Chapter 1: Introduction to the Peripheral Nervous System

A collection of flashcards to help review key concepts from the lecture on peripheral nerves, plexuses, and neuronal classification.

What is Requina syndrome?

A pathology involving the peripheral nerves.

What classification is used to categorize sensory and motor neurons?

Histological classification based on axon diameter and myelination.

What surrounds and protects a nerve?

The epineural membrane, or epineurium.

What is a fascicle in the context of nerves?

A bundle of nerve fibers surrounded by the perineurium.

What does the endoneurium surround?

Individual nerve fibers or axons.

How is conduction velocity of nerve fibers affected?

It depends on the diameter of the axon and the amount of myelin.

What type of nerves are spinal nerves primarily?

Mixed nerves, containing both sensory and motor fibers.

What distinguishes C1 spinal nerve from other spinal nerves?

C1 has no sensory neurons; it's purely motor.

How are sensory and motor nerve classifications different?

Motor classification uses A, B, C; sensory classification uses I, II, III, IV.

What do A alpha fibers typically refer to?

Alpha motor neurons, which are large and myelinated.

From where do the 1A sensory fibers originate?

Muscle spindle primary endings.

What types of fibers carry sensations from pain receptors?

Type III and IV sensory fibers.

How do the spinal nerves enter the vertebral column?

Through the intervertebral foramina.

What do the dorsal roots of spinal nerves carry?

Sensory (afferent) fibers to the dorsal gray horn.

What do the ventral roots of spinal nerves carry?

Motor (efferent) fibers from the ventral gray horns.

What is the cervical plexus formed from?

C1 to C4 spinal nerve roots.

What is the role of the phrenic nerve?

It innervates the diaphragm, essential for breathing.

What do cutaneous nerves supply?

Only the skin, with no motor fibers.

What is the significance of the anterior branches from the cervical plexus?

They give rise to purely sensory or motor peripheral nerves.

Which plexus supplies the lower limb?

Lumbar and sacral plexuses.

What are the two divisions of the sciatic nerve?

Tibial nerve and common fibular nerve.

What is cauda equina syndrome?

Impaired function of multiple nerves in the cauda equina.

What causes saddle anesthesia?

Damage to sensory fibers in the lower sacral area.

What is the primary function of the lumbar plexus?

To supply sensory and motor innervation to the lower limb.

What happens with the injury of the radial nerve?

Loss of the ability to extend the wrist, causing wrist drop.

What does the median nerve innervate?

The flexors of the forearm and several hand muscles.

What sensory area does the ulnar nerve supply?

The medial part of the hand, including the fourth and fifth fingers.

What are MAP nerves referring to in the cervical plexus?

Muscular branches, Ansa cervicalis, phrenic nerve.

What can compress the lateral femoral cutaneous nerve?

Tight clothing or pressure from overweight or pregnancy.

What are the muscles supplied by the superior gluteal nerve?

Gluteus medius, gluteus minimus, and tensor fascia lata.