Upper Extremity 9 : Lateral and Posterior Forearm Muscles

Page 1

  • Lateral forearm compartment muscles listed:
    • Brachioradialis M.
    • Flexor of forearm
    • Extensor Carpi Radialis Longus M.

Page 2

  • Brachioradialis M.
    • Origin: upper 2/3 of lateral supracondylar ridge of humerus
    • Insertion: styloid process of radius
    • Nerve supply: radial nerve
    • Action: flexion of forearm
    • Blood supply: radial and brachial aa.

Page 3

  • Muscles and nerves commonly appearing together (likely a diagram/list):
    • Biceps
    • Musculocutaneous nerve
    • Brachi alie (likely brachialis)
    • Radial nerve
    • Brachioradialis
    • Extensor carpi radialis longus
    • Deep branch of radial nerve
    • Radial recurrent artery
    • Extensor carpi radialis brevis
    • Superficial branch of radial nerve
    • Radial artery
    • Flexor carpi radialis
    • Supinator
    • Medial intermuscular septum
    • Inferior ulnar collateral artery
    • Ulnar nerve
    • Biceps brachii tendon
    • Brachial artery
    • Median nerve
    • Pronator teres
    • Ulnar artery
    • Deep head of pronator teres
    • Zoom (visual aid reference)

Page 4

  • Extensor Carpi Radialis Longus M.
    • Origin: Lateral supracondylar ridge of humerus
    • Insertion: posterior surface of base of second metacarpal bone
    • Nerve supply: radial nerve
    • Action: extends forearm; extension & radial flexion of hand
    • Blood supply: radial aa.

Page 5

  • Muscles/nerves/structures listed (posterior forearm region):
    • Anconeus
    • Deep branch of the radial nerve
    • Posterior interosseous recurrent artery
    • Branches of posterior interosseous nerve
    • Extensor digitorum
    • Extensor digiti minimi
    • Extensor carpi ulnaris
    • Brachioradialis
    • Extensor carpi radialis longus
    • Extensor carpi radialis brevis
    • Posterior interosseous nerve and artery
    • Pronator teres
    • Abductor pollicis longus
    • Extensor indicis
    • Extensor retinaculum
    • Dorsal carpal arch
    • Dorsalis indicis artery – Radialis indicis artery
    • 1st dorsal interosseous
    • Extensor pollicis brevis
    • Extensor pollicis longus
    • Radial artery (in the "snuff box")
    • Dorsalis pollicis arteries
    • Adductor pollicis
    • Zoom (visual aid reference)

Page 6

  • POSTERIOR FOREARM COMPARTMENT GENERAL CHARACTERISTICS:
    1) Superficial muscles all originate from a common tendon of origin that attaches to the lateral epicondyle of the humerus.
    2) Blood supply to the muscles from the posterior and anterior interosseous arteries.
    3) Deep branch of the radial nerve (posterior interosseous nerve) supplies most of the posterior forearm.

Page 7

  • Muscles of the posterior forearm – superficial mm.:
    • Extensor Carpi Radialis Brevis M.
    • Extensor Digitorum M.
    • Extensor Digiti Minimi M.
    • Anconeus M.

Page 8

  • Deep muscles (DEEP MM.):
    • Supinator M
    • Abductor Pollicis Longus M.
    • Extensor Pollicis Brevis M.
    • Extensor Pollicis Longus M.
    • Extensor Indicis M.

Page 9

  • Superficial posterior forearm muscles – Extensor Carpi Radialis Brevis M.:
    • Origin: common tendon attached to lateral epicondyle of humerus
    • Insertion: posterior surface of base of third metacarpal bone
    • Nerve supply: posterior interosseous N.
    • Action: extends forearm; extension & radial flexion of hand
    • Blood supply: radial A.

Page 10

  • Extensor Carpi Radialis Longus
  • Extensor Carpi Radialis Brevis
  • Extensor Carpi Ulnaris
  • Zoom (visual aid reference)

Page 11

  • Extensor Digitorum M.
    • Origin: common tendon
    • Insertion: posterior surface of each finger; the tendon becomes incorporated into the extensor expansion. This expansion splits into 3 parts at the M.P. joint:
    • Ext. Indicis: a central part which inserts into base of proximal phalanx of the index finger
    • Ext. Digiti Minimi: a portion of the expansion for the little finger to the middle phalanx
    • Lumbricals: two lateral parts which converge and insert into base of distal phalanx
    • Nerve supply: Posterior Interosseous Nerve
    • Action: extension of forearm, wrist; extends Metacarpophalangeal (MCP) joint, proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints
    • Blood supply: Posterior Interosseous Artery

Page 12

  • Extensor digitorum
  • Extensor digiti minimi
  • Zoom (visual aid reference)

Page 13

  • Extensor Digiti Minimi M.
    • Origin: common tendon attached to lateral epicondyle of humerus
    • Insertion: extensor (dorsal) expansion for little finger
    • Nerve supply: Posterior Interosseous Nerve
    • Action: extend MCP joint of little finger
    • Blood supply: Posterior Interosseous A.

Page 14

  • Extensor expansion (extensor digitorum expansion)
  • Extensor indicis
  • Body (shaft) of 2nd metacarpal
  • 1st dorsal interosseous
  • Dorsal digital vein
  • Extensor digiti minimi
  • Radial artery
  • Extensor carpi radialis longus
  • Extensor carpi radialis brevis
  • Ulnar nerve, dorsal branch
  • Extensor retinaculum
  • Radial nerve, superficial branch
  • Extensor pollicis longus
  • Extensor pollicis brevis
  • Abductor pollicis longus
  • Extensor carpi ulnaris
  • Extensor indicis
  • Extensor digiti minimi
  • Extensor digitorum
  • Zoom (visual aid reference)

Page 15

  • Extensor Carpi Ulnaris M.
    • Origin: common tendon
    • Insertion: 5th metacarpal bone
    • Nerve supply: Posterior Interosseous N.
    • Action: extend & ulnar flexion of hand
    • Blood supply: Posterior Interosseous A.

Page 16

  • Muscle group labeling overview:
    • Extensor Carpi Longus, Radialis (3)
    • Brevis
    • Extensor Pollicis Longus (1)
    • Abductor Pollicis Longus (2)
    • Extensor Pollicis Brevis
    • Dorsal radial tubercle deep to extensor retinaculum
    • Extensor Digiti Minimi (6)
    • Extensor Carpi Ulnaris (4)
    • Extensor Digitorum (5)
    • Extensor Indicis (5)
    • Extensor Retinaculum
    • Zoom (visual aid reference)

Page 17

  • Anconeus M. (considered as part of the Triceps M.)
    • Origin: Lateral epicondyle of humerus
    • Insertion: Olecranon of ulna
    • Nerve supply: Radial nerve
    • Action: Extend elbow (last 5 degrees)
    • Blood supply: Profunda brachii A.

Page 18

  • Anconeus
  • Supinator
  • Abductor Pollicis Longus
  • Extensor Pollicis Brevis
  • Extensor Pollicis Longus
  • Extensor Indicis
  • Zoom (visual aid reference)

Page 19

  • DEEP POSTERIOR FOREARM MUSCLES: Supinator M.
    • Origin: Lateral epicondyle of humerus; lateral ligaments of elbow; annular ligament of ulna
    • Insertion: Above oblique line of radius
    • Nerve supply: Posterior Interosseous N.
    • Action: Supination
    • Blood supply: Posterior Interosseous A.

Page 20

  • Re-listing of posterior forearm structures (deep to superficial and nerve/artery associations):
    • Anconeus
    • Deep branch of the radial nerve
    • Posterior interosseous recurrent artery
    • Branches of posterior interosseous nerve
    • Extensor digitorum
    • Extensor digiti minimi
    • Extensor carpi ulnaris
    • Brachioradialis
    • Extensor carpi radialis longus
    • Extensor carpi radialis brevis
    • Posterior interosseous nerve and artery
    • Pronator teres
    • Abductor pollicis longus
    • Extensor indicis
    • Extensor retinaculum
    • Dorsal carpal arch
    • Dorsalis indicis artery; Radialis indicis artery
    • 1st dorsal interosseous
    • Extensor pollicis brevis
    • Extensor pollicis longus
    • Radial artery (in the snuff box)
    • Dorsalis pollicis arteries
    • Adductor pollicis
    • Zoom (visual aid reference)

Page 21

  • Abductor Pollicis Longus M.
    • Origin: Ulna, Radius, Interosseous membrane
    • Insertion: 1st Metacarpal bone of the thumb
    • Nerve supply: Posterior Interosseous N.
    • Action: Abducts and extends the thumb
    • Blood supply: Posterior Interosseous A.

Page 22

  • Vascular landmarks around the dorsal/thenar region:
    • Dorsalis pollicis artery
    • Radial artery in snuff box
    • Abductor pollicis longus
    • Extensor pollicis brevis
    • Adductor pollicis
    • 1st dorsal interosseous
    • Dorsalis indicis artery
    • Bursa
    • Extensor carpi radialis brevis
    • Dorsal carpal branch
    • Extensor pollicis longus
    • Extensor carpi radialis longus
    • 729 (visual cue) / hubb (visual cue)
    • Zoom

Page 23

  • Extensor Pollicis Brevis M.
    • Origin: Radius, Interosseous membrane
    • Insertion: Proximal phalanx of the thumb
    • Nerve supply: Posterior Interosseous N.
    • Action: Extends the Metacarpophalangeal joint of the thumb
    • Blood supply: Posterior Interosseous A.

Page 24

  • Extensor carpi Longus
  • Extensor carpi Radialis (Longus 3, Brevis)
  • Extensor pollicis longus (1)
  • Abductor pollicis longus (2)
  • Extensor pollicis brevis
  • Dorsal radial tubercle deep to extensor retinaculum
  • Extensor digiti minimi (6)
  • Extensor carpi ulnaris (4)
  • Extensor digitorum (5)
  • Extensor indicis (5)
  • Extensor retinaculum
  • Zoom

Page 25

  • Extensor Pollicis Longus M.
    • Origin: Ulna, Interosseous membrane
    • Insertion: Distal phalanx of the thumb
    • Nerve supply: Post Interosseous N.
    • Action: Extends distal phalanx of the thumb
    • Blood supply: Posterior Interosseous A.

Page 26

  • Dorsalis indicis artery
  • Dorsalis pollicis arteries
  • Dorsal digital arteries
  • Dorsal metacarpal arteries
  • Dorsal carpal arch
  • Radial artery in snuff box
  • Anterior interosseous artery
  • Zoom

Page 27

  • Extensor Indicis M.
    • Origin: Ulna, Interosseous membrane
    • Insertion: Extensor expansion of the index finger
    • Nerve supply: Posterior Interosseous Nerve
    • Action: Extends MCP joint of index finger
    • Blood supply: Posterior Interosseous A.

Page 28

  • Lateral view of the thumb – Anatomical Snuff Box:
    • Anterior (volar) side notated
    • Extensor pollicis brevis M.
    • Extensor pollicis longus M.
    • Posterior abductor pollicis longus M.
    • Anatomical snuff box visualization

Page 29

  • Carpal bones (in typical arrangement):
    • Trapezium, Trapezoid, Metacarpal heads, Metacarpal shaft, Metacarpal base, Capitate, Hamate, Pisiform, Scaphoid, Triquetral, Lunate
    • Tunnel of Guyon – pisohamate ligament

Page 30

  • Palmar cutaneous branch of ulnar nerve
  • Ulnar artery
  • Palmaris longus
  • Flexor retinaculum
  • Median nerve
  • Palmar cutaneous branch of median nerve
  • Ulnar nerve
  • Flexor digitorum superficialis
  • Flexor digitorum profundus
  • Flexor synovial sheath (continuous into thumb and little finger)
  • Flexor carpi radialis M
  • Flexor pollicis longus M
  • Radial bursa contains extensor tendons
  • Extensor retinaculum
  • Carpal Tunnel Syndrome: infection or irritation of the hand compresses the median nerve
  • Lunate bone – Scaphoid bone

Page 31

  • Flexor retinaculum (2)
  • Palmaris longus (1)
  • Ulnar artery (19)
  • Ulnar nerve (19)
  • Flexor digitorum superficialis (18)
  • Hook of hamate (HH)
  • Flexor digitorum profundus (17)
  • Hypothenar muscles (16)
  • Extensor carpi ulnaris (15)
  • Extensor digiti minimi (14)
  • Hamate (H)
  • Median nerve (3)
  • Flexor pollicis longus (4)
  • Thenar muscles (5)
  • Flexor carpi radialis (6)
  • Trapezium (Tm)
  • Extensor pollicis brevis (7)
  • Extensor pollicis longus (8)
  • Abductor pollicis (missing label, context indicates thenar/thenar-adjacent region)
  • Extensor pollicis longus (9)
  • Radial artery (10)
  • Trapezoid (Tz)
  • Extensor carpi radialis longus (11) and brevis (12)
  • Capitate (c)
  • Extensor digitorum (13)
  • Extensor indicis
  • Zoom

Page 32

  • Numerical/figural labels from an image view: 3, 4, 2, 5, HH, P, Η, C, Td, TdTz, S, 1
  • Zoom

Page 33

  • Interosseous metacarpal ligament
  • Carpometacarpal joint of 5th digit
  • Ulnar collateral ligament
  • Articular disc
  • Metacarpal Carpometacarpal joint of thumb
  • Radial collateral ligament
  • Radiocarpal joint
  • Distal radioulnar joint
  • Ulna
  • Radius
  • Zoom