OCCIPITAL AND SPHENOID BONES
Terms
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- Occipital bone
- forms the posterior part and most of the base of the cranium
- Foramen magnum
-
inferior
medulla oblongata connects with the spinal cord
spinal arteries also pass through the foramen - Occipital condyles
-
oval processes with convex surfaces, one on either side of the foramen magnum
Articulate with depressions on the atlas of cervical vertabrae - External occipital protuberance
- a promininent midline projection on the posterior surface of the bone just superior to the foramen magnum
- Sphenoidal bone
-
lies at the middle part of the base of the skull
"keystone" of the cranial floor
articulates with all other cranial bone, holding them together
lies posterior and slightly superior to the nasal cavity and forms part of the floor, sidewalls, and rear wall of the orbit - Body
-
contains the sphenoidal sinuses
cube-like medial portion btwn. the ethmoid and occipital bones - Sphenoidal sinus
- drains into the nasal cavity
- Sella turcica
- a bony saddle-shaped structure on the superior surface of the body of the sphenoid
- tuberculum sallae
-
anterior in the sella turcica
forms the horn of the saddle - hypophyseal fossa
-
contains pituitary gland
seat of saddle is depression - dorsum sallae
-
posterior of sella turcica
back of saddle
Another ridge - Greater wings
- a broad curved winglike expanse on each side of the sphenoid bone
- Lesser wings
-
smaller than greater wings
form a ridge of bone anterior and superior to the greater.
floor of cranium
post. orbit of eye - Optic Foramen
- eye hole where the arteries and nerves of the eye pass
- superior orbital fissure
- btwn greater and lesser wings is a somewhat triangular slit
- Pterygoid processes
-
project inferiorly from the pints where the body greater wings unite and form the lateral posterior region of the nasal cavity.
muscles of mandible attach here - Foramen ovale
-
oval
and opening for the mandibular branch of the trigeminal nerve - Foramen Spinosum
-
resembling a spine
posterior angle of the sphenoid and trasmits the middle meningeal blood vessels - Foramen lacerum
-
lacerated
bounded anteriorly by the sphenoid bone and medially by the sphenoid and occipital bones
transmits a pharyngeal artery - Foramen rotundum
-
round
located at junction anterior and medial in sphenoid bone
maxillary branch of the trigeminal nerve