Head — MCQs

Head Indian Medical PG Practice Questions and MCQs

Question 241: The posterior 1/3 of the tongue is innervated by which nerve?

A. Hypoglossal nerve
B. Chorda tympani
C. Lingual nerve
D. Glossopharyngeal nerve (Correct Answer)

Explanation: The tongue has a complex nerve supply derived from its multiple embryological origins. The **Glossopharyngeal nerve (CN IX)** provides both **general sensation** (touch, pain, temperature) and **special sensation** (taste) to the **posterior 1/3 of the tongue**, including the circumvallate papillae [1]. This is because the posterior 1/3 develops from the **third pharyngeal arch**, which is supplied by CN IX. #### Analysis of Options: * **A. Hypoglossal nerve (CN XII):** This is the **motor nerve** for all intrinsic and extrinsic muscles of the tongue (except the Palatoglossus, supplied by the Vagus nerve). It does not carry sensory fibers. * **B. Chorda tympani (branch of CN VII):** This nerve carries **taste (special sensation)** from the **anterior 2/3** of the tongue. * **C. Lingual nerve (branch of CN V3):** This nerve carries **general sensation** (touch/pain) from the **anterior 2/3** of the tongue. #### NEET-PG High-Yield Pearls: 1. **Circumvallate Papillae:** Although located just anterior to the sulcus terminalis, they are innervated by the **Glossopharyngeal nerve**, not the lingual nerve [1]. 2. **Posterior-most part (Vallecula):** The base of the tongue near the epiglottis is supplied by the **Internal Laryngeal nerve** (branch of Vagus, CN X). 3. **Gag Reflex:** The Glossopharyngeal nerve (CN IX) forms the **sensory (afferent) limb** of the gag reflex, while the Vagus nerve (CN X) forms the motor (efferent) limb. 4. **Embryology:** Anterior 2/3 = 1st Arch; Posterior 1/3 = 3rd Arch; Posterior-most = 4th Arch.

Question 242: Which statement is NOT true regarding the mandible?

A. It originates from the second pharyngeal arch. (Correct Answer)
B. It consists of a body and a ramus.
C. It is the strongest bone in the skull.
D. It contains 16 sockets for teeth.

Explanation: ### Explanation **1. Why Option A is the correct (False) statement:** The mandible develops from the **first pharyngeal arch** (Mandibular arch), specifically from the mesoderm surrounding **Meckel’s cartilage**. While Meckel’s cartilage acts as a scaffold, the mandible itself develops via **intramembranous ossification**. The second pharyngeal arch (Hyoid arch) gives rise to structures like the stapes, styloid process, and the lesser cornu of the hyoid bone, but not the mandible. **2. Analysis of other options:** * **Option B:** Anatomically, the mandible is composed of a horizontal part called the **body** and two vertical parts called the **rami**. They meet at the angle of the mandible. * **Option C:** The mandible is indeed the **strongest, largest, and lowest** bone of the face. Its dense cortical bone allows it to withstand significant masticatory forces. * **Option D:** The alveolar part of the mandible contains **16 sockets** (alveoli) to accommodate the lower permanent dentition (4 incisors, 2 canines, 4 premolars, and 6 molars). **3. High-Yield Clinical Pearls for NEET-PG:** * **Ossification:** The mandible is the second bone in the body to start ossifying (after the clavicle). * **Nerve Supply:** The **mandibular nerve (V3)**, the largest division of the Trigeminal nerve, supplies the muscles of mastication derived from the first arch. * **Fracture Sites:** The most common sites for mandibular fractures are the **condyle (30%)**, followed by the body and the angle. * **Foramina:** The **mental foramen** (transmitting mental nerve and vessels) is usually located below the interval between the first and second premolars.

Question 243: Which muscles are supplied by the facial nerve?

A. Platysma (Correct Answer)
B. Superior belly of omohyoid
C. Stylohyoid
D. Buccinator

Explanation: The **Facial Nerve (CN VII)** is the nerve of the **second pharyngeal arch**. It provides motor innervation to all muscles of facial expression, as well as specific muscles derived from this arch. ### **Analysis of Options** * **Platysma (Correct):** This is a broad, thin sheet of muscle located in the subcutaneous tissue of the neck. Despite its location, it is functionally a muscle of facial expression and is supplied by the **Cervical branch of the Facial Nerve**. * **Superior belly of omohyoid (Incorrect):** This is an infrahyoid muscle. All infrahyoid muscles (except thyrohyoid) are supplied by the **Ansa Cervicalis (C1-C3)**. * **Stylohyoid (Incorrect):** While the stylohyoid *is* supplied by the facial nerve, in the context of single-best-answer MCQs for NEET-PG, the Platysma is often the preferred answer when testing superficial neck anatomy. *Note: If this were a multiple-choice "select all" question, Stylohyoid and Buccinator would also be correct.* * **Buccinator (Incorrect):** This is supplied by the **Buccal branch of the Facial Nerve**. However, in many standardized formats, the Platysma is highlighted to test the student's knowledge that a neck muscle can be supplied by a cranial nerve. ### **High-Yield Clinical Pearls for NEET-PG** 1. **Other muscles supplied by CN VII:** Stapedius (smallest muscle), Posterior belly of digastric, and Stylohyoid. 2. **The "Face" Rule:** Any muscle that moves the skin of the face or protects the eye (Orbicularis oculi) is CN VII. 3. **Clinical Correlation:** In **Bell’s Palsy** (LMN lesion), the patient will lose the ability to wrinkle the forehead and tense the skin of the neck (Platysma paralysis). 4. **Ansa Cervicalis:** Remember that the superior belly of the omohyoid is specifically supplied by the **superior root (C1)** of the ansa cervicalis.

Question 244: The middle superior alveolar nerve supplies the upper premolar teeth. It is a branch of which division?

A. Infraorbital portion of the maxillary nerve (Correct Answer)
B. Palatine division of the maxillary nerve
C. Anterior nasal division of the maxillary nerve
D. Infraorbital nerve

Explanation: ### Explanation **Correct Answer: A. Infraorbital portion of the maxillary nerve** The **Maxillary nerve ($V_2$)** provides sensory innervation to the upper teeth through the Superior Alveolar nerves. The nerve follows a specific branching pattern as it traverses the pterygopalatine fossa and the infraorbital canal: 1. **Posterior Superior Alveolar (PSA):** Branches from the maxillary nerve in the pterygopalatine fossa. 2. **Middle Superior Alveolar (MSA):** Branches from the **infraorbital portion** of the maxillary nerve within the infraorbital groove/canal. It supplies the upper premolars and the mesiobuccal root of the first molar. 3. **Anterior Superior Alveolar (ASA):** Branches from the infraorbital nerve further anteriorly to supply the incisors and canines. **Analysis of Incorrect Options:** * **B. Palatine division:** This gives rise to the Greater and Lesser palatine nerves, which supply the hard and soft palate mucosa, not the teeth. * **C. Anterior nasal division:** This refers to branches supplying the nasal cavity (like the nasopalatine nerve), which do not innervate the premolars. * **D. Infraorbital nerve:** While the MSA is technically a branch of the infraorbital nerve, NEET-PG questions often distinguish between the "Maxillary nerve" and its "Infraorbital portion." Option A is more anatomically precise as the MSA arises while the nerve is specifically in its infraorbital course. **High-Yield Clinical Pearls for NEET-PG:** * **Superior Dental Plexus:** Formed by the communication of the PSA, MSA, and ASA nerves. * **Absent MSA:** The Middle Superior Alveolar nerve is absent in about 30-40% of individuals; in such cases, its functions are taken over by the ASA. * **Maxillary Sinusitis:** Pain from the maxillary sinus can be referred to the upper teeth because these nerves (PSA, MSA, ASA) run in the walls of the sinus.

Question 245: What structure is superficial to the mylohyoid muscle in an anterior digastric triangle?

A. Deep part of submandibular gland
B. Hypoglossal nerve
C. Part of parotid gland
D. Mylohyoid artery and nerve (Correct Answer)

Explanation: The **mylohyoid muscle** forms the anatomical floor of the mouth. Understanding its relations is high-yield for NEET-PG, as it separates the sublingual space (superior/deep) from the submandibular space (inferior/superficial). ### **Why the Correct Answer is Right** The **mylohyoid nerve** (a branch of the inferior alveolar nerve) and the **mylohyoid artery** (a branch of the maxillary artery) run in the mylohyoid groove of the mandible. They descend into the submandibular triangle and lie on the **superficial (inferior) surface** of the mylohyoid muscle. They are situated deep to the superficial part of the submandibular gland but superficial to the muscle itself. ### **Analysis of Incorrect Options** * **A. Deep part of submandibular gland:** The submandibular gland is "C-shaped" around the posterior border of the mylohyoid. The **deep part** lies superior/deep to the muscle in the floor of the mouth. * **B. Hypoglossal nerve (CN XII):** This nerve, along with the submandibular duct and the lingual nerve, lies **deep (superior)** to the mylohyoid muscle. * **C. Part of parotid gland:** The parotid gland is located in the retromandibular fossa, posterior to the ramus of the mandible. It does not form a direct relation to the mylohyoid muscle in the digastric triangle. ### **High-Yield NEET-PG Pearls** * **"The Mylohyoid Partition":** Structures **Deep** to mylohyoid (Sublingual space) include the Submandibular duct (Wharton’s), Lingual nerve, Hypoglossal nerve, and Deep part of the submandibular gland. * **Nerve Supply:** The mylohyoid muscle is supplied by the **nerve to mylohyoid** (branch of Mandibular nerve V3), which also supplies the **anterior belly of the digastric**. * **Action:** It elevates the floor of the mouth and the hyoid bone during the first stage of deglutition.

Question 246: Which of the following is NOT a content of the middle ear?

A. Stapedius
B. Tensor tympani
C. Facial nerve (Correct Answer)
D. Chorda tympani

Explanation: The middle ear (tympanic cavity) is an air-filled space within the petrous part of the temporal bone [1]. Understanding its contents versus its boundaries is a high-yield topic for NEET-PG. ### **Why "Facial Nerve" is the Correct Answer** While the facial nerve (CN VII) is anatomically related to the middle ear, it is **not a content** of the cavity itself. It runs within the **Fallopian canal** (bony facial canal) located in the medial and posterior walls of the middle ear. Although the canal may occasionally be dehiscent (naturally open), the nerve remains structurally separated from the tympanic cavity by its sheath and the bony wall. ### **Analysis of Incorrect Options (Actual Contents)** * **Stapedius (Option A):** This is the smallest skeletal muscle in the body. Its tendon emerges from the pyramid (on the posterior wall) to insert into the neck of the stapes [2]. * **Tensor Tympani (Option B):** This muscle resides in a bony canal above the auditory tube; its tendon enters the middle ear to insert into the handle of the malleus [2]. * **Chorda Tympani (Option C):** A branch of the facial nerve that physically **crosses** the tympanic cavity, passing between the incus and the handle of the malleus. It is a true content. ### **NEET-PG High-Yield Pearls** * **Contents Summary:** The middle ear contains 3 ossicles (Malleus, Incus, Stapes), 2 muscles (Stapedius, Tensor tympani), 2 nerves (Chorda tympani, Tympanic plexus), and air [2], [3]. * **Clinical Correlation:** In chronic suppurative otitis media (CSOM), the facial nerve is at risk if the bony canal is eroded, leading to facial palsy. * **Nerve Supply:** Stapedius is supplied by the Facial nerve; Tensor tympani is supplied by the Mandibular nerve (V3).

Question 247: The nerve of Wrisberg contains all of the following except:

A. Motor fibers (Correct Answer)
B. Sympathetic fibers
C. Secretory fibers
D. Parasympathetic fibers

Explanation: The **Nerve of Wrisberg** (also known as the **Nervus Intermedius**) is the smaller, sensory, and parasympathetic root of the Facial Nerve (CN VII). It emerges from the brainstem between the motor root of the facial nerve and the vestibulocochlear nerve (CN VIII). ### Why "Motor fibers" is the correct answer: The facial nerve has two distinct roots: 1. **The Motor Root:** Carries special visceral efferent (SVE) fibers to the muscles of facial expression. 2. **The Nervus Intermedius (Nerve of Wrisberg):** Carries all other components **except** the motor fibers to facial muscles. Therefore, motor fibers are not a constituent of the Nerve of Wrisberg. ### Explanation of other options: * **Parasympathetic/Secretory fibers:** These are General Visceral Efferent (GVE) fibers. They provide secretomotor supply to the lacrimal, submandibular, and sublingual glands, as well as the glands of the nose and palate. * **Sympathetic fibers:** The nerve of Wrisberg often carries hitchhiking sympathetic fibers from the carotid plexus to their target organs. * **Sensory fibers (Not listed but relevant):** It also carries Special Visceral Afferent (SVA) fibers for **taste** from the anterior two-thirds of the tongue and General Somatic Afferent (GSA) fibers from the external auditory canal. ### High-Yield Clinical Pearls for NEET-PG: * **Origin:** It arises from the **nervus intermedius** portion of the facial nerve. * **Nuclei involved:** Superior salivatory nucleus (parasympathetic) and Nucleus tractus solitarius (taste). * **Geniculate Ganglion:** This is where the cell bodies of the sensory fibers within the nerve of Wrisberg are located. * **Clinical Correlation:** Lesions of the nervus intermedius can lead to **Ramsay Hunt Syndrome** (if involving Herpes Zoster), characterized by loss of taste and decreased lacrimation/salivation, alongside a vesicular rash.

Question 248: What are the branches of the facial nerve?

A. Digastric
B. Stylohyoid
C. Posterior auricular
D. All of the above (Correct Answer)

Explanation: The **Facial Nerve (CN VII)** is a mixed nerve that provides motor innervation to the muscles of facial expression. To understand its branches, it is essential to distinguish between those given off **within the skull**, **after exiting the stylomastoid foramen**, and **within the parotid gland**. ### **Explanation of the Correct Answer** The correct answer is **D (All of the above)** because all three listed options are branches given off by the facial nerve immediately after it exits the skull through the **stylomastoid foramen**, but *before* it enters the parotid gland: 1. **Posterior Auricular Nerve:** Supplies the auricularis posterior muscle and the occipital belly of the occipitofrontalis. 2. **Nerve to Stylohyoid:** Supplies the stylohyoid muscle. 3. **Nerve to Digastric:** Specifically supplies the **posterior belly** of the digastric muscle. ### **Analysis of Options** * **A, B, and C:** These are all correct extracranial branches. Since the question asks for the branches of the facial nerve and all three are valid, "All of the above" is the most accurate choice. ### **High-Yield NEET-PG Pearls** * **Intracranial Branches:** Remember the mnemonic **"GSPN"** (Greater Petrosal, Nerve to Stapedius, and Chorda Tympani). * **Terminal Branches:** Once inside the parotid gland, the nerve forms the *parotid plexus* and divides into five terminal branches: **T**emporal, **Z**ygomatic, **B**uccal, **M**arginal mandibular, and **C**ervical (**T**en **Z**ebras **B**it **M**y **C**ookie). * **Clinical Correlation:** In **Bell’s Palsy** (lower motor neuron lesion), there is paralysis of all muscles of facial expression on the affected side, loss of taste (chorda tympani), and hyperacusis (nerve to stapedius). * **Embryology:** The facial nerve is the nerve of the **2nd Pharyngeal Arch**. Therefore, it supplies all muscles derived from this arch (Stapedius, Stylohyoid, Posterior Digastric, and Muscles of Facial Expression).

Question 249: What type of epithelium lines the vocal cords?

A. Pseudostratified columnar
B. Stratified squamous (Correct Answer)
C. Simple columnar
D. Cuboidal epithelium

Explanation: The larynx is primarily lined by **respiratory epithelium** (ciliated pseudostratified columnar epithelium). However, the **vocal cords (true vocal folds)** are a notable exception. They are lined by **stratified squamous non-keratinized epithelium**. [1] **Why Stratified Squamous?** The vocal cords are subject to significant mechanical stress and constant friction during phonation (vibration). Stratified squamous epithelium is structurally designed to provide protection against such physical wear and tear, whereas delicate respiratory epithelium would be easily damaged. [1] **Analysis of Incorrect Options:** * **A. Pseudostratified columnar:** This is the standard respiratory epithelium found in the rest of the larynx (supraglottis and subglottis), trachea, and bronchi. * **C & D. Simple columnar/Cuboidal:** These are typically found in secretory surfaces or ducts (e.g., GI tract or renal tubules) and lack the protective layers required for the high-impact environment of the glottis. **High-Yield Clinical Pearls for NEET-PG:** * **Transition Zone:** The change from stratified squamous to pseudostratified columnar epithelium occurs at the junction of the vocal folds and the subglottis. * **Reinke’s Space:** This is a potential space between the vocal ligament and the overlying squamous epithelium. Accumulation of fluid here leads to **Reinke’s Edema**, often seen in chronic smokers. * **Laryngeal Cancer:** Because the vocal cords are lined by squamous cells, the most common histological type of laryngeal cancer is **Squamous Cell Carcinoma (SCC)**. * **Other Squamous Sites in Respiratory Tract:** The **epiglottis** (lingual surface and upper part of laryngeal surface) also features stratified squamous epithelium due to its contact with food.

Question 250: What nerve provides special sensory supply to the marked area?

A. Hypoglossal
B. Lingual
C. Chorda tympani (Correct Answer)
D. Glossopharyngeal

Explanation: ***Chorda tympani*** - Provides **special sensory (taste)** supply to the **anterior two-thirds** of the tongue, which is the marked area in question. - A branch of the **facial nerve (CN VII)** that joins the **lingual nerve** to carry taste fibers from the anterior tongue. *Hypoglossal* - The **hypoglossal nerve (CN XII)** provides **motor innervation** to the intrinsic and extrinsic muscles of the tongue, not sensory supply. - Has no role in **taste sensation** or special sensory functions of the tongue. *Lingual* - The **lingual nerve** provides **general sensation** (touch, temperature, pain) to the anterior two-thirds of the tongue, not taste. - A branch of the **mandibular division of trigeminal nerve (CN V3)** that carries general sensory fibers only. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** provides **special sensory (taste)** supply to the **posterior one-third** of the tongue, not the anterior portion. - Also provides **general sensation** to the posterior third of the tongue and **motor supply** to stylopharyngeus muscle.

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