In the same midesophageal position, the probe is rotated so that it now faces posteriorly. Which of the following structures will be best visualized with the probe's new orientation?

Question

In the same midesophageal position, the probe is rotated so that it now faces posteriorly.  Which of the following structures will be best visualized with the probe's new orientation?

Quizplus · Accepted Answer

11ec160b_3557_a41c_9249_954ea64c27cb_MD0001_00 The aorta has 4 major divisions: the ascending aorta, the aortic arch, the descending thoracic aorta, and the abdominal aorta. The ascending aorta lies posterior and to the right of the main pulmonary artery. The aortic arch travels above the right pulmonary artery and the left bronchus. The brachiocephalic, left common carotid, and left subclavian arteries (in that order) originate from its superior aspect. The descending thoracic aorta travels down the anterior surface of the vertebral column, becoming the abdominal aorta as it crosses the diaphragm. As it descends, the aorta moves from the left side of the vertebral column toward the midline; at the level of the cardiac chambers, the descending aorta lies posterior to the esophagus and the left atrium. This permits clear visualization of the descending aorta during transesophageal echocardiography (TEE), allowing for the detection of abnormalities such as dissection or aneurysm. The other answer choices describe structures located anterior to the esophagus. (Choice B) The main pulmonary artery ascends anteriorly and to the left of the ascending aorta and is directed toward the left shoulder. After the pulmonary artery bifurcates, the right pulmonary artery travels horizontally under the aortic arch posterior to the superior vena cava, and the left pulmonary artery courses superiorly over the left main bronchus. (Choice C) The superior and inferior pulmonary veins arise bilaterally from each lung and enter the left atrium. The proximal 2-3 cm of the pulmonary veins contain cardiac muscle within the media and function like sphincters during atrial systole. (Choice D) The superior vena cava (SVC) is formed behind the right first costal cartilage by the merger of the right and left brachiocephalic veins. It returns blood from the head, neck, and upper extremities to the right atrium of the heart. Mediastinal neoplasms can compress the SVC and result in SVC syndrome. (Choice E) The tricuspid valve is located between the right atrium and right ventricle and is composed of 3 valve leaflets, the annulus, supporting chordae tendineae, and the papillary muscles. It is commonly infected (endocarditis) in intravenous drug users. Educational objective: The descending thoracic aorta lies posterior to the esophagus and the left atrium. This position permits clear visualization of the descending aorta by transesophageal echocardiography, allowing for the detection of abnormalities such as dissection or aneurysm.

In the Same Midesophageal Position, the Probe Is Rotated So