The Thoracic Cavity

From WikiMD free wellness and medical encyclopedia
Jump to: navigation, search

Anatomy > Gray's Anatomy of the Human Body > V. Angiology > 4. The Thoracic Cavity

Henry Gray (1821–1865). Anatomy of the Human Body. 1918. 4. The Thoracic Cavity The heart and lungs are situated in the thorax, the walls of which afford them protection. The heart lies between the two lungs, and is enclosed within a fibrous bag, the pericardium while each lung is invested by a serous membrane, the pleura The skeleton of the thorax, and the shape and boundaries of the cavity, have already been described (page 117). The Cavity of the Thorax—The capacity of the cavity of the thorax does not correspond with its apparent size externally, because (1) the space enclosed by the lower ribs is occupied by some of the abdominal viscera; and (2) the cavity extends above the anterior parts of the first ribs into the neck. The size of the thoracic cavity is constantly varying during life with the movements of the ribs and diaphragm, and with the degree of distention of the abdominal viscera. From the collapsed state of the lungs as seen when the thorax is opened in the dead body, it would appear as if the viscera only partly filled the cavity, but during life there is no vacant space, that which is seen after death being filled up by the expanded lungs. The Upper Opening of the Thorax—The parts which pass through the upper opening of the thorax are, from before backward, in or near the middle line, the Sternohyoideus and Sternothyreoideus muscles, the remains of the thymus, the inferior thyroid veins, the trachea, esophagus, thoracic duct, and the Longus colli muscles; at the sides, the innominate artery, the left common carotid, left subclavian and internal mammary arteries and the costocervical trunks, the innominate veins, the vagus, cardiac, phrenic, and sympathetic nerves, the greater parts of the anterior divisions of the first thoracic nerves, and the recurrent nerve of the left side. The apex of each lung, covered by the pleura, also projects through this aperture, a little above the level of the sternal end of the first rib. The Lower Opening of the Thorax—The lower opening of the thorax is wider transversely than from before backward. It slopes obliquely downward and backward, so that the thoracic cavity is much deeper behind than in front. The diaphragm (see page 404) closes the opening and forms the floor of the thorax. The floor is flatter at the center than at the sides, and higher on the right side than on the left; in the dead body the right side reaches the level of the upper border of the fifth costal cartilage, while the left extends only to the corresponding part of the sixth costal cartilage. From the highest point on each side the floor slopes suddenly downward to the costal and vertebral attachments of the diaphragm; this slope is more marked behind than in front, so that only a narrow space is left between the diaphragm and the posterior wall of the thorax.

Gray's Anatomy Contents | Gray's Anatomy Subject Index

About Classic Gray's Anatomy

External Links

WikiMD Sponsors: W8MD Weight Loss, Sleep & Medical Aesthetics

Laser scar treatment before and after

Tired of being overweight or obese? W8MD's insurance weight loss program can HELP

  • W8MD IV Nutrition: Our IM and IV nutrition therapy includes booster shots for B12, vitamin B complex, Vitamin C, Detox treatments and IV nutrition therapy. learn more…
W8MD weight loss locations: Philadelphia weight loss | King of Prussia, PA weight loss | NYC weight loss | NJ weight loss

Medical Aesthetics

Contact us (718) 946-5501 | Why advertise on WikiMD?

Disclaimer: The entire contents of WIKIMD.ORG are for informational purposes only and do not render medical advice or professional services. If you have a medical emergency, you should CALL 911 immediately! Given the nature of the wiki, the information provided may not be accurate and or incorrect. Use the information on this wiki at your own risk! See full Disclaimers.WikiMD is supported by W8MD Weight loss, Poly-Tech Sleep & Medical Aesthetic Centers of America.