Peripheral Nerve Lesions

Question 1

Lesion in dorsal root before dorsal root ganglion has what effects?

Answer 1

Loss of sensation in dermatome supplied by corresponding spinal nerve
Can go undetected as dermatome may be innervated by another spinal nerve

Question 2

Lesion in ventral root before spinal nerve formation has what effects?

Answer 2

Weakness of the muscles supplied by corresponding nerve

Most limb muscles supplied by 2 or more spinal nerves so single lesion does not cause paralysis

Question 3

Lesion in spinal nerve (combination of ventral and dorsal roots) has what effects?

Answer 3

Combined effects of ventral/dorsal root lesions
Loss of sensation
Weakness

Question 4

Lesion in peripheral sensory nerve (after division of spinal nerve at plexus into sensory and motor nerves) has what effects?

Answer 4

Loss of sensation in the area of distribution of that peripheral nerve

Question 5

Lesion in peripheral motor nerve (after plexus) has what effects?

Answer 5

Weakness/paralysis of muscle supplied by that particular motor nerve

Question 6

What is a lesion?

Answer 6

Term to describe physiological damage, in this case damage to nerves.

Question 7

Causes of spinal root and spinal nerve damage?

Answer 7

Strain injuries to the spine e.g. prolapsed disc

Question 8

Causes of peripheral nerve damage?

Answer 8

Trauma

Disease (peripheral neuropathy)

Question 9

Plausibility and cause of injury in brachial and lumbosacral plexuses?

Answer 9

Brachial plexus can be affected by trauma to shoulder joint

Lumbosacral plexus is much better protected and therefore unlikely to be injured