Injured Nerve Deficits

Question 1

Axillary Nerve

Answer 1

The two most common injuries to the axillary nere are with an anterior dislocation of the humerus and a fracture of the surgical neck of the humerus
○ The resulting deficits are:
§ Weaknesss in abduction of the arm
§ Sensory loss on the lateral shoulder and upper arm

Question 2

Radial Nerve

Answer 2

The most common site of injury to the radial nerve is with midshaft fractures of the humerus
○ The resulting deficits are:
§ Loss of wrist and digit extension
§ Weakness of supination
§ Sensory loss on posterior arm and forearm along with the dorsum of the hand

Question 3

Median Nerve

Answer 3

○ Supraepicondylar fracture of the humerus
§ Weakened wrist flexion
§ Hand deviates to the ulnar side when wrist is flexed
§ Loss of index and middle finger flexion at MP, DIP, and PIP joints
§ Weakness of thumb abduction
□ Loss of thumb opposition and loss of thumb flexion
§ Loss of pronation
§ Sensory loss on palmar and dorsal aspects of index, middle, and half of ring fingers and palmar aspects of thumb
○ Carpal tunnel syndrome, fracture or laceration
§ Weakness of thumb abduction and flexion
§ Loss of thumb opposition
□ Atrophy of the thenar pad
§ Sensory loss on palmar and dorsal aspects of index, middle, and half of ring fingers and palmar aspect of thumb

Question 4

Deep branch of Median nerve (Anterior Interosseous Nerve)

Answer 4

○ Middle forearm (anterior interosseous syndrome)
§ Weakness of thumb flexion
§ Loss of flexion of the DIP joint of the index and middle fingers
§ Weakness of pronation
No sensory loss

Question 5

Ulnar Nerve

Answer 5

• Common injuries to the ulnar nerve may occur with fractures of the medial epicondyle or compression of the nerve against bone as with “tennis elbow” or with fractures or lacerations to the ventral medial side of the wrist
• The resulting deficits are:
○ Entrapment at the elbow or medial epicondyle fracture
§ Loss of abduction and adduction of fingers
§ Loss of thumb adduction
§ Loss of flexion of the 4th and 5th digits at the DIP joint
§ Hand deviates to the radial side when flexed
§ Sensory loss of medial side of hand and aspects of 4th and 5th digit
○ Wrist fracture or laceration
§ Loss of abduction and adduction of fingers
§ Loss of thumb adduction
§ Sensory loss on medial side of hand and aspects of 4th and 5th digit

Question 6

Musculocutaneous Nerve

Answer 6

• Are not that common but can occur 
• Result in: 
	○ Weakness of forearm flexion 
	○ Weakness of hand supination 
	○ Weakness of arm flexion 
           Sensory loss on lateral forearm

Question 7

Lesions of Brachial Plexus (Upper Brachial Plexus)

Answer 7

○ The upper brachial plexus injury most often occurs as a birth injury of fall on the shoulder
• Nerve lesions of the upper extremity
○ Causes
§ Undue separation of the head from the shoulder commonly encountered in birth injury of fall on the shoulder
○ Nerves most commonly involved
§ Musculocutaneous
§ Axillary
§ Suprascapular
○ Deformity (position of the limb)
§ Arm hands by the side
§ It is adduction and medially rotated
§ Forearm extended and hand probated
○ Disability (loss of function)
§ Abduction and lateral rotation of the arm
§ Flexion and supination of the forearm
§ Sensation lost over small area over the lower part of the shoulder

Question 8

Brachial Plexus (Lower Brachial Plexus)-Kumke’s Palsy

Answer 8

○ Causes 
	§ Undue abduction of the arms as in clutching something with hands after a fall from a height or sometimes birth injury 
○ Nerves most commonly involved 
	§ Ulnar 
	§ Median 
○ Deformity (position of the limb)
	§ Ulnar claw hand due to unopposed action fo the long flexors and extensors of the fingers 
		□ Hyperextension of the MP joints 
		□ Flexion at the IP joints 
○ Disability (loss of function) 
	§ Intrinsic muscles of the hand 
	§ Ulnar flexors of wrist and fingers 
	§ Sensation lost over small area along the ulnar border of the forearm and hand