Clinical Upper Limb

Question 1

describe function of axillary nerve

Answer 1

• from posterior cord
  
  • exits through quadrangular space w/ PHCA
• passes posterior to surgical neck of humerus
• supplies deltoid + teres minor muscles
• sensory supply: upper lateral part of arm

Question 2

describe an axillary nerve injury

Answer 2

• decreased ability to laterally rotate the arm (teres minor)
• loss of abduction from 15-90 degrees (deltoid)
• sensory loss to upper lateral part of arm

Question 3

describe effects of midshaft fracture of clavicle

Answer 3

• associated intrathoracic injuries:
  
  • pneumothorax
  • damage to subclavian vein + artery

Question 4

describe the effects of Erb’s Palsy

Answer 4

• Damages upper brachial plexus (C5/C6)
• damage to:
  
  • suprascapular: inability to initiate abduction and loss of external rotation
  • axillary: loss of abduction to 90 degrees and external rotation
  • musculocutaneous: loss of forearm flexion and weakened supination
• sensory loss along lateral border of limb

Question 5

describe Klumpke’s Palsy

Answer 5

• damage to lower brachial plexus (C8/T1)
• damage to ulnar nerve:
  
  • loss of FCU and medial 1/2 of FDP
• loss of intrinsic hand muscles (ulnar + median damage)
• sensory loss along medial border of hand and forearm and arm

Question 6

describe the function of the musculocutaneous nerve

Answer 6

• from lateral cord
• supplies flexor compartment of arm
• sensory supply:
  
  • continues as the lateral cutaneous nerve of the forearm

Question 7

describe the function of the radial nerve

Answer 7

• from posterior cord
• supplies extensors of arm, forearm, wrist and digitals
  
  • radial nerve, deep radial nerve, posterior interosseous
• sensory supply for:
  
  • arm - posterior and lower lateral
  • forearm - posterior
  • hand - dorsum of hand/lateral 3 ^_1/2 digits (proximal part of these digits)

Question 8

describe an injury to the radial nerve

Answer 8

• midshaft fracture of humerus = radial nerve damage
  
  • in midshaft fracture, still retain ability to extend elbow
• loss of ability to extend the elbow joint
• wrist-drop and loss of posterior compartment of the forearm
• impaired grip strength
• sensory loss:
  
  • arm - posterior + lower lateral
  • forearm - posterior
  • hand - dorsum of hand/lateral 3 ^1/2 digits (proximal part of these digits)

Question 9

contrast tennis elbow and golfer’s elbow

Answer 9

• tennis elbow
  
  • lateral epicondylitis
  • common extensor origin
• golfer’s elbow
  
  • medial epicondylitis
  • common flexor origin

Question 10

describe function of the median nerve

Answer 10

• from lateral + median cord
  
  • crosses through cubital fossa
• supplies all superifical flexors of forearm (except FCU)
• becomes anterior interosseous nerve
  
  • ​all deep flexors (except ulnar ^1/2 of FDP)
• travels through carpal tunnel
• motor innervation:
  
  • 1/2 LOAF (3 thenar, 2 lumbricals)
• sensory innervation:
  
  • lateral 3 ^1/2 fingers palmar side and their distal phalanx on the dorsal side

Question 11

describe injury to median nerve at or above elbow

Answer 11

• weakened wrist flexion
• ulnar deviation (FCU unopposed)
• loss of flexion of index and middle fingers at DIP and PIP
  
  • damage to FDS + ^1/2 FDP
• loss of pronation
• loss of opposition of thumb
• weakened abduction and loss of flexion of thumb
• sensory loss: palmar aspects of thumb, index, middle and half of ring finger up to the DIP on the dorsal aspect

Question 12

describe injury to median nerve at wrist

Answer 12

• injured by slashing, carpal tunnel syndrome or lunate dislocation
• flexor muscles in forearm are not paralyzed (no Pope hand)
• wrist flexion, forearm pronation and long flexor of thumb all intact
• 1/2 LOAF muscles of intrinsic hand are paralyzed
  
  • atrophy of thenar muscles
  • loss of opposition and weakened abduction and flexion of thumb

Question 13

describe function of the ulnar nerve

Answer 13

• from medial cord
• supplies 1 1/2 muslces in the forearm
  
  • FCU
  • ^1/2 FDP
• motor innervation:
  
  • deep motor branch to all the muscles of the hand except 1/2 LOAF (these are medial)
• sensory innervation:
  
  • superficial cutaneous branch and dorsal cutaneous branch: sensory to the palmar and dorsal medial 1 ^1/2 digits respectively

Question 14

describe injury to ulnar nerve at or above elbow

Answer 14

• can occur in medial epicondyle fracture
• paralysis of FCU; hand deviates radially
• paralysis of ulnar 1/2 FDP; lose flexion of ring and little fingers at DIP (FDS still intact for flexion at PIP)
• paralysis of 3rd and 4th lumbricals
• paralysis of all interosseous muscles (DAb and PAd)
• loss of adduction of thumb (adductor policis)

Question 15

Answer 15

• CT fracture
• fracture of the hook of the hamate
• ulnar nerve + ulnar artery at risk of being injured