Chapter 13 Spinal Cord Anatomy Quiz

Questions and Answers

Describe the cross-sectional anatomy of the spinal cord?

Contains 2 types of nervous tissue: central area of grey matter shaped like a butterfly surrounded by white matter in three columns. Grey matter consists of neuron cell bodies with little myelin; white matter consists of myelinated axons. The core has pairs of dorsal and ventral horns connected by grey commissure, punctured by a central canal. Dorsal root contains sensory neurons; ventral root contains motoneurons. White matter contains bundles of myelinated axons.

Describe the gross external anatomy of the spinal cord?

The spinal cord begins as a continuation of the medulla oblongata and terminates at about the second lumbar vertebrae in an adult. It contains cervical and lumbar enlargements, the conus medullaris, and is partially divided by anterior median fissure and posterior sulcus. Spinal nerves arise from spinal segments, with posterior (sensory) and anterior (motor) roots. Removal of cerebrospinal fluid is called a spinal tap.

Name the locations of the four major plexuses of spinal nerves?

Cervical, Brachial, Lumbar, Sacral

Describe the basic anatomy of spinal nerve plexuses?

Plexuses are networks formed by the ventral rami of spinal nerves. Emerging from the plexuses are nerves that are often named after the general regions they supply or their course. Signup and view all the answers

Discuss the clinical significance of dermatomes?

All spinal nerves except C1 innervate specific segments of skin called dermatomes. This helps physicians determine which segment of the spinal cord or which spinal nerve is malfunctioning. Signup and view all the answers

What does the Cervical Plexus supply?

Supplies the skin and muscles of the head, neck, and upper part of the shoulders; connects with some cranial nerves; supplies diaphragm. Signup and view all the answers

What does the Brachial Plexus supply?

Constitutes the nerve supply for the upper extremities and a number of neck and shoulder muscles. Signup and view all the answers

What does the Lumbar Plexus supply?

Supplies the anterolateral abdominal wall, external genitals, and part of the lower extremities. Signup and view all the answers

What does the Sacral Plexus supply?

Supplies the buttocks, perineum, and part of the lower extremities. Signup and view all the answers

Study Notes

Cross-Sectional Anatomy of the Spinal Cord

Composed of two types of nervous tissue: grey matter and white matter.
Grey matter is centrally located, butterfly-shaped, and consists of neuron cell bodies with minimal myelin.
White matter surrounds the grey matter and consists of myelinated axons, organized into three columns: dorsal, lateral, and anterior.
Dorsal horns contain sensory neuron cell bodies, while ventral horns contain motoneuron cell bodies.
Dorsal roots are entirely sensory fibers, whereas ventral roots are motor fibers, connecting to spinal nerves.
Grey commissure links sides of the spinal cord, housing the central canal that extends from the brain's fourth ventricle.

Gross External Anatomy of the Spinal Cord

Spinal cord extends from the medulla oblongata and ends near the second lumbar vertebra in adults.
Features cervical and lumbar enlargements that provide origins for nerves to the limbs.
The conus medullaris tapers at the end, giving rise to the filum terminale and cauda equina ("horsetail").
Anterior median fissure and posterior sulcus partially divide the spinal cord into left and right sections.
Each spinal nerve connects to the spinal cord via two roots:
- Dorsal (Posterior) Root: Contains sensory nerve fibers with a swelling (ganglion) holding cell bodies.
- Ventral (Anterior) Root: Contains motor neuron axons.
Spinal tap involves removing cerebrospinal fluid from the subarachnoid space.

Major Plexuses of Spinal Nerves

Four primary plexuses:
- Cervical
- Brachial
- Lumbar
- Sacral

Anatomy of Spinal Nerve Plexuses

Plexuses are formed by ventral rami of spinal nerves, creating complex networks.
Named peripheral nerves emerge from these plexuses, often indicating the areas they serve.

Clinical Significance of Dermatomes

All spinal nerves except C1 correspond to specific skin segments known as dermatomes.
Dermatomes are essential for mapping sensory nerve impulses entering the spinal cord.
Physicians utilize dermatomes to identify dysfunctions in spinal cord segments or spinal nerves.

Cervical Plexus

Innervates skin and muscles of the head, neck, upper shoulders.
Connects with certain cranial nerves and supplies the diaphragm.

Brachial Plexus

Provides nerve supply to upper extremities and several muscles in the neck and shoulders.

Lumbar Plexus

Supplies the anterolateral abdominal wall, external genitals, and part of the lower limbs.

Sacral Plexus

Innervates the buttocks, perineum, and parts of the lower limbs.

Description

Test your knowledge on the cross-sectional anatomy of the spinal cord with this quiz. Explore the structures of gray and white matter, and understand the arrangement of nervous tissues in the spinal cord. Perfect for students of neuroscience and anatomy!