Upper Limb Nerve Injuries Flashcards
Can regenerate if damaged as long as the cell body is not damaged and there is a pathway to travel upon to reach the deinnervated organ
Peripheral nerves
The rate of peripheral nerve regeneration averags about
1 cm per week
When a nerve that contains many axons is damaged, what will regain function first, proximal or distal structures innervated by that nerve?
Proximal
If the median nerve is lesioned at the level of the elbow, what will regain function first, the forearm or hand?
Forearm
Can be caused by stretch of the UPPER trunk caused by forceful separation of the shoulder away from the neck
Erb’s Palsy
The proximal limb muscles, i.e. intrinsic shoulder muscles and most muscles of the axillary wall are affected by
Erbss Palsy
In Erb’s Palsy, the limb tends to be held such that the shoulder is in an
Extended, adducted, and internally rotated position and forearm is pronated
In Erb’s Palsy, sensory loss is along the lateral side of the distal arm and proximal forearm, in other words, at the
C5 and C6 dermatomes
The appearance of the arm in Erb’s Palsy is called the
Waiters tip sign
Can be caused by stretch or compression of the LOWER trunk such as by upward traction on the limb or compression in the region of the “thoracic outlet” (e.g. cervical rib)
Klumpke’s Palsy
What is affected by Klumpke’s Palsy?
The distal limb (i.e. intrinsic muscles of the hand) are affected
Thenar mucles and the interossei may be atrophied in
Klumpke’s Palsy
What are some visual suggestors of Klumpke’s Palsy?
Clawing of digits II-V and loss of abduction/adduction in the fingers
Klumpke’s Palsy results in sensory loss along the medial side of the distal arm and proximal forearm, i.e. the
C8 and T1 dermatomes
May be caused by a fracture of the surgical neck of the humerus or a glenohumeral dislocation
Axillary nerve injury
Axillary nerve injury results in denervation of the
Deltoid
Results in sensory loss on the skin overlying the deltoid
Axillary nerve injury
May be caused by a fracture of the shaft of the humerus, fracture or dislocation of the head of the
radius, dislocation of the head of the humerus, or upward pressure in the floor of the axilla
Radial nerve injury
May cause wrist drop and difficulty in making a fist because of the inability to stabilize the wrist
Radial nerve injury
With a radial nerve injury, cutaneous sensory loss may occur on the
Dorsum of radial portion of hand
Which type of radial nerve injury results in more motor/sensory loss, a more proximal or a more distal injury?
Proximal
May be caused by trauma in the cubital fossa (e.g. supracondylar fracture) or at the wrist (e.g.
laceration), compression in the carpal tunnel or compression passing through the pronator teres
Median nerve injuries
Long term denervtion cause by a median nerve injury may result in
Thenar atrophy, loss of opposition, unapposed thumb (ape hand), and clawing of digits II and III
Can result in clawing of digits II and III and ape hand
Median nerve lesions
If the median nerve injury is at the level of the wrist, then flexion and abduction of the thumb is still possible because of the
Flexor pollicis longus and abductor pollicis longus
The flexor pollicis longus will be paralyzed and thumb flexion will not be possible if the median nerve injury is at the level of the
Elbow
Proximal median nerve injury results in ulnar deviation of the hand upon flexion at the wrist due to the paralysis of the
Flexor carpi radialis
Proximal median nerve injury results in ulnar deviation of the hand upon flexion at the wrist due to the loss of flexion of digits I through III resulting from paralyzed
Flexor pollicis longus and brevis, flexor digitorum superficialis and radial half of flexor digitorum profundus
Proximal median nerve injury results in a hand shape called the
Hand of benediction
Proximal median nerve injury results in sensory loss to the
Lateral portion of palmar surface of the hand and digits I-III
May be caused by trauma in the region of the medial epicondyle of the humerus or at the heel of the hand
Ulnar nerve injury
What are some physical symptoms of ulnar nerve injury?
Loss of abduction and adduction of digits II-V (interosseous muscles), and clawing most prominently in digits IV and V (lumbrical muscles)
Results in radial deviation of hand upon flexion at the wrist (paralysis of flexor carpi ulnaris) and loss of flexion
of the DIP of digits IV and V (flexor digitorum profundus)
Proximal Ulnar injury
An uncommon injury. Not likely to be injured by skeletal injuries such as fractures or dislocations
Musculocutaneous nerve injury
A musculocutaneous injury my occur by a
Penetrating wound
What are some physical symptoms of a musculocutaneous nerve injury?
Loss of function of anterior arm muscles, i.e. weakness of shoulder flexion, extreme weakness of elbow flexion, and weak supination
Which elbow flexor can still be used when there is a musculocutaneous injury?
Brachioradialis
With an ulnar nerve injury, there is cutaneous sensory loss on the
Medial side of the hand
With a musculocutaneous injury, there is sensory loss to the
Lateral side of the forearm
The distal continuation of the musculocutaneous nerve, which results in sensory loss when musculocutaneous nerve is injured
Lateral antebrchial cutaneous nerve
May be caused by trauma to the chest wall or surgical injury during axillary surgery
Long Thoracic Nerve
Presents as winging of the scapula due to loss of the serratus anterior muscle
Long thoracic nerve injury
With a long thoracic nerve injury, there will be limitation in
Upward rotation of scapula
Is there any cutaneous sensory loss with a long thoracic nerve injury?
No
A thoracodorsal injury would present with
Weakness of shoulder extension, adduction, and internal rotation due to loss of latissimus dorsi
Is there any cutaneous sensory loss for a thoracodorsal injury?
No
May be caused by trauma in the posterior triangle of the neck or at the base of the skull
Spinal accessory nerve injury
The physical symptoms of a spinal accessory nerve injury are?
Shoulder drop and inability to fully abduct or flex at the shoulder due to loss of the trap
Is there any cutaneous sensory loss with a spinal accessory nerve injury?
No
May stimulate the axon or may interfere with transmission along the axon
Compression of the axon
What is the delay period before a damaged axon will begin to regenerate?
Approximately 2 weeks
Provide a pathway for axon regeneration
Endoneurium and Schwann cells
Can be caused by downward force on the scapula and downward pull on the serratus anterior
Long Thoracic Nerve
Because the serratus anterior attaches the medial border of the scapula to the chest wall, paralysis of this muscle results in
Winging
The more distal the radial nerve injury, the
Less severe
If you want to test one motor function to see if the radial nerve is injured, test
Wrist Extension
Houses 4 tendons of the flexor digitorum superficialis, 4 tendons of the flexor digitorum profundus, the tendon of the palmaris longus, and the median nerve
Carpel Tunnel
If a nerve is injured, the digit with the injured nerve will be pulled in the direction opposite of the function of the denervated muscle, because of
Antagonistic muscles
In a median nerve injury, we see clawing of the digits due to
Lumbrical paralysis
Does not go through the caprel tunnel, but goes through the Guyon’s canal under the palmar carpel ligament
Ulnar nerve
Erb’s Palsy is an injury to which spinal nerve?
C5 and C6
Klumpke’s Palsy is an injury to which spinal nerves?
C8 and T1
