Which anatomical structure lies between the bulla ethmoidalis and the uncinate process of the ethmoid?
What lies between the middle and inferior turbinate?
What is the narrowest part of the nasal cavity?
In a patient with chronic sinusitis, which of the following structures is associated with the presence of ethmoidal bullae?
What is the type of epithelium of the adenoid?
Lens is attached to ciliary body via?
Anterior tonsillar pillar is formed by?
Which of the following is not an extrinsic laryngeal membrane?
Which is the narrowest portion of the esophagus?
The main muscle affected in congenital muscular torticollis is?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 141: Which anatomical structure lies between the bulla ethmoidalis and the uncinate process of the ethmoid?
- A. Ethmoidal infundibulum (Correct Answer)
- B. Bulla ethmoidalis
- C. Uncinate process of ethmoid
- D. Maxillary sinus
Explanation: ***Ethmoidal infundibulum*** - The **ethmoidal infundibulum** is a curved, three-dimensional space located within the **lateral wall of the nasal cavity**. - It forms a critical drainage pathway, often leading to the opening of the **maxillary sinus** and serving as the primary outflow tract for the anterior ethmoidal air cells. *Bulla ethmoidalis* - The **bulla ethmoidalis** is the largest and most constant anterior ethmoid air cell, bulging into the middle meatus. - It lies *superior and posterior* to the ethmoidal infundibulum, forming one of its boundaries, not the space itself. *Uncinate process of ethmoid* - The **uncinate process** is a sickle-shaped bony lamella that forms the *anterior and inferior boundary* of the ethmoidal infundibulum. - It helps define the pathway for drainage but is a bony structure, not the intervening space. *Maxillary sinus* - The **maxillary sinus** is a paranasal sinus located within the maxilla, which drains into the posterior part of the ethmoidal infundibulum or hiatus semilunaris. - It is a separate air-filled cavity, not the anatomical space between the bulla ethmoidalis and uncinate process.
Question 142: What lies between the middle and inferior turbinate?
- A. Middle meatus (Correct Answer)
- B. Superior meatus
- C. Inferior meatus
- D. Hiatus semilunaris
Explanation: ***Middle meatus*** - The **nasal meatuses** are passages in the nasal cavity that lie inferolateral to a corresponding **turbinate**. - Therefore, the **middle meatus** is located directly beneath the **middle turbinate** and superior to the **inferior turbinate**. *Superior meatus* - The **superior meatus** lies below the **superior turbinate**. - It drains the posterior ethmoid air cells and the sphenoid sinus. *Hiatus semilunaris* - The **hiatus semilunaris** is a curved opening located within the **middle meatus**. - It is an important drainage pathway for the frontal sinus, maxillary sinus, and anterior ethmoid air cells. *Inferior meatus* - The **inferior meatus** lies below the **inferior turbinate**. - It receives the opening of the **nasolacrimal duct**.
Question 143: What is the narrowest part of the nasal cavity?
- A. Vestibule
- B. Choanae
- C. Inferior turbinate
- D. Internal nasal valve area (Correct Answer)
Explanation: ***Internal nasal valve area*** - The **internal nasal valve** (ostium internum) is the **narrowest part of the nasal cavity**, located approximately 1.3 cm from the nostril - Formed by the **septal cartilage medially**, **upper lateral cartilage laterally**, **nasal floor inferiorly**, and **anterior head of inferior turbinate posteriorly** - The angle between the septum and upper lateral cartilage is typically **10-15 degrees**, creating the narrowest cross-sectional area - Accounts for approximately **50% of total nasal airway resistance** and is clinically the most critical site for airflow regulation - **Clinical significance**: Site of nasal valve collapse in breathing disorders *Vestibule* - The **nasal vestibule** is the most anterior part of the nasal cavity lined with **keratinized stratified squamous epithelium** and **vibrissae** (nasal hairs) - While it is a narrow region, it is **NOT the narrowest part** of the nasal cavity - Acts as the entrance to the nasal cavity but has a larger cross-sectional area than the internal nasal valve *Choanae* - The **choanae** are the **posterior openings** of the nasal cavity that open into the nasopharynx - They represent a transition point for airflow but are relatively **wide openings**, not the narrowest part *Inferior turbinate* - The **inferior turbinate** is a bony projection covered with erectile tissue that increases surface area for warming and humidifying air - While it can become engorged and narrow the airway pathologically, anatomically it does not constitute the narrowest fixed point of the nasal passage
Question 144: In a patient with chronic sinusitis, which of the following structures is associated with the presence of ethmoidal bullae?
- A. Posterior ethmoidal air cells
- B. Anterior ethmoidal air cells (Correct Answer)
- C. Superior ethmoidal air cells
- D. Inferior ethmoidal air cells
Explanation: ***Anterior ethmoidal air cells*** - The **ethmoidal bulla** is the largest and most constant **anterior ethmoidal air cell**, located in the lateral wall of the middle meatus. - It is a key component of the **ostiomeatal complex** and its inflammation or blockage can contribute to chronic sinusitis by obstructing drainage pathways. - The ethmoidal bulla drains into the **middle meatus** via the hiatus semilunaris and is positioned superior to the uncinate process. *Posterior ethmoidal air cells* - These are located more posteriorly and drain into the **superior meatus**, not the middle meatus where the ethmoidal bulla drains. - The posterior cells are separated from the anterior cells by the **basal lamella of the middle turbinate. - The **ethmoidal bulla** is an anterior structure, clearly distinguished from the posterior ethmoidal cell group. *Superior ethmoidal air cells* - This is **not a standard anatomical classification** for ethmoidal air cells. - The ethmoid labyrinth is divided into **anterior and posterior groups**, not superior/inferior or middle classifications. - The ethmoidal bulla belongs to the anterior ethmoid complex. *Inferior ethmoidal air cells* - This is **not a recognized anatomical classification** for ethmoidal air cells. - Standard classification divides ethmoidal cells into **anterior** (including the bulla) and **posterior** groups. - The ethmoidal bulla is specifically an anterior ethmoidal air cell, the largest of this group.
Question 145: What is the type of epithelium of the adenoid?
- A. Pseudostratified ciliated columnar epithelium (Correct Answer)
- B. Non-keratinized squamous epithelium
- C. Cuboidal epithelium
- D. Columnar epithelium with goblet cells
Explanation: ***Pseudostratified ciliated columnar epithelium*** - The adenoid (pharyngeal tonsil) is located in the nasopharynx, which is part of the upper respiratory tract and is lined with **pseudostratified ciliated columnar epithelium** with goblet cells [1]. - This type of epithelium is also known as **respiratory epithelium**, and its cilia and mucus-producing goblet cells help to trap and clear inhaled particles and pathogens [1]. *Non-keratinized squamous epithelium* - This type of epithelium is found in areas subject to friction and abrasion, such as the oral cavity, oro- and laryngopharynx, and esophagus, not typically in the nasopharynx. - It provides protection but lacks the ciliated and mucus-producing cells necessary for clearing respiratory passages. *Cuboidal epithelium* - This epithelium is typically found in glands and ducts, secretory and absorptive surfaces, such as renal tubules and thyroid follicles. - It does not have the specialized functions (cilia, mucus production) required for the respiratory system's protective lining. *Columnar epithelium with goblet cells* - While the adenoid epithelium does contain **goblet cells** for mucus production, specifically stating "columnar epithelium" is not as precise as "pseudostratified ciliated columnar epithelium." - The key feature of being **pseudostratified** and **ciliated** is crucial for its function in the nasopharynx [1].
Question 146: Lens is attached to ciliary body via?
- A. Limbus
- B. Vitreous Humour
- C. Root of iris
- D. Zonular fibers (Correct Answer)
Explanation: ***Zonular fibers*** - The **suspensory ligaments** of the lens, known as zonular fibers (or **Zonules of Zinn**), connect the lens capsule to the ciliary body. - These fibers play a crucial role in **accommodation** by transmitting the tension from the ciliary muscle to the lens, causing it to change shape [2]. *Limbus* - The **limbus** is the junction between the cornea and the sclera, serving as a transitional zone [3]. - It does not directly attach the lens to the ciliary body but is an important anatomical landmark for eye surgery. *Vitreous Humour* - The **vitreous humor** is the clear, gel-like substance that fills the space between the lens and the retina [4]. - It maintains the shape of the eye and holds the retina in place, but it does not provide structural attachment for the lens. *Root of iris* - The **root of the iris** is the outermost part of the iris where it attaches to the ciliary body. - While it is adjacent to the ciliary body, it is the iris structure itself and does not serve to attach the lens [1].
Question 147: Anterior tonsillar pillar is formed by?
- A. Palatopharyngeal fold
- B. Palatoglossal fold (Correct Answer)
- C. Pterygopalatine arch
- D. Valleculae
Explanation: Palatoglossal fold - The palatoglossal fold (anterior faucial pillar) is formed by the mucous membrane covering the palatoglossus muscle. - It defines the anterior boundary of the tonsillar fossa, hence forming the anterior tonsillar pillar. - Clinical relevance: This landmark is important during tonsillectomy and for identifying peritonsillar abscess location. Palatopharyngeal fold - This fold is formed by the mucous membrane covering the palatopharyngeus muscle. - It forms the posterior boundary of the tonsillar fossa, thus being the posterior tonsillar pillar (posterior faucial pillar). Pterygopalatine arch - This is not a recognized anatomical structure related to the tonsillar region. - The term appears to conflate "pterygopalatine fossa" (a skull space) with the palatine arches (tonsillar pillars), making it an effective distractor. Valleculae - The valleculae are depressions located between the base of the tongue and the epiglottis. - They are part of the laryngopharynx involved in swallowing and are not associated with the tonsillar pillars.
Question 148: Which of the following is not an extrinsic laryngeal membrane?
- A. Quadrangular membrane (Correct Answer)
- B. Hyoepiglottic ligament
- C. Cricotracheal membrane
- D. Thyrohyoid membrane
Explanation: **Quadrangular membrane** - The quadrangular membrane is an **intrinsic laryngeal membrane**, originating and inserting within the larynx itself, forming the false vocal cords and epiglottic folds. - It does not connect the larynx to external structures like the hyoid bone or trachea. *Hyoepiglottic ligament* - This is an **extrinsic laryngeal ligament** that connects the anterior surface of the epiglottis to the body of the hyoid bone. - It helps anchor the epiglottis to a structure outside the larynx. *Cricotracheal membrane* - The cricotracheal membrane is an **extrinsic laryngeal membrane** connecting the inferior border of the cricoid cartilage of the larynx to the first tracheal ring. - It forms the connection between the larynx and the trachea, an external structure. *Thyrohyoid membrane* - This is an **extrinsic laryngeal membrane** that connects the superior border of the thyroid cartilage of the larynx to the first tracheal ring. - It provides a broad connection between the larynx and the hyoid bone, an external laryngeal structure.
Question 149: Which is the narrowest portion of the esophagus?
- A. At the diaphragmatic aperture
- B. At the cricopharyngeal sphincter (Correct Answer)
- C. At the crossing of the left main bronchus
- D. At the level of the aortic arch
Explanation: ***At the cricopharyngeal sphincter*** - This is the **upper esophageal sphincter (UES)**, representing the **narrowest point of the entire esophagus** with a diameter of approximately **14 mm**. - It is formed by the **cricopharyngeus muscle**, which remains tonically contracted at rest to prevent air entry into the esophagus during respiration. - Located approximately **15 cm from the incisor teeth** at the level of the **C6 vertebra**. - **Clinical significance**: This is the most common site for impaction of foreign bodies and is a critical point during endoscopy. *At the crossing of the left main bronchus* - This represents the **middle constriction** where the esophagus is indented by the **left main bronchus** (approximately 22-23 cm from incisors). - This is a point of **extrinsic compression** rather than an intrinsic anatomical narrowing. - Diameter here is approximately **15.5 mm**, making it wider than the upper esophageal sphincter. - Foreign bodies and food boluses may lodge here, but it is not the narrowest point. *At the level of the aortic arch* - The **aortic arch** causes significant indentation and extrinsic compression, adjacent to the bronchial constriction. - This is also part of the **middle constriction** of the esophagus. - Despite this indentation, the lumen diameter is still greater than at the cricopharyngeal sphincter. *At the diaphragmatic aperture* - The esophagus passes through the **esophageal hiatus** at the level of **T10 vertebra** (approximately 40 cm from incisors). - This represents the **lower constriction** with a diameter of approximately **16-19 mm**. - While clinically important for hiatal hernias and lower esophageal sphincter pathology, it is the **widest of the three anatomical constrictions**.
Question 150: The main muscle affected in congenital muscular torticollis is?
- A. Sternocleidomastoid (Correct Answer)
- B. Trapezius
- C. Scalenus Anticus
- D. Omohyoid
Explanation: ***Sternocleidomastoid*** - Congenital muscular torticollis (CMT) is primarily caused by **unilateral fibrosis and shortening of the sternocleidomastoid muscle (SCM)**. - This leads to the characteristic **head tilt towards the affected side** and **chin rotation to the opposite side**. *Trapezius* - The trapezius muscle is primarily involved in **shrugging the shoulders**, extending and rotating the head and neck, but is not the main muscle affected in CMT. - While it can become secondarily tight in response to persistent head positioning, it is **not the primary pathological muscle** in CMT. *Scalenus Anticus* - The scalenus anticus (anterior scalene muscle) is involved in **neck flexion and elevation of the first rib** during forced inspiration. - It plays a role in various neck pain syndromes and brachial plexus compression, but it is **not the defining muscle in congenital muscular torticollis**. *Omohyoid* - The omohyoid is a **strap muscle of the neck** that depresses the hyoid bone. - It has no primary involvement in the **pathophysiology or clinical presentation of congenital muscular torticollis**.