Anatomy
8 questionsRight ovarian artery is a branch of ?
All are derived from ectoderm except for which of the following?
What is Little's area, also known as Kiesselbach's plexus?
Which of the following statements about the Corpus Callosum is correct?
What does Chamberlain's line refer to in anatomical terms?
What type of joint is the 1st carpometacarpal joint?
Coronary sinus develops from?
The right coronary artery supplies blood to all of the following structures, except?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 91: Right ovarian artery is a branch of ?
- A. Abdominal aorta (Correct Answer)
- B. Right internal iliac
- C. Common iliac
- D. External iliac
Explanation: ***Abdominal aorta*** - The **right ovarian artery** typically originates directly from the **abdominal aorta**, just inferior to the renal arteries [1]. - This is a direct branch, supplying blood to the **right ovary**, **fallopian tube**, and surrounding structures [1]. *Right internal iliac* - The **internal iliac artery** primarily supplies the **pelvic organs**, gluteal region, and medial thigh [1]. - While it has branches to pelvic structures, the ovarian artery does not originate from it. *Common iliac* - The **common iliac artery** bifurcates into the **internal and external iliac arteries** at the level of the sacroiliac joint. - It does not directly give off the ovarian artery. *External iliac* - The **external iliac artery** continues as the **femoral artery** below the inguinal ligament, primarily supplying the lower limb. - It does not give off branches to the ovary.
Question 92: All are derived from ectoderm except for which of the following?
- A. Hair follicles
- B. Nails
- C. Lens of the eye
- D. Adrenal cortex (Correct Answer)
Explanation: ***Adrenal cortex*** - The adrenal cortex is derived from the **intermediate mesoderm**, specifically from the cells lining the posterior abdominal wall. The cells migrate to develop into the adrenal cortex. - It produces various steroid hormones, including **aldosterone**, **cortisol**, and **androgens**, which regulate diverse bodily functions. *Lens of the eye* - The lens of the eye is derived from the **surface ectoderm**. It forms from an invagination of the surface ectoderm called the lens placode. - Its primary function is to **focus light** onto the retina. *Hair follicles* - Hair follicles develop from the **surface ectoderm** [1]; they are invaginations of the epidermis that extend into the dermis. - They produce hair, which provides **insulation** and **protection** [1]. *Nails* - Nails are also derivatives of the **surface ectoderm**, forming thickened plates on the dorsal surface of the distal phalanges. - They provide **protection** to the fingertips and aid in grasping objects.
Question 93: What is Little's area, also known as Kiesselbach's plexus?
- A. Anteroinferior lateral wall
- B. Anteroinferior nasal septum (Correct Answer)
- C. Posteroinferior lateral wall
- D. Posteroinferior nasal septum
Explanation: ***Anteroinferior nasal septum*** - **Little's area**, or **Kiesselbach's plexus**, is a well-vascularized region located on the **anteroinferior portion of the nasal septum**. - This area is a common site for **anterior epistaxis** (nosebleeds) due to its superficial position and rich anastomotic blood supply from several arteries. *Anteroinferior lateral wall* - While the lateral nasal wall also contributes to the nasal blood supply, the specific region of **Little's area** is on the **septum**, not the lateral wall. - The **lateral wall** contains structures like the turbinates and their associated vascular networks, which are distinct from Kiesselbach's plexus. *Posteroinferior lateral wall* - The **posterior and inferior aspects** of the nasal cavity are not where Kiesselbach's plexus is predominantly located. - Bleeding from this posterior region often indicates **posterior epistaxis**, which can be more severe and difficult to control. *Posteroinferior nasal septum* - The **posterior nasal septum** is supplied by different arteries, such as branches of the **sphenopalatine artery**. - Bleeding from this part of the septum is also considered **posterior epistaxis** and is not typically associated with Kiesselbach's plexus.
Question 94: Which of the following statements about the Corpus Callosum is correct?
- A. All of the options
- B. Connects distant areas of the two sides of the brain
- C. Connects the two frontal lobes
- D. Connects the left and right hemispheres (Correct Answer)
Explanation: ***Connects the left and right hemispheres*** - The **corpus callosum** is the largest **commissural white matter tract** in the brain, uniquely designed to facilitate communication between the **corresponding regions** of the left and right cerebral hemispheres [1]. - Its primary function is to integrate **sensory, motor, and cognitive information** processed in each hemisphere, ensuring coordinated brain activity [1]. *Connects distant areas of the two sides of the brain* - While it connects regions on the two sides of the brain, the statement is too broad and does not specify its role in connecting **corresponding** or **homologous** areas across the hemispheres. - Other fiber tracts (e.g., **anterior commissure**) also connect different areas between the two sides, but the corpus callosum is specific to the **cerebral hemispheres**. *Connects the two frontal lobes* - The corpus callosum connects all four lobes (frontal, parietal, temporal, occipital) between the two hemispheres, not exclusively the **frontal lobes**. - While it does contain fibers connecting the frontal lobes, this statement is **incomplete** and does not capture its overall function. *All of the options* - Since the other options are either **incorrect** or **incomplete**, this option cannot be correct. - The most accurate and encompassing description of the corpus callosum's function among the choices is connecting the left and right hemispheres.
Question 95: What does Chamberlain's line refer to in anatomical terms?
- A. Palate to occiput
- B. Palate to temporal
- C. Palate to foramen magnum (Correct Answer)
- D. Palate to parietal
Explanation: ***Palate to foramen magnum*** - **Chamberlain's line** is a measurement used in radiology to assess for **basilar invagination** or impression. - It extends from the **posterior margin of the hard palate** to the **posterior lip of the foramen magnum**. *Palate to occiput* - This description is too general and does not precisely define Chamberlain's line, which specifically uses the **posterior lip of the foramen magnum** as its posterior anchor point. - While the foramen magnum is within the occipital bone, "occiput" can refer to a broader area. *Palate to temporal* - The **temporal bone** is not part of the anatomical landmarks used for Chamberlain's line. - This line is focused on structures in the midline skull base. *Palate to parietal* - The **parietal bone** is located superiorly and laterally to the structures involved in Chamberlain's line. - It is not used as a landmark for this specific measurement.
Question 96: What type of joint is the 1st carpometacarpal joint?
- A. Pivot
- B. Hinge
- C. Ball and Socket
- D. Saddle (Correct Answer)
Explanation: ***Saddle*** - The **1st carpometacarpal joint** (thumb CMC joint) is a classic example of a **saddle joint** due to the reciprocal concave-convex opposing surfaces of the trapezium and the first metacarpal [1]. - This unique shape allows for a wide range of motion, including **flexion/extension**, **abduction/adduction**, and **opposition**, which is crucial for thumb function. *Pivot* - A **pivot joint** allows for rotational movement around a single axis, like the **atlantoaxial joint** (C1-C2) or the **proximal radioulnar joint**. - This type of motion is not characteristic of the 1st carpometacarpal joint. *Hinge* - A **hinge joint** permits movement in only one plane, like the **elbow** or **interphalangeal joints**, allowing for **flexion and extension**. - The 1st carpometacarpal joint has a greater degree of freedom than a hinge joint. *Ball and Socket* - A **ball and socket joint** offers the greatest range of motion, allowing for movement in all planes, including **circumduction and rotation**, such as the **shoulder** and **hip joints**. - While the 1st carpometacarpal joint is highly mobile, it does not achieve the full range of motion of a ball and socket joint.
Question 97: Coronary sinus develops from?
- A. Truncus arteriosus
- B. Conus
- C. Sinus venosus (Correct Answer)
- D. AV canal
Explanation: Sinus venosus - The sinus venosus is a primordial cardiac chamber that receives venous blood from the body and placenta in the early embryonic heart. - The left horn of the sinus venosus loses its connection with the systemic venous circulation and becomes the coronary sinus, which drains most of the cardiac veins into the right atrium [1, 4]. Truncus arteriosus - The truncus arteriosus is the embryonic precursor to the ascending aorta and pulmonary trunk. - It does not contribute to the development of the coronary sinus. Conus - The conus (or conus cordis) is the outflow portion of the primitive ventricle and differentiates into the outflow tracts of the right (infundibulum) and left (aortic vestibule) ventricles. - It is not involved in the formation of the coronary sinus. AV canal - The atrioventricular (AV) canal connects the primitive atrium and ventricle and is crucial for the formation of the AV valves and septation of the heart chambers. - It does not directly develop into the coronary sinus.
Question 98: The right coronary artery supplies blood to all of the following structures, except?
- A. Posterior wall of left ventricle
- B. SA node
- C. Anterior 2/3 of ventricular septum (Correct Answer)
- D. AV node
Explanation: ***Anterior 2/3 of ventricular septum*** - The **anterior two-thirds of the interventricular septum** is primarily supplied by the **septal branches of the left anterior descending artery** (LAD) [1], a branch of the left coronary artery. - Therefore, the right coronary artery does not typically supply this region. *SA node* - The **SA node** (sinoatrial node) is the heart's natural pacemaker and receives its blood supply from the **right coronary artery** in about 60% of individuals. - Occlusion of the RCA can lead to symptomatic **bradycardia** or **SA node dysfunction**. *AV node* - The **AV node** (atrioventricular node), crucial for coordinating ventricular contraction, is supplied by the **right coronary artery** in approximately 90% of individuals [1]. - Infarcts in the RCA territory can manifest as various degrees of **heart block**. *Posterior wall of left ventricle* - The **posterior wall of the left ventricle** is predominantly supplied by the **posterior descending artery (PDA)**, which in about 80% of people, is a terminal branch of the **right coronary artery** [1]. - This supply is vital for the contractile function of the left ventricle's posterior aspect.
Physiology
1 questionsWhat is the consequence of tibial nerve injury/palsy?
NEET-PG 2012 - Physiology NEET-PG Practice Questions and MCQs
Question 91: What is the consequence of tibial nerve injury/palsy?
- A. Loss of plantar flexion (Correct Answer)
- B. Dorsiflexion of foot at ankle joint
- C. Loss of sensation of dorsum of foot
- D. Paralysis of muscles of anterior compartment of leg
Explanation: **Loss of plantar flexion** - The **tibial nerve** innervates the muscles of the **posterior compartment of the leg**, which are primarily responsible for **plantar flexion** of the foot. - Injury to this nerve directly impairs the function of muscles like the gastrocnemius, soleus, and tibialis posterior, leading to a significant loss of the ability to point the foot downwards. *Dorsiflexion of foot at ankle joint* - **Dorsiflexion** is primarily mediated by muscles in the **anterior compartment of the leg**, such as the tibialis anterior, which are innervated by the **deep fibular nerve**. - Tibial nerve injury would not directly affect these muscles or their function; rather, it leads to issues with the opposing action. *Loss of sensation of dorsum of foot* - Sensation to the **dorsum of the foot** is primarily supplied by the **superficial fibular nerve** (for most of the dorsum) and the **deep fibular nerve** (for the first web space). - While the tibial nerve provides sensation to the sole of the foot, it does not typically innervate the dorsum. *Paralysis of muscles of anterior compartment of leg* - The muscles of the **anterior compartment of the leg** (e.g., tibialis anterior, extensor digitorum longus, extensor hallucis longus) are innervated by the **deep fibular nerve**. - A tibial nerve injury would paralyze muscles in the posterior compartment, not the anterior compartment.
Surgery
1 questionsWhat is the appropriate treatment for an incidentally detected appendicular carcinoid tumor measuring 2.5 cm?
NEET-PG 2012 - Surgery NEET-PG Practice Questions and MCQs
Question 91: What is the appropriate treatment for an incidentally detected appendicular carcinoid tumor measuring 2.5 cm?
- A. Right hemicolectomy (Correct Answer)
- B. Limited resection of the right colon
- C. Total colectomy
- D. Appendicectomy
Explanation: ***Right hemicolectomy*** - An appendiceal carcinoid tumor **larger than 2 cm** (or with **mesoappendix invasion, positive margins, or high-grade features**) warrants a right hemicolectomy due to a significantly higher risk of lymph node metastasis (20-30%). - This 2.5 cm tumor clearly exceeds the 2 cm threshold, making right hemicolectomy the standard of care. - This procedure ensures adequate oncological margins and removal of regional lymph nodes, which is crucial for complete treatment. *Limited resection of the right colon* - This option is insufficient for an appendiceal carcinoid of this size, as it may not remove all regional lymph nodes or provide adequate oncological margins. - Limited resection lacks the systematic lymphadenectomy required for tumors exceeding 2 cm. *Total colectomy* - This is an **overly aggressive** and unnecessary procedure for an isolated appendiceal carcinoid tumor, even one of this size. - Total colectomy is typically reserved for diffuse colonic involvement, multifocal tumors, or specific genetic syndromes, which is not indicated here. *Appendicectomy* - An appendicectomy alone is only appropriate for very small appendiceal carcinoid tumors, typically **less than 1 cm** in size, with negative margins and without evidence of mesoappendix invasion or aggressive features. - For a 2.5 cm tumor, the risk of regional lymph node involvement (20-30%) is too high for appendicectomy to be considered adequate oncological treatment.