Our Axial Skeleton

In UC Berkeley’s Human Anatomy lectures three and four, Professor Marian C. Diamond talks about our axial skeleton, the part of our bone system that includes everything in our heads and chest. Anatomically, the axial skeleton runs through the medial access of the body, which is the portion closer to the midline. Not sure what the midline is? Go back two posts and read my intro to Functional Human Anatomy. 🙂

Another way to consider the axial skeleton is to think of it as your head and upper body. Bone-wise this consists of the:

• skull
• ear ossicles
• hyoid (in the neck)
• sternum (our ribs), also called the thorax or
thorasic cavity
• vertebral column

I was introduced to some wonderful sounding words and interesting facts. For instance, girdles attach our appendicular skeleton (more on that in another post) to our axial skeleton. Our skull houses 14 facial bones and 8 calvarium bones. (The calvarium is our skull cap.) And the foramen magnum in the occipital bone is where the spinal cord attaches to the brain. Those two words sound impressive to me, denoting the important activity taking place in that area.

Of the 14 facial bones, two stand out – the maxilla and the mandible. The maxilla is the upper jaw and the keystone of the facial bones. (A keystone provides the main anchor point from which the rest of an object, in this case the facial bones, get their initial support.) All of the facial bones, with one exception, touch the maxilla. That one exception is the mandible, the lower jaw and the only movable joint in the skull.

As for our vertebral column, there are 33 bones, or vertebra, of which the first 24 are flexible, and the remaining 9 are immovable. The thoracic cavity houses the sternum, costal cartilages, and ribs. All of the ribs attach posteriorly (at the back) to the thoracic vertebrae. (There are 12 thoracic vertebrae in the vertebral column.) Not all the ribs attach anteriorly (at the front); numbers 1-7 attach to the sternum, and the rest attach elsewhere or simply “float” at the front. I practice yoga, and in anjali mudra we bring our hands together with palms facing and fingers facing up, and position them at our sternum. We begin and end our yoga sessions seated with our hands in this position. Let’s hear it for the sternum!

Lecture 3

@brainbits: Axial & Appendicular skeletons attached by girdles (not just to hold in flabby tummies ;-). We sit on our ischium (who knew!)

@brainbits: “Fascinating, isn’t it, and you’ve lived with it (your body) all this time & how much do you know about it?” Human Anatomy w/Marian Diamond

Lecture 4

@brainbits: Axial skeleton consists of the skull,ear ossicles, hyoid (in the neck), sternum & ribs, and our wonderful vertebral column of 33 bones

@brainbits: http://www.visiblebody.com – interactive 3D human anatomy online – free demo; 7 day free trial; ed pricing available for longer term use

@brainbits: Anyone out there with a slipped disc? I hope not (!), but if so, it’s the nucleus pulposus slipping out and pressing on nerve roots. Ouch!

@brainbits: Am not actually following @IBatBerkeley but Marian Diamond’s Human Anatomy lecs are from Integrative Biology Dept at Berkeley (prev tweets)

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2 thoughts on “Our Axial Skeleton

  1. Pingback: Holistic Home Remedies

  2. Pingback: Preamble to Our Appendicular Skeleton « Neurons Firing

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