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Flashcards in Nerves Deck (20):

Common Fibular


Lower Extremity Femoral


Lower Extremity Obturator


Lower Extremity Tibial


Upper Extremity Median


Upper Extremity Musculocutaneous




Upper Extremity Radial and Axillary


Upper Extremity Ulnar


Lower Extremity Myotomes


Upper Extremity Myotomes


Upper extremity musculocutaneous

  • lateral cord, opposite the lower border of the pectoralis major - C5, C6, C7 (coracobrachialis, biceps brachii, brachialis)
  • branch to coracobrachialis given off close to its origin

  • penetrates coracobrachialis, innervates biceps brachii and brachialis; passes obliquely b/t biceps & brachialis, to the lateral side of the arm

  • just above elbow, pierces the deep fascia lateral to the tendon of the biceps brachii, continues in forearm as lateral cutaneous nerve of the forearm.



Upper extremity radial nerve (description)

  • posterior cord (C5-T1) through triangular space (teres major - sup, biceps LH - med, humerus - lat) with deep artery 
  • posterior compartment of the arm
    • medial triceps, spiral groove,  lateral triceps
    • Post cutaneous nerve of arm (originates in axilla)

    • Inf lateral cutaneous nerve of arm (originates in arm)

    • Post cutaneous nerve of forearm (originates in arm)

  • anterior compartment of the arm,b/t brachialis & brachioradialis mm
    • aconeus, brachioradialis, ECRL
  • posterior compartment of the forearm
    • superficial - sensory only
    • deep branch - ECRB, supinator
    • PIN (after supinator) (7 total; 6xEXT, 3xpollicis) 
      • Extensor digitorum, extensor indicis, extensor digiti minimi

      • Extensor carpi ulnaris

      • Extensor pollicis brevis

      • Extensor pollicis longus

      • Abductor pollicis longus 


Upper extremity median nerve (description)

  • lateral (C5-C7) and medial cords (C8-T1);inferior to teres major; with the brachial artery & in  cubital fossa; through 2 heads of pronator teres
  • b/t FDS & FDP then FDS & FPL;
  • as AIN innervates all flexor muscles (7) except FCU & 1/2 FDP (ulnar)
    • superficial

      • Pronator teres

      • flexor carpi radialis

      • palmaris longus

    • Intermediate

      • FDS

    • Deep

      • FDP (lat 1/2)

      • FDL

      • pronator quadratus

  • through carpal tunnel, into hand LOAF

    • 1st & 2nd lumbricals

    • opponens pollicis

    • ABD-ductor pollicis brevis

    • flexor pollics brevis



Median nerve injury

  • AIN syndrome
    • Motor deficit: pronator teres, FDP (lat 1/2)
    • Sensory deficit: None

  • Carpal tunnel

    • Motor deficit: FDP (lat 1/2); loss of abduction and opposition of thumb.

      • ape hand deformity (hand is at rest) with hyperext of index D1,D2; D1 ADD

      • benediction sign (attempt fist) due to weakness in flexion of radial half of digits.

    • Sensory deficit: lateral  3 1⁄2 digits including their nail beds, (NOT carpal if sensation lost in thenar area b/c palmar cutaneous branch)


Radial nerve injury

  • Above elbow
    • elbow extension
    • wrist drop
  • Below elbow
    • wrist drop


Upper extremity axillary nerve (description)

  • upper trunk, posterior division, posterior cord (C5-C6); thru quadrangular space (Sup: teres minor, Inf:teres major; Med: LH biceps; Lat: humerus)
  • Sensory:
    • shoulder patch by superior lateral cut nerve of arm
  • Motor:
    • deltoid, teres minor, long head of triceps


Upper extremity ulnar nerve (description)

  • Medial cord (C8-T1)
  • posteromedial aspect of the humerus, behind medial epicondyle
  • anterior forearm with ulnar artery
    • motor: FCU, 1/2 FDP (med)

    • sensory: palmar & dorsal branch: 

  • through guyon canal into hand (deep branch) 

    • Opponens DM, ABD DM & flexor digiti minimi brevis

    • 3&4 lumbrical

    • PAD & DAB

    • adductor pollicis

    • FPB (deep)

  • NOT through guyon via superficial branch: palmaris brevis


Ulnar nerve injury

Guyon canal:

  • Motor deficit:
    • Weakness in flexion of the hand at the wrist, loss of flexion of D4-D5; cannot "cross" digits
    • claw hand (hand at rest) b/c hyperEXT of D4-D5 @ MCP + FLEX @ IP; worse if lesion @ wrist
      • Froment's (thumb ADD)
  • Sensory deficit: ulnar half of palm, medial 1½ digits (palmar & dorsal) --> DORSAL HAND AFFECTED ONLY if lesion is at elbow


Axillary nerve injury

shoulder dislocation

  • Sensory:
    • shoulder patch by superior lateral cut nerve of arm
  • Motor:
    • deltoid, teres minor, long head of triceps