Lecture 23 – Thoracic Cavity

Do remember my earlier lecture about anatomy being for everyone?  Do not ignore these lectures because you are not a nursing student or a medical student.  If you are a breathing being you need to know about your chest cavity.  Remember, an informed patient is a better patient.  One of my goals is to educate the public about our bodies.  You anatomy will be with you, so do not ignore these great lessons.  We all like to get something for free, and these lessons are free.  I love to make complex medical topics simpler.  I see many people in the hospital who do not know simple medical terms and are totally confused when family members have medical problems.  Let’s break the cycle of ignorance by learning our bodies.  Now that we are into the 23rd lecture, the numbers are dropping.  NOW is when you need to read the information.  I know that we are all very busy, but this is important.  I read the prayer requests on Facebook and they are full of stories about people with illnesses.  Read these lectures in more than one session if needed.  Too many times we fill up on unnecessary information and skip the wholesome stuff!  If there is something that you would like to have clarified, just say so.  Just like the telephone banking voice, you can say, “Repeat that!” or “That does not make sense to me.”  I will gladly find another way to make the point.

The sternum is the proper name for the breast bone.  It is a flat bone.  (I previously gave you a way to categorize all bones by the type of bone.  The sternum has costal cartilages which attach the ribs.

Thoracic Cavity –

Sternum – Major parts – manubrium, body, and xiphoid process

Costal cartilages


Thoracic vertebrae

The sterna angle is the articular point between the manubrium and the body.  It is the most commonly fractured area of the sternum.  Beware parents of little league football players!

There are 12 ribs –

7 true ribs – Numbers 1 through 7, costal cartilages attach directly to the sternum.

5 False ribs – Do not attach directly to the sternum.  (3 attach directly to the superior costal cartilage and 2 floating do not attach anteriorly at all.)  Review anatomic directions if necessary.

11 and 12 are floating ribs-

10 attaches to 9

9 attaches to 8

8 attaches to 7

All ribs have posterior attachments to the thoracic vertebrae.  Do you remember the appendicular skeleton?  The whole upper extremity only articulates (meets) with the axial skeleton at the sternoclavicular joint.  It is all held up by muscles.  The clavicle articulates with the sternum at the manubrium.  (Clavicle – anterior; scapula – posterior)

The scapula is thin and lies over ribs 2 through 7 posteriorly.  It is triangular shaped.  The acromion process divides the scapula into the supraspinous fossa and the infraspinous fossa.  The ‘spine’ comes across and expands into the acromion process.  You cannot see this process because it lies underneath the scapula and clavicle.  It is medial to the head of the humerus.  The glenoid cavity lies just inferior to it.  This is where the head of the humerus articulates.

Let’s digest these principles before moving on.  Do well with this information.  You just get one body.  Take care of it by first getting to know it.


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