Risorius is a muscle of?
Which of the following is an operculated sulcus ?
What is the outer layer of the blastocyst called?
Corpora arenacea is seen in?
Waldeyer's fascia lies?
Which of the following is a tributary of the coronary sinus?
Which of the following is not a boundary of Koch's triangle?
Which is the primary segment of the liver drained by the right hepatic vein?
Where is the Bartholin gland situated?
Lymphatic drainage of cervix is to
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 51: Risorius is a muscle of?
- A. Mastication
- B. Deglutition
- C. Facial expression (Correct Answer)
- D. Eye movement
Explanation: Facial expression - The **risorius muscle** retracts the **corner of the mouth** laterally, contributing to smiling or grimacing. - It falls under the category of **mimetic muscles**, all of which are innervated by the **facial nerve (cranial nerve VII)**. *Mastication* - Muscles of mastication, such as the **masseter**, **temporalis**, and **pterygoids**, are primarily involved in **chewing** and moving the mandible. - These muscles are innervated by the **trigeminal nerve (cranial nerve V)**, not the facial nerve. *Deglutition* - Deglutition refers to the process of **swallowing**, involving muscles of the **pharynx** and **larynx**. - Examples include the **palatoglossus**, **stylopharyngeus**, and **superior pharyngeal constrictor**. *Eye movement* - Muscles responsible for eye movement are the **extrinsic ocular muscles**, such as the **recti** and **oblique muscles** [1]. - These muscles are innervated by the **oculomotor (III)**, **trochlear (IV)**, and **abducens (VI)** cranial nerves. *Note: No provided references mention the risorius muscle, mimetic muscles, or muscles of mastication; citations are applied only to supported sub-topics.*
Question 52: Which of the following is an operculated sulcus ?
- A. Lunate
- B. Calcarine
- C. Central
- D. Sylvian fissure (lateral sulcus) (Correct Answer)
Explanation: ***Sylvian fissure (lateral sulcus)*** - The **lateral sulcus**, also known as the Sylvian fissure, is a deep groove on the lateral surface of the brain that **separates the frontal and parietal lobes from the temporal lobe**. - It is considered an **operculated sulcus** because its banks contain the insula, which is a buried part of the cerebral cortex covered by the surrounding cortical folds called opercula. *Calcarine* - The **calcarine sulcus** is located on the medial surface of the occipital lobe, forming the primary visual cortex, and is not an operculated sulcus. - It delineates the **upper and lower banks of the visual cortex** and does not involve overlying cortical structures. *Lunate* - The **lunate sulcus** is found on the posterior part of the occipital lobe and is not typically described as an operculated sulcus. - It represents a boundary in the visual cortex, but its banks do not hide a buried cortical region like the insula. *Central* - The **central sulcus** (Rolandic fissure) separates the frontal lobe from the parietal lobe and is a prominent sulcus, but it is not operculated. - Its banks contain the **precentral gyrus** (primary motor cortex) and **postcentral gyrus** (primary somatosensory cortex) directly facing each other.
Question 53: What is the outer layer of the blastocyst called?
- A. Embryo proper
- B. Trophoblast (Correct Answer)
- C. Primitive streak
- D. Yolk sac
Explanation: ***Trophoblast*** - The **trophoblast** is the outer layer of cells of the blastocyst, which goes on to form the **placenta** and other extraembryonic tissues [1]. - It plays a crucial role in the **implantation** of the blastocyst into the uterine wall and in producing hormones [1]. *Primitive streak* - The **primitive streak** is a structure that forms during **gastrulation**, much later than the initial blastocyst stage. - It establishes the **anterior-posterior axis** and initiates the formation of the three germ layers. *Yolk sac* - The **yolk sac** is an extraembryonic membrane that forms within the blastocyst cavity, but it is not the outermost layer of the entire structure. - It is involved in early **nutrient transfer** and **blood cell formation** before the placenta is fully functional. *Embryo proper* - The **embryo proper**, derived from the **inner cell mass (ICM)**, is the part of the blastocyst that will develop into the actual embryo [2]. - It is located *inside* the trophoblast layer, not forming the outer boundary of the blastocyst [2].
Question 54: Corpora arenacea is seen in?
- A. Pineal (Correct Answer)
- B. Seminal vesicle
- C. Breast
- D. Prostate
Explanation: ***Pineal*** - **Corpora arenacea**, also known as **brain sand**, are calcium deposits found in the pineal gland. - Their presence is a normal, age-related finding and increases with age, though their exact physiological role is not fully understood. *Prostate* - The prostate gland contains **corpora amylacea**, which are concentric calcifications found within the glandular acini. - While similar in appearance to corpora arenacea, they are distinct structures specific to the prostate. *Seminal vesicle* - The seminal vesicles produce a fluid component of semen, and while they may occasionally show calcifications, these are typically due to stones or chronic inflammation, not the characteristic "brain sand" seen in the pineal gland. - They do not contain corpora arenacea as a normal physiological feature. *Breast* - Calcifications in the breast are common and can be either benign (e.g., **fibrocystic changes**, vascular calcifications) or malignant (e.g., **ductal carcinoma in situ**). - These calcifications are generally not referred to as corpora arenacea and have different clinical implications and microscopic appearances.
Question 55: Waldeyer's fascia lies?
- A. In front of the bladder.
- B. Behind the rectum. (Correct Answer)
- C. Between the bladder and uterus.
- D. Between the uterus and rectum.
Explanation: ***Behind the rectum*** - **Waldeyer’s fascia**, also known as the **sacrorectal fascia**, is a retrorectal connective tissue sheet located between the **rectum** and the **sacrum**. - It plays a crucial role in supporting the rectum and forms part of the posterior rectosacral space, separating the rectum from the sacral bone and nerves. *In front of the bladder* - The space in front of the bladder is typically referred to as the **retropubic space of Retzius**, containing loose connective tissue and fat. - No specific fascial layer named Waldeyer's fascia is located in this anterior position relative to the bladder. *Between the bladder and uterus* - This space, known as the **vesicouterine pouch** or **anterior cul-de-sac**, is a peritoneal reflection between the bladder and the uterus [1]. - It does not contain a structure known as Waldeyer's fascia. *Between the uterus and rectum* - This space is the **rectouterine pouch** or **Pouch of Douglas**, which is the deepest part of the peritoneal cavity in females [2]. - While important surgically, it does not correspond to the location of Waldeyer's fascia.
Question 56: Which of the following is a tributary of the coronary sinus?
- A. Anterior cardiac vein
- B. Smallest cardiac vein
- C. Thebesian vein
- D. Great cardiac vein (Correct Answer)
Explanation: ***Great cardiac vein*** - The **great cardiac vein** is a major tributary that drains into the **coronary sinus**, carrying deoxygenated blood from the anterior and left ventricular walls [1]. - It travels alongside the **anterior interventricular artery** (LAD) and then wraps around the left side of the heart to join the coronary sinus [1]. *Anterior cardiac vein* - The **anterior cardiac veins** typically collect blood directly into the **right atrium**, bypassing the coronary sinus [1]. - They primarily drain the anterior wall of the right ventricle. *Thebesian vein* - **Thebesian veins** (or venae cordis minimae) are small veins that drain blood from the **myocardium directly into the heart chambers**, predominantly the atria [1]. - They represent a direct communication between the myocardial capillaries and the heart chambers, not tributaries of the coronary sinus. *Smallest cardiac vein* - The term "smallest cardiac vein" is often used synonymously with **Thebesian veins** [1]. - These veins empty directly into the **heart chambers**, serving as an ancillary drainage system, rather than converging into the coronary sinus.
Question 57: Which of the following is not a boundary of Koch's triangle?
- A. Limbus fossa ovalis (Correct Answer)
- B. Tricuspid valve ring
- C. Coronary sinus
- D. Tendon of Todaro
Explanation: ***Limbus fossa ovalis*** - The **limbus fossa ovalis** is a prominent oval ridge on the **interatrial septum** that surrounds the fossa ovalis. - It is **not involved** in forming the boundaries of Koch's triangle, which is located in the **right atrium** near the AV node [1]. *Tricuspid valve ring* - The **tricuspid valve ring** (or annulus) forms one of the key anatomical boundaries of **Koch's triangle**, specifically its base [1]. - This **fibrous ring** anchors the tricuspid valve leaflets and marks the inferior aspect of the triangle [1]. *Coronary sinus* - The **coronary sinus ostium** (opening) forms another crucial boundary of **Koch's triangle** [1]. - It is located at the **inferior-posterior aspect** of the interatrial septum, opening into the right atrium [1]. *Tendon of todaro* - The **Tendon of Todaro** is a fibrous structure that forms the superior boundary of **Koch's triangle** [1]. - It extends from the **Eustachian valve** (of the inferior vena cava) towards the central fibrous body, playing a role in **AV nodal localization** [1].
Question 58: Which is the primary segment of the liver drained by the right hepatic vein?
- A. I
- B. II
- C. IV
- D. VII (Correct Answer)
Explanation: ***VII*** - The **right hepatic vein** drains the **posterior segment** of the right lobe, which includes segments **VI and VII**. Segment VII is particularly well-drained by this vein. [3] - Understanding hepatic venous drainage is crucial for **surgical planning** and interpreting imaging studies of the liver. [4] *I* - Segment I, the **caudate lobe**, is unique in its venous drainage, often by small veins directly into the **inferior vena cava (IVC)** or occasionally into the left and middle hepatic veins. [1] - It has a separate blood supply and drainage which differentiates it from other segments. [4] *II* - Segment II is part of the **left lateral segment** and is primarily drained by the **left hepatic vein**. - The left hepatic vein typically drains segments II and III. [2] *IV* - Segment IV, or the **quadrate lobe**, is primarily drained by the **middle hepatic vein**. - The middle hepatic vein also drains segment VIII and the anterior aspect of segment V.
Question 59: Where is the Bartholin gland situated?
- A. Superficial perineal pouch (Correct Answer)
- B. Deep perineal pouch
- C. Inguinal canal
- D. Ischiorectal fossa
Explanation: ***Superficial perineal pouch*** - The **Bartholin glands** are located posterolateral to the vaginal orifice within the boundaries of the **superficial perineal pouch** [1]. - They are covered by the **bulbospongiosus muscle** and their ducts open into the vestibule of the vagina [1]. *Deep perineal pouch* - This pouch contains structures like the **urethra**, part of the **vagina**, and the **deep transverse perineal muscle**, but not the Bartholin glands [2]. - It is located superior to the superficial perineal pouch and separated by the **perineal membrane**. *Inguinal canal* - The **inguinal canal** is a passage in the anterior abdominal wall that transmits the **round ligament of the uterus** in females and the **spermatic cord** in males. - It is anatomically distinct from the perineum and does not house the Bartholin glands. *Ischiorectal fossa* - The **ischiorectal fossae** are fat-filled spaces located lateral to the anal canal, inferior to the levator ani muscles. - They are known for their susceptibility to abscess formation but do not contain the Bartholin glands.
Question 60: Lymphatic drainage of cervix is to
- A. Iliac lymph nodes (Correct Answer)
- B. Para-aortic lymph nodes
- C. Deep inguinal lymph nodes
- D. Superficial inguinal lymph nodes
Explanation: ***Iliac lymph nodes*** - The primary lymphatic drainage of the cervix is to the **internal**, **external**, and **common iliac lymph nodes**. - This pathway is crucial for understanding the spread of **cervical cancer**. *Para-aortic lymph nodes* - While sometimes involved in advanced cases, the **para-aortic nodes** are typically considered a secondary drainage site, usually after the iliac nodes are affected. - They are the primary drainage for organs like the **ovaries** and **testes**. *Deep inguinal lymph nodes* - These nodes primarily drain structures of the **lower limb** and some external genital areas, but not the cervix directly. - They are located deeper in the groin region, distinct from the internal pelvic drainage. *Superficial inguinal lymph nodes* - These nodes drain the **skin of the lower abdomen**, perineum, and external genitalia, as well as the lower limbs. - They do not receive direct lymphatic drainage from the **cervix**.