1. Skeletal System: Skull
Learning Target #4

2. Cranial Bones:
8 large, flat bones make up the cranium, which encloses and protects the brain.
All are single bones with the exception of the parietals and the temporals.
Frontal (1), parietal (2), temporal (2), occipital (1), sphenoid (1), ethmoid (1)

3. Cranial Bones: Parietal bone Frontal bone Sphenoid bone Ethmoid bone
Occipital bone
Temporal bone

4. Cranial Bones:
Frontal
Ethmoid
Sphenoid
Temporal
Parietal
Occipital

5. Associated Structures of the Skull
Foramen magnum = opening in the occipital bone that the spinal cord passes through
Occipital condyles (2) = articular surfaces of the occipital bone
Form the joint between the occipital bone and the first cervical vertebrae
Occipital condyles
Foramen magnum

6. Associated Structures of the Skull
Sutures = “seam” or “stitch;” immoveable joint found between the bones of the skull
Coronal  between frontal and parietal bones
Lambdoid  between parietal and occipital bones
Sagittal  between parietal bones
Squamous  between parietal and temporal bones
Coronal
Sagittal
Lambdoid
Squamous

7. Associated Structures of the Skull
Sella turcica = depression in the superior surface of the sphenoid bone
Surrounds and protects the pituitary gland
Sella turcica

8. Associated Structures of the Skull
External auditory meatus (2) = ear canal, located in the temporal bone, contains 3 additional bones:
Malleus (hammer)
Incus (anvil)
Stapes (stirrup)
External auditory meatus

9. Associated Structures of the Skull
Mastoid process (2) = projection of the temporal bone behind the ear
Site of attachment for muscles of the neck
Styloid process (2) = projection of the temporal bone inferior to the ear
Site of attachment for tongue muscle
Mastoid process
Styloid process

10. Associated Structures of the Skull
Fontanels = soft spots; fibrous membranes between the bones of the fetal skull
Allow the skull to compress slightly during childbirth and allow for brain growth during late fetal life.
These areas ossify as the infant ages, completing the process by age months.

11. Facial Bones:
These bones form the base for the muscles of the face, which allows us to chew our food and show emotion/expressions.
All are paired except the mandible and the vomer.
Maxilla (2), mandible (1), lacrimal (2), nasal (2), zygomatic (2), palatine (2), and vomer (1)

12. Facial Bones:
Nasal
Zygomatic
Lacrimal
Maxilla
Vomer
Mandible

13. Facial Bones:
Nasal
Lacrimal
Zygomatic
Mandible
Maxilla

14. Facial Bones:
Zygomatic
Maxilla
Vomer
Palatine

15. Associated Structures of the Skull
Paranasal sinuses = cavities lined with mucus membranes found in 4 skull bones.
Lighten the skull
Act as resonance chambers for speech

16. Hyoid Bone
Only bone that does not articulate with the rest of the skeleton.
Not classified as a facial or cranial bone.
Suspended from the styloid processes of the temporal bone.
Supports the tongue and serves as an attachment point for neck muscles moving the larynx.

17. Disorders of the Skull Sinusitis- inflammation of the sinuses
Deviated septum- air flow is restricted to one nostril or the other; can be partial or complete

18. Disorders of the Skull
Cleft palate = palatine process of the maxilla fails to unite with the palatine bone
Leaves a hole in the roof of the mouth.
Can be surgically corrected by closing the tissue gap