Sacrotuberous ligament is pierced by
Line from midinguinal point to adductor tubercle represents?
Sacral promontory is the landmark for
Esophagus is present in which mediastinum?
Which chamber of the heart forms the posterior surface?
Which chamber of the heart is located anterior to the sternum?
Which of the following statements is false about the right bronchus?
Upper two posterior intercostal arteries arise from ?
Which testis is typically positioned higher?
Which part of the heart is located in the anterosuperior sternal region?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 31: 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 32: 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 33: 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 34: 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 35: Which chamber of the heart forms the posterior surface?
- A. Right Atrium (RA)
- B. Left Atrium (LA) (Correct Answer)
- C. Left Ventricle (LV)
- D. Right Ventricle (RV)
Explanation: ***Left Atrium (LA)*** - The **left atrium** forms the posterior surface of the heart, lying in front of the esophagus and thoracic aorta [1]. - Its posterior position makes it susceptible to enlargement, which can compress the **esophagus** and cause dysphagia [1]. *Right Atrium (RA)* - The **right atrium** primarily forms the right border of the heart and receives deoxygenated blood from the systemic circulation. - It lies anteriorly and to the right, behind the sternum and costal cartilages. *Left Ventricle (LV)* - The **left ventricle** forms the apex of the heart and part of the left border. - It is positioned *inferiorly* and *anteriorly*, contributing significantly to the *diaphragmatic surface* of the heart. *Right Ventricle (RV)* - The **right ventricle** forms the majority of the anterior surface of the heart, directly behind the sternum. - It also contributes to the *inferior surface* of the heart, resting on the diaphragm.
Question 36: Which chamber of the heart is located anterior to the sternum?
- A. Left ventricle
- B. Right atrium
- C. Right ventricle (Correct Answer)
- D. Left atrium
Explanation: ***Right ventricle*** - The **right ventricle** forms the majority of the **anterior surface of the heart** and is the chamber closest to the sternum [2]. - This anatomical position is important clinically, for instance, in cases of **pericardial effusion** or **chest trauma**. *Left atrium* - The **left atrium** is located most **posteriorly** in the heart, adjacent to the esophagus [1], [2]. - Due to its posterior position, an enlarged left atrium can compress the esophagus, causing **dysphagia**. *Left ventricle* - The **left ventricle** forms the **apex of the heart** and is located more on the left and posterior aspect compared to the right ventricle [2]. - While it contributes to the anterior surface, the **right ventricle** is more directly anterior to the sternum [2]. *Right atrium* - The **right atrium** is positioned to the right and slightly posterior to the right ventricle. - It receives venous blood from the body and forms the **right border of the heart**.
Question 37: 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 38: 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 39: Which testis is typically positioned higher?
- A. It varies between individuals
- B. Left testis
- C. Right testis (Correct Answer)
- D. Both are at the same level
Explanation: ***Right testis*** - The **right testis** is commonly positioned slightly higher than the left testis in most males [1]. - This anatomical variation is due to the **left spermatic cord** being inherently longer, which allows the left testis to hang lower. *Left testis* - The **left testis** is typically positioned lower than the right testis. - Its lower position is attributed to the generally **longer left spermatic cord**. *It varies between individuals* - While minor individual variations exist, a consistent pattern of the **right testis** being higher is observed in the majority of males. - The differences in cord length lead to a general trend, not complete randomness in height. *Both are at the same level* - It is uncommon for both testes to be at precisely the **same level**. - The **asymmetrical length** of the spermatic cords makes equal positioning rare.
Question 40: 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].