NEET-PG 2013 - Anatomy Practice Questions

Q: Which muscles are known as 'Triceps surae'?

Gastro-soleus. ***Gastro-soleus*** - The **Triceps surae** refers to the two heads of the **gastrocnemius muscle** and the **soleus muscle**, which together form the powerful calf muscle. - These three muscles converge to form the **Achilles tendon** (calcaneal tendon) and are prime movers for **plantarflexion** of the ankle. *Popliteus* - The popliteus muscle is located behind the knee joint and acts to **unlock the knee** during flexion. - It does not contribute to the bulk of the calf and is not part of the Triceps surae group. *Extensor hallucis longus* - This muscle is located in the **anterior compartment** of the leg and is responsible for **dorsiflexion** of the ankle and extension of the great toe. - It is an antagonist to the Triceps surae, which primarily performs plantarflexion. *Extensor digitorum longus* - The extensor digitorum longus is also in the **anterior compartment** of the leg, responsible for **dorsiflexion** of the ankle and extension of the lateral four toes. - It is functionally opposite to the actions of the Triceps surae and in a different muscle compartment.

Q: Medulla oblongata arises from which of the following?

Myelencephalon. ***Myelencephalon*** - The **myelencephalon** is the most caudal of the three primary brain vesicles and is the developmental origin of the **medulla oblongata**. - It differentiates from the **rhombencephalon** (hindbrain) and is responsible for vital autonomic functions. *Rhombencephalon* - The **rhombencephalon** is the hindbrain and is a primary brain vesicle that further divides into the **metencephalon** and **myelencephalon**. - While it is the parent structure, it does not directly give rise to the medulla oblongata as a final differentiated structure without further division. *Mesencephalon* - The **mesencephalon** is the midbrain, a primary brain vesicle that develops into structures like the **tectum** and **tegmentum** [1]. - It is located rostral to the rhombencephalon and is not involved in the development of the medulla oblongata [1]. *None of the options* - This option is incorrect because the **myelencephalon** is the direct embryonic precursor of the medulla oblongata.

Q: Which of the following is NOT a content of the occipital triangle?

Suprascapular nerve. Suprascapular nerve - The **suprascapular nerve** originates from the brachial plexus and supplies the supraspinatus and infraspinatus muscles; it travels through the suprascapular notch and is not found within the occipital triangle. - Its primary course and innervation are associated with the shoulder, entirely separate from the neck region defining the occipital triangle. *Great auricular nerve* - The **great auricular nerve** emerges from the cervical plexus and supplies sensory innervation to the skin over the parotid gland, mastoid process, and auricle, courses superficially across the sternocleidomastoid in the region of the occipital triangle. - It is a recognized content of the posterior triangle of the neck, which encompasses the occipital triangle. *Lesser occipital nerve* - The **lesser occipital nerve** arises from the cervical plexus at C2 and C3, providing sensory innervation to the skin of the neck and scalp posterior to the auricle. - It ascends along the posterior border of the sternocleidomastoid muscle, placing it within the boundaries of the occipital triangle. *Occipital artery* - The **occipital artery** is a branch of the external carotid artery that supplies blood to the posterior scalp. - It traverses the apex of the posterior triangle (including the occipital triangle) as it ascends to the back of the head.

Q: Type of collagen found in space of Disse in liver is -

Collagen III & IV. ***Collagen III & IV*** - The **space of Disse** in the liver contains a delicate extracellular matrix predominantly composed of **collagen type III (reticular fibers)**, which provides structural support, and **collagen type IV**, a major component of basement membranes. - This specific collagen composition is crucial for regulating the exchange of solutes between **sinusoidal blood** and **hepatocytes**, as well as for the functional integrity of the liver [1]. *Collagen I & II* - **Collagen type I** is the most abundant collagen in the human body, found in connective tissues like **bone, skin, tendons, and ligaments**, but is not primary in the space of Disse. - **Collagen type II** is characteristic of **hyaline cartilage** and vitreous humor, and is not a significant component of the liver's extracellular matrix in the space of Disse. *Collagen II* - As mentioned, **collagen type II** is primarily found in **cartilage** and vitreous humor, which are distinct from the architectural requirements of the liver sinusoidal space. - Its presence in the space of Disse would not provide the necessary structural flexibility and support for the metabolic functions of the liver. *Collagen II & V* - While **collagen type V** is a minor fibrillar collagen that associates with collagen type I in many tissues, it is not a primary component of the space of Disse. - **Collagen type II** is, again, largely confined to cartilaginous structures, making this an unlikely combination for the liver microenvironment.

Q: What is the approximate ratio of connective tissue to smooth muscle in the cervix?

Approximately 8:1. ***Approximately 8:1*** - The **cervix** is predominantly composed of **fibrous connective tissue**, which provides its structural integrity and rigidity [1]. - This high ratio of **collagenous connective tissue** to smooth muscle is crucial for maintaining pregnancy and undergoing significant remodeling during parturition [1]. - The approximate ratio is **8:1 to 10:1**, with connective tissue forming about 85-90% of cervical tissue [1]. *2:1* - This ratio would imply a significantly higher proportion of **smooth muscle** (33%), making the cervix much more muscular and less fibrous than it actually is. - Such a composition would compromise the cervical function of maintaining a **closed uterine orifice** during pregnancy. *5:1* - While higher than 2:1, this ratio still underestimates the true dominance of **connective tissue** in the cervical structure. - The **cervix's mechanical properties**, including its ability to resist stretching, are primarily due to its abundant collagen content. *15:1* - This ratio overestimates the proportion of connective tissue, suggesting less than 7% smooth muscle. - While the cervix is indeed fibrous, it does contain a modest amount of **smooth muscle** (10-15%) particularly in the internal os region, making this ratio too extreme [1].

Q: Sacrotuberous ligament is pierced by

Perforating cutaneous nerve. ***Perforating cutaneous nerve*** - The **perforating cutaneous nerve** typically pierces the sacrotuberous ligament to innervate the skin over the medial part of the lower gluteal region. - This nerve originates from the **S2 and S3 anterior rami**. *Posterior femoral cutaneous* - The **posterior femoral cutaneous nerve** runs inferior to the piriformis muscle, superficial to the sacrotuberous ligament, but does not pierce it. - It supplies the skin on the posterior thigh and popliteal fossa. *Superior gluteal nerve* - The **superior gluteal nerve** exits the pelvis through the greater sciatic foramen, superior to the piriformis muscle, and does not interact with the sacrotuberous ligament in this manner. - It innervates the **gluteus medius, gluteus minimus**, and **tensor fasciae latae muscles**. *Sciatic nerve* - The **sciatic nerve** exits the pelvis via the greater sciatic foramen, inferior to the piriformis muscle, and passes superficial to the sacrotuberous ligament. - It does not pierce the ligament, but rather lies in close proximity to its inferior border.

Q: Interosseous membrane of forearm is pierced by?

Anterior interosseous artery. ***Anterior interosseous artery*** - The **anterior interosseous artery** pierces the **interosseous membrane** in the **distal forearm** (approximately 5 cm above the wrist) to anastomose with the **posterior interosseous artery** and contribute to the **palmar carpal arch**. - This artery arises from the **common interosseous artery**, a branch of the **ulnar artery**. - This is the **classically taught structure** that pierces the interosseous membrane and is the standard answer in examination contexts. *Brachial artery* - The **brachial artery** is the main artery of the arm and terminates in the **cubital fossa** by dividing into the **radial** and **ulnar arteries**. - It does not pierce the **interosseous membrane** of the forearm as it is located in the arm, not the forearm. *Posterior interosseous artery* - The **posterior interosseous artery** arises from the **common interosseous artery** and passes **posteriorly between the oblique cord and the upper border of the interosseous membrane** to enter the posterior compartment of the forearm. - While it may pierce the membrane distally to anastomose anteriorly, the **anterior interosseous artery** is the structure **classically described** as piercing the membrane in standard anatomical teaching and examination contexts. *Ulnar recurrent artery* - The **ulnar recurrent arteries** (anterior and posterior branches) arise from the **ulnar artery** near the **cubital fossa** and ascend to participate in the **anastomosis around the elbow joint**. - These arteries do not pierce the **interosseous membrane** of the forearm.

Q: How many ossification centers develop at the distal end of the humerus?

3. ***3*** - The distal end of the humerus develops **three primary ossification centers**: the capitellum, trochlea, and medial epicondyle [1]. - These centers appear sequentially and their ossification pattern is important for assessing **skeletal maturity** in children using the CRITOE mnemonic [1]. - The capitellum appears at 1 year, medial epicondyle at 5 years, and trochlea at 9 years. *2* - This number is too low and only accounts for the **capitellum and medial epicondyle**, missing the trochlea. - While these are the first two to appear, there is an additional primary ossification center (trochlea) that develops later. *5* - This number is incorrect; there are only **three primary ossification centers** at the distal humerus, not five. - This may cause confusion with other joints or by counting secondary ossification centers. *4* - This number is incorrect; while the lateral epicondyle does ossify, it is not consistently counted as a **primary ossification center**. - The standard anatomical teaching recognizes **three primary centers**: capitellum, trochlea, and medial epicondyle.

Q: What is the nerve supply of the larynx above the level of the vocal cords?

Superior laryngeal. ***Superior laryngeal*** - The **superior laryngeal nerve** branches into the internal and external laryngeal nerves. The **internal laryngeal nerve** (a branch of the superior laryngeal nerve) provides all sensory innervation to the larynx **above the vocal cords**. - It also carries **parasympathetic fibers** to the laryngeal glands in this region. *Recurrent laryngeal* - The **recurrent laryngeal nerve** provides sensory innervation to the larynx **below the vocal cords** [1]. - It also innervates all of the intrinsic muscles of the larynx except for the cricothyroid muscle [1]. *Glossopharyngeal* - The **glossopharyngeal nerve (CN IX)** primarily provides sensory innervation to the **posterior one-third of the tongue**, tonsils, pharynx, and middle ear. - It does not directly provide sensory innervation to the larynx. *External laryngeal nerve* - The **external laryngeal nerve**, a branch of the superior laryngeal nerve, is primarily **motor** and innervates the **cricothyroid muscle**. - It provides **no sensory innervation** to any part of the larynx.

Q: Esophagus is present in which mediastinum?

Posterior. ***Posterior*** - The **esophagus** is primarily located in the **posterior mediastinum**, where the bulk of its length (from T4/T5 to T10) traverses [2]. - It lies **posterior** to the **trachea** and **heart**, anterior to the vertebral column [2]. - For examination purposes, the esophagus is considered a **key structure of the posterior mediastinum** [2]. - Note: The uppermost part (cervical and upper thoracic) does pass through the superior mediastinum, but the majority lies in the posterior compartment. *Anterior* - The **anterior mediastinum** is a small space located between the **sternum** and the pericardium. - It primarily contains **connective tissue**, remnants of the thymus, lymph nodes, and the internal thoracic vessels [1]. - The esophagus does not traverse this compartment. *Middle* - The **middle mediastinum** is centrally located and prominently contains the **heart** and the roots of the great vessels [1]. - It also houses the **pericardium**, the main bronchi, and the phrenic nerves [1]. - The esophagus passes **posterior** to this compartment, not through it. *Superior* - The **superior mediastinum** extends from the thoracic inlet to the level of the sternal angle (T4/T5). - It contains large vessels like the **aortic arch** and its branches, the SVC, trachea, and thymus [1]. - While the **uppermost part of the thoracic esophagus** does pass through the superior mediastinum, this represents only a small portion of its total length.

Question 1

Which muscles are known as 'Triceps surae'?

Accepted Answer

Gastro-soleus

Answer

Popliteus

Answer

Extensor hallucis longus

Answer

Extensor digitorum longus

Question 2

Medulla oblongata arises from which of the following?

Accepted Answer

Myelencephalon

Answer

Mesencephalon

Answer

Rhombencephalon

Answer

None of the options

Question 3

Which of the following is NOT a content of the occipital triangle?

Accepted Answer

Suprascapular nerve

Answer

Lesser occipital nerve

Answer

Occipital artery

Answer

Great auricular nerve

Question 4

Type of collagen found in space of Disse in liver is -

Accepted Answer

Collagen III & IV

Answer

Collagen I & II

Answer

Collagen II

Answer

Collagen II & V

Question 5

What is the approximate ratio of connective tissue to smooth muscle in the cervix?

Accepted Answer

Approximately 8:1

Answer

2:1

Answer

5:1

Answer

15:1

Question 6

Sacrotuberous ligament is pierced by

Accepted Answer

Perforating cutaneous nerve

Answer

Posterior femoral cutaneous nerve

Answer

Superior gluteal nerve

Answer

Sciatic nerve

Question 7

Interosseous membrane of forearm is pierced by?

Accepted Answer

Anterior interosseous artery

Answer

Brachial artery

Answer

Posterior interosseous artery

Answer

Ulnar recurrent artery

Question 8

How many ossification centers develop at the distal end of the humerus?

Accepted Answer

3

Answer

2

Answer

5

Answer

4

Question 9

What is the nerve supply of the larynx above the level of the vocal cords?

Accepted Answer

Superior laryngeal

Answer

Recurrent laryngeal

Answer

Glossopharyngeal

Answer

External laryngeal nerve

Question 10

Esophagus is present in which mediastinum?

Accepted Answer

Posterior

Answer

Answer

Middle

Answer

Superior

NEET-PG 2013 — Anatomy