Understand Peripheral Nerve Lesions

Question 1

Endoneurium

Answer 1

Surrounds individual nerve fibers

Question 2

Perineurium

Answer 2

Surrounds the fascicle

Question 3

Epineurium

Answer 3

Outer layer + further protect the fascile, making up a nerve

Question 4

Causes of peripheral nerve lesions

Answer 4

●Compression-
-internally: mm, bone, tumors
-Externally: prolonged compression, use of crutches
●Trauma- crushing, Sever wounds
●Systemic disorders- leprosy
●Systemic edematous condition: pregnancy, hypothyroidism, diabetes, kidney + heart conditions

Question 5

Neuritis

Answer 5

Inflammation of a nerve
- Myelin sheath and CT are affected

Question 6

Neuralgia

Answer 6

Nerve px
-attacks of sudden + excruticiating px along the nerve
No change to nerve itself

Question 7

Trigeminal neuralgia

Answer 7

Affect trigeminal nerve
- nerve divided into 3 regions- ophthalmic, maxillary,mandibular
- provides sensory awareness to face + motor function to mm of mastication. + tensor tympani of the ear

Question 8

Intercostal neuralgia

Answer 8

Affects intercostal nerve that travels between intercostal mms

Question 9

Neuroma

Answer 9

Tumor composed of nerve cells
- after severance- sending nerve sprouts towards distal endoneurial tube stump
- grow indiscriminately until a Pathway is provided

Question 10

Definition of peripheral nerve lesions

Answer 10

An injury to a peripheral nerve. Depending on the severity of the injury it can result in motor loss, sensory loss, weakness, pain, sensory impairment

Question 11

Difference between CNS and PNS

Answer 11

PNS- any part of nervous system that lays outside brain + spinal cord.
- nerve axons can be up to a meter long
- much of the PNS has the ability to regenerate
-PNS has mixed nerves- motor + sensory
CNS- Brain + spinal cord
- nerve axons much shorter, rarely longer than a few millimeters
-CNS can’t regenerate

Question 12

Neuropraxia (first degree)

Answer 12

No structure damage to axon or tissue distal to the lesion. Often caused by compression.
Loss of motor function occurs but sensory or autonomic fibers not affected

Question 13

Axonotmesis (secondary degree)

Answer 13

Prolonged or Severe compression of nerve. Degeneration distal to injury endoneurial tube remains intact.
- there will be motor/sensory/autonomic loss.
- regeneration promising

Question 14

Neurotmesis (3rd degree)

Answer 14

Severance of part or all of nerve trunk, including endoneurial tube. Results in degeneration of the nerve.
- sensory, motor + autonomic loss occurs, + regeneration not as promising as there is no clear Pathway for nerve to regenerate

Question 15

Lesions can be

Answer 15

Complete or partial, may be regenerating or permanent