Head Practice Questions

Q: Following endarterectomy on the right common carotid, a patient is found to be blind in the right eye. It appears that a small thrombus embolized during surgery and lodged in the artery supplying the retina. Which artery would be blocked?

Central artery of the retina. ***Central artery of the retina*** - The **central artery of the retina** is a branch of the **ophthalmic artery** that supplies blood to the inner two-thirds of the retina, including the **photoreceptors** and **ganglion cells**. - Its occlusion, often due to an **embolus** like in this scenario, leads to sudden, **painless monocular vision loss**, often described as a "curtain" coming down, which aligns with **blindness in the right eye**. *Nasociliary artery* - The **nasociliary artery** supplies structures like the **ethmoid sinuses**, **dura mater**, and part of the **nasal cavity**. - It does not directly supply the **optic nerve** or the **retina** and its occlusion would not cause blindness. *Infraorbital artery* - The **infraorbital artery** supplies structures in the **maxilla**, **lower eyelid**, and part of the **cheek**. - Its occlusion would primarily affect these areas and would not result in **blindness**. *Lacrimal artery* - The **lacrimal artery** primarily supplies the **lacrimal gland**, which produces tears, as well as parts of the **eyelids** and **conjunctiva**. - While it's a branch of the ophthalmic artery, its occlusion would not directly cause **blindness** by affecting the retina or optic nerve.

Q: All of the following arteries are branches of ECA that supply nasal septum except:

Anterior ethmoidal artery. ***Anterior ethmoidal artery*** - The **anterior ethmoidal artery** is a branch of the **ophthalmic artery**, which itself is a branch of the **internal carotid artery (ICA)**, not the external carotid artery (ECA). - It supplies the **upper anterior nasal septum** and lateral wall of the nasal cavity. *Facial artery* - The **facial artery** is a direct branch of the **external carotid artery (ECA)**. - It contributes to the blood supply of the nasal septum through its septal branches. *Superior labial artery* - The **superior labial artery** is a branch of the **facial artery**, meaning it indirectly originates from the **external carotid artery (ECA)**. - It sends a septal branch to supply the **anterior inferior part of the nasal septum**. *Sphenopalatine artery* - The **sphenopalatine artery** is a direct terminal branch of the **maxillary artery**, which is one of the terminal branches of the **external carotid artery (ECA)**. - It is the major blood supply to the **posterior nasal septum** and lateral wall, forming part of Kesselbach's plexus.

Q: Which vessel is most likely damaged in an extradural (epidural) hemorrhage?

Middle meningeal artery. 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.

Q: Which of the following is the PRIMARY action of the superior oblique muscle?

Intorsion. ***Intorsion*** - The **primary action** of the **superior oblique muscle** is **intorsion** (internal rotation), which means rotating the top of the eyeball medially (towards the nose). - This action helps to counteract the **extorsion** caused by the inferior oblique muscle and stabilize the visual field during head tilt. *Depression* - While the superior oblique muscle does contribute to **depression** (moving the eye downwards), this is a **secondary action**, particularly when the eye is in **abduction** [1]. - The **inferior rectus muscle** is the primary depressor of the eye [1]. *Abduction* - The superior oblique has a minor **tertiary action** of **abduction** (moving the eye away from the midline) [1]. - However, the **lateral rectus muscle** is the primary abductor of the eye [1]. *Adduction* - **Adduction** (moving the eye towards the midline) is primarily performed by the **medial rectus muscle** [1]. - The superior oblique muscle does **NOT** contribute to adduction; this is not one of its actions [1].

Q: Which cranial nerve innervates the tensor tympani muscle?

Mandibular division of the trigeminal nerve (V3). ***Mandibular division of the trigeminal nerve (V3)*** - The **tensor tympani muscle** is primarily innervated by a branch from the **mandibular division of the trigeminal nerve (V3)**, specifically the nerve to the medial pterygoid. - This muscle helps to dampen loud sounds by pulling the **malleus** medially, thereby tensing the **tympanic membrane**. *Facial nerve* - The **facial nerve (CN VII)** innervates the **stapedius muscle**, which is another muscle involved in dampening loud sounds. - It controls muscles of **facial expression**, taste sensation from the anterior two-thirds of the tongue, and some glandular functions. *Glossopharyngeal nerve* - The **glossopharyngeal nerve (CN IX)** provides sensory innervation to the **posterior one-third of the tongue**, pharynx, and middle ear. - It also innervates the **stylopharyngeus muscle** and provides parasympathetic innervation to the parotid gland. *Hypoglossal nerve* - The **hypoglossal nerve (CN XII)** primarily innervates the **intrinsic and extrinsic muscles of the tongue**, controlling tongue movements. - It has no direct involvement in the innervation of middle ear muscles like the tensor tympani.

Q: Which muscle is primarily responsible for opening the Eustachian tube?

Tensor veli palatini. ***Tensor veli palatini*** - The **tensor veli palatini muscle** is directly involved in *opening* the **Eustachian tube** during swallowing and yawning. [1] - Its contraction pulls on the lateral wall of the cartilaginous part of the tube, allowing for *equilibration of pressure* between the middle ear and the nasopharynx. [1] *Stapedius* - The **stapedius muscle** is located in the middle ear and is responsible for *stabilizing the stapes*, reducing the transmission of loud sounds to the inner ear. [1] - It plays no direct role in the *opening or closing* of the Eustachian tube. [1] *Levator veli palatini* - The **levator veli palatini muscle** primarily *elevates the soft palate* during swallowing, helping to separate the oral cavity from the nasopharynx. - While it has a minor and indirect effect on the Eustachian tube, it is not the *primary muscle* responsible for its opening. *Tensor tympani* - The **tensor tympani muscle** is also located in the middle ear and functions to *dampen vibrations* of the malleus and stiffen the tympanic membrane in response to loud noises. - It is not involved in the *function or patency* of the Eustachian tube.

Q: A patient presents with CSF rhinorrhea following head trauma. Which anatomical structure is most likely fractured and what is the most significant clinical risk?

Cribriform plate fracture; meningitis risk. ***Cribriform plate fracture; meningitis risk*** - **CSF rhinorrhea** (cerebrospinal fluid leaking from the nose) following trauma is a classic sign of a **cribriform plate fracture** of the ethmoid bone [1]. - A fracture in this area creates a direct communication between the outside environment (nasal cavity) and the **subarachnoid space**, significantly increasing the risk of **ascending bacterial meningitis**. - The cribriform plate is the most common site for traumatic CSF rhinorrhea due to its thin, delicate structure [1]. *Occipital bone fracture; vision impairment* - An **occipital bone fracture** is typically associated with trauma to the posterior skull and can potentially affect the **visual cortex**, leading to **vision impairment** or cortical blindness. - However, it does not explain **CSF rhinorrhea**, which is indicative of an **anterior cranial fossa fracture**, not posterior fossa. *Sphenoid bone fracture; CN II, III, IV, VI damage* - A **sphenoid bone fracture**, particularly involving the **superior orbital fissure** or **optic canal**, can lead to damage to cranial nerves II, III, IV, and VI. - While CSF leaks can occur with sphenoid fractures, they more commonly present as **CSF otorrhea** (ear) rather than rhinorrhea, and sphenoid involvement is less common than cribriform plate fractures for traumatic CSF rhinorrhea. *Zygomatic arch fracture; facial asymmetry* - A **zygomatic arch fracture** primarily involves the malar (cheek) bone and presents with **facial asymmetry**, swelling, and sometimes **trismus** (difficulty opening the mouth due to impingement on the temporalis muscle). - This type of fracture does not cause **CSF rhinorrhea** as it does not involve the cranial base or breach the dura mater.

Q: A patient with a fracture in the middle third of the face would likely have damage to which of the following bones?

Maxilla. ***Maxilla*** - The **maxilla** forms the central part of the **midface**, including the upper jaw, floor of the nose, and lower orbital rim [1]. - Fractures in the middle third of the face, often classified as **Le Fort fractures**, predominantly involve the maxilla. - The maxilla is the **key bone** defining middle third facial fractures in clinical classification [1]. *Mandible* - The **mandible** is the bone of the **lower jaw** and is considered part of the lower third of the face. - Fractures of the mandible would present as damage to the chin and lower jaw region, not the middle third [1]. *Zygomatic bone* - The **zygomatic bone** (cheekbone) is anatomically part of the midface and can be involved in midface trauma. - However, isolated zygomatic fractures are classified separately as **zygomaticomaxillary complex (ZMC)** fractures. - The term "middle third facial fracture" clinically refers primarily to **maxillary fractures**, particularly the Le Fort classification system. *Frontal bone* - The **frontal bone** forms the forehead and the roof of the orbital cavities, placing it in the **upper third of the face**. - Damage to the frontal bone would typically result from trauma to the forehead, not the middle third of the face.

Question 1

Following endarterectomy on the right common carotid, a patient is found to be blind in the right eye. It appears that a small thrombus embolized during surgery and lodged in the artery supplying the retina. Which artery would be blocked?

Accepted Answer

Central artery of the retina

Answer

Nasociliary artery

Answer

Infraorbital artery

Answer

Lacrimal artery

Question 2

Which of the following DOESN'T supply dura mater?

Accepted Answer

Meningeal branch of internal carotid artery in posterior cranial fossa

Answer

Middle meningeal artery

Answer

Anterior and posterior ethmoidal arteries

Answer

Accessory meningeal artery

Question 3

All of the following arteries are branches of ECA that supply nasal septum except:

Accepted Answer

Anterior ethmoidal artery

Answer

Facial artery

Answer

Superior labial artery

Answer

Sphenopalatine artery

Question 4

Which vessel is most likely damaged in an extradural (epidural) hemorrhage?

Accepted Answer

Middle meningeal artery

Answer

Basilar artery

Answer

Vertebral artery

Answer

Anterior cerebral artery

Question 5

Which of the following is the PRIMARY action of the superior oblique muscle?

Accepted Answer

Intorsion

Answer

Adduction

Answer

Abduction

Answer

Depression

Question 6

Which cranial nerve innervates the tensor tympani muscle?

Accepted Answer

Mandibular division of the trigeminal nerve (V3)

Answer

Facial nerve

Answer

Glossopharyngeal nerve

Answer

Hypoglossal nerve

Question 7

Which muscle is primarily responsible for opening the Eustachian tube?

Accepted Answer

Tensor veli palatini

Answer

Stapedius

Answer

Levator veli palatini

Answer

Tensor tympani

Question 8

A patient presents with CSF rhinorrhea following head trauma. Which anatomical structure is most likely fractured and what is the most significant clinical risk?

Accepted Answer

Cribriform plate fracture; meningitis risk

Answer

Occipital bone fracture; vision impairment

Answer

Sphenoid bone fracture; CN II, III, IV, VI damage

Answer

Zygomatic arch fracture; facial asymmetry

Question 9

Post-tonsillectomy, a patient presents with altered posterior tongue sensation and taste. Which nerve is responsible for these changes, and what are its other functions?

Accepted Answer

Glossopharyngeal; responsible for swallowing and the gag reflex.

Answer

Facial; responsible for facial movements.

Answer

Hypoglossal; responsible for tongue movements.

Answer

Vagus; involved in parasympathetic functions in the thorax.

Question 10

A patient with a fracture in the middle third of the face would likely have damage to which of the following bones?

Accepted Answer

Maxilla

Answer

Mandible

Answer

Zygomatic bone

Answer

Frontal bone

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