Cranial cavity, brain and spinal cord

Question 1

What are the three layers of meninges covering the brain, and what are their roles?

Answer 1

The meninges consist of the dura mater (tough outer layer), arachnoid mater (middle web-like layer with CSF), and pia mater (delicate inner layer). They protect the brain and spinal cord​

Question 2

Name the main arteries involved in supplying blood to the brain

Answer 2

The brain is supplied by the internal carotid arteries and vertebral arteries, which contribute to the circle of Willis

Question 3

How do specific vertebral features contribute to spine movement?

Answer 3

Cervical vertebrae allow rotation and flexion-extension, thoracic vertebrae support limited rotation, and lumbar vertebrae enable flexion-extension and minimal rotation

Question 4

What is an extradural (epidural) hemorrhage, and which vessel is commonly involved?

Answer 4

An extradural hemorrhage occurs between the skull and dura mater, often due to middle meningeal artery rupture from trauma near the pterion

Question 5

Describe a subdural hemorrhage and the vessels involved.

Answer 5

A subdural hemorrhage occurs between the dura and arachnoid mater, typically due to tearing of bridging veins, especially in older adults​

Question 6

What characterizes a subarachnoid hemorrhage, and what are common causes?

Answer 6

A subarachnoid hemorrhage occurs in the space between the arachnoid and pia mater, often due to cerebral artery aneurysms, especially in the circle of Willis​

Question 7

How does an intracerebral (intraparenchymal) hemorrhage differ from other types?

Answer 7

An intracerebral hemorrhage involves bleeding within brain tissue, often due to ruptured deep cerebral vessels, leading to localized brain damage​

Question 8

What is hydrocephalus, and what causes it?

Answer 8

Hydrocephalus is an abnormal accumulation of CSF in the ventricles, caused by obstruction, excessive production, or impaired absorption​

Question 9

Describe the formation and circulation of CSF.

Answer 9

CSF is produced by the choroid plexus, circulates through the brain ventricles, exits into the subarachnoid space, and is absorbed into venous blood via arachnoid granulations in the superior sagittal sinus​

Question 10

What is a stroke, and what are its primary causes?

Answer 10

A stroke is a cerebrovascular accident due to either ischemia (blockage of blood flow) or hemorrhage, leading to brain tissue damage

Question 11

Outline the arterial supply to the brain.

Answer 11

The brain receives blood from the anterior, middle, and posterior cerebral arteries, which arise from the internal carotid and vertebral arteries, forming the circle of Willis​

Question 12

What is the significance of the circle of Willis in cerebrovascular health?

Answer 12

The circle of Willis provides collateral blood flow, which can help maintain perfusion if one artery is blocked​

Question 13

Describe the venous drainage of the brain

Answer 13

The brain drains venous blood through dural venous sinuses, including the superior sagittal sinus, transverse sinus, and internal jugular vein​

Question 14

Where is the cavernous sinus located, and what structures does it contain?

Answer 14

The cavernous sinus is located on either side of the sphenoid bone and contains the internal carotid artery and cranial nerves III, IV, V1, V2, and VI

Question 15

How can infections spread to the cavernous sinus from the face?

Answer 15

Infections from the facial area can spread through ophthalmic veins or emissary veins into the cavernous sinus​

Question 16

What are the specific features of cervical vertebrae, and how do they influence movement?

Answer 16

Cervical vertebrae have transverse foramina for vertebral arteries and a smaller vertebral body, allowing for rotation and flexion-extension

Question 17

Describe the extent and coverings of the spinal cord.

Answer 17

The spinal cord extends from the medulla oblongata to around L1-L2 in adults and is covered by dura mater, arachnoid mater, and pia mater​

Question 18

What happens in a prolapsed intervertebral disc, and how can it affect nerves?

Answer 18

A prolapsed disc occurs when the nucleus pulposus herniates through the annulus fibrosus, often compressing nearby spinal nerves, causing pain and neurological deficits

Question 19

What is the pterion, and why is it clinically significant?

Answer 19

The pterion is the thinnest part of the skull where the frontal, parietal, temporal, and sphenoid bones meet. A fracture here can rupture the middle meningeal artery, causing an extradural hemorrhage​

Question 20

What structures pass through the foramen magnum?

Answer 20

The foramen magnum transmits the spinal cord, vertebral arteries, and some cranial and spinal nerves, along with the meninges covering these structures​

Question 21

Which cranial nerve passes through the cribriform plate, and what is its function?

Answer 21

The olfactory nerve (CN I) passes through the cribriform plate, providing the sense of smell by innervating the olfactory epithelium​

Question 22

Name the structures that pass through the jugular foramen.

Answer 22

The jugular foramen transmits cranial nerves IX, X, and XI, as well as the internal jugular vein​

Question 23

Describe the route of CSF circulation from its production to reabsorption.

Answer 23

CSF is produced in the ventricles, flows through the lateral ventricles to the third ventricle, then to the fourth ventricle via the cerebral aqueduct, and enters the subarachnoid space through the median and lateral apertures. It is reabsorbed into the venous system via arachnoid granulations in the superior sagittal sinus

Question 24

What veins drain into the cavernous sinus, and what is the clinical importance?

Answer 24

The ophthalmic veins drain into the cavernous sinus, providing a route for infections from the face to reach the brain. This can lead to serious complications, such as cavernous sinus thrombosis​

Question 25

Which cranial nerves are associated with the cavernous sinus, and what might an infection here affect?

Answer 25

Cranial nerves III, IV, V1, V2, and VI pass through or near the cavernous sinus. Infections can affect these nerves, potentially causing ophthalmoplegia, ptosis, and sensory loss in the face​