Anatomy clinical correlates: Heart

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A 24-year-old man is brought to the emergency department after an altercation. Per emergency medical services, the patient sustained a stab wound to the right anterior chest. The patient’s temperature is 37°C (98.6°F), pulse is 132/min, respirations are 24/min, blood pressure is 90/64 mmHg, and O2 saturation is 94% on room air. Physical examination demonstrates a 1 cm stab wound at the fourth intercostal space parasternally,  in addition to jugular venous distension. A bedside ultrasound of the patient’s heart is demonstrated below. A procedure to alleviate the worsening of this patient’s clinical condition should take place at which of the following anatomic locations?  


Reproduced from: wikipedia 

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Have you ever wondered what the secret to someone’s heart is? That's right, a chest x-ray! All right, so, here at Osmosis we don't actually have the secret to one’s heart, but we do know how to identify the different medical conditions that can affect the heart.

Let's start off by identifying the heart borders on a chest x-ray. The heart silhouette is between the lungs, and the right border, made up by the right atrium, as well as the left border, made up by the left ventricle and part of the left auricle, can be clearly seen. Above the left auricle, we can identify the pulmonary artery and the aortic arch. And in some clinical circumstances, the silhouette sign can be present, which is when the normal heart silhouette of the heart compared to the lungs is lost. More appropriately, you might want to think about it as a “loss of the heart silhouette”. The loss of the heart silhouette only occurs when the pathological process is in direct anatomical contact with the heart. Usually, the middle lobe is seen close to the right border of the heart. So, consolidation in the right middle lobe can also obscure the x-ray silhouette of the right heart border.

All right, now, even though the heart is protected by the sternum and thoracic cage, it’s still susceptible to injury. During penetrating trauma, like, for example, a stab wound, the right ventricle is the most commonly injured structure because of its anterior position in the chest and the fact that it forms the majority of the anterior surface of the heart, followed by the left ventricle which forms the apex of the heart and may be injured as far laterally as the left midclavicular line at the 5th intercostal space. The atria are less commonly injured than the ventricles. It’s also worth noting that the lungs overlap most of the anterior surface of the heart, so many penetrating injuries to the heart will also result in concurrent lung injury particularly to the parietal pleura.

Are you ready to listen to your heart? We’re now going to talk about heart auscultation! The gist of it is to listen to the areas that best project the sound coming from each heart valve. Blood tends to carry the sounds in the direction of its flow so each area is situated superficial to the chamber or vessel into which the blood has passed and in a direct line with the valve orifice.

Sources

  1. "Essential Clinical Anesthesia Review" Cambridge University Press (2015)
  2. "Textbook of Cardiovascular Medicine" Lippincott Williams & Wilkins (2006)
  3. "Understanding Heart Disease" Univ of California Press (1992)
  4. "Cardiac tamponade" Journal of the American Academy of Physician Assistants (2014)
  5. "A Historical Review of Penetrating Abdominal Trauma" Critical Care Nursing Clinics of North America (2006)
  6. "Paroxysmal Supraventricular Tachycardia" Critical Care Nursing Clinics of North America (2016)
  7. "The development of coronary artery surgery: personal recollections" Tex Heart Inst Journal (2002)