Anatomy
10 questionsThe blood supply to femoral head is mostly by?
Line from midinguinal point to adductor tubercle represents?
Sacrotuberous ligament is pierced by
Sacral promontory is the landmark for
Esophagus is present in which mediastinum?
Which of the following statements is false about the right bronchus?
Upper two posterior intercostal arteries arise from ?
Which part of the heart is located in the anterosuperior sternal region?
Which muscle will be paralyzed when the radial nerve is injured just below the spiral groove?
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 ?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 131: The blood supply to femoral head is mostly by?
- A. Lateral epiphyseal artery
- B. Medial epiphyseal artery
- C. Artery of ligamentum teres
- D. Profunda femoris (Correct Answer)
Explanation: ***Profunda femoris*** - The profunda femoris artery (deep femoral artery) gives rise to the **medial and lateral circumflex femoral arteries**, which are the primary blood supply to the femoral head in adults - Specifically, the **medial circumflex femoral artery** and its branches (lateral epiphyseal arteries and retinacular arteries) form an extracapsular arterial ring and penetrate the joint capsule to supply the femoral head - The profunda femoris is thus the main parent vessel responsible for femoral head blood supply *Lateral epiphyseal artery* - This artery is a branch of the **medial circumflex femoral artery**, which originates from the profunda femoris - While it directly supplies the femoral head and is the dominant terminal branch, it represents a more specific component of the arterial network rather than the main source vessel - It provides blood to the lateral and superior portions of the femoral head *Medial epiphyseal artery* - This artery is also a branch of the circumflex femoral arteries, which originate from the profunda femoris - It contributes to the blood supply but is less dominant than the lateral epiphyseal branches - Similar to lateral epiphyseal artery, it is part of the retinacular arterial system *Artery of ligamentum teres* - The **artery of the ligamentum teres** (foveal artery) is an inconsistent and often small vessel, typically a branch of the **obturator artery** or medial circumflex femoral artery - While it contributes to blood supply especially in children, its contribution is usually minor in adults and often insufficient to sustain the femoral head alone - It enters through the fovea capitis and its contribution diminishes with age
Question 132: Line from midinguinal point to adductor tubercle represents?
- A. Inferior epigastric artery
- B. Femoral artery (Correct Answer)
- C. Superior epigastric artery
- D. None of the options
Explanation: The line from the **midinguinal point** to the **adductor tubercle** accurately maps the anatomical course of the **femoral artery** in the thigh. This anatomical landmark is crucial for palpating the **femoral pulse** and locating the artery for clinical procedures like catheter insertion. *Inferior epigastric artery* - The **inferior epigastric artery** originates from the external iliac artery and ascends superiorly in the anterior abdominal wall [1]. - Its course is significantly more medial and superior, far from the line described. *Superior epigastric artery* - The **superior epigastric artery** is a terminal branch of the internal thoracic artery, descending into the rectus sheath in the upper abdomen [1]. - Its location is entirely within the anterior abdominal wall, high above the inguinal region. *None of the options* - This option is incorrect because the line from the midinguinal point to the adductor tubercle clearly represents the anatomical course of the femoral artery. - The other arteries listed are not found along this specific anatomical path.
Question 133: Sacrotuberous ligament is pierced by
- A. Perforating cutaneous nerve (Correct Answer)
- B. Posterior femoral cutaneous nerve
- C. Superior gluteal nerve
- D. Sciatic nerve
Explanation: ***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.
Question 134: Sacral promontory is the landmark for
- A. Termination of presacral nerve (Correct Answer)
- B. None of the options
- C. Origin of inferior mesenteric artery
- D. Origin of superior mesenteric artery
Explanation: ***Termination of presacral nerve*** - The **sacral promontory** is the key anatomical landmark where the **superior hypogastric plexus** (presacral nerve) **bifurcates** into the right and left hypogastric nerves. - This bifurcation typically occurs at the level of the **sacral promontory**, making it a crucial landmark for **presacral neurectomy** procedures. - The superior hypogastric plexus is formed by the fusion of sympathetic fibers and lies anterior to the L5 vertebra and sacral promontory. - Clinically important for **pelvic surgery** and **pain management** procedures. *Origin of superior mesenteric artery* - The **superior mesenteric artery (SMA)** originates from the **anterior aspect of the abdominal aorta** at the level of the **L1 vertebra**. - This is far superior to the sacral promontory, which is at the lumbosacral junction (L5-S1). - The SMA supplies the midgut derivatives. *Origin of inferior mesenteric artery* - The **inferior mesenteric artery (IMA)** originates from the **anterior aspect of the abdominal aorta** at the level of the **L3 vertebra**. - This is also well above the sacral promontory. - The IMA supplies the hindgut derivatives. *None of the options* - This is incorrect as the sacral promontory is indeed a recognized landmark for the **bifurcation/termination of the presacral nerve** (superior hypogastric plexus).
Question 135: Esophagus is present in which mediastinum?
- A. Anterior
- B. Posterior (Correct Answer)
- C. Middle
- D. Superior
Explanation: ***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 136: Which of the following statements is false about the right bronchus?
- A. Shorter
- B. More horizontal (Correct Answer)
- C. In the line of trachea
- D. Wider
Explanation: ***More horizontal*** - The right bronchus is traditionally described as **more vertical** or **more directly in line with the trachea** compared to the left bronchus. - This anatomical orientation makes it more susceptible to the aspiration of foreign bodies. *Shorter* - The **right main bronchus** is indeed shorter than the left main bronchus. - Its length is typically 2-3 cm, while the left main bronchus is about 5 cm long. *Wider* - The **right main bronchus** has a larger diameter than the left main bronchus. - This wider lumen contributes to the ease with which foreign bodies can enter it. *In the line of trachea* - The right main bronchus diverges from the trachea at a **less acute angle** (approximately 25 degrees) compared to the left (approximately 45 degrees). - This makes it appear more as a **direct continuation of the trachea**, facilitating aspiration into the right lung.
Question 137: Upper two posterior intercostal arteries arise from ?
- A. Internal mammary artery
- B. Bronchial artery
- C. Aorta
- D. Superior intercostal artery (Correct Answer)
Explanation: ***Superior intercostal artery*** - The **superior intercostal artery** is a branch of the **costocervical trunk**, which itself arises from the subclavian artery. - It supplies the **first two posterior intercostal spaces**, hence the "upper two" mentioned in the question. *Aorta* - The **descending thoracic aorta** directly supplies the posterior intercostal arteries from the **3rd to the 11th intercostal spaces**. - It does not, however, supply the first two posterior intercostal arteries. *Internal mammary artery* - The **internal mammary artery** (also known as the internal thoracic artery) supplies the **anterior intercostal arteries** [1]. - It arises from the **subclavian artery** [1] but is not involved in supplying the posterior intercostal spaces. *Bronchial artery* - **Bronchial arteries** primarily supply the **lungs and bronchi**, providing oxygenated blood to the lung tissue. - They are not the main source of blood supply for the intercostal spaces.
Question 138: Which part of the heart is located in the anterosuperior sternal region?
- A. Right atrium and auricle.
- B. Left atrium.
- C. Left ventricle.
- D. Right ventricle. (Correct Answer)
Explanation: ***Right ventricle*** - The **right ventricle** forms the **most anterior part of the heart**, located directly behind the sternum and costal cartilages [1]. - Its position explains why **sternal precordial leads** (e.g., V1, V2) on an ECG primarily reflect right ventricular activity [1]. *Right atrium and auricle* - While part of the right atrium is anterior, the **right ventricle is significantly more anterior** and occupies the majority of the anterosuperior sternal region [1]. - The **right auricle** is a small, anterior appendage, but the broader chamber occupying this region is the ventricle [1]. *Left atrium* - The **left atrium** is the **most posterior chamber of the heart**, forming the base [1]. - It lies near the esophagus, making it susceptible to compression by an enlarged left atrium. *Left ventricle* - The **left ventricle** forms the **apex of the heart** and is located primarily on the **left and inferior** aspects. - It is not the most anterior structure; the right ventricle is positioned anteriorly to it [1].
Question 139: 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 140: 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.