Neuroanatomy MCQ Quiz – Part 2 (Question:11-20)

Explanation:

The cavernous sinus receives

• the superior and inferior ophthalmic veins
• sphenoparietal sinus
• superficial middle cerebral vein (coursing from superiorly to inferiorly in the Sylvian fissure).

It drains via

• superior petrosal sinus (to the junction of the transverse and sigmoid sinuses)
• via basilar plexus into the inferior petrosal sinus (to the internal jugular vein)

Right and left cavernous sinuses are also connected across the midline anterior and posteriorly to the pituitary gland via the anterior and posterior intercavernous sinuses, resulting in the circular sinus.

Each cavernous sinus is also connected to the pterygoid venous plexus via small branches in the foramen Vesalii, foramen ovale and foramen lacerum.

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 2.

Explanation:

• The neural crest cells give rise to the posterior root ganglia.
• The neural crest cells are formed from the lateral margin of the neural plate
• The neural crest cells form the neurons of the autonomic ganglia
• The Schwann cells of peripheral nerves are formed from neural crest cells
• The neural crest cells form the cells of the suprarenal medulla

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 18

Explanation:

• In the adult, the lower end of the spinal cord lies at the level of the lower border of the first lumbar vertebra.
• The alar plates form the neurons in the posterior gray columns.
• The nerve cells of the sympathetic outflow are formed from the basal plates.
• At birth, the lower end of the spinal cord lies at the level of the third lumbar vertebra.
• The meninges of the spinal cord are developed from the mesenchyme that surrounds the neural tube.

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 18

The mnemonic SALFOPSI is very useful in remembering the branches of the ECA in ascending order (proximal to distal)

1. Superior thyroid artery
2. Ascending pharyngeal artery
3. Lingual artery
4. Facial artery.
5. Occipital artery.
6. Posterior auricular artery.
7. Superfcial temporal artery.
8. (Internal) maxillary artery

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 1.

Explanation:

• The carotid siphon is the S-shaped part of the ICA which begins at the posterior bend of the cavernous ICA and ends at the ICA bifurcation.
• The intracavernous and the supraclinoid segments of the ICA make up the carotid siphon.
• Begins at the posterior bend of the cavernous ICA and ends at the ICA bifurcation

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Chapter 2.

Explanation:

• Subthalamic nucleus is a small lens-shaped nucleus
• Part of the basal ganglia system
• Subthalamic nucleus is located ventral to the thalamus
• Dorsal to the substantia nigra
• medial to the internal capsule
• It was first described by Jules Bernard Luys in 1865
• Also known as: corpus Luysi or Luys’ body or Body of Luys

Ref: https://en.wikipedia.org/wiki/Subthalamic_nucleus

Explanation:

• In the developing brain, myelination is carried out by oligodendrocytes and not by neurons.
• In the developing brain, myelination begins at about the sixth month of fetal life.
• In the developing brain, the sensory fibers are myelinated first.
• Myelination of the nerve tracts is not haphazard but systematic, occurring in different nerve fibers at specific times.
• Myelination of the nerve tracts is largely complete by the end of the second year.

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 18

Explanation:

• The nerve fibers in the marginal zone of the developing neural tube become myelinated and form the white matter of the spinal cord.
• The wall of the neural tube is formed of a single layer of pseudostratified columnar epithelial cells
• The neuroblasts migrate peripherally to form the Intermediate zone
• The repeated division of the matrix cells of the neural tube results in an increase in the length and diameter of the tube.
• The Intermediate zone of the neural tube will form the gray matter of the spinal cord.

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 18

Explanation:

• Spinal cord at birth ends at L3 Vertebrae (upper border)
• Adult spinal cord ends at L1 vertebra (lower border)
• Subarachnoid sheath or Subarachnoid space or Subdural space of spinal cord extends upto- S2 vertebra (Lower Border)

References:

Ref: Greenberg Textbook of Neurosurgery, 9th Edition, Ch 1

Explanation:

• Spina bifida is one of the most common congenital anomalies of the central nervous system.
• The most common form of spina bifida is spina bifida occulta
• Spina bifida occurs most often in the lower thoracic, lumbar, and sacral regions
• In a myelocele, the neural tube fails to close in the region of the defect
• Most cases of spina bifida occulta require no treatment

Ref: Snell’s Neuroanatomy, 8th Edition, Chapter 18