NEET-PG 2013 - Anatomy Practice Questions

Q: Which muscle is attached to the lateral surface of the greater trochanter?

Gluteus medius. ***Gluteus medius*** - The **gluteus medius** inserts onto the **lateral surface of the greater trochanter** of the femur. - Its primary actions include **abduction** and **internal rotation** of the hip. *Gluteus maximus* - The **gluteus maximus** inserts primarily into the **iliotibial tract** and the **gluteal tuberosity** of the posterior femur, not the lateral greater trochanter. - Its main roles are **hip extension** and **external rotation**. *Gluteus minimus* - The **gluteus minimus** inserts onto the **anterior part of the lateral surface (anterolateral aspect)** of the greater trochanter, anterior to the gluteus medius insertion. - Like the gluteus medius, it also contributes to **hip abduction** and **internal rotation**. *Piriformis* - The **piriformis** muscle inserts onto the **superior and medial aspect of the greater trochanter**. - Its main actions are **external rotation** and **abduction** of the hip, particularly when the hip is flexed.

Q: Main blood supply to the head and neck of femur comes from

Medial circumflex femoral artery. ***Medial circumflex femoral artery*** - The **medial circumflex femoral artery** is the primary arterial supply to the **head and neck of the femur**, particularly via its **retinacular branches**. - These branches ascend along the femoral neck within the joint capsule, supplying most of the femoral head. *Lateral circumflex femoral artery* - The **lateral circumflex femoral artery** primarily supplies the muscles of the **anterior compartment of the thigh**, including the quadriceps femoris. - While it contributes to anastomoses around the hip, its direct supply to the femoral head and neck is less significant than the medial circumflex. *Artery of ligamentum teres* - The **artery of the ligamentum teres** (foveal artery) supplies a small, variable portion of the **femoral head**, mainly in children. - Its contribution to the overall blood supply to the adult femoral head and neck is often negligible or absent. *Popliteal artery* - The **popliteal artery** is located in the **popliteal fossa** behind the knee joint and is the continuation of the femoral artery. - Its branches supply the structures around the knee and lower leg, not the femoral head and neck.

Q: Helicine arteries are branches of which artery?

Internal pudendal artery. ***Internal pudendal artery*** - The **internal pudendal artery** is the primary arterial supply to the external genitalia, and its branches, including the **helicine arteries**, are crucial for erectile function. - In males, these arteries supply the **corpus cavernosa** of the penis, and in females, they supply the **clitoris**, playing a key role in sexual arousal. *Femoral artery* - The **femoral artery** is a large artery in the thigh that supplies blood to the lower limb, but it does not directly branch into the helicine arteries of the genitalia. - Its main branches include the **deep femoral artery** and the **superficial femoral artery**, which are involved in blood supply to the muscles and skin of the thigh. *External pudendal artery* - The **external pudendal artery** branches off the femoral artery and supplies the skin of the external genitalia and the perineum, but not the deeper erectile tissues via helicine arteries. - It primarily provides superficial blood supply, such as to the **scrotum** or **labia majora**, and is distinct from the internal pudendal artery's deeper distribution. *None of the options* - This option is incorrect because the **internal pudendal artery** is indeed the origin of the helicine arteries. - The other options provided are incorrect as they do not directly give rise to the helicine arteries.

Q: What is the approximate number of cones in the human retina?

Approximately 3-5 million cones. Approximately 3-5 million cones - The human retina contains roughly **4.5 million cones**, concentrated in the **fovea**, which is responsible for **high-acuity vision** and color perception [1]. - Cones are light-sensitive cells that detect **fine details** and are essential for vision in **bright light conditions** [1]. *Approximately 10-20 million cones* - This range is significantly higher than the actual number of cones found in the human retina. - While there are millions of photoreceptors, the *majority are rods*, not cones [1]. *Approximately 25-50 million cones* - This figure vastly *overestimates* the number of cones in the human eye. - The total number of photoreceptor cells (rods and cones combined) in the retina typically ranges from **100-125 million** [1]. *Approximately 50-100 million cones* - This range is incorrect as it refers more closely to the *total number of rods* in the human retina, which is about **90-120 million** [1]. - Cones constitute a much smaller proportion of the total photoreceptor population [1].

Q: Which of the following structures is not found in the midpalmar space?

1st lumbrical. ***1st lumbrical*** - The **1st lumbrical** is typically found within the **thenar space** or the **central compartment of the palm**, not the midpalmar space [1]. - Its position is associated with the **index finger's flexor tendons**, which do not traverse the midpalmar space. *2nd lumbrical* - The **2nd lumbrical** is located in the **midpalmar space**, situated on the radial side of the **flexor digitorum profundus (FDP) tendon** to the third digit [1]. - It arises from the radial side of the **FDP tendon** of the **middle finger** [1]. *FDP of 3rd finger* - The **flexor digitorum profundus (FDP) tendon** to the **third finger** (middle finger) passes through the **midpalmar space** [1]. - These tendons, along with their associated lumbricals, are key components of the **midpalmar space**. *FDP of 4th finger* - The **flexor digitorum profundus (FDP) tendon** to the **fourth finger** (ring finger) also travels through the **midpalmar space** [1]. - The midpalmar space contains the **FDP tendons** for the middle, ring, and little fingers, as well as their corresponding lumbricals (2nd, 3rd, and 4th).

Q: What is the typical length of the anal canal in adults?

35 - 40 mm. ***35 - 40 mm*** - The **anal canal** in adults typically measures between **3.5 to 4.0 cm** (35 to 40 mm) in length. - This length is measured from the **anorectal ring** to the **anal verge**. *10 - 15 mm* - This length is too short for the **adult anal canal**; it's approximately one-third of the actual length. - Such a short measurement would be anatomically incorrect and clinically significant for various colorectal conditions. *15 - 20 mm* - This measurement is still significantly shorter than the average length of the **adult anal canal**. - A canal this short would likely be pathological or developmental in origin. *25 - 30 mm* - While closer, this range is still generally below the accepted average length of the **adult anal canal**. - Precise anatomical measurements are crucial for diagnostic and surgical procedures in proctology.

Q: A person had injury to right upper limb, he is not able to extend fingers but able to extend wrist and elbow. Nerve injured is ?

Posterior interosseous. ***Posterior interosseous*** - This nerve supplies the muscles responsible for **finger extension**, such as the **extensor digitorum**, **extensor indicis**, and **extensor digiti minimi**. - A lesion here would spare wrist and elbow extension because the nerves to the **extensor carpi radialis longus/brevis** and **triceps brachii** branch off the radial nerve proximal to the origin of the posterior interosseous nerve. *Radial* - A more proximal **radial nerve injury** would result in the inability to extend the wrist (leading to **wrist drop**), fingers, and thumb, which is not seen here as wrist extension is preserved. - It also innervates the **triceps brachii**, and a high radial nerve injury would affect elbow extension; this patient can extend their elbow. *Median* - The **median nerve** primarily innervates muscles responsible for **flexion** of the wrist and fingers, as well as **thumb opposition** and **pronation**. - Its injury would not directly lead to an inability to extend the fingers, but rather weakness in flexion and specific thumb movements. *Ulnar* - The **ulnar nerve** innervates most of the **intrinsic hand muscles** and the **flexor carpi ulnaris**, leading to weakness in finger abduction/adduction and flexion of the 4th and 5th digits. - It does not control finger extension, so an injury would not cause this specific deficit.

Q: Which of the following statements about the linea aspera is correct?

Continues as gluteal tuberosity. Correct: Continues as gluteal tuberosity - The lateral lip of the linea aspera continues superiorly as the gluteal tuberosity (also called the gluteal ridge or line) - This anatomical continuation is a key feature of the femur's posterior surface - The gluteal tuberosity serves as the attachment site for the gluteus maximus muscle - The medial lip continues superiorly as the pectineal line (spiral line), which then joins the lesser trochanter Incorrect: Forms lateral border of femur - The linea aspera is located on the posterior surface of the femoral shaft, not on the lateral border - The lateral border of the femur is formed by the smooth lateral surface of the shaft - The linea aspera's lateral lip is a posterior ridge, distinct from the true lateral border Incorrect: Forms medial border of femur - The linea aspera is on the posterior aspect of the femur, not the medial border - The medial border of the femur is formed by the smooth medial surface of the shaft - The medial lip of the linea aspera is a muscle attachment site on the posterior surface, not a border

Q: What anatomical structure does the pineal gland form part of?

Part of the roof of the third ventricle. **_Part of the roof of the third ventricle_** - The **pineal gland** is a small, pinecone-shaped endocrine gland that forms part of the **roof of the third ventricle** [1]. - It is attached to the roof by the **pineal stalk** and projects posteriorly from the **epithalamus**. - The roof of the third ventricle consists of the **tela choroidea**, the **pineal gland**, and the **choroid plexus** [1]. - The pineal gland regulates circadian rhythms through **melatonin** secretion. *Part of the posterior wall of the third ventricle* - The **posterior wall** of the third ventricle is formed by the **posterior commissure**, the **pineal recess**, and the **habenular commissure**. - While the pineal gland is located posteriorly, it is anatomically classified as part of the roof, not the posterior wall itself. *Part of the anterior wall of the third ventricle* - The **anterior wall** is formed by the **lamina terminalis**, **anterior commissure**, and columns of the fornix. - This is located at the opposite end of the third ventricle from the pineal gland. *Part of the floor of the third ventricle* - The **floor** is formed by structures of the **hypothalamus**, including the **optic chiasm**, **tuber cinereum**, **infundibulum**, and **mammillary bodies**. - The pineal gland is situated dorsally (superiorly), not in the floor.

Q: Which thalamic nuclei can produce basal ganglia symptoms?

Ventral anterior. ***Ventral anterior*** - The **ventral anterior (VA)** and **ventral lateral (VL)** nuclei of the thalamus receive significant input from the **basal ganglia** and project to the motor cortex [1]. - Dysfunction in these nuclei can disrupt the basal ganglia's influence on motor control, leading to symptoms like **dyskinesia** or **rigidity** [1]. *Lateral dorsal* - The **lateral dorsal nucleus** is primarily involved in **limbic system** functions and episodic memory. - It does not have direct nor significant connections with the basal ganglia motor circuits that would produce typical basal ganglia symptoms. *Pulvinar* - The **pulvinar** is the largest thalamic nucleus, primarily involved in **visual processing**, attention, and eye movements. - While it has extensive cortical connections, it is not directly involved in the motor circuits of the basal ganglia. *Intralaminar* - The **intralaminar nuclei** (e.g., centromedian and parafascicular) receive input from the basal ganglia but primarily project diffusely to the cerebral cortex and are involved in **arousal** and consciousness [2]. - While they modulate cortical activity, their dysfunction typically wouldn't produce the classic motor symptoms associated with basal ganglia disorders.

Question 1

Which muscle is attached to the lateral surface of the greater trochanter?

Accepted Answer

Gluteus medius

Answer

Gluteus maximus

Answer

Gluteus minimus

Answer

Piriformis

Question 2

Main blood supply to the head and neck of femur comes from

Accepted Answer

Medial circumflex femoral artery

Answer

Lateral circumflex femoral artery

Answer

Artery of ligamentum teres

Answer

Popliteal artery

Question 3

Helicine arteries are branches of which artery?

Accepted Answer

Internal pudendal artery

Answer

None of the options

Answer

Femoral artery

Answer

External pudendal artery

Question 4

What is the approximate number of cones in the human retina?

Accepted Answer

Approximately 3-5 million cones

Answer

Approximately 25-50 million cones

Answer

Approximately 50-100 million cones

Answer

Approximately 10-20 million cones

Question 5

Which of the following structures is not found in the midpalmar space?

Accepted Answer

1st lumbrical

Answer

2nd lumbrical

Answer

FDP of 4th finger

Answer

FDP of 3rd finger

Question 6

What is the typical length of the anal canal in adults?

Accepted Answer

35 - 40 mm

Answer

10 - 15 mm

Answer

15 - 20 mm

Answer

25 - 30 mm

Question 7

A person had injury to right upper limb, he is not able to extend fingers but able to extend wrist and elbow. Nerve injured is ?

Accepted Answer

Posterior interosseous

Answer

Median

Answer

Ulnar

Answer

Radial

Question 8

Which of the following statements about the linea aspera is correct?

Accepted Answer

Continues as gluteal tuberosity

Answer

Forms lateral border of femur

Answer

Forms medial border of femur

Answer

None of the options

Question 9

What anatomical structure does the pineal gland form part of?

Accepted Answer

Part of the roof of the third ventricle

Answer

Part of the anterior wall of the third ventricle

Answer

Part of the floor of the third ventricle

Answer

Part of the posterior wall of the third ventricle

Question 10

Which thalamic nuclei can produce basal ganglia symptoms?

Accepted Answer

Ventral anterior

Answer

Lateral dorsal

Answer

Pulvinar

Answer

Intralaminar

NEET-PG 2013 — Anatomy