[ANA] Thorax/Abdomen/Pelvis Reviewer (2026) Flashcards
- Which structure separates the thoracic cavity from the abdominal cavity?
- A) Trachea
- B) Esophagus
- C) Diaphragm
- D) Sternum
C) Diaphragm
Rationale: The diaphragm is a large, dome-shaped muscle that plays a crucial role in breathing and acts as a physical barrier between the thoracic cavity (containing the heart and lungs) and the abdominal cavity (containing digestive organs).
- Which of the following is NOT a part of the sternum?
- A) Manubrium
- B) Body
- C) Xiphoid process
- D) Clavicle
D) Clavicle
Rationale: The sternum consists of three parts: the manubrium, body (gladiolus), and xiphoid process. The clavicle, or collarbone, is a separate bone that articulates with the sternum but is not part of it.
- Which major vessel carries deoxygenated blood from the right ventricle to the lungs?
- A) Aorta
- B) Pulmonary artery
- C) Pulmonary vein
- D) Superior vena cava
B) Pulmonary artery
Rationale: The pulmonary artery is the vessel that carries deoxygenated blood from the right ventricle of the heart to the lungs for oxygenation.
- The primary muscle involved in inspiration is the:
- A) External intercostal muscles
- B) Internal intercostal muscles
- C) Diaphragm
- D) Abdominal muscles
C) Diaphragm
Rationale: During inspiration, the diaphragm contracts and flattens, increasing the thoracic cavity’s volume and allowing air to be drawn into the lungs.
- Which structure is located in the mediastinum?
- A) Lungs
- B) Heart
- C) Liver
- D) Kidneys
B) Heart
Rationale: The mediastinum is the central compartment of the thoracic cavity, which contains the heart, great vessels, trachea, esophagus, and other structures, but not the lungs themselves.
- The right lung has how many lobes?
- A) 2
- B) 3
- C) 4
- D) 5
B) 3
Rationale: The right lung has three lobes: the superior, middle, and inferior lobes. The left lung has only two lobes due to space taken up by the heart.
- The trachea bifurcates at the level of the:
- A) Sternal angle
- B) Jugular notch
- C) Xiphoid process
- D) Clavicular notch
A) Sternal angle
Rationale: The trachea bifurcates, or splits, into the right and left main bronchi at the level of the sternal angle (the angle of Louis), which is located at the junction of the manubrium and the body of the sternum, around the level of the second rib.
- The pleural cavity is the space between the:
- A) Heart and lungs
- B) Visceral and parietal pleurae
- C) Lungs and diaphragm
- D) Ribs and intercostal muscles
B) Visceral and parietal pleurae
Rationale: The pleural cavity is the thin fluid-filled space between the two layers of the pleurae—the visceral pleura (covering the lungs) and the parietal pleura (lining the thoracic cavity).
- Which structure is responsible for the conduction of electrical impulses in the heart?
- A) Atrioventricular node
- B) Sinoatrial node
- C) Bundle of His
- D) Purkinje fibers
B) Sinoatrial node
Rationale: The sinoatrial (SA) node is known as the natural pacemaker of the heart. It generates electrical impulses that spread throughout the heart, prompting it to contract.
- The main function of the intercostal muscles is to:
- A) Protect the heart
- B) Assist in breathing
- C) Support the ribs
- D) Maintain posture
B) Assist in breathing
Rationale: The intercostal muscles, located between the ribs, play a key role in the mechanics of breathing by helping to expand and contract the chest cavity during inspiration and expiration.
- Which vessel returns oxygenated blood from the lungs to the heart?
- A) Pulmonary artery
- B) Pulmonary vein
- C) Superior vena cava
- D) Aorta
B) Pulmonary vein
Rationale: The pulmonary veins carry oxygenated blood from the lungs back to the left atrium of the heart.
- Which nerve innervates the diaphragm?
- A) Vagus nerve
- B) Phrenic nerve
- C) Intercostal nerve
- D) Spinal accessory nerve
B) Phrenic nerve
Rationale: The phrenic nerve originates from the cervical spinal cord (C3-C5) and is responsible for motor and sensory innervation of the diaphragm, essential for breathing.
- The thoracic duct drains lymph into the:
- A) Right subclavian vein
- B) Left subclavian vein
- C) Superior vena cava
- D) Inferior vena cava
B) Left subclavian vein
Rationale: The thoracic duct drains lymph from the majority of the body into the left subclavian vein at its junction with the internal jugular vein.
- The azygos vein is primarily associated with draining blood from the:
- A) Abdomen
- B) Lower limbs
- C) Thoracic wall
- D) Heart
C) Thoracic wall
Rationale: The azygos vein drains the thoracic wall and the posterior walls of the abdomen into the superior vena cava.
- The structure that prevents food from entering the respiratory tract is the:
- A) Epiglottis
- B) Trachea
- C) Larynx
- D) Esophagus
A) Epiglottis
Rationale: The epiglottis is a flap of tissue that covers the trachea during swallowing to prevent food from entering the respiratory tract.
- Which of the following is a branch of the aortic arch?
- A) Left coronary artery
- B) Right common carotid artery
- C) Brachiocephalic trunk
- D) Left subclavian vein
C) Brachiocephalic trunk
Rationale: The aortic arch gives rise to three major branches: the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery.
- The cardiac notch is a feature of which lung?
- A) Right lung
- B) Left lung
- C) Both lungs
- D) Neither lung
B) Left lung
Rationale: The cardiac notch is an indentation in the left lung that accommodates the space taken up by the heart.
- Which structure forms the anterior border of the thoracic inlet?
- A) Manubrium
- B) First rib
- C) Clavicle
- D) T1 vertebra
A) Manubrium
Rationale: The thoracic inlet is bounded anteriorly by the manubrium of the sternum.
- The coronary arteries arise from which part of the heart?
- A) Left atrium
- B) Right atrium
- C) Ascending aorta
- D) Descending aorta
C) Ascending aorta
Rationale: The coronary arteries branch off from the ascending aorta and supply blood to the heart muscle itself.
- The hilum of the lung is where:
- A) The ribs attach
- B) The diaphragm attaches
- C) The bronchi, blood vessels, and nerves enter and exit
- D) The lung attaches to the heart
C) The bronchi, blood vessels, and nerves enter and exit
Rationale: The hilum is the region of the lung where the bronchi, pulmonary arteries and veins, and nerves enter and exit.
- Which structure is located most anteriorly in the superior mediastinum?
- A. Trachea
- B. Esophagus
- C. Arch of aorta
- D. Thymus
D. Thymus
Rationale: The thymus is the most anterior structure in the superior mediastinum, located immediately behind the sternum and in front of the other structures like the trachea, esophagus, and the arch of the aorta.
- The sternal angle (Angle of Louis) is a landmark for the level of which structure?
- A. T2 vertebra
- B. T4/T5 intervertebral disc
- C. T6 vertebra
- D. T8 vertebra
B. T4/T5 intervertebral disc
Rationale: The sternal angle is located at the level of the T4/T5 intervertebral disc. It is a useful anatomical landmark for locating the bifurcation of the trachea and the beginning of the aortic arch.
- Which vessel is not a direct branch of the aortic arch?
- A. Brachiocephalic trunk
- B. Left common carotid artery
- C. Left subclavian artery
- D. Right subclavian artery
D. Right subclavian artery
Rationale: The aortic arch gives rise to three branches: the brachiocephalic trunk (which further divides into the right subclavian artery and right common carotid artery), the left common carotid artery, and the left subclavian artery. The right subclavian artery is a branch of the brachiocephalic trunk, not a direct branch of the aortic arch.
- The phrenic nerve provides motor innervation to which muscle?
- A. Intercostal muscles
- B. Diaphragm
- C. Serratus anterior
- D. Pectoralis major
B. Diaphragm
Rationale: The phrenic nerve originates from the cervical spinal cord (C3-C5) and provides motor innervation to the diaphragm, the primary muscle involved in breathing.
- Which structure passes through the diaphragm at the level of T10?
- A. Inferior vena cava
- B. Esophagus
- C. Aorta
- D. Thoracic duct
B. Esophagus
Rationale: The esophagus passes through the diaphragm at the level of the T10 vertebra.
- The left recurrent laryngeal nerve loops under which structure?
- A. Right subclavian artery
- B. Aortic arch
- C. Left subclavian artery
- D. Right brachiocephalic vein
B. Aortic arch
Rationale: The left recurrent laryngeal nerve loops under the aortic arch before ascending to the larynx.
- Which vein drains directly into the right atrium?
- A. Azygos vein
- B. Hemiazygos vein
- C. Left superior intercostal vein
- D. Inferior vena cava
D. Inferior vena cava
Rationale: The inferior vena cava is a large vein that carries deoxygenated blood from the lower half of the body directly into the right atrium of the heart.
- The carina is located at which vertebral level?
- A. T2
- B. T4
- C. T6
- D. T8
B. T4
Rationale: The carina, the point where the trachea bifurcates into the right and left main bronchi, is located at the level of the T4 vertebra.
- The coronary sinus primarily drains blood from which area?
- A. Lungs
- B. Heart
- C. Liver
- D. Spleen
B. Heart
Rationale: The coronary sinus collects deoxygenated blood from the heart muscle (myocardium) and drains it into the right atrium.
- The apex of the heart is located at the level of which intercostal space?
- A. 2nd
- B. 4th
- C. 5th
- D. 6th
C. 5th
Rationale: The apex of the heart is located at the level of the 5th intercostal space, along the midclavicular line.
- The parietal pleura is innervated by which nerve?
- A. Phrenic nerve
- B. Vagus nerve
- C. Intercostal nerves
- D. Greater splanchnic nerve
C. Intercostal nerves
Rationale: The parietal pleura, which lines the thoracic cavity, is innervated by the intercostal nerves and the phrenic nerve, providing sensory innervation.
- Which muscle is primarily responsible for the elevation of the ribs during inspiration?
- A. Internal intercostal muscles
- B. External intercostal muscles
- C. Diaphragm
- D. Rectus abdominis
B. External intercostal muscles
Rationale: The external intercostal muscles contract during inspiration, elevating the ribs and expanding the thoracic cavity to allow air to enter the lungs.
- Which structure separates the superior and inferior mediastinum?
- A. Sternal angle
- B. Manubrium
- C. Diaphragm
- D. Heart
A. Sternal angle
Rationale: The sternal angle (Angle of Louis) is the anatomical landmark that separates the superior mediastinum from the inferior mediastinum, located at the level of the T4/T5 intervertebral disc.
- The primary function of the thoracic duct is to:
- A. Transport bile
- B. Carry oxygenated blood
- C. Drain lymph
- D. Transmit nerve impulses
C. Drain lymph
Rationale: The thoracic duct is the largest lymphatic vessel in the body, and its primary function is to drain lymph from most of the body into the venous system.
- Which heart chamber forms the apex of the heart?
- A. Right atrium
- B. Right ventricle
- C. Left atrium
- D. Left ventricle
D. Left ventricle
Rationale: The apex of the heart is formed by the left ventricle, which is responsible for pumping oxygenated blood to the rest of the body.
- The trachea bifurcates into the main bronchi at which anatomical landmark?
- A. T2
- B. T4
- C. T6
- D. T8
B. T4
Rationale: The trachea bifurcates into the right and left main bronchi at the level of the T4 vertebra, near the sternal angle.
- Which of the following structures is not found in the posterior mediastinum?
- A. Esophagus
- B. Thoracic duct
- C. Aorta
- D. Thymus
D. Thymus
Rationale: The thymus is located in the anterior part of the superior mediastinum and does not extend into the posterior mediastinum. The posterior mediastinum contains structures like the esophagus, thoracic duct, and descending aorta.
- The interventricular septum is primarily composed of:
- A. Connective tissue
- B. Adipose tissue
- C. Cardiac muscle
- D. Smooth muscle
C. Cardiac muscle
Rationale: The interventricular septum is a thick wall of cardiac muscle that separates the left and right ventricles.
- Which artery supplies the anterior interventricular septum?
- A. Right coronary artery
- B. Left anterior descending artery
- C. Circumflex artery
- D. Posterior interventricular artery
B. Left anterior descending artery
Rationale: The left anterior descending artery (LAD), a branch of the left coronary artery, supplies the anterior part of the interventricular septum.
- The right lung differs from the left lung in that it:
- A. Has two lobes
- B. Is narrower
- C. Has three lobes
- D. Is longer
C. Has three lobes
Rationale: The right lung has three lobes (superior, middle, and inferior), whereas the left lung has only two lobes (superior and inferior) to accommodate space for the heart.
- Which structure separates the superior and inferior mediastinum?
- A. Sternal angle
- B. Manubrium
- C. Diaphragm
- D. Pericardium
A. Sternal angle
Rationale: The sternal angle, also known as the Angle of Louis, marks the division between the superior and inferior mediastinum.
- Which vein drains into the right atrium?
- A. Pulmonary vein
- B. Superior vena cava
- C. Azygos vein
- D. Coronary sinus
B. Superior vena cava
Rationale: The superior vena cava drains deoxygenated blood from the upper body into the right atrium of the heart.
- The phrenic nerve innervates which muscle?
- A. Intercostal muscles
- B. Diaphragm
- C. Pectoralis major
- D. Serratus anterior
B. Diaphragm
Rationale: The phrenic nerve provides motor innervation to the diaphragm, the primary muscle involved in breathing.
- Which structure is found in the middle mediastinum?
- A. Thymus
- B. Heart
- C. Trachea
- D. Esophagus
B. Heart
Rationale: The middle mediastinum contains the heart, enclosed in the pericardium, as well as the roots of the great vessels.