Lecture Notes: Anatomy of the Thoracic Cavity

Overview

• Focus: Examination of internal organs in the thoracic cavity.
• Definition: The thorax is the area between the neck and the abdomen, encompassing the rib cage and upper back but excluding the clavicle and scapula.

Components of the Thorax

• Sternum

  • Three parts: Manubrium (upper), Body (middle), Xiphoid Process (tip).
  • Connected via costocartilage to ribs.

• Thoracic Vertebrae

  • Total of 12, each connected to a rib.

• Ribs

  • 12 ribs corresponding to the 12 thoracic vertebrae.

• Skeletal Muscles

  • Pectoralis Major and Pectoralis Minor

Internal Organs in the Thoracic Cavity

• Diaphragm

  • Skeletal muscle separating the thoracic and abdominal cavities; aids in breathing.

• Lungs

  • Right lung: 3 lobes.
  • Left lung: 2 lobes, includes the lingula, possibly a remnant of a third lobe.

• Mediastinum

  • Houses the heart, aorta, pulmonary trunk, and nerves.
  • Contains the pericardium, a connective tissue layer around the heart.
  • Heart: Positioned within the mediastinum.

• Blood Vessels

  • Ascending Aorta: Largest blood vessel.
  • Pulmonary Trunk: Works with the ascending aorta to transport blood away from the heart.
  • Superior and Inferior Vena Cava: Carry deoxygenated blood to the heart.

• Nerves

  • Phrenic Nerve: Controls the diaphragm, essential for breathing.

• Other Structures

  • Esophagus and Trachea: Located behind the heart and aorta, transporting food and air respectively.

Additional Information

• Thymus: A gland that degenerates with age, situated in the thoracic cavity.
• Epicardial Fat: Normal fat tissue residing on the heart.

Conclusion and Call to Action

• Observation: Although the thoracic cavity seems simple, it contains many critical structures.
• Encouragement: Like, comment, subscribe, explore additional resources like the digital coloring book based on lab cadaver images.