A surgeon removes a part of the liver located to the left of the falciform ligament. Which segments of the liver are removed?
Superior wall of middle ear is formed by ?
All are infraclavicular branches of brachial plexus except ?
What is the largest branch of the brachial plexus?
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 ?
Which muscle will be paralyzed when the radial nerve is injured just below the spiral groove?
Which muscle receives a muscular branch from the ulnar nerve?
How many ossification centers develop at the distal end of the humerus?
Which of the following statements regarding axillary lymph nodes is incorrect?
Which of the following statements about the mammary gland is false?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 51: A surgeon removes a part of the liver located to the left of the falciform ligament. Which segments of the liver are removed?
- A. Segments I & IV
- B. Segments V & VI
- C. Segments VII & VIII
- D. Segments II & III (Correct Answer)
Explanation: ***Segments II & III*** - The liver segments are defined by their **vascular supply** originating from the **portal vein** and **hepatic artery**, and their **biliary drainage** [1]. - The **falciform ligament** separates the **left lobe** of the liver into **medial** and **lateral** sections. The portion to its left corresponds to the lateral left lobe, which includes **segments II and III** [1, 2]. *Segments I & IV* - **Segment I** (`caudate lobe`) is located **posteriorly**, independent of the falciform ligament, and is supplied by both the left and right portal and hepatic arterial systems [1]. - **Segment IV** (`quadrate lobe`) is part of the **medial left lobe** and is situated to the **right of the falciform ligament** [1]. *Segments V & VI* - These segments are located in the **right lobe** of the liver, which is to the **right of the main portal fissure**, and are not associated with the falciform ligament's immediate left. - **Segment V** is **anterior** and **inferior**, and **Segment VI** is **posterior** and **inferior** within the right lobe. *Segments VII & VIII* - These segments are also located in the **right lobe** of the liver, specifically in the **superior** aspects [1]. - **Segment VII** is **posterior** and **superior**, while **Segment VIII** is **anterior** and **superior** in the right lobe, far from the falciform ligament.
Question 52: Superior wall of middle ear is formed by ?
- A. Tegmen tympani (Correct Answer)
- B. Jugular bulb
- C. Tympanic membrane
- D. Carotid wall
Explanation: ***Tegmen tympani*** - The **tegmen tympani** is a thin plate of **petrous temporal bone** that forms the roof or superior wall of the middle ear cavity. - This structure separates the middle ear from the **middle cranial fossa** and its contents, including the **temporal lobe of the brain**. *Jugular bulb* - The **jugular bulb** is the dilated superior portion of the **internal jugular vein** and forms part of the **floor (inferior wall)** of the middle ear cavity, not the superior wall. - Its close proximity to the middle ear makes it vulnerable to injury during otologic surgery. *Tympanic membrane* - The **tympanic membrane** (eardrum) forms the **lateral wall** of the middle ear cavity, separating it from the external auditory canal. - It is crucial for **sound transmission** by vibrating in response to sound waves. *Carotid wall* - The **carotid wall** forms the **anterior wall** of the middle ear cavity and is related to the **internal carotid artery** as it narrows through the carotid canal. - This wall is not the superior boundary of the middle ear.
Question 53: All are infraclavicular branches of brachial plexus except ?
- A. Axillary nerve
- B. Thoracodorsal nerve
- C. Long thoracic nerve (Correct Answer)
- D. Ulnar nerve
Explanation: Long thoracic nerve - The long thoracic nerve originates directly from the roots (C5, C6, C7) of the brachial plexus, making it a supraclavicular branch. - It does not arise from the cords of the brachial plexus, which are located infraclavicularly. Ulnar nerve - The ulnar nerve arises from the medial cord of the brachial plexus, which is an infraclavicular structure. - It supplies many intrinsic hand muscles and the ulnar half of the flexor digitorum profundus. Axillary nerve - The axillary nerve is a branch of the posterior cord of the brachial plexus, classifying it as an infraclavicular branch. - It innervates the deltoid and teres minor muscles. Thoracodorsal nerve - The thoracodorsal nerve also originates from the posterior cord of the brachial plexus, making it an infraclavicular branch [1]. - It provides motor innervation to the latissimus dorsi muscle [1].
Question 54: What is the largest branch of the brachial plexus?
- A. Ulnar nerve
- B. Radial nerve (Correct Answer)
- C. Axillary nerve
- D. Median nerve
Explanation: ***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 55: 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 ?
- A. Median
- B. Ulnar
- C. Radial
- D. Posterior interosseous (Correct Answer)
Explanation: ***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.
Question 56: Which muscle will be paralyzed when the radial nerve is injured just below the spiral groove?
- A. Extensor Digitorum
- B. Extensor Carpi Radialis Brevis (Correct Answer)
- C. Supinator
- D. Abductor Pollicis Longus
Explanation: Extensor Carpi Radialis Brevis - The radial nerve travels in the spiral groove of the humerus and gives off branches in a specific sequence. - Proximal to the spiral groove: Branches to triceps and anconeus - Within/at the spiral groove: Branches to brachioradialis and extensor carpi radialis longus (ECRL) - Just distal to the spiral groove: Branch to extensor carpi radialis brevis (ECRB) [1] - this is the first branch after exiting the spiral groove - More distally: The nerve divides into superficial and deep branches (posterior interosseous nerve) [1] - An injury just below the spiral groove would paralyze ECRB while sparing muscles innervated proximal to or within the groove (triceps, anconeus, brachioradialis, ECRL). Supinator - The supinator is innervated by the deep branch of the radial nerve (posterior interosseous nerve), which branches off more distally in the proximal forearm. - This muscle would only be affected by injuries distal to the bifurcation of the radial nerve into superficial and deep branches, not by an injury just below the spiral groove. Extensor Digitorum - The extensor digitorum is supplied by the posterior interosseous nerve, which is a continuation of the deep branch [1]. - This innervation occurs significantly distal to the spiral groove in the posterior forearm compartment. - It would be affected by posterior interosseous nerve injuries, not by lesions just below the spiral groove. Abductor Pollicis Longus - The abductor pollicis longus is innervated by the posterior interosseous nerve in the distal forearm [1]. - This is the most distal of all the options and would only be affected by posterior interosseous nerve palsy, not by radial nerve injury at the spiral groove level [1].
Question 57: Which muscle receives a muscular branch from the ulnar nerve?
- A. Both FCU and FDP (Correct Answer)
- B. FCU
- C. None of the options
- D. FDP
Explanation: ***Both FCU and FDP*** - The **flexor carpi ulnaris (FCU)** is solely innervated by the **ulnar nerve** in the forearm. - The **flexor digitorum profundus (FDP)** has dual innervation: the **ulnar nerve** supplies the medial half (tendons to ring and little fingers), while the anterior interosseous nerve (branch of median nerve) supplies the lateral half (tendons to index and middle fingers). - Both muscles receive muscular branches from the ulnar nerve, making this the most complete and accurate answer. *FCU* - While the FCU does receive innervation from the ulnar nerve (and only the ulnar nerve), this option is incorrect because the FDP also receives branches from the ulnar nerve. - Selecting only FCU ignores the dual innervation of FDP and is therefore an incomplete answer when "Both FCU and FDP" is available. *FDP* - While the medial half of FDP does receive innervation from the ulnar nerve, this option is incorrect because FCU also receives innervation from the ulnar nerve. - Selecting only FDP ignores the complete innervation of FCU and is therefore an incomplete answer when "Both FCU and FDP" is available. *None of the options* - This option is incorrect because both the **flexor carpi ulnaris** and the medial portion of the **flexor digitorum profundus** definitively receive muscular branches from the ulnar nerve. - The ulnar nerve provides motor innervation to these specific forearm muscles before continuing into the hand.
Question 58: How many ossification centers develop at the distal end of the humerus?
- A. 2
- B. 3 (Correct Answer)
- C. 5
- D. 4
Explanation: ***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.
Question 59: Which of the following statements regarding axillary lymph nodes is incorrect?
- A. Posterior group lies along subscapular vessels
- B. Lateral group lies along lateral thoracic vessels (Correct Answer)
- C. Apical group is terminal lymph nodes
- D. Apical group lies along axillary vessels
Explanation: ***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.
Question 60: Which of the following statements about the mammary gland is false?
- A. Is a modified sweat gland
- B. Extends from 2nd to 6th rib vertically
- C. Supplied by internal mammary artery
- D. Nipple is supplied by 6th intercostal nerve (Correct Answer)
Explanation: ***Nipple is supplied by 6th intercostal nerve*** - The **nipple and areola** are primarily supplied by branches of the **4th intercostal nerve**. - The 6th intercostal nerve supplies the lower part of the breast and is not the primary innervation for the nipple. *Is a modified sweat gland* - The mammary gland, or breast, is indeed a **modified apocrine sweat gland**. - This embryological origin explains its glandular structure and function of milk production. *Extends from 2nd to 6th rib vertically* - The vertical extent of the mammary gland typically ranges from the **2nd to the 6th rib**. - This anatomical positioning is consistent with its location on the anterior thoracic wall. *Supplied by internal mammary artery* - The **internal mammary artery (internal thoracic artery)** is a major blood supply to the medial aspect of the breast [2]. - Other significant arteries include the lateral thoracic and thoracoacromial arteries for the lateral aspect. The mammary gland is embedded in subcutaneous fat, although fat is absent beneath the nipple and areola [1]. Mature resting breasts lie between the skin and the pectoralis major muscle, supported by Cooper's ligaments [3].