Cranial Cavity Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Cranial Cavity. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Cranial Cavity Indian Medical PG Question 1: Normal cerebrospinal fluid pressure is
- A. 5-10 mmH2O
- B. 180-300 mmH2O
- C. 110-180 mmH2O (Correct Answer)
- D. 200-400 mmH2O
Cranial Cavity Explanation: ***110-180 mmH2O***
- This range represents the **upper portion of normal CSF pressure** and is the best answer among the given options.
- Complete normal **cerebrospinal fluid (CSF) pressure**, as measured during lumbar puncture in lateral decubitus position, is typically **60-180 mmH2O** (or 50-180 mmH2O per some references).
- While 110 mmH2O is slightly higher than the traditional lower limit, this option is acceptable as it falls within normal range and is clearly superior to the other choices.
- Normal CSF pressure is crucial for maintaining **brain homeostasis** and protecting it from injury.
*180-300 mmH2O*
- This range indicates **elevated CSF pressure (intracranial hypertension)**, exceeding normal limits.
- Such pressures may be seen in disorders like **idiopathic intracranial hypertension** or **hydrocephalus**.
- Values above 200-250 mmH2O are generally considered significantly elevated.
*200-400 mmH2O*
- This represents **severely elevated CSF pressure**, indicating significant intracranial hypertension.
- Pressures this high demand urgent medical attention as they can lead to **brain herniation** and irreversible neurological damage.
- This is clearly pathological and well above normal range.
*5-10 mmH2O*
- This is significantly **lower than normal CSF pressure** and indicates **intracranial hypotension**.
- Normal CSF pressure should not fall below 50-60 mmH2O.
- Low CSF pressure can cause symptoms such as **postural headaches**, nausea, and dizziness, often seen after lumbar puncture or CSF leak.
Cranial Cavity Indian Medical PG Question 2: Which of the following DOESN'T supply dura mater?
- A. Middle meningeal artery
- B. Meningeal branch of internal carotid artery in posterior cranial fossa (Correct Answer)
- C. Anterior and posterior ethmoidal arteries
- D. Accessory meningeal artery
Cranial Cavity Explanation: ***Meningeal branch of internal carotid artery in posterior cranial fossa***
- The **internal carotid artery** does give off meningeal branches (cavernous branches, tentorial branches), but these supply the dura mater in the **anterior** and **middle cranial fossae**, NOT the **posterior cranial fossa**.
- The **posterior cranial fossa** dura is primarily supplied by meningeal branches from the **vertebral artery**, **ascending pharyngeal artery**, and **occipital artery**.
- Therefore, a "meningeal branch of internal carotid artery in posterior cranial fossa" does not exist as a typical arterial supply to the dura mater.
*Middle meningeal artery*
- The **middle meningeal artery** is the **major blood supply** to the dura mater of the **middle cranial fossa**.
- It enters the cranial cavity through the **foramen spinosum** and branches extensively over the lateral surface of the dura.
- This is the most important meningeal artery clinically (often involved in epidural hematomas).
*Anterior and posterior ethmoidal arteries*
- The **anterior and posterior ethmoidal arteries** are branches of the **ophthalmic artery** that pass through the anterior and posterior ethmoidal foramina.
- While they primarily supply the **nasal cavity** and **ethmoid sinuses**, they also contribute to the blood supply of the **dura mater** in the **anterior cranial fossa**, particularly around the **cribriform plate** region.
- Therefore, these arteries DO supply dura mater.
*Accessory meningeal artery*
- The **accessory meningeal artery** typically originates from the **maxillary artery** (or sometimes the middle meningeal artery).
- It enters the cranium via the **foramen ovale** and supplies the dura mater in the **middle cranial fossa**, particularly around the trigeminal ganglion and foramen ovale region.
Cranial Cavity Indian Medical PG Question 3: Which vessel is most likely damaged in an extradural (epidural) hemorrhage?
- A. Basilar artery
- B. Vertebral artery
- C. Middle meningeal artery (Correct Answer)
- D. Anterior cerebral artery
Cranial Cavity Explanation: Middle meningeal artery
- An extradural (epidural) hemorrhage often results from head trauma, especially to the temporal region, which can cause a fracture across the course of the middle meningeal artery [1].
- This artery runs in a groove on the inner surface of the temporal bone, making it vulnerable to laceration during trauma [1].
Basilar artery
- The basilar artery is located at the base of the brainstem and is a common site for strokes, but not typically involved in an extradural hemorrhage.
- Damage to the basilar artery usually leads to subarachnoid hemorrhage or ischemic stroke, not an epidural hematoma.
Vertebral artery
- The vertebral arteries ascend through the cervical vertebrae and join to form the basilar artery, supplying the posterior circulation of the brain.
- Damage to these arteries is typically associated with neck trauma or dissection, leading to subarachnoid hemorrhage or ischemia, not an epidural hemorrhage.
Anterior cerebral artery
- The anterior cerebral artery supplies the frontal lobes and medial aspects of the cerebral hemispheres.
- While it can be involved in subarachnoid or intracranial hemorrhages from aneurysm rupture or trauma, it is not the typical source of an epidural hematoma.
Cranial Cavity Indian Medical PG Question 4: A 43-year-old man presents to the emergency department after falling down a flight of stairs and landing on his head. He did not lose consciousness. He complains of severe headache, marked decreased acuity in hearing in the left ear, and a "runny nose" since the fall. On physical examination, he is found to have a left-sided Battle's sign (an ecchymosis in the area of the left mastoid process) and hemotympanum. He has a constant dripping of a clear, watery fluid through his nose. Findings on his neurologic examination, other than the hearing loss, are completely normal. X-ray studies will reveal which of the following?
- A. A temporal bone fracture with CSF rhinorrhea (Correct Answer)
- B. Occipital bone fracture
- C. A skull-base fracture with a mucocele
- D. A fracture of the cribriform plate with a CSF leak into the paranasal sinuses
Cranial Cavity Explanation: ***A temporal bone fracture with CSF rhinorrhea***
- The combination of **Battle's sign**, **hemotympanum**, unilateral hearing loss, and clear nasal discharge after head trauma strongly indicates a **temporal bone fracture**.
- **CSF rhinorrhea** refers to cerebrospinal fluid leaking from the nose due to a skull base fracture involving the temporal bone, typically affecting the petrous part.
- The CSF can reach the nasal cavity via the **eustachian tube** or through fracture lines extending to the middle ear and mastoid air cells.
*Occipital bone fracture*
- While occipital fractures are possible with head trauma, they do not directly explain the specific findings of **hemotympanum** or unilateral hearing loss.
- An occipital fracture would typically cause symptoms related to damage to the **brainstem** or **cerebellum**, depending on the extent.
*A skull-base fracture with a mucocele*
- A **mucocele** is a cyst filled with mucus, usually resulting from obstruction of a sinus ostium, and is not an acute traumatic finding.
- While a skull-base fracture is present, the presence of a mucocele does not fit the acute injury presentation.
*A fracture of the cribriform plate with a CSF leak into the paranasal sinuses*
- A **cribriform plate fracture** would result in CSF rhinorrhea, but it typically causes CSF to leak directly from the anterior cranial fossa into the nasal cavity.
- It would not explain the **hemotympanum**, Battle's sign, or unilateral hearing loss, which are characteristic of **temporal bone injury**.
Cranial Cavity Indian Medical PG Question 5: Bleeding as shown in the image is due to which of the following vessels?
- A. Lenticulostriate artery
- B. Vertebral artery
- C. Bridging veins (Correct Answer)
- D. Middle meningeal artery
Cranial Cavity Explanation: ***Bridging veins***
- The image depicts a **subdural hemorrhage (subdural hematoma)**, a collection of blood between the dura mater and the arachnoid mater, typically appearing as a **crescent-shaped** hyperdensity that conforms to the brain surface.
- This type of hemorrhage is caused by the tearing of **bridging veins** that traverse the subdural space, connecting the cerebral cortex to the dural venous sinuses.
- Tearing of these veins occurs due to rapid acceleration-deceleration forces causing the brain to move relative to the dura, stretching and rupturing the veins. This is common in **head trauma**, especially in the elderly (due to brain atrophy increasing vein vulnerability) or infants.
*Lenticulostriate artery*
- Rupture of the lenticulostriate arteries (perforating branches of the middle cerebral artery) typically leads to **intraparenchymal hemorrhage**, specifically in the basal ganglia or internal capsule.
- This type of bleeding is confined within the brain parenchyma, rather than collecting in the subdural space as seen in the image.
- Associated with hypertensive hemorrhage.
*Vertebral artery*
- The vertebral arteries supply the posterior circulation of the brain, and their rupture can lead to **subarachnoid hemorrhage** (if a posterior circulation aneurysm ruptures) or **intraparenchymal bleeding** in the brainstem or cerebellum.
- Bleeding from the vertebral artery is not associated with the subdural collection pattern shown in the image.
*Middle meningeal artery*
- The middle meningeal artery runs in the epidural space, and its rupture (often due to temporal bone fracture) causes an **epidural hematoma**.
- An epidural hematoma is characterized by a **biconvex (lentiform) shape** on imaging and is situated between the dura mater and the skull, which is distinct from the **crescent-shaped** subdural collection shown.
- Does not cross suture lines, unlike subdural hematomas which can extend over multiple lobes.
Cranial Cavity Indian Medical PG Question 6: Following are the features of raised intracranial tension except -
- A. Convulsions
- B. Papilloedema
- C. Altered sensorium
- D. Tachycardia (Correct Answer)
Cranial Cavity Explanation: ***Tachycardia***
- **Tachycardia** (increased heart rate) is generally *not* a direct feature of raised intracranial tension (ICT); rather, the classic cardiovascular response is **bradycardia** (decreased heart rate) as part of the Cushing's reflex [1].
- The Cushing's reflex, triggered by increased ICP, involves hypertension, bradycardia, and irregular respirations, a protective mechanism to maintain cerebral perfusion.
*Convulsions*
- **Convulsions** can occur due to focal brain irritation or global cerebral dysfunction caused by severe or rapidly rising intracranial pressure.
- Elevated ICP can compromise neuronal function and integrity, leading to abnormal electrical activity.
*Papilloedema*
- **Papilloedema** (swelling of the optic disc) is a classic and frequently observed sign of chronic or sustained raised intracranial tension [2].
- It results from the obstruction of axoplasmic flow and venous return in the optic nerve due to increased pressure in the subarachnoid space surrounding the optic nerve.
*Altered sensorium*
- **Altered sensorium**, ranging from confusion and disorientation to stupor and coma, is a common and serious manifestation of raised intracranial tension [1].
- It occurs due to diffuse cerebral dysfunction as the brain is compressed and its blood supply is compromised.
Cranial Cavity Indian Medical PG Question 7: Which one of the following is a branch of the first part of the maxillary artery?
- A. Middle meningeal
- B. Inferior alveolar
- C. Anterior ethmoidal
- D. Anterior tympanic (Correct Answer)
Cranial Cavity Explanation: ***Anterior tympanic***
- This artery arises from the **first part** (mandibular part) of the maxillary artery.
- It supplies structures within the **tympanic cavity**, including the inner surface of the tympanic membrane.
- Among the options listed, this is a **classic branch** consistently mentioned in anatomy texts.
*Anterior ethmoidal*
- This artery is a branch of the **ophthalmic artery**, which itself is a branch of the internal carotid artery, **not the maxillary artery**.
- It supplies the **ethmoid air cells**, frontal sinus, and nasal cavity.
- This is the **definitively incorrect option** as it does not arise from the maxillary artery at all.
*Middle meningeal*
- This artery **also arises from the first part** (mandibular part) of the maxillary artery.
- It is a significant artery that supplies the **dura mater** and cranial bones.
- While anatomically correct, **anterior tympanic** is the more specific answer being tested in this context.
*Inferior alveolar*
- This artery **also arises from the first part** (mandibular part) of the maxillary artery.
- It descends to supply the **mandible**, its teeth, and the lower lip and chin.
- While anatomically correct, it is not the best answer in this specific question context.
Cranial Cavity Indian Medical PG Question 8: Hinge fracture is seen in
- A. Posterior cranial fossa
- B. Anterior cranial fossa
- C. Middle cranial fossa (Correct Answer)
- D. Vault
Cranial Cavity Explanation: ***Middle cranial fossa***
- A **hinge fracture** is a term sometimes used to describe a **linear skull fracture** that extends across the floor of the **middle cranial fossa**.
- This type of fracture often involves the **temporal bone** and can lead to damage to structures within, such as the facial nerve or auditory ossicles.
*Posterior cranial fossa*
- Fractures in the **posterior cranial fossa** are usually related to trauma to the back of the head.
- While they can be severe and involve the occipital bone, they are not typically referred to as hinge fractures.
*Anterior cranial fossa*
- Fractures of the **anterior cranial fossa** commonly involve the frontal bone, ethmoid bone, or sphenoid bone.
- These fractures can cause **CSF rhinorrhea** or periorbital ecchymosis (raccoon eyes), but the term hinge fracture is not associated with this location.
*Vault*
- Fractures of the **cranial vault** typically refer to fractures of the flat bones forming the top and sides of the skull.
- These can be linear, depressed, or comminuted, but the characteristic "hinge" description specifically applies to the base of the skull, particularly the middle fossa.
Cranial Cavity Indian Medical PG Question 9: Among the following trigeminal nerve divisions, which one is involved in orbital apex syndrome?
- A. Olfactory nerve
- B. Mandibular division of trigeminal nerve
- C. Maxillary division of trigeminal nerve
- D. Ophthalmic division of trigeminal nerve (Correct Answer)
Cranial Cavity Explanation: ***Ophthalmic division of trigeminal nerve***
- Orbital apex syndrome involves deficits of nerves passing through the **superior orbital fissure** and **optic canal**, which includes the ophthalmic division of the trigeminal nerve (CN V1).
- Involvement of CN V1 leads to **sensory loss** in the forehead, upper eyelid, and side of the nose.
*Olfactory nerve*
- The **olfactory nerve (CN I)** is responsible for the sense of smell and does not pass through the orbital apex.
- Its involvement would manifest as **anosmia**, which is not a characteristic feature of orbital apex syndrome.
*Maxillary division of trigeminal nerve*
- The **maxillary division (CN V2)** exits the skull through the **foramen rotundum** and innervates the midface.
- It is generally **not involved** in orbital apex syndrome, as its anatomical course is distinct from the structures within the orbital apex.
*Mandibular division of trigeminal nerve*
- The **mandibular division (CN V3)** exits the skull through the **foramen ovale** and innervates the lower face and muscles of mastication.
- Its involvement is **not associated** with orbital apex syndrome, as it is anatomically distant from the orbital apex.
Cranial Cavity Indian Medical PG Question 10: Which of the following drains into the middle meatus except?
- A. Lacrimal duct (Correct Answer)
- B. Maxillary sinus
- C. Frontal sinus
- D. Ethmoidal sinus
Cranial Cavity Explanation: ***Lacrimal duct***
- The **nasolacrimal duct**, also known as the lacrimal duct, drains tears from the eye into the **inferior meatus** of the nasal cavity.
- It is not associated with the drainage of the paranasal sinuses into the middle meatus.
*Maxillary sinus*
- The **maxillary sinus** drains into the **middle meatus** via the **semilunar hiatus**, an opening located on the lateral wall of the meatus.
- Obstruction of this drainage can lead to **maxillary sinusitis**.
*Frontal sinus*
- The **frontal sinus** drains into the **middle meatus** via the **frontonasal duct**, which opens into the anterior part of the meatus, often into the ethmoidal infundibulum.
- Its drainage is crucial for preventing the accumulation of mucus and infection in the forehead.
*Ethmoidal sinus*
- The **anterior ethmoidal cells** and **middle ethmoidal cells** drain into the **middle meatus**, typically into the ethmoidal infundibulum or onto the **ethmoidal bulla**.
- Note: The **posterior ethmoidal cells** drain into the **superior meatus**, not the middle meatus.
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