmar branch - motor to all the
  muscles
• in the hypothenar and adductor-interosseous
  compartments
• the medial two lumbrical muscles