Human rib cage

From Wikipedia, the free encyclopedia

(Redirected from Rib cage)
Jump to: navigation, search
Human rib cage
The human rib cage. (Source: Gray's Anatomy of the Human Body, 20th ed. 1918.)
Dorlands/Elsevier c_01/12204262

The human rib cage is a part of the human skeleton within the thoracic area. A typical human ribcage consists of 24 ribs, 12 on each side of the thoracic cavity, the sternum and the 12 thoracic vertebrae in both males and females.

Contents

The number of ribs was noted by the Flemish anatomist Vesalius in 1543, setting off a wave of controversy, as it was traditionally assumed from the Biblical story of Adam and Eve that men's ribs would number one fewer than women's. (De humani corporis fabrica[1]) A small proportion of people have one pair more or fewer but this is unrelated to sex. Humans have seven true ribs, each with its own connection to the sternum. Humans also have five false ribs, the first three of which connect to the one above it. The last two, which don't connect to the sternum, are called floating ribs.

Ribs are attached behind the vertebral column.Your ribs help you to be able to breathe as when you inhale the ribs lift the rib cage allowing your lungs to expand and when you exhale they close squeezing the air out of your lungs.

The 12 pairs of ribs are attached behind to the thoracic vertebrae. The upper 7 are attached to the sternum by means of costal cartilage. Due to their elasticity they allow movement during inspiration and expiration. The 8th, 9th and 10th ribs join to the costal cartilages above and the 11th and 12th ribs are known as floating ribs. The rib cage encases and protects the lungs and the heart.

Anterior surface of sternum and costal cartilages.
Anterior surface of sternum and costal cartilages.
  • The first seven pairs of ribs are connected to the sternum in front and are known as true ribs or vertebrosternal ribs (costae verae, I-VII).
  • The eighth, ninth, and tenth attached in front to the cartilaginous portion of the next rib above and are known as false ribs or vertebrochondral ribs (costae spuriae, VIII-X).
  • The lower two, that is the eleventh and twelfth, are not attached in front and are called floating ribs or vertebral ribs (costae fluitantes, XI-XII).
  • In some humans, the rib remnant of the 7th cervical vertebra on one or both sides is replaced by a free extra rib called a cervical rib, which can cause problems in the nerves going to the arm.

The spaces between the ribs are known as intercostal spaces; they contain the intercostal muscles, nerves, and arteries. The rib cage allows for breathing due to its elasticity.

The atypical ribs are the 1st, 2nd, and 10th to 12th.

  • The first rib has a shaft that is wide and nearly horizontal, and has the sharpest curve of the seven true ribs. Its head has a single facet to articulate with the first thoracic vertebra (T1). It also has two grooves for the subclavian vessels, which are separated by the scalene tubercle.
  • The second rib is thinner, less curved, and longer than the first rib. It has two facets to articulate with T2 and T1, and a tubercle for muscles to attach to.
  • The 10th to 12th ribs have only one facet on their head; the 11th and 12th ribs are short with no necks or tubercles and terminate in the abdominal wall before fusing with the costal cartilages.

  • Rib fractures can occur. These most frequently affect the middle ribs. When several ribs are injured, this can result in a flail chest.

  1. ^ Chapter 19 On the Bones of the Thorax. Retrieved on 2007-08-23.
  • Clinically Oriented Anatomy, 4th ed. Keith L. Moore and Robert F. Dalley. pp. 62-64
  • Principles of Anatomy and Physiology, 11th ed. Gerard J. Tortora and Bryan Derrickson. pp. 222-4
Advanced Search
Included Web Search Engines


Safe Search

close

Top Matching Results

Occasionally Search.com will highlight specialized results that are based on the context of your query. Examples of specialized results include specific links to news, images, or video.

Top Matching Results may highlight information from other Search.com pages, content from the CNET Network of sites, or third party content. The listings are based purely on relevance. Search.com does not receive payment for listings in this section but our partners that provide this data may get paid for listing these products.

Sponsored Links

This section contains paid listings which have been purchased by companies that want to have their sites appear for specific search terms and related content. These listings are administered, sorted and maintained by a third party and are not endorsed by Search.com.

Search Results

Search.com sends your search query to several search engines at one time and integrates the results into one list which has been sorted by relevance using Search.com's proprietary algorithm. You can customize the list of search engines included in your metasearch from the preferences.

The search engines that are used in your metasearch may allow companies to pay to have their Web sites included within the results. To view the Paid Inclusion policy for a specific search engine, please visit their Web site. Search.com does not accept payment or share revenue with any search engine partner for listings in this section.