The Skull

1. The Skull By Billy Joe Image from http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/8915.jpg

2. Facial bones vs. cranial bones • Everybody thinks of the skull as bones that make up the head but do you know the difference between cranial and facial bones? …………anyone? ....anyone??? No? ....anyone???? Well, I’ll be glad to tell you then: The cranium is the part that encases your brain and protects it; and the facial bones form all the facial structures that you recognize like the cheeks, chin, parts of the nose, and parts of the eye socket. So this means the facial bones form all the bones that form what we recognize collaboratively as “the face” See/ that wasn’t so hard! But its good to know the difference because you need to know which bones belong to the cranium and which belong to the face.

3. Bones of the face are: • Use your plastic models in front of you and your probes to follow along with me as I point out on my own model for you, bones of the face. They are: • Mandible • Vomer • Hyoid- That one’s special! • Maxillae • Zygomatic bone • Nasal bone • Lacrimal bone • Palentine bone • Inferior nasal conchae, • Malleus, incus, and stapes- Together known as the “auditory ossicles” The hyoid does not articulate with any other bone directly! Its kind of a free floater lonely bone, but it is considered part of the facial bones so it’s not so lonely. The auditory ossicles are the smallest bones in the body!

4. Bones of the Cranium • Keep using your plastic models as I point out for you the bones of the cranium, they are: • Frontal bone • Occipital bone • Sphenoid bone • Ethmoid bone • Temporal bone • Parietal bone Sorry these bones aren’t as exciting or have special facts like the facial bones….I like the facial bones better

5. Sutures • If you look at your skull you notice all those tiny little lines that kind of make what looks like a grid on the head. These are called sutures. There are four sutures that you need to know. Point them out with your probe as I do the same. • Coronal suture • Sagittal suture • Lambdoidal suture • Squamosal suture The lambdoidal suture is easy to recognize because it looks like the Greek letter lambda which looks like this λ The squamosal suture is easy to recognize because it has the same shape of a squamous cell, if you don’t know what that cell looks like, its kind of like a fried egg looking cell

6. The sphenoid bone • The sphenoid bone is a very special bat looking bone that makes up the floor and some walls of the cranium. There are a lot of structures on this bone, and since this is a beginning anatomy course, the only one you need to remember is the sellatursica which is a little saddle shaped structure on this bat bone that houses the pituitary gland This whole bone is the sphenoid bone and it sits inside the skulls and makes up some walls of the cranium That is the sellatursica and hiding inside there would be the pituitary gland Image from http://faculty.tcc.fl.edu/scma/mccrackenb/sphenoid_model_superiolat.jpg

7. Ethmoid bone • This bone forms a large portion of your nasal cavity in fact if you were to look in someone’s nose with a probe you could probably see the formation of this bone. But lets not do that because it’s gross! This bone also has several structures that you’ll learn in a more in dept anatomy class. But for this class, it’s important to know that the pointy prominent structure is called the cristagalli and it attaches to the dura matter 9which is a membrane that covers the brain.) Another important structure is the cribiform plate of the ethmoid bone it is the plate part on the bottom of the bone that the olfactory nerves pass through (these help you smell) There’s the cristagalli The cribiform plate is on the bottom portion here, it can be seen better on a model than in this picture. Image from http://faculty.tcc.fl.edu/scma/mccrackenb/ethmoid_model_posterior.jpg

8. Now that we have seen and covered important parts of the skull you will divide into groups and go over all the bones and important structures. But before you do that lets take a quick check to see what we have learned. • What bones make up the Skull? • What bones make up the cranium? • What bones make up the facial bones? • What is special about the hyoid bone? • What are the smallest bones in the human body? • What all the smallest bones collectively called? • What houses the pituitary gland? • What bone is that on? • What does the cristagalli of the ethmoid bone attach to? • What passes through the cribiform plate? • What sense do the olfactory nerves help us with? • What is the lambdoidal suture named after? • How can you remember the shape of the squamosal suture? • *Mandible, Vomer, Hyoid, , Maxillae, Zygomatic bone, Nasal bone, Lacrimal bone, Palentine bone, Inferior nasal conchae, Malleus, incus, and stapes, Frontal bone, Occipital bone, Sphenoid bone, Ethmoid bone, Temporal bone, Parietal bone • Frontal bone, Occipital bone, Sphenoid bone, Ethmoid bone, Temporal bone, Parietal bone • Mandible, Vomer, Hyoid, , Maxillae, Zygomatic bone, Nasal bone, Lacrimal bone, Palentine bone, Inferior nasal conchae, Malleus, incus, and stapes • The hyoid bone does not directly articulate with any other bone! • Malleus, incus, and stapes • Auditory aussicles • The sellaturscia • The sphenoid bone • Dura matter • The olfactory nerves • Smelling! Yay! • The Greek letter lambda, which it looks like. • A squamous cell (which looks like a fried egg!)

9. Good Job! The End Have fun doing your class activities now and try to remember what you learned