Nerves

Question 1

Common Fibular

Answer 1

Question 2

Lower Extremity Femoral

Answer 2

Question 3

Lower Extremity Obturator

Answer 3

Question 4

Lower Extremity Tibial

Answer 4

Question 5

Upper Extremity Median

Answer 5

Question 6

Upper Extremity Musculocutaneous

(pic)

Answer 6

Question 7

Upper Extremity Radial and Axillary

Answer 7

Question 8

Upper Extremity Ulnar

Answer 8

Question 9

Lower Extremity Myotomes

Answer 9

Question 10

Upper Extremity Myotomes

Answer 10

Question 11

Upper extremity musculocutaneous

Answer 11

• 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.

*

Question 12

Upper extremity radial nerve (description)

Answer 12

• 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

Question 13

Upper extremity median nerve (description)

Answer 13

• 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
  *

Question 14

Median nerve injury

Answer 14

• 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)

Question 15

Radial nerve injury

Answer 15

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

Question 16

Upper extremity axillary nerve (description)

Answer 16

• 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

Question 17

Upper extremity ulnar nerve (description)

Answer 17

• 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

Question 18

Ulnar nerve injury

Answer 18

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

Question 19

Axillary nerve injury

Answer 19

shoulder dislocation

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