Head Practice Questions

Q: Ptosis in Horner syndrome is due to the involvement of which muscle?

Müller muscle. ***Müller muscle*** - **Ptosis** in **Horner syndrome** results from the paralysis of the **smooth muscle fibers** of the Müller muscle (also known as the superior tarsal muscle), which is innervated by the **sympathetic nervous system**. - This muscle contributes a small amount to upper eyelid elevation, and its denervation causes a **mild unilateral ptosis**. *Levator aponeurosis* - The **levator aponeurosis** is involved in eyelid elevation but is primarily innervated by the **oculomotor nerve (III cranial nerve)**, not the sympathetic system. - Damage to the oculomotor nerve or the aponeurosis itself would cause a more **severe ptosis** than seen in Horner syndrome. *Horner's muscle* - **Horner's muscle**, also known as the **lacrimal part of the orbicularis oculi muscle**, is involved in the drainage of tears, not eyelid elevation. - It does not play a role in the ptosis associated with **Horner syndrome**. *Orbicularis oculi* - The **orbicularis oculi muscle** is responsible for **eyelid closure** and is innervated by the **facial nerve (VII cranial nerve)**. - Its dysfunction would lead to difficulty closing the eye, not ptosis or an inability to open it.

Q: Ptosis in Horner syndrome is due to paralysis of which muscle?

Superior tarsal muscle. ***Superior tarsal muscle*** * The **superior tarsal muscle** (Müller's muscle) is a sympathetically innervated smooth muscle. * Its paralysis due to sympathetic denervation in **Horner syndrome** causes partial ptosis. *Orbitalis* * The **orbitalis muscle** (Müller's muscle) is a smooth muscle that spans the inferior orbital fissure and may help in protrusion of the eyeball; it is not directly responsible for eyelid elevation. * While also sympathetically innervated, its paralysis does not directly cause ptosis but may contribute to other subtle signs or symptoms. *Orbicularis oculi* * The **orbicularis oculi muscle** is responsible for eyelid closure, not elevation. * It is innervated by the **facial nerve (CN VII)**, and its dysfunction would lead to difficulty closing the eye, not ptosis. *Sphincter pupillae* * The **sphincter pupillae muscle** constricts the pupil and is innervated by the **parasympathetic system**. * In Horner syndrome, the dilator pupillae (sympathetically innervated) is affected, leading to miosis (small pupil), not ptosis, and the sphincter pupillae function is preserved.

Q: What is the action of the superior oblique muscle?

Intorsion, abduction, depression. ***Intorsion, abduction, depression*** - The **superior oblique muscle** has three actions: **depression** (downward movement - primary action), **abduction** (movement away from the midline), and **intorsion** (medial/internal rotation of the globe) [1]. - The depressor action is most effective when the eye is **adducted** (turned inward), as the muscle's line of pull is then optimally aligned with the vertical axis. - Mnemonic: **SO-DAI** (Superior Oblique: Depression, Abduction, Intorsion) *Intorsion, adduction, elevation* - While **intorsion** is correct, this option incorrectly includes **adduction** and **elevation**. - The superior oblique causes **abduction** (not adduction) and **depression** (not elevation) [1]. - **Elevation** is performed by the superior rectus and inferior oblique muscles [1]. *Extorsion, adduction, elevation* - All three actions are incorrect for the superior oblique muscle. - The correct actions are **intorsion**, **abduction**, and **depression**. - **Extorsion** is performed by the inferior oblique and inferior rectus muscles [1]. *Extorsion, abduction, depression* - While **abduction** and **depression** are correct, **extorsion** is wrong. - The superior oblique causes **intorsion** (internal rotation), not extorsion (external rotation). - This is a common point of confusion - remember the superior oblique **intorts**, while the inferior oblique **extorts**.

Q: Identify the incorrect statement regarding the marked structure.

Accessory middle meningeal artery lies under this structure. *It is the meeting point of frontal, parietal, temporal and greater wing of sphenoid bone.* - The marked structure is the **pterion**, which is the junction of the **frontal, parietal, temporal, and greater wing of the sphenoid bone**. - This statement is **correct**, as it accurately describes the anatomical composition of the pterion. ***Accessory middle meningeal artery lies under this structure*** - This is the **INCORRECT statement** and hence the correct answer. - The **middle meningeal artery** (not the accessory middle meningeal artery) runs in a groove deep to the pterion. - A fracture at the pterion can lacerate the **middle meningeal artery**, leading to an **epidural hematoma**. - The accessory middle meningeal artery is a separate vessel that does not typically lie under the pterion. *Blow to the lateral side of the skull injures the marked structure* - The pterion is the **thinnest part of the lateral wall of the skull**, making it vulnerable to fracture from a lateral blow. - Due to its thinness and underlying structures, trauma to this area is clinically significant. - This statement is **correct**. *It corresponds to site of anterolateral fontanelle of fetal skull* - The pterion in the adult skull corresponds to the former site of the **anterolateral (sphenoidal) fontanelle** in the fetal skull. - This fontanelle allows for skull molding during birth and brain growth postnatally. - This statement is **correct**.

Q: Which nerve is blocked in the image given below?

Long ciliary nerve. ***Long ciliary nerve*** - The image depicts a nerve block performed around the **globe of the eye**, specifically targeting the structures involved in sensing the anterior segment - The **long ciliary nerves** are responsible for carrying **sensory innervation** from the cornea, iris, and ciliary body, making them a target for anesthesia when performing procedures involving these structures - This is a **peribulbar or retrobulbar block** technique targeting the long ciliary nerves near the globe *Nasociliary nerve* - The **nasociliary nerve** is a branch of the **ophthalmic nerve** (V1) that supplies sensation to parts of the eye and nasal cavity - While the long ciliary nerve is a branch of the nasociliary nerve, the image specifically shows a more **distal block** targeting the ciliary nerves near the globe, rather than the main trunk of the nasociliary nerve more proximally *Supratrochlear nerve* - The **supratrochlear nerve** is a branch of the **frontal nerve**, which is also a branch of the ophthalmic nerve - It supplies sensation to the **medial part of the upper eyelid** and the forehead, not directly to the anterior structures of the eye itself - This nerve would not be targeted in a peribulbar block *Anterior ethmoidal nerve* - The **anterior ethmoidal nerve** is a branch of the **nasociliary nerve** that provides sensation to parts of the nasal septum and the anterior part of the nasal cavity - It does not directly innervate the cornea or other anterior structures of the eye - This nerve exits the orbit through the anterior ethmoidal foramen

Q: A patient after a road traffic accident presents to the emergency room with difficulty in swallowing and slurred speech. Investigations reveal fractures in the occipitotemporal region. Which of the following areas should be tested in order to find the nerve which is involved?

Posterior one-third of tongue. ***Posterior one-third of tongue*** - This symptom complex of **dysphagia** (difficulty swallowing) and **dysarthria** (slurred speech) after trauma to the occipitotemporal region is highly suggestive of damage to **Cranial Nerves IX (Glossopharyngeal)** and **X (Vagus)**. - The **Glossopharyngeal nerve (CN IX)** supplies general and special sensation (taste) to the **posterior one-third of the tongue** [1]. *Anterior two-thirds of tongue* - The **facial nerve (CN VII)** is responsible for taste sensation from the **anterior two-thirds of the tongue** [1]. - General sensation from the anterior two-thirds of the tongue is supplied by the **trigeminal nerve (CN V)** via the lingual nerve. *Hard palate* - Sensation to the **hard palate** is primarily supplied by branches of the **trigeminal nerve (CN V)**, specifically the greater palatine and nasopalatine nerves. - Damage to these nerves would primarily affect sensation in the palate, not cause dysphagia and dysarthria. *Soft palate* - The **vagus nerve (CN X)** is responsible for motor innervation to most muscles of the **soft palate**, allowing for its elevation during swallowing and speech. - While soft palate dysfunction can contribute to dysphagia and dysarthria, directly testing sensation here would be less specific than testing the posterior tongue for Glossopharyngeal involvement.

Q: A 6-month-old boy was brought to the casualty with seizures. The pediatrician tries to do CSF sampling. What are the structures punctured by the pediatrician while piercing through the marked structure?

Scalp, dura, arachnoid. ***Scalp, dura, arachnoid*** - The image shows a needle piercing through the **anterior fontanelle**, which allows direct access to the intracranial space. - When accessing the **subarachnoid space** via the fontanelle, the needle would penetrate the overlying **scalp**, then the outer and inner layers of the **dura mater**, and finally the **arachnoid mater** before reaching the cerebrospinal fluid. *Scalp, epicranium, endocranium and dura* - The terms **epicranium** and **endocranium** refer to layers associated with the bone itself, which is largely absent as a solid structure at the fontanelle in an infant. - CSF sampling through the fontanelle bypasses the need to penetrate mature bone layers like epicranium and endocranium. *Scalp synchondral membrane, dura, arachnoid* - A **synchondral membrane** is found between bones that are joined by cartilage, such as at the base of the skull, not typically within the fontanelle itself. - The primary layers to be penetrated at the fontanelle are the soft tissues of the scalp and the meningeal layers. *Pericranium, dura, arachnoid* - The **pericranium** is the dense connective tissue layer that covers the outer surface of the bones of the skull. - While present, it's considered part of the overall scalp layers and is not a separate primary penetration layer in the same context as the meninges for CSF sampling.

Q: In pediatric assessment, a cephalic index of 75-80 is classified as:

Mesocephalic head shape. ***Mesocephalic head shape*** - A cephalic index between **75 and 80** indicates a **mesocephalic** head shape, which means the head has a medium or normal width-to-length ratio. - This is considered the **average** or typical head shape in most populations. *Dolichocephalic head shape* - A **dolichocephalic** head shape is characterized by a cephalic index typically **below 75**, meaning the head is relatively **long and narrow**. - This head shape is often seen in individuals with certain genetic backgrounds or conditions that affect skull development. *Brachycephalic head shape* - A **brachycephalic** head shape is characterized by a cephalic index typically **above 80**, meaning the head is relatively **short and wide**. - This can be naturally occurring or a result of conditions like **craniosynostosis** [1] or positional molding. *Scaphocephalic head shape* - **Scaphocephaly** is a specific type of **dolichocephaly** resulting from the premature fusion of the **sagittal suture** [1]. - This condition leads to a very long, narrow, and keeled head shape that would fall into the severe dolichocephalic range (cephalic index well below 75).

Q: Masseter is supplied by which nerve?

Mandibular. ***Mandibular*** - The **masseter muscle** is a muscle of mastication, and all muscles of mastication are exclusively innervated by the **mandibular division** (V3) of the trigeminal nerve. - The mandibular nerve carries both **motor and sensory fibers**; its motor branches supply the masseter, temporalis, medial and lateral pterygoids, mylohyoid, anterior belly of digastric, tensor veli palatini, and tensor tympani. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** primarily supplies sensation to the posterior third of the tongue, the pharynx, and the tympanic membrane. - It also has motor functions, innervating the **stylopharyngeus muscle** and providing parasympathetic innervation to the parotid gland. *Facial* - The **facial nerve (CN VII)** is primarily responsible for innervating the **muscles of facial expression**. - It also carries taste sensation from the anterior two-thirds of the tongue and provides parasympathetic innervation to the lacrimal, submandibular, and sublingual glands. *Hypoglossal* - The **hypoglossal nerve (CN XII)** is exclusively a motor nerve. - It innervates all of the **intrinsic and extrinsic muscles of the tongue**, except for the palatoglossus muscle (which is innervated by the vagus nerve).

Question 1

Ptosis in Horner syndrome is due to the involvement of which muscle?

Accepted Answer

Müller muscle

Answer

Levator aponeurosis

Answer

Horner's muscle

Answer

Orbicularis oculi

Question 2

Ptosis in Horner syndrome is due to paralysis of which muscle?

Accepted Answer

Superior tarsal muscle

Answer

Orbitalis

Answer

Orbicularis oculi

Answer

Sphincter pupillae

Question 3

A pregnant woman presents with fever, retroorbital pain, headache, pulsatile proptosis of the right eye, and tinnitus. BP and fundus were normal. Which of the following structures are involved?

Accepted Answer

Abducens nerve, Oculomotor nerve, Internal carotid artery, Cavernous sinus

Answer

Oculomotor nerve, Internal carotid artery, Cavernous sinus

Answer

Abducens nerve, Internal carotid artery, Cavernous sinus

Answer

Abducens nerve, Oculomotor nerve, Internal carotid artery

Question 4

What is the action of the superior oblique muscle?

Accepted Answer

Intorsion, abduction, depression

Answer

Intorsion, adduction, elevation

Answer

Extorsion, adduction, elevation

Answer

Extorsion, abduction, depression

Question 5

Identify the incorrect statement regarding the marked structure.

Accepted Answer

Accessory middle meningeal artery lies under this structure

Answer

Blow to the lateral side of the skull injures the marked structure

Answer

It corresponds to site of anterolateral fontanelle of fetal skull

Answer

It is the meeting point of frontal, parietal, temporal and greater wing of sphenoid bone.

Question 6

Which nerve is blocked in the image given below?

Accepted Answer

Long ciliary nerve

Answer

Nasociliary nerve

Answer

Supratrochlear nerve

Answer

Anterior ethmoidal nerve

Question 7

A patient after a road traffic accident presents to the emergency room with difficulty in swallowing and slurred speech. Investigations reveal fractures in the occipitotemporal region. Which of the following areas should be tested in order to find the nerve which is involved?

Accepted Answer

Posterior one-third of tongue

Answer

Anterior two-thirds of tongue

Answer

Hard palate

Answer

Soft palate

Question 8

A 6-month-old boy was brought to the casualty with seizures. The pediatrician tries to do CSF sampling. What are the structures punctured by the pediatrician while piercing through the marked structure?

Accepted Answer

Scalp, dura, arachnoid

Answer

Scalp, epicranium, endocranium and dura

Answer

Scalp, synchondral membrane, dura, arachnoid

Answer

Pericranium, dura, arachnoid

Question 9

In pediatric assessment, a cephalic index of 75-80 is classified as:

Accepted Answer

Mesocephalic head shape

Answer

Dolichocephalic head shape

Answer

Brachycephalic head shape

Answer

Scaphocephalic head shape

Question 10

Masseter is supplied by which nerve?

Accepted Answer

Mandibular

Answer

Glossopharyngeal

Answer

Facial

Answer

Hypoglossal

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