Exercise 14 Cranial Bones Flashcards
How many bones in the Axial Skeleton??
80 and consists of:
1: skull bones
2: auditory ossicles
3: hyoid bone
4: ribs
5: sternum
6: vertebral column.
7: sacrum
8: coccyx
Define Axial Skeleton??
Portion of the human skeleton that consists of the bones of the head and trunk.
How many bones in the vertebral column??
- 24 vertebrae
- 1 sacrum
- 1 coccyx
How many bones in the human skull??
22
How are the bones of the skull organized??
- 8 plate-shaped cranial bones
- 14 facial bones.
List the Associated Bones of the skull?
- 6 auditory ossicles (middle ear)
- hyoid bone
Define Foramina??
Natural openings or perforation through bone, where nerves and blood vessels pass.
Define Orbits??
Eye sockets made by facial and cranial bones.
List the 8 bones of the Neurocranium??
- frontal bone
- occipital bone (distal/posterior)
- 2 parietal bones (posterior)
- 2 temporal bones
- sphenoid bone
- ethmoid bone
Describe the Frontal Bone??
Anterior roof, wall, floor of cranium, and contains the Frontal Squama.
Forms upper portion of orbits.
Describe Frontal Squama??
The forehead with the remain of the Metopic Suture.
Describe the Occipital Bone??
Saucer-shaped bone forming Posterior floor and wall of cranium.
- Foramen Magnum
- Occipital Condyles
- Hypoglossal Canal
- external occipital protuberance
Describe the Foramen Magnum??
Large opening at base of the occipital bone where spinal cord enters.
Describe the occipital Condyles??
Two flattened bones of the occipital bone that articulate with the Atlas.
Describe Hypoglossal Canal??
A bony canal of the occipital bone that transmits the Hypoglossal nerve used for tongue movement. Located at anterior Foramen magnum.
Describe External Occipital Protuberance?
Small bump posterior of Foramen Magnum where muscles and ligaments attach.
Describe Parietal Bones??
2 bones that form the posterior crest of the skull and are joined by the Sagittal Suture. Smooth with no major Foramina.
Describe the Temporal Bone??
2 bones located at the sides and base of the cranium and housing the inner ear.
Articulates with the Zygomatic Bone.
- zygomatic arch
- zygomatic process
- mandibullar fossa
- external acoustic meatus
- mastoid process
- styloid process
- internal acoustic meatus
- jugular foramen
- carotid canal
Describe the Zygomatic Arch??
The arch formed by the temporal process that bridges the zygomatic process of the temporal bone.
Describe the Zygomatic Process??
Slender process projecting from squamous portion of temporal bone. Articulates with Zygomatic Bone.
Describe Mandibullar Fossa??
A concavity in the temporal bone where the mandible articulates.
Describe External Acoustic Meatus??
The canal of the ear made of bone and cartilage. Located inferior of Squamous Part of Temporal Bone.
Describe Mastoid Process??
A protrusion of the Temporal Bone posterior to the external acoustic meatus. Serves as point of attachment for muscles.
Describe Styloid Process??
A pointy piece of bone akin to a stylus just below the ear on the Temporal Bone. Used for muscle attachment.
Describe Internal Acoustic Meatus??
Located in the petrous part of temporal bone. Carries cranial nerves from inside skull to inner and middle ear.
Describe Jugular Foramen??
A passage between the temporal and occipital bones containing jugular veins and cranial nerves.
Describe the Sphenoid Bone??
Situated at the base of the skull anterior of the temporal bone.
Articulates to form the Orbit. Each cranial bone articulates with it.
Describe the Orbital Surface of Sphenoid??
Part of the Greater Wing that contributes to the Orbit.
Describe the Sella Turcica (Hypophysial Fossa) of the Sphenoid??
A saddle-shaped depression also known as the Hypophysial Fossa. Houses the Pituitary Gland.
Describe the Foramen Ovale and Foramen spinosum of Sphenoid Bone??
Passageways in the greater wing for parts of the trigeminal nerve of the head.
Describe Foramen Rotundum of sphenoid bone??
Anterior to Foramen Ovale, passage way for major nerve of the face.
Describe Foramen Lacerum of Sphenoid Bone??
Where auditory tube enters the skull.
Describe the Superior Orbital Fissure of the Sphenoid Bone??
Cleft where the ocular muscles pass.
Describe the Optical Canal of the Sphenoid Bone??
Where the Optic Nerve enters the skull.
Describe the Ethmoid Bone??
Rectangular bone anterior to the Sphenoid bone. Separates the nasal cavity from the brain. Located at the roof of the nose between the 2 Orbits.
Describe the Crista Galli of the Ethmoid??
Median ridge that projects from the Cribiform Plate. Protects and supports brain.
Describe the Cribiform Plate of ethmoid?
Screen like surface punctured by many Foramina.
Describe the Olfactory Foramina of Ethmoid Bone??
Passageways for olfactory nerve on Cribiform Plate.
