Bones and joints of the thoracic wall
00:00 / 00:00
Notes
Bones and Joints of the Thoracic Wall
Transcript
The thorax is the area between the neck and abdomen and consists of the thoracic cavity, its contents, and the walls that surround it.
The thoracic skeleton forms the osteocartilaginous thoracic cage that protects the thoracic viscera and some of the abdominal organs.
This skeleton is made up of the sternum, 12 pairs of ribs and associated costal cartilages, as well as 12 thoracic vertebrae and intervertebral discs interposed between them.
The ribs and costal cartilages form the largest part of the thoracic cage and both can be identified numerically, going from 1 to 12 for the ribs, and going from 1 to 10 for the costal cartilage, as ribs 11 and 12 do not have an associated costal cartilage.
Now, the true thoracic wall includes the thoracic cage and the muscles between the ribs and the skin, as well as subcutaneous tissue, muscles and fascia that cover its anterolateral aspect.
The structures that cover its posterior aspect are considered to belong to the back.
Additionally, the mammary glands of the breasts lie within the thoracic wall subcutaneous tissue, and the anterolateral axioappendicular muscles are also considered part of the thoracic wall.
Okay, let’s start talking about the ribs, which form most of the thoracic cage.
They’re curved, flat, lightweight, and highly resilient bones.
Each rib has a spongy interior that contains bone marrow or hematopoietic tissue which forms blood cells.
There are three types of ribs based on their connection to the sternum: true, false, and floating ribs.
The true or vertebrosternal ribs are the first 7 pairs of ribs, and they attach directly to the sternum through their own costal cartilages.
The false or vertebrochondral ribs are the 8th, 9th, and usually the 10th pair of ribs, and their cartilages are connected to the cartilage of the rib above them.
Consequently, their connection to the sternum is indirect.
The floating ribs or vertebral or free ribs are the 11th, the 12th pair of ribs, and sometimes the 10th pair of ribs.
The cartilages of these ribs don’t connect anteriorly to the sternum at all; instead they end up in the posterior abdominal musculature.
Ribs can further be classified as either typical or atypical ribs.
Summary
The bones and joints of the thoracic wall play a vital role in protecting the heart, lungs, and other vital organs. The ribs attach to the spine in the back and flare out to form the rib cage. Ribs attach to the sternum by costal cartilages, which help to hold the ribs in place and absorb shocks. The sternum, or breastbone, is located in the center of the chest and forms the front of the rib cage. The clavicle, or collarbone, attaches the arm to the body and also helps to support the structure of the rib cage. Some of the joints in the chest include the costovertebral joints, the sternoclavicular joint, the sternocostal joints, and the xiphisternal joint.
Sources
- "Clinically Oriented Anatomy" Lippincott Williams & Wilkins (2013)
For Institutions
Copyright © 2024 Elsevier, its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Cookies are used by this site.
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.
