NEET-PG 2013 - Anatomy Practice Questions

Q: Chorda tympani is a branch of which cranial nerve?

Facial nerve (CN VII). ***Facial nerve (CN VII)*** - The **chorda tympani** is a branch of the **facial nerve (CN VII)**, carrying special sensory (taste) innervation to the anterior two-thirds of the tongue and preganglionic parasympathetic fibers to the submandibular and sublingual salivary glands. - It arises from the facial nerve within the **temporal bone**, passes through the middle ear, and then joins the lingual nerve. *Trigeminal nerve (CN V)* - The **trigeminal nerve** is primarily responsible for **sensory innervation of the face** and motor innervation of the muscles of mastication. - While the lingual nerve (a branch of the trigeminal nerve) carries the fibers of the chorda tympani, the chorda tympani itself originates from the facial nerve. *Vestibulocochlear nerve (CN VIII)* - The **vestibulocochlear nerve** is responsible for **hearing** and **balance**. - It does not have any branches that innervate taste buds or salivary glands. *Glossopharyngeal nerve (CN IX)* - The **glossopharyngeal nerve** innervates the posterior one-third of the tongue for **taste** and general sensation, the parotid gland for parasympathetic secretion, and the stylopharyngeus muscle. - It does not give rise to the chorda tympani.

Q: Which of the following statements regarding axillary lymph nodes is incorrect?

Lateral group lies along lateral thoracic vessels. ***Lateral group lies along lateral thoracic vessels*** - The **lateral group** of axillary lymph nodes is located along the **axillary vein**, receiving lymph primarily from the upper limb [1]. - The **lateral thoracic vessels** are associated with the central and posterior groups of axillary lymph nodes, not the lateral group. *Posterior group lies along subscapular vessels* - The **posterior (subscapular) group** of axillary lymph nodes is indeed located along the **subscapular vessels**. - This group receives lymph from the posterior wall of the trunk and the posterior shoulder region. *Apical group is terminal lymph nodes* - The **apical group** (also known as the subclavian group) is considered the **terminal lymph nodes** of the axilla. - Lymph from all other axillary nodes eventually drains into the apical group before continuing to the supraclavicular nodes and then into the subclavian lymphatic trunk [2]. *Apical group lies along axillary vessels* - The **apical group** of axillary lymph nodes is situated in the apex of the axilla, superior to the pectoralis minor muscle, and lies in close proximity to the **axillary vessels** [1]. - This location allows it to receive lymph from other axillary groups and drain into the supraclavicular lymph nodes.

Q: Axillary nerve is accompanied by which artery ?

Posterior circumflex humeral artery. ***Posterior circumflex humeral artery*** - The **axillary nerve** and the **posterior circumflex humeral artery** both pass through the **quadrangular space** in the axilla. - This anatomical relationship makes them vulnerable to injury together, particularly in cases of **shoulder dislocation** or **fractures of the surgical neck of the humerus**. *Axillary artery* - The **axillary artery** is the main arterial trunk of the axilla, but the axillary nerve is not typically described as directly accompanying the main trunk. - While branches of the axillary artery do supply the region where the axillary nerve travels, the specific artery that accompanies the nerve is a direct branch. *Subscapular artery* - The **subscapular artery** is the largest branch of the axillary artery and gives rise to the circumflex scapular and thoracodorsal arteries. - It does not directly accompany the axillary nerve through the quadrangular space; instead, it mostly supplies muscles like the **subscapularis** and **latissimus dorsi**. *Anterior circumflex humeral artery* - The **anterior circumflex humeral artery** also branches from the axillary artery and wraps around the surgical neck of the humerus. - However, it typically runs anteriorly and does not accompany the axillary nerve as it emerges from the quadrangular space posteriorly.

Q: What is the number of muscles in the middle ear?

Two. ***Two*** - The middle ear houses two muscles: the **tensor tympani** and the **stapedius muscle** [1]. - These muscles play a crucial role in the **acoustic reflex**, protecting the inner ear from loud sounds. *One* - This option is incorrect as there are two muscles, not one, involved in middle ear function [1]. - Specifying one muscle would neglect the complementary role of the other in the acoustic reflex. *Three* - This option is incorrect because the middle ear only contains two muscles [1]. - There are no additional muscles associated with the ossicles or tympanic membrane. *Four* - This option is incorrect as the middle ear is only comprised of the **tensor tympani** and **stapedius** muscles [1]. - The number four is not associated with the muscular anatomy of the middle ear.

Q: Blood tissue barrier in testis is formed by?

Adjacent Sertoli cells with basal lamina. ***Adjacent Sertoli cells with basal lamina*** - The **blood-testis barrier** is primarily formed by **tight junctions** between adjacent **Sertoli cells**, which divide the seminiferous epithelium into basal and adluminal compartments [1]. - The **basal lamina** of the seminiferous tubule also contributes to this barrier, regulating the passage of substances from the interstitial fluid to the basal compartment [1]. *Basal lamina & interstitial cells* - While the **basal lamina** is part of the barrier, **interstitial cells (Leydig cells)** are located outside the seminiferous tubules and are primarily involved in **testosterone production**, not barrier formation [1]. - **Interstitial cells** are part of the connective tissue between the tubules and do not form tight junctions that would restrict molecular movement into the seminiferous epithelium. *Basal lamina & spermatogonia* - **Spermatogonia** are germ cells located in the **basal compartment** of the seminiferous tubule, *beneath* the Sertoli cell tight junctions [1]. - They are able to cross the barrier as they differentiate and move into the adluminal compartment, but they do not form the barrier itself. *Basal lamina & leydig cells* - As mentioned previously, **Leydig cells** (interstitial cells) are responsible for **androgen synthesis** and are located outside the seminiferous tubule [2]. - They do not form components of the physical blood-testis barrier.

Q: The primary oocyte remains arrested in which stage until ovulation?

Diplotene stage. ***Diplotene stage*** - The primary oocyte enters **meiosis I** during fetal development but arrests in the **prophase I substage of diplotene**. - This arrest is maintained until **puberty** and **ovulation**, when hormonal surges trigger the completion of meiosis I. *Pachytene stage* - The **pachytene stage** of prophase I is when **crossing over** (recombination) occurs between homologous chromosomes. - While an important step in meiosis, it precedes the **diplotene arrest** point. *Metaphase* - **Metaphase** is a stage where chromosomes align at the metaphase plate, either in meiosis I or meiosis II. - The primary oocyte's arrest occurs much earlier, during **prophase I**, not metaphase. *Telophase* - **Telophase** is the final stage of mitosis or meiosis where chromosomes decondense and nuclear envelopes reform. - The oocyte's initial arrest point is in **prophase I**, long before telophase.

Q: Which of the following structures pass through the superior orbital fissure?

All of the options. ***All of the options*** - The **superior orbital fissure** is a key opening in the skull that allows passage of several important cranial nerves and vessels into the orbit. - The **oculomotor nerve**, **trochlear nerve**, and **superior ophthalmic vein** are all established structures that pass through this fissure. *Oculomotor nerve* - The **oculomotor nerve (CN III)** passes through the superior orbital fissure to innervate most of the extrinsic eye muscles. - It controls movements such as **adduction**, **elevation**, and **depression** of the eyeball, and also innervates the **levator palpebrae superioris** muscle for eyelid elevation [1]. *Trochlear nerve* - The **trochlear nerve (CN IV)**, which innervates the **superior oblique muscle**, also passes through the superior orbital fissure. - The superior oblique muscle is responsible for **intorsion** and **depression** of the eye, particularly when the eye is adducted [1]. *Superior ophthalmic vein* - The **superior ophthalmic vein** drains blood from structures within the orbit and passes through the superior orbital fissure to drain into the **cavernous sinus**. - This vein provides a connection between the facial veins and the cavernous sinus, which can be clinically relevant in cases of infection spread.

Q: Which of the following muscles is not in the pectoral region?

Infraspinatus. ***Infraspinatus*** - The **infraspinatus** muscle is located in the **posterior scapular region**, specifically on the posterior aspect of the scapula, filling the infraspinous fossa. - Its primary function is **external rotation** of the humerus, and it is a key component of the **rotator cuff**. *Pectoralis major* - The **pectoralis major** is a large, superficial muscle located in the **anterior chest wall**, forming the bulk of the chest. [1] - It plays a significant role in **adduction**, **flexion**, and **medial rotation** of the humerus. *Pectoralis minor* - The **pectoralis minor** is a smaller, triangular muscle situated beneath the pectoralis major in the **anterior thoracic wall**. [1] - Its functions include **stabilizing the scapula** by pulling it inferiorly and anteriorly, and assisting in forced inspiration. [1] *Subclavius* - The **subclavius** is a small, triangular muscle located inferior to the clavicle in the **pectoral region**. - Its primary role is to **depress and stabilize the clavicle**, protecting the underlying neurovascular structures.

Q: All of the following muscles have dual nerve supply except which one?

Biceps brachii. ***Biceps brachii*** - The **biceps brachii** muscle is solely innervated by the **musculocutaneous nerve (C5, C6, C7)**. - This muscle is a prime mover for forearm supination and elbow flexion and does not receive nerve supply from any other nerve. *Subscapularis* - The **subscapularis** muscle has a dual nerve supply from both the **upper and lower subscapular nerves (C5, C6)**. - This dual innervation ensures motor control of the subscapularis, which is an important medial rotator of the humerus. *Pectoralis major* - The **pectoralis major** muscle receives a dual nerve supply from both the **medial and lateral pectoral nerves** [1]. - The **lateral pectoral nerve** primarily supplies the clavicular head, while the **medial pectoral nerve** supplies both the sternocostal head and a portion of the clavicular head [1]. *Flexor digitorum profundus* - The **flexor digitorum profundus** muscle has a dual nerve supply from the **median nerve** (innervating the lateral half for digits 2 and 3) and the **ulnar nerve** (innervating the medial half for digits 4 and 5). - This dual innervation allows for independent or coordinated flexion of the distal phalanges of the fingers.

Q: What is the largest branch of the brachial plexus?

Radial nerve. ***Radial nerve*** - The **radial nerve** is considered the largest branch of the brachial plexus due to its extensive innervation of numerous muscles in the posterior compartment of the arm and forearm. - It arises from the **posterior cord** of the brachial plexus and innervates all the extensors of the arm and forearm, including the triceps brachii and supinator. *Ulnar nerve* - The ulnar nerve is a significant branch, but it is **smaller** in cross-sectional area and muscular distribution compared to the radial nerve. - It mainly innervates muscles of the **hand** and some forearm flexors. *Median nerve* - The median nerve is a large and clinically important nerve, formed by contributions from both the **lateral and medial cords**, but it is generally *not* considered the largest in terms of overall bulk or number of muscular branches. - It primarily innervates the **flexor muscles of the forearm** and some muscles of the hand (thenar eminence). *Axillary nerve* - The axillary nerve is one of the **smaller** terminal branches of the brachial plexus. - It primarily innervates the **deltoid** and **teres minor muscles**, and a small area of skin over the shoulder.

Question 1

Chorda tympani is a branch of which cranial nerve?

Accepted Answer

Facial nerve (CN VII)

Answer

Vestibulocochlear nerve (CN VIII)

Answer

Trigeminal nerve (CN V)

Answer

Glossopharyngeal nerve (CN IX)

Question 2

Which of the following statements regarding axillary lymph nodes is incorrect?

Accepted Answer

Lateral group lies along lateral thoracic vessels

Answer

Posterior group lies along subscapular vessels

Answer

Apical group is terminal lymph nodes

Answer

Apical group lies along axillary vessels

Question 3

Axillary nerve is accompanied by which artery ?

Accepted Answer

Posterior circumflex humeral artery

Answer

Axillary artery

Answer

Subscapular artery

Answer

Anterior circumflex humeral artery

Question 4

What is the number of muscles in the middle ear?

Accepted Answer

Two

Answer

One

Answer

Three

Answer

Four

Question 5

Blood tissue barrier in testis is formed by?

Accepted Answer

Adjacent Sertoli cells with basal lamina

Answer

Basal lamina & interstitial cells

Answer

Basal lamina & spermatogonia

Answer

Basal lamina & leydig cells

Question 6

The primary oocyte remains arrested in which stage until ovulation?

Accepted Answer

Diplotene stage

Answer

Pachytene stage

Answer

Metaphase

Answer

Telophase

Question 7

Which of the following structures pass through the superior orbital fissure?

Accepted Answer

All of the options

Answer

Oculomotor nerve

Answer

Trochlear nerve

Answer

Superior ophthalmic vein

Question 8

Which of the following muscles is not in the pectoral region?

Accepted Answer

Infraspinatus

Answer

Pectoralis major

Answer

Pectoralis minor

Answer

Subclavius

Question 9

All of the following muscles have dual nerve supply except which one?

Accepted Answer

Biceps brachii

Answer

Pectoralis major

Answer

Flexor digitorum profundus

Answer

Subscapularis

Question 10

What is the largest branch of the brachial plexus?

Accepted Answer

Radial nerve

Answer

Ulnar nerve

Answer

Axillary nerve

Answer

Median nerve

NEET-PG 2013 — Anatomy