functional organizations of the arm and hand Flashcards Preview

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Flashcards in functional organizations of the arm and hand Deck (49):


each contains one or more functional groups of muscles, deep fascia divides the arm and forearm into post and ant components


anterior/flexor compartment of arm

contains muscles that flex the elbow joint and supinate the radioulnar joint


posterior/extensor compartment of arm

contains muscles that extend the elbow joint


innervation of anterior compartment of arm

musculocutaneous: from lateral cord of the brachial plexus. C5-C7, C6 is the main contributor. Motor innervation to muscles in the anterior brachial compartment and carries sensory from the lateral portion of the forearm (C6 dermatome)


innervation of posterior compartment of arm

radial nerve: derived from pot cord of brachial plexus, C5-T1, C5-7 are the main contributors. Motor to triceps and anconeus, sensation from post lat portion of arm (C5 dermatome)


anterior compartment of the forearm

contains muscles that flex the wrist joint, pronate the radioulnar joint and flex the digits


posterior compartment of the forearm

contains muscles that extend the wrist joint, supinate the radioulnar joint, and extend and abduct the digits


innervation of the posterior compartment of the forearm

radial nerve


innervation of the anterior compartment of the forearm

ulnar and medial nerve


transition zones (3)

provide a passageway for the contents (particularly nerves and vessels) of one compartment to enter another 1. axilla 2. cubital fossa 3. wrist


muscles in the anterior compartment of the arm (3)

1. biceps brachii 2. brachialis 3. coracobrachialis


blood supply to muscles in ant compartment of arm

brachial artery, branches include: 1. muscular branches to the muscles in the ant compartment of the arm 2. collateral branches in elbow anastomosis 3. deep brachial artery: extensor compartment


Muscles in the post compartment of the arm (2)

1. triceps brachii 2. anconeus


Blood supply of the posterior compartment of the arm

Deep profunda brachial artery (1st brach of the brachial) gives off: -muscular branches to the muscles in the extensor compartment -collateral branches in elbow anastomosis


Veins in the arm (3)

Cephalic (lateral) Basilic (medial) Median cubital (connects the 2)


Biceps rupture

could tear the biceps from an attachment on the supraglenoid tubercle, the radial tuberosity or both. Make the bicep appear higher or lower on the arm depending on where it is torn. Sometimes if the person is not an athlete they won't repair it, if they do, they sew the tendon back onto the bone


Cubital Fossa

region anterior to the elbow joint, passageway for nerves and vessels traveling from the arm into the forearm, venipuncture usually performed here


Cubital Fossa Boundaries

Superior: imaginary line connecting condyles Medial: pronator teres lateral: brachioradialis roof: skin, fascia, bicipital apaneurosis floor: medial: brachilis lateral: supinator


Cubital Fossa Contents (4ish)

1. radial nerve 2. biceps tendon 3. brachial artery and vein terminal branches: radial and ulnar artery 4. median nerve


Ulnar Artery branches

branches off into common interossius artery which is very short and splits very quickly into the anterior and posterior interossius artery



-main articulation of the wrist -articulate with the ulna, humerus, scaphoid, and lunate bones -the tuberosity of the radius is where the biceps tendon attaches



-more stable because it has a hook -articulates with humerus and radius -has a fibrocartilagenous disc at the wrist


Muscles of the anterior portion of the arm (characteristic)

common origin at the medial epicondyle of the humerus


Radio-ulnar pronators

cause the radius to rotate on a fixed ulna bringing the forearm and hang "palms down" 1. pronator teres 2. pronator quadratus


Wrist flexors

attach to the medial epicondyle of the humerus and bring the palm of the hand toward the elbow (flexion)

  1. flexor carpi radialis
  2. palmaris longus
  3. flexor carpi ulnaris


Digital Flexors

extrinsic, bellies of origin in forearm but exert actions of wrist and hand

  1. flexor digitorum superficialis
  2. flexor digitorum profundus
  3. flexor pollicis longus


Movement of the thumb


median motor nerve muscle supply (7)

  1. pronator teres
  2. pronator quadratus
  3. flexor carpi radialis
  4. palmaris longus
  5. flexor digitorum superficialis
  6. radial 1/2 of flexor digitorum profundus
  7. flexor pollicis longus


ulnar motor nerve supply (2)

1. flexor carpi radialis

2.ulna portion of the flexor digtorum profundus


cutaneous innervation of the forearm

Lateral/radial side

  • lateral antibrachial cutaneous (C6), cutaneous branch of musculocutaneous nerve

Medial/ulna side

  • medial antibrachial cutaneous carries sensory axons from T1. Branch of medial cord of brachial plexus


blood supply to flexor compartment of the forearm

provided by radial and ulnar arteries which brach from brachial artery


branches of the radial artery

  1. muscular branches to muscles in flexor compartment
  2. recurrent branch in elbow anastomosis


branches of the ulnar artery

  1. muscular branch to the muscle in the flexor compartment
  2. recurrent in elbow anastomosis
  3. common interosseous branch
    1. anterior: deep lying muscles in flexor
    2. posterior: main blood supply to muscles in extensor


posterior compartment of the forarm characteristic

wrist and finger extensors have a common attachment from the lateral epicondyle of the humerus


Anatomical Snuff box muscles

act on the 1st metacarpal and joints of the thumb

  1. abductor pollicis longus
  2. extensor pollicis brevis
  3. extensor pollicis longus


wrist extensors

1. extensor carpi radialis longus

2. extensor carpi radialis brevis

3. extensor carpi ulnaris (weaker than other 2, why extension usually occurs along with radial deviation)



finger extensors

  1. extensor digitorum
  2. extensor digiti minimi
  3. extensor indicis


misc. muscles in the forearm

1. supinator: weak supinator of the radioulnar joint (biceps is the strongest)

2. brachioradialis: flexes elbow when the hand is in neutral position


Extensor compartments

6 tunnels that are comprised of a tendon(s) surrounded by a synovial sheath. located within tunnels bound by portions of the extensor retinaculum


Compartment 1

abductor pollicis longus and extensor pollicis brevis.


most clincally significant. repetitive movements of the thumb and wrist can result in De Quervain's Disease


Compartment 2

extensor carpi radialis longus and brevis tendons


Compartment 3

Extensor pollicis longus tendon (wraps around tubercle on radius)


Compartment 4

extensor digitorum and etensor indicis


Compartment 5

Extensor digiti minimi


Compartment 6

extendor carpi radialis tendon


De Quervain's Disease

caused by repetitve movents of the thumb and wrist, especially flexion of the thumb and ulnar deviation of the wrist results in pain to the dorsal aspect of wrist


asking the patient to fold their thumb under the fingers and move the wrist toward the ulna (ulnar deviation) produces a pain that tests positive for this condition


Innervation of the extensor compartment

Radial Nerve: enters the cubital fossa and winds arounf the shaft of the humerus. Branches into:

  • muscular branches that supply extensor carpi radialis longus and brachioradialis
  • a superficial branch that conveys sensory ONLY from the dorsum of the hand and thumb
  • a deep branch: pierces the supinator muscle and supplies ECRB


blood supply of the extensor compartment of the forearm

posterior interosseus branch of the common interosseus artery to all of the muscles


tennis elbow

overuse of extensors, tearing or inflammation on or around the lateral epicondyle. common treatment is to put a strap around the tendons


also medial epicondylitis which is the same thing only on the lateral epicondyle