Cranial Anatomy Matching

Cranial Fossa

• There are three indentations within the skull's cranial floor

Anterior Cranial Fossa

• This supports the anterior cerebrum

Middle Cranial Fossa

• Supports the middle section of the brain

Posterior Cranial Fossa

• Supports the cerebellum

Frontal Bone

• The frontal bone defines the forehead
• Forms the superior roof of the orbits
• Includes the frontal squama, which is the expanse of the forehead

Supraorbital Foramen/Notch

• This is at the superior margin of the orbit and allows passage for blood vessels and nerves

Parietal Bones

• There is one parietal bone is on either side of the skull, and is flat
• Sutures include sagittal which sutures parietal bones along the mid sagittal plane
• Coronal suture sutures frotnal and parietal bones

Occipital Bone

Foramen Magnum

• Is a part of the occipital bone
• Is a large, oval base opening for the spinal cord

Occipital Condyles

• Occipital condyles are located on either side of the foramen magnum
• Are smooth, articulating surfaces that allow the skull to rock back and forth on the neck,
• Are prominent, rounded elevations

Hypoglossal Canal

• Also located on either side of the Forman Magnum
• Passes through the occipital condyle
• Allows for the hypoglossal nerve to exit

Temporal Bones

• There is one temporal bone on either side
• These are irregular bones that form inferior, lateral walls of the cranium
• Its external features include the external auditory canal/meatus--an opening into the interior of the ear
• Its zygomatic process helps to form the zygomatic arch (cheekbone), allowing attachment for chewing muscles.
• Its mandibular fossa is a depression anterior to the auditory canal that articulates wit the mandible(lower jaw) -Located posteriorly under the skull, the mastoid process is a bump for neck attachment

Internal Features

• The petrous portion of the temporal bones is a large, raised region of the cranial floor
• It houses the inner ear structures
• Divides middle and posterior cranial fossa
• The jugular foramen is a large jagged opening at the posterior edge of the temporal bone, and allows the jugular vein to exit and drain the brain
• The foramen lacerum allows the carotid artery to bring blood to the brain with an Opening to carotid canal at the base of cranium

Sphenoid Bone

• Lies at the base of the cranium
• Extends out to the temples
• Keystone bone, which articulates with all other cranial bones
• Has a distinct bat-like shape with the following external features
• Lesser wing: Anterior portion
• Greater wing: Posterior portion
• Body: In between lesser and greater wing. Cube-shaped mass

Other Features

• Sella turcica: Indentation within body where the pituitary gland sits
• Optic canal: Paired canals on either side of body, inferior to lesser wing
• Superior Orbital Fissure: Elongated opening in the orbit, tucked under lesser wing
• Foramen Rotundum: Small, round passages on lateral sides of sella turcica.
• Foramen Ovale: Oval shaped opening, posterior to foramen rotundum
• Foramen Spinosum: Lateral and posterior to foramen ovale

Ethmoid Bone

• Forms the majority of the nasal structures
• Majority lies within nasal cavity
• Is a sponge-like bone

Crista Galli

• Prominent projection which comes through frontal bone, so it communicates with cranium
• Behind nasal bones
• medial to the orbits of the eye
• Tiny portion of bony orbit
• Crista galli is vertical projection on the ethmoid bone where the brain attaches to in order to secure in place

Cribriform Plate

• Plate of porous bone in the middle of the frontal bone which allows for olfactory nerves to pass from the brain into the nasal cavity
• Runs perpendicular to the crista galli
• The Lateral masses house the nasal conchae/turbinates, which slow down, warm, and humidify incoming air
• The perpendicular plate forms the superior aspect of the nasal septum, dividing the nasal cavity in half

Suture Characteristics

• Tight immovable joins that are found only in the skull
• Binds cranial bones together
• Dense irregular CT

Coronal Suture

• Sutures frontal bone and perital bones

Sagittal Suture

• Sutures perital bones

Squamous Suture

• Sutures temporal and perital bones

Lambdoid Suture

• Sutures occipital bone and perietal bones
• Looks like lambda symol

Fontanels

• Temporary fibrous connections between the cranial bones of the fetal and the infant skull
• Soft spaces that allow for neonates to grow.
• Allows the head of a fetus or baby to pass through the birth canal

Mandible

• The lower jaw
• Largest, strongest, only movable bone in the skull
• The body is the U-shaped portion
• The ramus is an element that sticks up at 90 degree angle and means branch
• The ramus has two projections: First the coronoid process, which is anteriormost, shaped like a fin, and tucked under the zygomatic bone
• Second, the condylar process, which is posteriormost and articulates with at mandibular fossa of temporal bone
• Part of the mandible are: Alveolar process that includes the sockets for the teeth
• Includes the mental foramen that is a rounded opening in chin region and allows for massage of mandiblular nerve

Other facts on the mandible

• The mandibular foramen in on the ramus
• The mental term refers to the chin region

Maxillary Bones

• These unite to form the upper jaw and holds upper teeth
• Articulate with every bone in the face except the mandible
• Its parts include alveolar processes that hold sockets for the teeth

Other features include

• Inferior Orbital Fissure: Elongated hole in the inferior part of the Orbit
• Palatine Process: Section of bone that Forms anterior three quarters of hard palate and forms 90-degree angle

Zygomatic Bones

• Form lateral wall of orbit
• Anterior portion of zygomatic arch

Zygomatic Features.

• Temporal process: Articulates with temporal bone

Nasal Bones

• These are two small thin rectangles of bone
• Make up the superior bridge of nose

###Lacrimal Bones

• These are the smallest bones of the skull
• They form part of the medial orbit of the eye and have one big indentation ###Lacrimal Features.
• Include the lacrimal fossa which drains tears from the eye ###Lacrimal Foramen
• The opening the lacrimal fossa drains into

Vomer Bone

• Foms the inferior portion, bony septum of the nasal septum
• The vomer articulates withthe perpendicular plate of thmoid bone
• Deviated septum comes from the displacement of the vomer bone
• The inferior nasal concha's have the same structure and fuction/air flow as the masses of ethmoid bone
• The bone circulates warm humid air
• The concha's have their own bone of a different origin

Palatine Bones

• Paired L-shaped bones
• These form the posterior 1/3 of the hard palate
• Project upward to form some of the walls of the nasal cavity and floor of the orbit

Miscellaneous Bones

Hyoid Bone

• The hyoid bone is U-shaped or horseshoe shaped
• It does not articulate with any other bones
• Is inferior to the skull _ Provides a lot of attachment for muscles of the tongue, neck, and pharynx
• Helps with tongue and swallowing process

Middle Ear Ossicles

• Tiniest bones in the human skeleton
• Amplify sounds for hearing within inner ear structure
• 3 bones include malleus aka (hammer) is the most lateral
• Incus (anvil)
• Stapes (stirrup) the most meidal ossicle bone

Teeth

• Teeth are not bone, but similar to it because both are made of hydroyapatite
• Teeth cannot be repaired or recycled throughour life
• The 2-1-2-3 dental formula describes each set of blade shaped teeth

Canines

• Each tooth contains 1 canine/cusped tooth
• Each of which has one singular conical shaped base root

Premolars Characteristics:

• Each tooth contains 2 premolars/bicuspids
• Each with flat teeth and 2 roots

Molars

• There is a 3 set of tricuspids
• Only 2 adults get theird wisdom the 3rd molar to be removed

Match cranial fossae with brain regions. Identify bones, features, sutures, and processes by their locations and descriptions in the human skull.