1st Semester Anatomy TA Week 12 Questions

2.

Which or the following malformations occurring in embryonic development is most likely to cause ONLY dysphagia?

Double SVC
Persistent L. Anterior Cardinal Vein
Retroesophageal Right Subclavian
Double Aortic Arch

Correct Answer

A. Retroesophageal Right Subclavian

Explanation

all the others may compress the trachea as well, but the RSC doesn't involve the trachea. Double SVC would not necessarily cause dysphagia.

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3.

What type of fibers are contained in the Greater Thoracic Splanchnic Nerve?

Post-ganglionic sympathetics fibers from the lateral horn of the spinal cord
Pre-ganglionic parasympathetic fibers that originate from the sympathetic chain ganglia
Post ganglionic parasympathetic fibers from the lateral horn of the spinal cord
Pre-ganglionic sympathetic fibers from the lateral horn of the spinal cord
Pre-ganglionic sympathetic fibers that originate from the sympathetic chain ganglia

Correct Answer

A. Pre-ganglionic sympathetic fibers from the lateral horn of the spinal cord

Explanation

The greater splanchnic nerve contains pre-ganglionic sympathetic fibers that exit the spinal cord from the lateral horn. The lateral horn is associated with sympathetics “thoraco-lumbar”. There is no lateral horn in the “cranio-sacral” (parasympathetic) portions of the spinal cord.
The fibers that exit the spinal cord go through the sympathetic chain, but they do not synapse there. They exit the chain ganglia as the Greater Splanchnic nerve. This nerve the travels to the celiac ganglion (where it synapses) and provides innervation to the abdominal viscera.

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4.

A 65 year-old man presents with dysphagia and hoarseness of voice. A series of images were ordered and you discover a tumor of the posterior mediastinum. Which of the following is the tumor most likely compressing?

Azygos vein
Pulmonary trunk
Trachea
Esophagus
Inferior Vena Cava

Correct Answer

A. Esophagus

Explanation

Of the answer choices listed, only the azygos vein and esophagus are located in the posterior mediastinum. The difficulty in swallowing (dysphagia) suggests it is most likely compressing the esophagus.

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5.

A 54 year-old woman presents to the ER with cardiac tamponade. A pericardiocentesis needs to be done immediately. Where can this procedure be done without puncturing the lungs?

Costomediastinal recess
Costodiaphragmatic recess
Cardiac notch
Cupola
Anterior Mediastinum

Correct Answer

A. Cardiac notch

Explanation

A pericardiocentesis can be done through the 5th or 6th intercostal space at the left sternal border at the cardiac notch of the left lung to avoid puncturing the lungs.

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6.

There are several major structures located at the vertebral level of T4-T5. Which structure is not considered part of this important anatomical location?

Angle of Louis
Border of superior and inferior mediastinum
Rib 2
Ascending aorta
Tracheal Bifurcation

Correct Answer

A. Ascending aorta

Explanation

the Arch of the aorta is more commonly located at the T4-T5 vertebral level.

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7.

The structure lying in between the esophagus and the azygous vein in the posterior mediastinum is injured. The result of injury to this structure may cause:

Hemothorax
Pneumothorax
Chylothorax
Pyothorax
Hydrothorax

Correct Answer

A. Chylothorax

Explanation

Chyle, a form of lymphatic fluid that drains in the Thoracic duct. It lays in between the esophagus and azygos vein before it drains into the brachiocephalic trunk in the superior mediastinum.

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8.

A Floridian returning on an airline flight from China arrives at the emergency department with unexplained shortness of breath, chest pain, and coughing up blood. A blood clot (embolus) is found in the left pulmonary artery. Which of the following structures did this embolus most likely come from?

Pulmonary veins
Left atrium
Right ventricle
Left brachiocephalic vein
Left ventricle

Correct Answer

A. Right ventricle

Explanation

the pulmonary arteries receive blood from the right ventricle. The left ventricle shuttles blood into the aorta. The pulmonary veins contain oxygenated blood and fill the left atrium. The left brachiocephalic vein shuttles blood into the SVC and then into the right atrium. Emboli often arise from stagnant blood in the legs (deep vein thrombosis) and can occur during long flight travel or prolonged bed rest. This travels up the IVC and into the right atrium without involving the left brachiocephalic vein.

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9.

A patient has a 4 day history of a recurrent hiccup reflex. You perform an X-ray and discover a tumor just anterior to the pericardium that you suspect is a germ cell tumor. What nerve being irritated is most likely responsible for the hiccup reflex?

Left Vagus n.
Left recurrent laryngeal n.
Right Vagus n.
Right recurrent laryngeal n.
Left Phrenic n.

Correct Answer

A. Left Phrenic n.

Explanation

The left phrenic nerve travels over the pericardium to innervate the left side of the diaphragm. A mass that irritates it is likely to cause a hiccup reflex. The recurrent laryngeal nerves either loop around the right subclavian or the arch of the aorta and do not travel over the pericardium. If one these nerves were compressed, it would result in hoarseness of voice. The vagus nerves dive deep to the pericardium and form a plexus around the esophagus. Hiccup reflex afferents are phrenic, vagus, and sympathetic T6-T12 (Bailey 1943).

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10.

A patient arrives at the emergency department with neck, face and arm edema, distended arm and neck veins, as well as dilated and tortuous veins on their upper chest and back. You suspect that there is a supra-azygous SVC obstruction. In the lateral thoracic pathway how does the blood make its way back to the heart?

Lateral thoracic --> Intercostals --> Accessory hemiazygos or hemiazygos --> Azygos.
Internal thoracic --> Intercostals --> Accessory hemiazygos or hemiazygos --> Azygos
Lateral thoracic --> thoracoepigastric --> superficial circumflex --> femoral veins --> IVC
Lateral thoracic --> superficial circumflex --> thoracoepigastric --> femoral veins --> IVC
Lateral thoracic --> intercostals --> superficial circumflex --> femoral veins --> IVC

Correct Answer

A. Lateral thoracic --> thoracoepigastric --> superficial circumflex --> femoral veins --> IVC

Explanation

There are three pathways of venous collateral circulation: the azygos-hemiazygous pathway, the internal thoracic pathway, and the lateral thoracic pathway. This one is straight from Posterior mediastinum slides.

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11.

A 65 year-old male presents to the clinic with an acute onset of dyspnea, chest discomfort, and general malaise. On physical examination, the patient presents with enlarged neck veins and edema in the facial and brachial regions. Radiological imaging shows an enlarged thymic shadow. Biopsy results confirm the surgeon's suspected diagnosis and the patient is prepped for surgery. During surgery, the resident surgeon notices a collateral circulation. The attending physician then asks which vascular structure is MOST likely involved in this anastomosis?

Internal Jugular Vein
Subclavian Vein
Gonadal Vein
Azygos Vein
Internal Thoracic Artery

Correct Answer

A. Azygos Vein

Explanation

This is a classic clinical finding of Superior Vena Cava Syndrome. The enlarged thymus and a confirmatory biopsy most likely indicates a thymoma. Remember, after puberty the thymus undergoes involution and its largely replaced with fat in the adult. Hence, a thymic shadow in adults is considered pathological. Furthermore, SVC Syndrome patients commonly present with dyspnea (shortness of breath), enlarged neck veins, and edema due to compression of enlarged surrounding structure(s) such as a thymoma in this case. Think of it kind of like a backlogged toilet if you will ;). To circumvent the situation, your body naturally develops collateral circulation to return the deoxygenated venous blood back into the right atrium. The most important vein involved in this venous anastomoses, is the azygos vein. Physiologically, the azygos vein drains into the SUPERIOR vena cava. During collateral circulation, the azygos vein follows a different route into the lumbar veins, then into the INFERIOR vena cava, and finally into the right atrium.

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1st Semester Anatomy Ta Week 12 Questions

A tumor arising in the posterior mediastinum is LEAST likely to cause which of the following symptoms?

Quiz Preview

Which or the following malformations occurring in embryonic development is most likely to cause ONLY dysphagia?

What type of fibers are contained in the Greater Thoracic Splanchnic Nerve?

A 65 year-old man presents with dysphagia and hoarseness of voice. A series of images were ordered and you discover a tumor of the posterior mediastinum. Which of the following is the tumor most likely compressing?

A 54 year-old woman presents to the ER with cardiac tamponade. A pericardiocentesis needs to be done immediately. Where can this procedure be done without puncturing the lungs?

There are several major structures located at the vertebral level of T4-T5. Which structure is not considered part of this important anatomical location?

The structure lying in between the esophagus and the azygous vein in the posterior mediastinum is injured. The result of injury to this structure may cause:

A Floridian returning on an airline flight from China arrives at the emergency department with unexplained shortness of breath, chest pain, and coughing up blood. A blood clot (embolus) is found in the left pulmonary artery. Which of the following structures did this embolus most likely come from?

A patient has a 4 day history of a recurrent hiccup reflex. You perform an X-ray and discover a tumor just anterior to the pericardium that you suspect is a germ cell tumor. What nerve being irritated is most likely responsible for the hiccup reflex?