NEET-PG 2015 - Anatomy Practice Questions

Q: Which part of the bone is considered the most vascular zone?

Metaphysis. ***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.

Q: Traumatic optic neuropathy due to closed head trauma commonly affects which part of the optic nerve?

Optic canal. ***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.

Q: Which of the following structures is present in an XY child but absent in an XX child?

Prostate gland. ***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.

Q: Anterior Mediastinal nodes are included in which level of lymph nodes?

VI. ***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.

Q: Number of stem villi at term in human placenta is?

240. ***240*** - At term, the **human placenta** contains numerous **stem villi** which branch extensively to form the villous tree. - The approximate number of **stem villi** at term is around **240**, contributing to the large surface area for maternal-fetal exchange. *60* - This number is significantly **lower** than the actual count of **stem villi** found in a mature, term placenta. - Such a low number would result in an **insufficient surface area** for effective nutrient and gas exchange. *120* - While higher than 60, this number is still **underestimated** for the quantity of **stem villi** present in a full-term human placenta. - A placenta with only 120 stem villi might not be able to adequately support a fetus at term. *480* - This number is an **overestimation** of the typical count of **stem villi** in a human placenta at term. - While villi are extensive, 480 stem villi represent a significantly higher number than usually observed.

Q: What is the shape of caecum in the newborn?

Conical. ***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**.

Q: Cephalic index is calculated as

Biparietal Diameter / Occipitofrontal Diameter. ***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.

Q: Most common location of ectopic salivary gland is -

Cervical lymph nodes. 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.

Q: Embryo gets implanted at what stage of development?

Blastocyst. 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 1

Which part of the bone is considered the most vascular zone?

Accepted Answer

Metaphysis

Answer

Diaphysis

Answer

Epiphysis

Answer

Medullary Cavity

Question 2

Traumatic optic neuropathy due to closed head trauma commonly affects which part of the optic nerve?

Accepted Answer

Optic canal

Answer

Intraocular part

Answer

Intracranial part

Answer

Optic tract

Question 3

Which of the following structures is present in an XY child but absent in an XX child?

Accepted Answer

Prostate gland

Answer

Urethral glands (Cowper's glands)

Answer

Ovaries

Answer

Vestibular glands (Bartholin's glands)

Question 4

Anterior Mediastinal nodes are included in which level of lymph nodes?

Accepted Answer

VI

Answer

I

Answer

V

Answer

VII

Question 5

Number of stem villi at term in human placenta is?

Accepted Answer

240

Answer

60

Answer

120

Answer

480

Question 6

What is the shape of caecum in the newborn?

Accepted Answer

Conical

Answer

Ovoid

Answer

Trapezoid

Answer

Globular

Question 7

Cephalic index is calculated as

Accepted Answer

Biparietal Diameter / Occipitofrontal Diameter

Answer

Biparietal Diameter / Head Circumference

Answer

Head Circumference / Femur Length

Answer

Occipitofrontal Diameter / Biparietal Diameter

Question 8

Which bones form the floor of the nasal cavity in children?

Accepted Answer

Palatine process of the maxilla and horizontal plate of the palatine bone

Answer

Nasal bone and maxilla

Answer

Vomer and ethmoid

Answer

Nasal crest of maxilla and palatine process of maxilla

Question 9

Most common location of ectopic salivary gland is -

Accepted Answer

Cervical lymph nodes

Answer

Posterior triangle

Answer

Parathyroid gland

Answer

Anterior mediastinum

Question 10

Embryo gets implanted at what stage of development?

Accepted Answer

Blastocyst

Answer

Two cell stage

Answer

Four cell stage

Answer

Morula

NEET-PG 2015 — Anatomy