Anatomy
10 questionsAzygos vein drains into:
Arch of aorta begins at which vertebral level?
Intercostal nerve is a branch of?
Distance of cricopharynx from incisor teeth
All veins open in sinus venarum except -
Which of the following statements about the atrioventricular groove is true?
Which artery supplies the anterior part of the interventricular septum?
Which of the following does not directly drain into right atrium?
Which are the segments of the upper lobe of the right lung?
What is the uppermost structure in left lung hilum?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 121: Azygos vein drains into:
- A. Right subcostal vein
- B. Right ascending lumbar vein
- C. Superior vena cava (Correct Answer)
- D. Brachiocephalic
Explanation: ***Superior vena cava*** - The **azygos vein** is a major venous channel that drains the walls of the thorax and abdomen, emptying directly into the **superior vena cava (SVC)**. [1] - This connection is crucial for venous return from the posterior thoracic wall, pericardium, and bronchi, especially bypassing the inferior vena cava if it's obstructed. [1] *Right subcostal vein* - The right subcostal vein is a tributary that helps form the **azygos vein**; it does not receive drainage from the azygos vein. - It contributes to the initial formation of the azygos system, not its termination. *Brachiocephalic* - The **brachiocephalic veins** are formed by the union of the internal jugular and subclavian veins, and they merge to form the **superior vena cava**. - The azygos vein drains into the superior vena cava, not directly into the brachiocephalic veins. *Right ascending lumbar vein* - The **right ascending lumbar vein** is a major tributary that contributes to the formation of the **azygos vein** in the lumbar region. - It drains into the azygos system, illustrating its origin rather than its termination.
Question 122: Arch of aorta begins at which vertebral level?
- A. T2
- B. T5
- C. T3
- D. T4 (Correct Answer)
Explanation: ***T4*** - The **arch of the aorta** typically begins at the level of the **upper border of the fourth thoracic vertebra (T4)**. - This anatomical landmark is crucial for understanding the **topography of the mediastinum** and the branching of the great vessels. *T2* - The **T2 vertebral level** is too high; the arch of the aorta does not begin this superiorly. - This level is often associated with structures like the **trachea** and **esophagus** in the superior mediastinum, but not the aortic arch's origin. *T3* - The **T3 vertebral level** is also too high for the typical origin of the aortic arch. - The **manubrium of the sternum** generally extends down to this level, but the aorta's arch begins slightly lower. *T5* - The **T5 vertebral level** is too low; at this point, the arch of the aorta has usually already passed posteriorly and begun its descent as the **descending aorta** [1]. - The **bifurcation of the trachea** typically occurs at the T4/T5 intervertebral disc level. *T2* - The left recurrent laryngeal nerve (RLN) separates from the vagus as it passes anterior to the arch of the aorta [1].
Question 123: Intercostal nerve is a branch of?
- A. Brachial plexus
- B. Dorsal rami of thoracic spinal nerves
- C. Ventral rami of thoracic spinal nerves (Correct Answer)
- D. Ventral rami of cervical spinal nerves
Explanation: ***Ventral rami of thoracic spinal nerves*** - Intercostal nerves are direct continuations of the **ventral rami of the thoracic spinal nerves** (T1-T11) [1]. - These nerves run within the **intercostal spaces**, providing sensory and motor innervation to the thoracic wall [2]. *Brachial plexus* - The brachial plexus is formed by the **ventral rami of spinal nerves C5-T1**. - It primarily innervates the **upper limb**, not the intercostal spaces. *Dorsal rami of thoracic spinal nerves* - The dorsal rami of thoracic spinal nerves supply the **deep back muscles** and the skin over the back. - They do not contribute to the innervation of the intercostal spaces or the anterior/lateral thoracic wall. *Ventral rami of cervical spinal nerves* - The ventral rami of cervical spinal nerves form the **cervical plexus (C1-C4)** and contribute to the **brachial plexus (C5-T1)**. - They innervate structures in the neck, diaphragm, and upper limb, but not the intercostal region.
Question 124: Distance of cricopharynx from incisor teeth
- A. 22 cm
- B. 27 cm
- C. 40 cm
- D. Approximately 15 cm (Correct Answer)
Explanation: ***Approximately 15 cm*** - The **cricopharynx** (upper esophageal sphincter at C6 level), which is the narrowest part of the pharynx, is typically located about **15 cm** from the incisor teeth in adults. - This anatomical landmark is crucial in procedures such as **endoscopy**, **intubation**, and **nasogastric tube insertion** to avoid injury. *22 cm* - This distance corresponds to the level of the **aortic arch** (second physiological narrowing of the esophagus). - This is where the aorta crosses anterior to the esophagus, creating the broncho-aortic constriction. *27 cm* - A distance of 27 cm from the incisor teeth corresponds to the level where the **left main bronchus** crosses the esophagus (third physiological narrowing). - This is well beyond the location of the **cricopharynx** and represents the mid-esophageal region. *40 cm* - This measurement represents the approximate total length of the **esophagus**, reaching the **gastroesophageal junction** at the level of the **diaphragmatic hiatus** (cardia of the stomach). - The **cricopharynx** is at the very beginning of this path, much closer to the incisors.
Question 125: All veins open in sinus venarum except -
- A. SVC
- B. Coronary sinus
- C. Anterior cardiac vein (Correct Answer)
- D. Small cardiac vein
Explanation: ***Anterior cardiac vein*** - The **anterior cardiac veins** are unique in that they drain **directly into the right atrium** through small openings (foramina) in the anterior atrial wall, **bypassing the sinus venarum entirely**. - Unlike other cardiac veins, they do **not** drain into the **coronary sinus** or the **sinus venarum**. - They typically number 2-3 veins and drain the anterior surface of the right ventricle. *SVC* - The **superior vena cava (SVC)** opens directly into the **superior part of the sinus venarum** of the right atrium. - It carries deoxygenated blood from the upper body, head, neck, and upper limbs to the heart. *Coronary sinus* - The **coronary sinus** is the largest venous drainage channel of the heart and opens into the **posteromedial part of the sinus venarum**. - It collects blood from most cardiac veins, including the great cardiac vein, middle cardiac vein, and small cardiac vein. *Small cardiac vein* - The **small cardiac vein** drains into the **coronary sinus**, which then opens into the **sinus venarum**. - It runs along the right atrioventricular (coronary) groove and drains the right atrium and right ventricle.
Question 126: Which of the following statements about the atrioventricular groove is true?
- A. Contains left anterior descending coronary artery
- B. Also called coronary sulcus (Correct Answer)
- C. Contains posterior descending artery
- D. Contains left coronary artery
Explanation: ***Also called coronary sulcus*** - The **atrioventricular groove** is a critical anatomical landmark that separates the atria from the ventricles on the external surface of the heart. - This anatomical division is consistently referred to as the **coronary sulcus**, which encircles the entire heart. *Contains left anterior descending coronary artery* - The **left anterior descending (LAD) coronary artery**, also known as the anterior interventricular artery, lies within the **interventricular groove** (or sulcus), not the atrioventricular groove. - The interventricular groove separates the left and right ventricles, distinct from the atrioventricular separation. *Contains left coronary artery* - The **left coronary artery (LCA)** is a short main trunk that almost immediately divides into the **left anterior descending** (LAD) and **circumflex arteries** [1]. - While the **circumflex artery** (a branch of the LCA) runs in the left part of the atrioventricular groove, the main left coronary artery itself is too short to be considered within the groove [1]. *Contains posterior descending artery* - The **posterior descending artery (PDA)**, also known as the posterior interventricular artery, lies within the **posterior interventricular groove**, separating the ventricles posteriorly. - The PDA is a branch of either the right coronary artery (in most people) or the circumflex artery, but it follows the interventricular septum, not the atrioventricular border.
Question 127: Which artery supplies the anterior part of the interventricular septum?
- A. Right coronary artery
- B. Posterior descending coronary artery
- C. Left anterior descending artery (LAD) (Correct Answer)
- D. None of the options
Explanation: ***Left anterior descending artery (LAD)*** - The **LAD** is a branch of the **left main coronary artery** and is also known as the "widowmaker" due to its critical supply to a large portion of the left ventricle and the interventricular septum [1]. - It gives rise to **septal branches** that typically supply the anterior two-thirds of the interventricular septum [1]. *Right coronary artery* - The **right coronary artery (RCA)** primarily supplies the **right ventricle**, the right atrium, the SA node (in 60% of people), and the AV node (in 90% of people). - It typically supplies the **inferior wall** of the left ventricle and the posterior one-third of the interventricular septum [1]. *Posterior descending coronary artery* - The **posterior descending artery (PDA)** arises from the **RCA** (in approximately 85% of individuals, known as right dominance) or less commonly from the circumflex artery (in left dominance) [1]. - It supplies the **posterior one-third** of the interventricular septum and typically the inferior wall of the left ventricle [1]. *None of the options* - This option is incorrect because the **LAD** clearly and predominantly supplies the anterior part of the interventricular septum.
Question 128: Which of the following does not directly drain into right atrium?
- A. Inferior vena cava
- B. Great cardiac vein (Correct Answer)
- C. Anterior cardiac vein
- D. Venae cordis minimi
Explanation: ***Great cardiac vein*** - The **great cardiac vein** drains into the **coronary sinus**, which then empties into the right atrium [1]. - It does not drain directly into the right atrium, distinguishing it from the other options. *Inferior vena cava* - The **inferior vena cava** is one of the major vessels that drains directly into the **right atrium**. - It carries deoxygenated blood from the lower body to the right atrium. *Anterior cardiac vein* - The **anterior cardiac veins** drain directly into the **right atrium**. - They tend to drain the anterior surface of the right ventricle. *Venae cordis minimi* - Also known as **Thebesian veins**, these are small veins that drain directly into the cardiac chambers, including the **right atrium**. - They represent a direct communication between the myocardial capillaries and the cardiac chambers.
Question 129: Which are the segments of the upper lobe of the right lung?
- A. Lateral, medial, superior
- B. Apical, anterior, posterior (Correct Answer)
- C. Basal, medial, lateral
- D. Anterior, posterior, medial
Explanation: ***Apical, anterior, posterior*** - The **right upper lobe** is consistently divided into three bronchopulmonary segments: **apical**, **anterior**, and **posterior** [1]. - These segments are named according to their anatomical position and the branching of the **tertiary bronchi** that supply them [1]. *Anterior, posterior, medial* - While **anterior** and **posterior** segments exist, the "medial" segment is not a standard division of the right upper lobe. - The term "medial" is typically associated with the **middle lobe** of the right lung (medial and lateral segments) [1]. *Lateral, medial, superior* - The segments **lateral** and **medial** are characteristic of the **right middle lobe** [1]. - "Superior" is a general directional term and not a specific segment name within the upper lobe in this context, although the apical segment is superiorly located. *Basal, medial, lateral* - **Basal** segments are found in the **lower lobes** of the lungs (e.g., anterior basal, medial basal, posterior basal, lateral basal). - **Medial** and **lateral** segments are typical of the **right middle lobe**, not the upper lobe [1].
Question 130: What is the uppermost structure in left lung hilum?
- A. Pulmonary artery (Correct Answer)
- B. Pulmonary vein
- C. Bronchial artery
- D. Left mainstem bronchus
Explanation: ***Pulmonary artery*** - In the **left lung hilum**, the **pulmonary artery** typically lies superior to the bronchus. - This anatomical position helps differentiate it from the relations in the right lung hilum, where the pulmonary artery is anterior to the bronchus. *Pulmonary vein* - The **pulmonary veins** are usually located anterior and inferior to the bronchus in both lung hila. - They tend to be the most anterior and inferior structures carrying oxygenated blood from the lungs. *Bronchial artery* - **Bronchial arteries** are smaller vessels that typically run on the posterior surface of the bronchi. - They are not considered the uppermost main structure in the hilum. *Left mainstem bronchus* - The **left mainstem bronchus** is usually found inferior to the pulmonary artery and posterior to the pulmonary veins in the left hilum. - It is a prominent structure but not the most superior.