What is the shape of caecum in the newborn?
Embryo gets implanted at what stage of development?
Traumatic optic neuropathy due to closed head trauma commonly affects which part of the optic nerve?
Which of the following statements about the bare area of the liver is false?
Cephalic index is calculated as
Which bones form the floor of the nasal cavity in children?
Which of the following structures is present in an XY child but absent in an XX child?
Which part of the bone is considered the most vascular zone?
Most common location of ectopic salivary gland is -
Anterior Mediastinal nodes are included in which level of lymph nodes?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 151: What is the shape of caecum in the newborn?
- A. Ovoid
- B. Trapezoid
- C. Globular
- D. Conical (Correct Answer)
Explanation: ***Conical*** - In newborns, the **caecum** is typically described as having a **conical** shape. - This shape gradually changes as the individual grows and develops. *Ovoid* - The ovoid shape is more characteristic of the adult **caecum**, which tends to be broader and less pointed. - This shape is not typically observed in newborns. *Globular* - A globular shape implies a more rounded and spherical form, which is not accurate for the newborn **caecum**. - This term is sometimes used to describe the general appearance of some organs but not the specific shape of the neonatal caecum. *Trapezoid* - A trapezoid shape is defined by four sides with at least one pair of parallel sides, which does not accurately describe the normal anatomical configuration of the **caecum** at any age. - This shape is completely inconsistent with the morphology of the **caecum**.
Question 152: Embryo gets implanted at what stage of development?
- A. Two cell stage
- B. Four cell stage
- C. Morula
- D. Blastocyst (Correct Answer)
Explanation: Blastocyst - Implantation into the uterine wall occurs when the embryo has developed into a blastocyst, typically around day 6 post-fertilization [1]. - The blastocyst consists of an inner cell mass (which forms the embryo) and an outer layer called the trophoblast (which contributes to the placenta) [1]. Two cell stage - This stage occurs very early in development, usually within the first 24-30 hours after fertilization [1]. - At this point, the embryo is still in the fallopian tube and has not yet reached the uterus for implantation [1]. Four cell stage - The four-cell stage is also an early cleavage stage, occurring around 2 days post-fertilization [1]. - Like the two-cell stage, the embryo is still in transport through the fallopian tube and is not ready for implantation [1]. Morula - The morula is a solid ball of cells formed by cleavage, typically around day 3-4 post-fertilization [1]. - While it has moved closer to the uterus, it has not yet formed the distinct inner cell mass and trophoblast necessary for successful implantation [1].
Question 153: Traumatic optic neuropathy due to closed head trauma commonly affects which part of the optic nerve?
- A. Optic canal (Correct Answer)
- B. Intraocular part
- C. Intracranial part
- D. Optic tract
Explanation: ***Optic canal*** - The **optic nerve** is highly susceptible to injury within the **optic canal** due to its tight anatomical confines and the close proximity of the optic nerve to rigid bone. - Trauma to this region can lead to direct compression, shearing injury, or ischemia from damage to surrounding vasculature, resulting in significant visual impairment. *Intra ocular part* - The intraocular part of the optic nerve, including the **optic disc**, is typically protected by the globe and orbit against blunt trauma. - Direct intraocular trauma, such as a penetrating injury, would be required to significantly affect this segment, which is not usually the cause in closed head trauma. *Intracranial part* - The intracranial part of the optic nerve is relatively mobile within the cerebrospinal fluid and is less prone to direct compression or shearing forces from closed head trauma compared to the optic canal. - While it can be affected by diffuse axonal injury or mass effects within the cranium, it is not the most commonly affected segment for traumatic optic neuropathy in closed head injuries. *Optic tract* - The **optic tract** lies posterior to the optic chiasm and is part of the central nervous system pathways for vision, not the optic nerve itself. - Injuries to the optic tract are more likely to cause homonymous hemianopia rather than the profound unilateral vision loss characteristic of traumatic optic neuropathy, and are generally less vulnerable to direct mechanical trauma from closed head injury.
Question 154: Which of the following statements about the bare area of the liver is false?
- A. It is circular in shape (Correct Answer)
- B. It is not a site of portocaval anastomosis
- C. Formed by the reflections of coronary ligaments
- D. Infection can spread from the abdominal to thoracic cavity at this area
Explanation: ***It is circular in shape*** - The bare area of the liver is **triangular** in shape, bordered by the reflections of the **coronary ligaments** and the inferior vena cava. [1] - Its shape is dictated by the anatomical arrangement of these peritoneal folds, making it distinctly non-circular. *Infection can spread from the abdominal to thoracic cavity at this area* - This statement is true because the bare area is the only part of the liver not covered by **peritoneum**, allowing direct contact between the liver and the diaphragm. [1] - This anatomical arrangement facilitates the spread of infections, like **subphrenic abscesses**, from the abdominal cavity to the posterior mediastinum and pleural cavity. [2] *It is not a site of portocaval anastomosis* - This statement is true; there is **no direct portosystemic shunt** at the bare area of the liver that becomes significant in portal hypertension. - While small veins connect the liver capsule to the diaphragm, these do not represent major portocaval anastomoses like those found at the gastroesophageal junction or rectum. *Formed by the reflections of coronary ligaments* - This statement is true; the bare area is specifically demarcated by the points where the **anterior and posterior layers of the coronary ligament** diverge, leaving a triangular region of the liver directly apposed to the diaphragm. [1] - The **coronary ligaments** are reflections of the peritoneum from the diaphragm onto the superior surface of the liver.
Question 155: Cephalic index is calculated as
- A. Biparietal Diameter / Occipitofrontal Diameter (Correct Answer)
- B. Biparietal Diameter / Head Circumference
- C. Head Circumference / Femur Length
- D. Occipitofrontal Diameter / Biparietal Diameter
Explanation: ***Biparietal Diameter / Occipitofrontal Diameter*** - The **cephalic index** is a measure used in **craniometry** to describe the shape of the skull, calculated by dividing the maximum **biparietal diameter** (width) by the maximum **occipitofrontal diameter** (length) and multiplying by 100. [1] - This ratio helps classify head shapes into **brachycephalic** (short, wide), **mesocephalic** (medium), and **dolichocephalic** (long, narrow). *Biparietal Diameter / Head Circumference* - This ratio is not the standard definition for the **cephalic index**; head circumference is a measure of overall head size, not its proportional shape in terms of width to length. - While both parameters are used in fetal biometry, their ratio does not define the **cephalic index**. *Head Circumference / Femur Length* - This ratio is completely unrelated to the **cephalic index**. - **Head circumference** estimates head size, and **femur length** estimates fetal long bone growth, both used for gestational age assessment, but not for skull shape. *Occipitofrontal Diameter / Biparietal Diameter* - This formula represents the inverse of the **cephalic index**, which would yield a different and non-standard index for skull shape. - The traditional and medically recognized formula for the **cephalic index** places the **biparietal diameter** in the numerator.
Question 156: Which bones form the floor of the nasal cavity in children?
- A. Nasal bone and maxilla
- B. Vomer and ethmoid
- C. Palatine process of the maxilla and horizontal plate of the palatine bone (Correct Answer)
- D. Nasal crest of maxilla and palatine process of maxilla
Explanation: ***Palatine process of the maxilla and horizontal plate of the palatine bone*** - These two bones form the **hard palate**, which also serves as the **floor of the nasal cavity**. - The **palatine process of the maxilla** forms the anterior two-thirds, while the **horizontal plate of the palatine bone** forms the posterior one-third of the hard palate. *Vomer and ethmoid* - The **vomer** and part of the **ethmoid bone** (specifically the perpendicular plate) contribute to the **nasal septum**, which divides the nasal cavity. - They do not form the floor of the nasal cavity. *Nasal bone and maxilla* - The **nasal bones** form the **bridge of the nose** and part of the roof of the nasal cavity anteriorly. - While the **maxilla** contributes to the floor via its palatine process, the nasal bones do not. *Nasal crest of maxilla and palatine process of maxilla* - The **palatine process of the maxilla** does form part of the floor of the nasal cavity. - However, the **nasal crest of the maxilla** is part of the vomer's articulation and is involved in the septum, not the primary floor structure.
Question 157: Which of the following structures is present in an XY child but absent in an XX child?
- A. Urethral glands (Cowper's glands)
- B. Prostate gland (Correct Answer)
- C. Ovaries
- D. Vestibular glands (Bartholin's glands)
Explanation: ***Prostate gland*** - The **prostate gland** is the most characteristic male-specific accessory reproductive organ that is **definitively present in XY and absent in XX individuals**. - It develops from the **urogenital sinus** under the influence of **dihydrotestosterone (DHT)** during embryonic development. - The prostate is a **substantial glandular structure** that surrounds the urethra and produces approximately 30% of seminal fluid. - It has **no homologous structure in females**—there is no female equivalent organ. *Incorrect: Urethral glands (Cowper's glands)* - **Cowper's glands (bulbourethral glands)** are indeed male-specific structures present only in XY individuals. - However, they are **homologous to Bartholin's glands** in females—meaning both develop from similar embryonic tissue (urogenital sinus). - While the question technically could accept this answer, the **prostate gland is the more definitive answer** as it is larger, more clinically significant, and has no female homologue. - Cowper's glands are small pea-sized glands that contribute to pre-ejaculate fluid. *Incorrect: Ovaries* - **Ovaries** are the primary female gonads present in **XX individuals**, not XY individuals [1]. - They produce ova and female sex hormones (estrogen and progesterone) [1]. - In XY individuals, the **testes** develop instead under the influence of the SRY gene. *Incorrect: Vestibular glands (Bartholin's glands)* - **Bartholin's glands** are female-specific structures present in **XX individuals**, not XY individuals. - Located at the posterior vaginal opening, they secrete mucus for vaginal lubrication. - They are homologous to Cowper's glands in males but are distinct structures.
Question 158: Which part of the bone is considered the most vascular zone?
- A. Metaphysis (Correct Answer)
- B. Diaphysis
- C. Epiphysis
- D. Medullary Cavity
Explanation: ***Metaphysis*** - The metaphysis is the most **vascular** part of the bone, containing numerous blood vessels that supply the growing bone. - This high vascularity makes it a common site for **osteomyelitis** and bone tumors due to the abundant blood supply [1]. *Diaphysis* - The diaphysis is the **shaft** or central part of a long bone, primarily composed of **compact bone** [2]. - While it has blood supply through nutrient arteries, its vascularity is less dense compared to the metaphysis. *Epiphysis* - The epiphysis is the **end portion** of a long bone, typically covered by articular cartilage. - It receives its blood supply from periarticular vessels, but is less vascular than the metaphysis, especially in mature bone. *Medullary Cavity* - The medullary cavity is the central cavity of bone shafts where **bone marrow** is stored [2]. - While it contains hematopoietic stem cells and a rich blood supply, the surrounding bone tissue of the metaphysis itself is considered more vascular in terms of nutrient delivery and growth.
Question 159: Most common location of ectopic salivary gland is -
- A. Posterior triangle
- B. Parathyroid gland
- C. Cervical lymph nodes (Correct Answer)
- D. Anterior mediastinum
Explanation: Cervical lymph nodes - **Ectopic salivary gland tissue** is most frequently found within or adjacent to **cervical periparotid lymph nodes**. - This is thought to be due to inclusion of salivary gland anlage within lymph nodes during embryological development. *Anterior mediastinum* - While ectopic tissues can occur in the mediastinum, **salivary gland tissue** is not a common finding there. - The **mediastinum** is more commonly associated with ectopic **thymic** or **thyroid** tissue. *Posterior triangle* - The **posterior triangle of the neck** is a common site for various neck masses , but **ectopic salivary gland tissue** is rare in this location. - Masses here are more typically **lymphadenopathy**, **brachial cleft cysts**, or **fibromas**. *Parathyroid gland* - The **parathyroid glands** are endocrine glands located near or within the thyroid, and are not typically associated with containing **ectopic salivary gland tissue**. - Their embryological development is distinct from that of salivary glands.
Question 160: Anterior Mediastinal nodes are included in which level of lymph nodes?
- A. I
- B. V
- C. VI (Correct Answer)
- D. VII
Explanation: ***VI*** - Level VI lymph nodes are the **prevascular and retrotracheal nodes** located in the **anterior mediastinum** [1]. - According to the **IASLC (International Association for the Study of Lung Cancer)** lymph node mapping system, Level 6 nodes are specifically classified as anterior mediastinal nodes [1]. - These include nodes anterior to the superior vena cava and ascending aorta, and nodes between the trachea and esophagus [1]. *I* - Level I lymph nodes are located in the **low cervical, supraclavicular, and sternal notch** regions. - These are **extra-thoracic nodes** and not part of the mediastinal compartments. - They represent the highest mediastinal, supraclavicular, and sternal notch nodes [1]. *V* - Level V lymph nodes are the **subaortic (aortopulmonary window)** nodes [1]. - These are located in the space between the **aorta and pulmonary artery**, lateral to the ligamentum arteriosum [1]. - While mediastinal, they are specifically in the aortopulmonary window, not classified as anterior mediastinal. *VII* - Level VII lymph nodes are the **subcarinal nodes** located below the carina in the **middle mediastinum** [1]. - These nodes are positioned in the space beneath where the trachea bifurcates into the main bronchi [1]. - They are classified as middle mediastinal nodes, not anterior mediastinal nodes.