Spinal Cord Anatomy and Function

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Questions and Answers

Which of the following accurately describes the relationship between the denticulate ligaments and the spinal cord?

The denticulate ligaments are extensions of the pia mater that attach to the dura mater, helping to suspend the spinal cord within the vertebral canal. (correct)

The denticulate ligaments are extensions of the arachnoid mater that attach to the pia mater, creating a barrier between the spinal cord and the dura mater.

The denticulate ligaments are extensions of the dura mater that attach to the pia mater, helping to anchor the spinal cord to the vertebral canal.

The denticulate ligaments are extensions of the pia mater that attach to the arachnoid mater, forming channels for the passage of cerebrospinal fluid.

A patient presents with weakness and numbness in the right hand. Which of the following spinal nerve roots is most likely affected?

C7 (correct)

What is the primary function of the cerebrospinal fluid (CSF) found within the subarachnoid space?

To act as a shock absorber for the spinal cord and brain. (correct)

To regulate the temperature of the spinal cord.

To provide nutrients to the spinal cord and nerve roots.

To facilitate communication between the brain and the spinal cord.

Where do the cell bodies of the motor neurons that innervate skeletal muscles reside?

Anterior horns of gray matter (B) Signup and view all the answers

A patient presents with pain radiating down the back of their leg and into their foot. Which of the following spinal nerves is most likely contributing to this pain?

S1 (B) Signup and view all the answers

Which of the following is NOT a component of the spinal meninges?

Epidural space (A) Signup and view all the answers

At what vertebral level does the spinal cord typically end in an adult?

L1-L2 (A) Signup and view all the answers

Which of the following statements accurately describes the formation of a spinal nerve?

A spinal nerve is formed by the union of an anterior root and a posterior root, exiting the vertebral canal through the intervertebral foramen. (C) Signup and view all the answers

Which of the following layers is NOT pierced by a needle during a lumbar puncture?

Periosteum (A) Signup and view all the answers

What is the anatomical landmark used to identify the level of the L4 vertebra in a lumbar puncture?

The top of the iliac crest (D) Signup and view all the answers

What is the advantage of performing a lumbar puncture with the vertebral column flexed?

It reduces the risk of needle-induced spinal cord damage. (D) Signup and view all the answers

Which of the following statements is TRUE regarding the arterial supply to the spinal cord?

Segmental medullary arteries are smaller vessels that enter the spinal cord via the nerve roots. (D) Signup and view all the answers

Caudal epidural anesthesia involves injecting an anesthetic agent into which anatomical space?

The extradural space through the sacral hiatus. (C) Signup and view all the answers

What is the key difference between epidural anesthesia and lumbar puncture?

Epidural anesthesia involves injecting an anesthetic agent, while lumbar puncture involves withdrawing cerebrospinal fluid. (B) Signup and view all the answers

Which of the following is NOT a potential complication of lumbar puncture?

Increased blood pressure (A) Signup and view all the answers

Which of the following arteries DOES NOT contribute to the arterial supply of the spinal cord?

Basilar artery (C) Signup and view all the answers

What is a critical indicator that necessitates immediate MRI for diagnosis in spinal conditions?

Saddle-area anaesthesia (B) Signup and view all the answers

What is the primary function of the cerebrospinal fluid found in the spinal meninges?

To support and protect the spinal cord (C) Signup and view all the answers

Which part of the spinal meninges is the toughest and most external?

Dura mater (B) Signup and view all the answers

Where does the dura mater terminate inferiorly in the spinal column?

At the second sacral vertebra level (D) Signup and view all the answers

What separates the arachnoid mater from the pia mater?

Subarachnoid space (D) Signup and view all the answers

Which anatomical structure acts as an anchor for the spinal cord and meninges?

Filum terminale (B) Signup and view all the answers

What characterizes the epidural space in the vertebral canal?

Filled with connective tissue and venous plexus (C) Signup and view all the answers

Why is the lumbar cistern significant in medical procedures?

It is where spinal anesthesia is performed (C) Signup and view all the answers

What is the anatomical function of the conus medullaris in the spinal cord?

To taper off the spinal cord at the L2 vertebral level (B) Signup and view all the answers

Which statement accurately describes the cervical enlargement of the spinal cord?

It is associated with the brachial plexus of nerves (B) Signup and view all the answers

What causes cauda equina syndrome?

Compression of the cauda equina nerves (C) Signup and view all the answers

Which of the following correctly describes the spinal meninges?

They surround the spinal cord and contain cerebrospinal fluid (C) Signup and view all the answers

What is the significance of the lumbar enlargement in the spinal cord?

It contributes to lumbar and sacral plexuses for lower limb innervation (D) Signup and view all the answers

Which of the following structures primarily contains cerebrospinal fluid?

The spinal meninges (C) Signup and view all the answers

What anatomical feature allows the spinal cord to access the lumbar cistern?

The cauda equina (C) Signup and view all the answers

From which part of the central nervous system does the spinal cord arise?

The medulla oblongata (D) Signup and view all the answers

Study Notes

Spinal Cord

The spinal cord is a tubular bundle of nervous tissue and supporting cells.
It extends from the brainstem to the lumbar vertebrae.
Together, the spinal cord and brain form the central nervous system.
It is a cylindrical structure, greyish-white in color.

Spinal Cord Enlargements

There are two points of enlargement along the spinal cord: cervical and lumbar.
The cervical enlargement extends from C4 to T1 segments. Most anterior rami of spinal nerves arising from this area form the brachial plexus, which innervates the upper limbs.
The lumbosacral (lumbar) enlargement extends from L1 to S3 segments. Anterior rami of these nerves form the lumbar and sacral plexuses, innervating the lower limbs.

Cauda Equina

At the L2 vertebral level, the spinal cord tapers off, forming the conus medullaris.
The spinal nerves arising from the cord's lower end form the cauda equina.
This structure occupies about two-thirds of the vertebral canal.

Spinal Meninges

The spinal cord is surrounded by three membranes called meninges: dura mater, arachnoid mater, and pia mater.
These meninges contain cerebrospinal fluid, acting as support and protection to the spinal cord.
The dura mater is the outermost layer, forming a dural sac.
It extends from the foramen magnum to the second sacral vertebra.
The arachnoid mater is between the dura and pia mater. The space between them is called the subarachnoid space, which contains cerebrospinal fluid.
The pia mater is the innermost layer directly covering the spinal cord.
Distally, the meninges attach to the coccyx via the filum terminale.

Epidural Space

The epidural space lies between the inner walls of the vertebral canal and dura mater.
It contains fat and the internal vertebral venous plexus.
The venous plexus extends throughout the length of the epidural space and connects to the dural sinuses in the cranial cavity.

Subarachnoid Space

Located between the arachnoid mater and pia mater.
Contains cerebrospinal fluid (CSF).
Distal to the conus medullaris, the subarachnoid space forms the lumbar cistern, used for lumbar puncture.
The lumbar cistern extends from the L2-L3 vertebral level to the S2 vertebral level.

Spinal Nerves

31 pairs of spinal nerves attach to the spinal cord.
These nerves connect the CNS with different parts of the body.
Each spinal nerve is composed of a posterior (sensory) and an anterior (motor) root.
These roots unite at the intervertebral foramina to form a single spinal nerve.
Spinal nerve roots consist of motor fibers connecting to skeletal muscle and many presynaptic autonomic fibers, whose cell bodies lie in the anterior horns of gray matter.
Posterior roots contain axons from sensory neurones whose cell bodies reside in the posterior root ganglia, outside of the spinal cord.
Dorsal rami innervate parts of the back and neck.
Ventral rami innervate the skin of the anterolateral trunk and limbs and the skeletal muscles in this area and form the brachial and lumbosacral plexuses.

Lumbar Puncture

Used to inject anesthetic or withdraw CSF from the subarachnoid space.
Typically performed at the L4-L5 interspace, marked by a horizontal line drawn at the top of the iliac crest.

Epidural Anesthesia

Anesthetic agent injection into the epidural space.
Anesthetizes spinal nerve roots of the cauda equina.

Spinal Cord Blood Supply

The spinal cord is supplied by arteries (three major arteries: Anterior spinal artery, Posterior spinal arteries).
The anterior spinal artery branches off vertebral arteries, carrying blood to the anterior median fissure of the spinal cord.
The posterior spinal arteries arise from the vertebral artery or the posteroinferior cerebellar artery, anastomosing to one another within the pia mater.
Additional supply is via the anterior and posterior segmental medullary arteries that originate from the spinal nerve roots.

Spinal Cord Venous Drainage

Venous drainage occurs via three anterior and three posterior spinal veins.
They form an anastomosing network and drain into the internal and external vertebral plexuses.
These plexuses empty into the segmental veins or dural venous sinuses.

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Description

This quiz focuses on the anatomy and function of the spinal cord, including its structure, the spinal cord enlargements, and the cauda equina. Test your knowledge on how these components contribute to the central nervous system and their relevance in neurology.