Head — MCQs

Head Indian Medical PG Practice Questions and MCQs

Question 1241: MacEwen's triangle is the landmark for:

A. Maxillary sinus
B. Frontal sinus
C. Mastoid antrum (Correct Answer)
D. None of the options

Explanation: ***Mastoid antrum*** - **MacEwen's triangle** (or suprameatal triangle) is an important anatomical landmark on the lateral surface of the mastoid process, indicating the approximate position of the **mastoid antrum**. - It is bounded anteriorly by the posterior free margin of the **bony external auditory canal**, superiorly by the supramastoid crest (temporal line), and posteriorly by a line tangential to the posterior external auditory canal. *Maxillary sinus* - The **maxillary sinus** (antrum of Highmore) is located within the body of the maxilla, inferior to the orbit and lateral to the nasal cavity. - Its location is not related to MacEwen's triangle, which is found on the temporal bone. *Frontal sinus* - The **frontal sinus** is located within the frontal bone, superior to the orbits and nasal cavity. - This sinus is not anatomically associated with MacEwen's triangle; the triangle is a landmark for the mastoid air cells. *None of the options* - This is incorrect because **MacEwen's triangle** is indeed a well-established landmark for the **mastoid antrum**. - Its clinical significance lies in providing a guide for surgical access to the mastoid antrum during mastoidectomy.

Question 1242: Epistaxis after ligating external carotid artery is due to which vessel?

A. Anterior ethmoidal artery (Correct Answer)
B. Superior labial artery
C. Sphenopalatine artery
D. Greater palatine artery

Explanation: ***Anterior ethmoidal artery*** - The **anterior ethmoidal artery** is a branch of the **ophthalmic artery**, which in turn is a branch of the **internal carotid artery**. - Since the external carotid artery has been ligated, branches from the internal carotid system, like the anterior ethmoidal artery, can still supply the nasal cavity and cause continued epistaxis. *Superior labial artery* - The **superior labial artery** is a terminal branch of the **facial artery**, which originates from the **external carotid artery**. - Ligation of the external carotid artery would reduce blood flow to this vessel, making it an unlikely source of persistent epistaxis. *Sphenopalatine artery* - The **sphenopalatine artery** is a terminal branch of the **maxillary artery**, which is also a branch of the **external carotid artery**. - Ligation of the external carotid artery would significantly reduce flow through this artery, making it an unlikely cause of continued bleeding. *Greater palatine artery* - The **greater palatine artery** is a branch of the **descending palatine artery**, which is a branch of the **maxillary artery** (from the external carotid system). - Ligation of the external carotid artery would essentially eliminate blood flow from this vessel to the nasal cavity, thus it would not be the source of persistent epistaxis.

Question 1243: Tensor tympani is attached to?

A. Malleus (Correct Answer)
B. Incus
C. Stapes
D. Tympanic membrane

Explanation: ***Malleus*** - The **tensor tympani muscle** contracts to pull the malleus inward, **increasing tension** on the tympanic membrane [1]. - This action **dampens vibrations** transmitted to the inner ear, particularly protecting against loud sounds [1]. *Incus* - The incus is the **middle ossicle** in the sound conduction chain, connected to the malleus and stapes [1]. - It does not have a direct muscular attachment from the tensor tympani. *Stapes* - The stapes is the **innermost ossicle**, articulating with the oval window [1]. - The **stapedius muscle** attaches to the stapes, not the tensor tympani, and also dampens sound [1]. *Tympanic membrane* - While the tensor tympani's action **increases tension** on the **tympanic membrane** via the malleus, it does not directly attach to the membrane [1]. - The malleus is embedded within the tympanic membrane [1].

Question 1244: Trismus in parapharyngeal abscess is due to spasm of:

A. Medial pterygoid (Correct Answer)
B. Temporalis
C. Masseter muscle
D. Lateral pterygoid

Explanation: ***Medial pterygoid*** - The **medial pterygoid muscle** is intimately associated with the parapharyngeal space, and inflammation or infection (abscess) in this region directly irritates it. - **Spasm** of the medial pterygoid muscle, a primary muscle of mastication involved in jaw closure, is the direct cause of **trismus** (difficulty opening the mouth) in parapharyngeal abscess. *Masseter muscle* - While the **masseter** is a strong muscle of mastication and contributes to jaw closure, it is located more superficially and is less directly affected by an abscess in the parapharyngeal space. - Its involvement in trismus due to parapharyngeal abscess is typically secondary, arising from generalized muscle guarding rather than direct irritation. *Lateral pterygoid* - The **lateral pterygoid muscle** is primarily involved in jaw opening (depression) and protrusion. - Spasm of this muscle would typically lead to difficulty closing the jaw or deviations, rather than the profound difficulty in opening characteristic of trismus. *Temporalis* - The **temporalis muscle** is a major muscle for jaw elevation and retraction, contributing significantly to biting force. - While temporalis spasm can cause trismus, it is less directly impacted by a parapharyngeal abscess compared to the medial pterygoid muscle.

Question 1245: Nasal vestibule is

A. Lateral part of nasal cavity
B. Supero-medial part of nose
C. Posterior aperture of nose
D. Most anterior part of the nasal cavity (Correct Answer)

Explanation: ***Most anterior part of the nasal cavity*** - The **nasal vestibule** is the dilated, most anterior part of the nasal cavity, just inside the nostrils. - It is lined by **skin** that contains hair follicles (vibrissae), sebaceous glands, and sweat glands, and is continuous with the skin of the face [1]. *Lateral part of nasal cavity* - The lateral walls of the nasal cavity contain the **nasal conchae** (turbinates) and meatuses, which are involved in air conditioning, but this is not the vestibule. - This region is primarily concerned with *filtering*, *warming*, and *humidifying* inhaled air, distinct from the primary entry point function of the vestibule [2]. *Supero - medial part of nose* - The **superior and medial aspects** of the nasal cavity include the **cribriform plate** and the **nasal septum**, respectively. - These areas are crucial for **olfaction** and separating the nasal passages, playing different roles than the vestibule [3]. *Posterior aperture of nose* - The **posterior aperture of the nose** refers to the **choanae**, which are the openings connecting the nasal cavity to the nasopharynx. - These are located at the *back* of the nasal cavity, providing a pathway for air into the pharynx, not the entrance.

Question 1246: Which of the following structures is NOT pierced by the parotid duct?

A. Buccopharyngeal fascia
B. Buccinator muscle
C. Buccal fat pad
D. Investing layer of deep cervical fascia (Correct Answer)

Explanation: ***Investing layer of deep cervical fascia*** - The parotid duct (Stensen's duct) **does not pierce** the investing layer of the deep cervical fascia. - The investing layer **forms the capsule** of the parotid gland itself, and the duct **emerges from within** this fascial investment at the anterior border of the gland. - Since the duct originates from within the parotid gland (which is enclosed by the investing fascia), it does not pierce through this layer. *Buccopharyngeal fascia* - This is **also NOT pierced** by the parotid duct in its typical course. - The buccopharyngeal fascia covers the outer surface of the buccinator muscle and pharyngeal constrictors. - The parotid duct runs **superficial** to this fascial layer before piercing the buccinator muscle itself. - However, for exam purposes, the **investing layer of deep cervical fascia** is the most clearly established structure that is NOT pierced. *Buccinator muscle* - The parotid duct **definitively pierces** the buccinator muscle to reach the oral cavity. - It enters the oral vestibule **opposite the upper second molar tooth**. - This is a consistent anatomical landmark. *Buccal fat pad* - The parotid duct runs **lateral and superficial** to the buccal fat pad (Bichat's fat pad). - The duct does **not typically pierce through** the buccal fat pad; rather, it courses along its superficial surface. - The buccal fat pad lies deep to the buccinator muscle and provides cushioning in the cheek.

Question 1247: Nerve supply to the tip of the nose is from?

A. The ophthalmic division of the trigeminal nerve (Correct Answer)
B. Greater auricular nerve
C. The maxillary division of the trigeminal nerve
D. Mandibular nerve

Explanation: ***The ophthalmic division of the trigeminal nerve*** * The **nasociliary nerve**, a branch of the **ophthalmic division (CN V1)**, gives rise to the **anterior ethmoidal nerve**. * The **anterior ethmoidal nerve** further branches into the **external nasal nerve**, which supplies the skin over the tip and ala of the nose. *Greater auricular nerve* * The greater auricular nerve is a branch of the **cervical plexus (C2-C3)** and primarily supplies the skin over the **auricle (ear)** and the **mastoid region**. * It has no involvement in the sensory innervation of the nose. *The maxillary division of the trigeminal nerve* * The **maxillary division (CN V2)** primarily provides sensory innervation to the **midface**, including the cheeks, upper lip, upper teeth, and palate. * While it supplies parts of the nose (e.g., via the infraorbital nerve and external nasal branches of the anterior superior alveolar nerve to the anterior septum and nasal vestibule), it does not innervate the **tip of the nose**. *Mandibular nerve* * The **mandibular nerve (CN V3)**, supplies the **lower face**, including the lower lip, chin, lower teeth, and temporal region. * It is also responsible for the motor innervation of the **muscles of mastication**. It has no role in the sensory supply of the nose.

Question 1248: Which of the following passes through the Hypoglossal canal?

A. Hypoglossal nerve (Correct Answer)
B. External jugular vein
C. Facial nerve
D. Mandibular nerve

Explanation: ***Hypoglossal nerve*** - The **hypoglossal canal** is an opening in the occipital bone that transmits the **hypoglossal nerve (cranial nerve XII)**. - This nerve is responsible for the **motor innervation of all intrinsic and extrinsic muscles of the tongue**, except for the palatoglossus. *External jugular vein* - The **external jugular vein** drains blood from the superficial face and neck, eventually emptying into the subclavian vein. - It does not pass through any cranial foramina but runs superficially in the neck. *Facial nerve* - The **facial nerve (cranial nerve VII)** exits the skull through the **stylomastoid foramen**, not the hypoglossal canal. - It controls muscles of facial expression, taste sensation from the anterior two-thirds of the tongue, and some glandular secretions. *Mandibular nerve* - The **mandibular nerve (V3)**, a branch of the trigeminal nerve, exits the skull through the **foramen ovale**. - It provides sensory innervation to the lower face and motor innervation to the muscles of mastication.

Question 1249: Which area of the face is NOT drained by the submandibular lymph nodes?

A. Medial part of cheek
B. Central part of lower lip (Correct Answer)
C. Medial half of eyelids
D. Lateral part of lower lip

Explanation: ***Central part of lower lip*** - The **central part of the lower lip** is primarily drained by the **submental lymph nodes**, not the submandibular nodes. - The submental nodes are located inferior to the chin and receive lymph from the chin, central lower lip, and floor of the mouth. - This is the key distinguishing feature as the submandibular nodes drain the lateral parts of the lower lip but not the central part. *Medial part of cheek* - The **medial part of the cheek** is drained by the **submandibular lymph nodes**. - Lymphatic drainage from the cheek includes superficial and deep networks leading to these nodes. *Medial half of eyelids* - The **medial half of the eyelids** is drained by the **submandibular lymph nodes**. - This drainage path is important in understanding the spread of infections or malignancies in the periorbital region. *Lateral part of lower lip* - The **lateral part of the lower lip** is drained by the **submandibular lymph nodes**. - Only the central portion of the lower lip drains to submental nodes; the lateral portions drain to submandibular nodes.

Question 1250: Which layer of the scalp is vascular?

A. Pericranium
B. Superficial fascia (Correct Answer)
C. Skin
D. Aponeurosis

Explanation: ***Superficial fascia*** - This layer of the scalp, also known as the **connective tissue layer**, is highly vascular and contains numerous arteries and veins. - The extensive vasculature in the superficial fascia is responsible for significant bleeding following scalp injuries due to the **fibrous septa** that prevent vessel constriction. *Pericranium* - The pericranium is the **dense connective tissue membrane** that adheres closely to the outer surface of the skull bones. - It is relatively **avascular** compared to the other layers, serving primarily as the periosteum of the skull. *Skin* - While the skin itself is vascularized, the density of large vessels within the **dermis** is not as high as the superficial fascia. - Its primary role is protection, and its vasculature supports cellular metabolism and thermoregulation. *Aponeurosis* - The aponeurosis, or **galea aponeurotica**, is a tough, fibrous sheet that connects the frontal and occipital bellies of the occipitofrontalis muscle. - It contains minimal blood vessels compared to the superficial fascia and is generally considered to be of **low vascularity**.

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