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Flashcards in Nerves Deck (20):

Common Fibular

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Lower Extremity Femoral

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Lower Extremity Obturator

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Lower Extremity Tibial

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Upper Extremity Median

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Upper Extremity Musculocutaneous



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Upper Extremity Radial and Axillary

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Upper Extremity Ulnar

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Lower Extremity Myotomes

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Upper Extremity Myotomes

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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