THORAX FORUM What is the blood supply and innervation (sensory/motor) to the superior and inferior surface of the diaphragm? Thoracic Wall Case 1: During your third year rotations you observe a resident perform a thoracocentesis to sample pleural fluid. He inserts the needle near the lower border of the 8th rib at the right midaxillary line. The next day, during rounds, his patient is complaining of tingling and loss of sensation over the skin of his chest near the 8th rib and down toward his umbilicus on the same side as his thoracocentesis. Why did the resident select the 8th intercostal space for insertion? Why did the patient develop numbness and tingling (paresthesia)? What structure was damaged resulting in the paresthesia? What other structures are associated with the damaged structure? How are they arranged? What two muscle layers are they between? Where should the insertion have been made to avoid damage? Other than sampling fluid, thoracocentesis could be used to…? What structures, in order, would the needle pass through during a thoracocentesis? Lung Case A 12 year old boy was helping his mom clean up the morning after a party when he suddenly started to choke. The mother tried to do a Heimlich maneuver on him to no avail. Nothing was expelled from his mouth. He started to have difficulty breathing (dyspnea) so she called the doctor and went to the ER. When asked what the child ate she responded that she didn’t see him eat anything but maybe he got a peanut off of the floor. The child was in respiratory distress, with coughing and dyspnea. The doctor noted limited movement of the right side of his chest and reduced breath sounds on the right. A bronchoscopy revealed a peanut in the right middle lobe bronchus which was removed with forceps passed through the bronchoscope. Why had the peanut fallen down the right side? What do you suppose would have eventually happened to the lobes blocked by the peanut? How do collapsed lungs differ from aerated lungs on radiographs? Cardio Case 1: A 57 year old male is brought into the ER by his wife. The wife explains that her husband complains of a sharp, squeezing pain behind his sternum and has had such bouts repeatedly over several years. A diagnosis of an acute myocardial infarction (MI) is made. What is the most common site of occlusion responsible for MI? What part of the cardiac conduction system might be affected by occlusion to this artery? What neural structure carries visceral pain fibers from the heart and results in referred pain from the heart? And to what levels is the pain referred? Superior Mediastinum Case 1: An 18 year old student has high blood pressure (b.p.) during a physical exam. His b.p. is significantly higher in both upper limbs than it is in his lower limbs. What condition covered in lecture could result in higher b.p. in upper vs. lower limbs? What osteological effects, if any, would help in the diagnosis? What would angiography reveal? What vessels would have retrograde flow of blood? Superior Mediastinum Case 2: Examining a 12 y.o. boy on a routine physical to play school soccer, the physician noticed a heart murmur. The mother recalled that he had bouts of cyanosis and breathlessness as an infant, but his pediatrician was not concerned. The boy also admits that he tires easily. Radiographs revealed left ventricular hypertrophy, and ultrasound revealed a patent ductus arteriosus. Surgery was performed to ligate his ductus arteriosus. The surgery was successful, but he experienced hoarseness when speaking following the procedure. What probably was the cause of the boy’s hoarseness? Superior Mediastinum Case 3: While inserting a central line into his patient’s subclavian vein, a surgical resident had a difficult time and had three attempts before he was successful. Examination of a chest radiograph revealed a pneumothorax. Why had the lung probably collapsed? Breast Case/Lymphatics: A 54 year old woman presents to her physician complaining of chest and back pain following a fall. On physical examination, the physician finds a mass in her breast. The woman admits that she does not perform self breast exams and has not had them examined for several years. A mammogram shows a large mass consistent with cancer in her breast. Is breast tissue confined to the “breast”? What lymph nodes might show cancer cells? Thoracic ANS Case 1: An 80 year old patient who has smoked since the age of 16 presents to your office with hoarseness of his voice and a constricted pupil in his right eye. Where is his lung tumor located? Thorax General Case 1: After a surgery to his upper chest, a patient has lost innervation to the right side of his diaphragm. What nerve supplies the diaphragm and was injured? On inspiration, the right side of his diaphragm moves upward. Why? The diaphragm has three large hiatuses. What major structure passes through them and at what vertebral level? And what other structures pass through with each of them? Thorax General Case 2: After a 24 hour plane flight in cramped conditions, a 45 year old woman suffers a DVT which leads to a stroke (blockage of brain arteries). How could the thrombus end up in her brain? What is the path of a DVT that results in a pulmonary embolus? Thorax General Case 3: A 65 year old. woman is admitted to the hospital complaining of shortness of breath and difficulty swallowing. She coughs up blood during the exam and speaks with a hoarse voice. Diagnosis is made of an esophageal carcinoma that commonly occurs at a site of constriction of the esophagus where it is indented by the left main bronchus. What other structures constrict/indent the esophagus? Why would the patient have a hoarse voice? If her carcinoma expands anteriorly into the middle mediastinum, what structure might initially become compressed? Thorax General questions: 1. Explain why regional referred pain is found in predictable areas based on the organ experiencing pain. What dermatomal levels does heart pain refer to? 2. You see a patient who you diagnose with pleurisy. One of her complaints is pain in the dermatomal area of C3-C5. Why is her pain occurring in this region? What does this tell you about the region of her pleura that is affected? Heart/Lung questions: Explain why pulmonary valve stenosis or tricuspid valve regurgitation could lead to edema in the limbs. Explain why mitral valve regurgitation or aortic valve stenosis could lead to pulmonary edema.
