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Questions and Answers
Which of the following structures is most directly responsible for anchoring the spinal cord and meninges within the vertebral canal?
Which of the following structures is most directly responsible for anchoring the spinal cord and meninges within the vertebral canal?
Which of the following structures is NOT directly involved in the passage of cerebrospinal fluid?
Which of the following structures is NOT directly involved in the passage of cerebrospinal fluid?
Which of the following spaces contains the internal vertebral venous plexus?
Which of the following spaces contains the internal vertebral venous plexus?
A patient presents with saddle-area anesthesia and reduced anal tone. Which of the following is the MOST likely diagnosis?
A patient presents with saddle-area anesthesia and reduced anal tone. Which of the following is the MOST likely diagnosis?
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A lumbar puncture is performed to obtain cerebrospinal fluid. Which of the following spaces is accessed during this procedure?
A lumbar puncture is performed to obtain cerebrospinal fluid. Which of the following spaces is accessed during this procedure?
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Which of the following statements accurately describes the relationship between the dura mater and the spinal nerves?
Which of the following statements accurately describes the relationship between the dura mater and the spinal nerves?
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Which of the following statements accurately describes the relationship between the dura mater and the vertebral canal?
Which of the following statements accurately describes the relationship between the dura mater and the vertebral canal?
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Which of the following conditions is NOT a potential complication of an epidural injection?
Which of the following conditions is NOT a potential complication of an epidural injection?
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What marks the termination point of the spinal cord?
What marks the termination point of the spinal cord?
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Which of the following structures arises from the cervical enlargement?
Which of the following structures arises from the cervical enlargement?
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What is the primary function of cerebrospinal fluid surrounding the spinal cord?
What is the primary function of cerebrospinal fluid surrounding the spinal cord?
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Which condition is characterized by compression of the cauda equina?
Which condition is characterized by compression of the cauda equina?
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How many points of enlargement are present in the spinal cord?
How many points of enlargement are present in the spinal cord?
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What part of the spinal cord is involved in innervating the lower limbs?
What part of the spinal cord is involved in innervating the lower limbs?
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Which of the following is NOT a potential cause of cauda equina syndrome?
Which of the following is NOT a potential cause of cauda equina syndrome?
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What is the anatomical course of the spinal cord within the vertebral canal?
What is the anatomical course of the spinal cord within the vertebral canal?
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What is the primary purpose of a lumbar puncture?
What is the primary purpose of a lumbar puncture?
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What is the primary function of the subarachnoid space?
What is the primary function of the subarachnoid space?
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Which interspace is typically used for spinal tap procedures?
Which interspace is typically used for spinal tap procedures?
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At which vertebral level does the dural sac and subarachnoid space terminate?
At which vertebral level does the dural sac and subarachnoid space terminate?
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Which of the following layers is not penetrated during a lumbar puncture?
Which of the following layers is not penetrated during a lumbar puncture?
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Which structure is formed by the fusion of the pia mater and the filum terminale?
Which structure is formed by the fusion of the pia mater and the filum terminale?
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What type of anesthesia is achieved by injecting anesthetic into the sacral canal?
What type of anesthesia is achieved by injecting anesthetic into the sacral canal?
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Which region of the spinal cord contains cell bodies of somatic axons contributing to the anterior roots?
Which region of the spinal cord contains cell bodies of somatic axons contributing to the anterior roots?
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What is the role of the artery of Adamkiewicz?
What is the role of the artery of Adamkiewicz?
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Which arteries supply the spinal cord and are formed from branches of the vertebral arteries?
Which arteries supply the spinal cord and are formed from branches of the vertebral arteries?
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Which type of nerve fibers are found in the anterior roots of spinal nerves?
Which type of nerve fibers are found in the anterior roots of spinal nerves?
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What is true about the origins of the spinal nerves?
What is true about the origins of the spinal nerves?
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Which of the following is a potential consequence of epidural anesthesia?
Which of the following is a potential consequence of epidural anesthesia?
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Venous drainage from the spinal cord occurs via how many anterior and posterior spinal veins?
Venous drainage from the spinal cord occurs via how many anterior and posterior spinal veins?
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Where are the cell bodies of the axons making up the posterior roots located?
Where are the cell bodies of the axons making up the posterior roots located?
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Which roots of the spinal nerve innervate the skin of the anterolateral trunk and limbs?
Which roots of the spinal nerve innervate the skin of the anterolateral trunk and limbs?
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Flashcards
Spinal Cord
Spinal Cord
A tubular bundle of nervous tissue extending from the brainstem to lumbar vertebrae.
Conus Medullaris
Conus Medullaris
The tapered end of the spinal cord located at the L2 vertebra level.
Cauda Equina
Cauda Equina
A bundle of spinal nerves that run inferior to the spinal cord.
Cervical Enlargement
Cervical Enlargement
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Lumbar Enlargement
Lumbar Enlargement
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Spinal Meninges
Spinal Meninges
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Cauda Equina Syndrome
Cauda Equina Syndrome
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Cerebrospinal Fluid
Cerebrospinal Fluid
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Saddle-area anaesthesia
Saddle-area anaesthesia
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Dura mater
Dura mater
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Epidural space
Epidural space
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Subarachnoid space
Subarachnoid space
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Cerebrospinal fluid (CSF)
Cerebrospinal fluid (CSF)
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Filum terminale
Filum terminale
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Lumbar cistern
Lumbar cistern
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Dural Sac
Dural Sac
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Pia Mater
Pia Mater
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Anterior Roots
Anterior Roots
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Posterior Roots
Posterior Roots
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Spinal Nerves
Spinal Nerves
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Lumbar Puncture
Lumbar Puncture
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CSF
CSF
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Interlaminar Space
Interlaminar Space
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Epidural Anesthesia
Epidural Anesthesia
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Anterior Spinal Artery
Anterior Spinal Artery
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Artery of Adamkiewicz
Artery of Adamkiewicz
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Posterior Spinal Arteries
Posterior Spinal Arteries
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Venous Drainage of the Spinal Cord
Venous Drainage of the Spinal Cord
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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.
- The spinal cord and the brain form the central nervous system.
- The spinal cord is cylindrical, greyish-white in color.
- It has a relatively simple anatomical course.
- It arises cranially as a continuation of the medulla oblongata (part of the brainstem).
- It travels inferiorly within the vertebral canal surrounded by the spinal meninges that contain cerebrospinal fluid.
- At the L2 vertebral level, the spinal cord tapers off, forming the conus medullaris.
- The termination of the spinal cord at L2, it occupies around two thirds of the vertebral canal.
- The spinal nerves arising from the end of the spinal cord are bundled together, forming a structure known as the cauda equina.
Spinal Cord Enlargements
- During the course of the spinal cord, there are two points of enlargement.
- The cervical enlargement extends from C4 through T1 segments of the spinal cord.
- The majority of the anterior rami of the spinal nerves that arise form the brachial plexus of nerves.
- This plexus leads to the innervation of the upper limbs.
- The lumbosacral (lumbar) enlargement extends from L1 through S3 segments of the spinal cord.
- Anterior rami of the spinal nerves that arise from the lumbosacral enlargement contributing to lumbar and sacral plexuses.
- Innervates the lower limbs.
- Spinal nerve roots arising from the lumbosacral enlargement and conus medullaris form the cauda equina, a bundle of the spinal nerve running inferior to the spinal cord through the lumbar cistern.
Cauda Equina Syndrome
- The cauda equina is a bundle of spinal nerves arising from the distal end of the spinal cord, running in subarachnoid space before exiting at their appropriate vertebral level.
- Compression of these nerves causes a range of signs and symptoms collectively termed cauda equina syndrome.
- Causes for compression include: intervertebral disc prolapse, extrinsic or primary cord tumors, spinal stenosis, trauma, and abscess formation.
Spinal Meninges
- The spinal meninges are three membranes that surround the spinal cord: dura mater, arachnoid mater, and pia mater.
- They are analogous with the cranial meninges.
- The meninges contain cerebrospinal fluid, acting to support and protect the spinal cord.
- Distally, the meninges form a strand of fibrous tissue called the filum terminale, attaching to the vertebral bodies of the coccyx.
- The filum terminale acts as an anchor for the spinal cord and meninges.
Dura Mater
- The spinal dura mater is the most external of the meninges.
- It's tough, cylindrical connective tissue that forms a dural sac that surrounds the entire spinal cord and cauda equina.
- It extends from the foramen magnum to the filum terminale, separated from the vertebral canal walls by the epidural space.
- This space contains loose connective tissue and the internal vertebral venous plexus. The dura mater and dural sac terminate at the second sacral vertebra.
Epidural Space
- The epidural space is located between the inner walls of the vertebral canal and dura mater, containing fat and the internal vertebral venous plexus.
- The venous plexus runs the entire length to connect with dural venous sinuses in the cranial cavity.
Arachnoid Mater
- The spinal arachnoid mater is a delicate membrane separating the dura mater and pia mater.
- It is separated by the subarachnoid space, which contains cerebrospinal fluid.
- Distal to the conus medullaris, the subarachnoid space widens, forming the lumbar cistern.
- This space is accessed for lumbar puncture to obtain cerebrospinal fluid for diagnoses and spinal anesthesia.
Subarachnoid Space
- The subarachnoid space is a pressurized space between the arachnoid and pia mater layers.
- It contains cerebrospinal fluid that bathes the spinal cord, spinal nerve roots within the dural sac and terminates at the second sacral vertebral level.
- The L1 or L2 vertebra is the inferior limit of the spinal cord (conus medullaris) in adults.
- S2 vertebra is the inferior limit of the dural sac and subarachnoid space.
Pia Mater
- The spinal pia mater is the innermost layer of the meninges.
- It's a thin membrane covering the spinal cord, nerve roots, and blood vessels.
- Inferiorly, the pia mater fuses with the filum terminale.
- Between the nerve roots, the pia mater thickens, forming the denticulate ligaments that attach to the dura mater, suspending the spinal cord in the vertebral canal.
Spinal Nerves
- There are 31 pairs of spinal nerves arising from the spinal cord.
- These include 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal nerves.
- Spinal nerves are mixed nerves arising as anterior (motor) and posterior (sensory) roots.
- These roots unite to form a single spinal nerve at the intervertebral foramina.
- Anterior roots contain efferent (motor) fibers to skeletal muscles and many presynaptic autonomic fibers.
- Cell bodies of somatic axons contributing to anterior roots are in the gray matter of the anterior horns.
- Posterior roots have cell bodies of axons making up the posterior (dorsal) roots are located outside the spinal cord, found in the spinal ganglia (posterior root ganglia).
Lumbar Puncture
- A lumbar puncture, also known as a spinal tap, is a procedure for injecting anesthetic material into the epidural space or to withdraw cerebrospinal fluid (CSF) from the subarachnoid space.
- It's usually performed at the L4-L5 interspace.
- A horizontal line drawn at the iliac crest marks the L4 vertebra.
Epidural Anesthesia
- An anesthetic agent is injected into the extradural (epidural) space using the described position for lumbar spinal puncture.
- The anesthetic has a direct effect on spinal nerve roots of the cauda equina after exiting the dural sac.
Spinal Cord Vasculature
Anterior spinal artery - formed from branches of the vertebral arteries, traveling in the anterior median fissure. Posterior spinal arteries – originate from the vertebral artery or the posteroinferior cerebellar artery; they anastomose with each other in the pia mater.
Venous drainage – via three anterior and three posterior spinal veins; these veins form an anastomosing network along the spinal cord surface, draining into internal and external vertebral plexuses. The internal vertebral plexus further empties into the dural venous sinuses superiorly.
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Description
Explore the intricate structure and function of the spinal cord in this quiz. Learn about its anatomical features, the central nervous system, and the significance of spinal cord enlargements. Test your knowledge on vital concepts related to this essential part of the nervous system.
