Skeletal System 7.6

skull

number of bones that make up the human skull

22

number of bones that make up the cranium

8

number of bones that make up the facial skeleton

14

cranium

encloses and protects the brain

provides attachment for muscles that make chewing and head movements possible

contain paranasal sinuses

paranasal sinuses

air-filled cavities

lined with mucous membranes

connected by passageways to the nasal cavity

reduce skull’s weight

increase intensity of the voice

frontal bone

forms anterior portion of the skull above the eyes

marked by supraorbital foramen, which blood vessels and nerves pass to the tissues of the forehead

parietal bones

located on each side of the skull just behind the frontal bone

joined at the midline along sagittal suture and meet frontal bone at coronal suture

occipital bone

joins parietal bones along the lambdoid suture

forms back of the skull and the base of the cranium

large opening on its lower surface is the foramen magnum, where nerve fibers from the brain enter the vertebral canal to become part of the spinal cord

rounded processes called the occipital condyles, located on each side of the foramen magnum, articulate w the first vertebra (atlas) of the vertebral column)

temporal bones

each side of the skull joins the parietal bone along a squamous suture

form parts of the sides and base of the cranium

have depressions called the mandibular fossae that articulate with condyles of the mandible

sphenoid bone

wedged between several other bones in the anterior portion of the cranium

helps form the base of the cranium sides of the skull, and floors and sides of the orbits

pituitary gland occupies this depression

contains two sphenoidal sinuses

ethmoid bone

located in front of the sphenoid bone

two masses - one on each side of the nasal cavity, joined horizontally by thin cribriform plates

form part of the roof of the nasal cavity

crista galli

triangular process of the ethmoid bone that projects upward into the cranial cavity between the cribriform plates

facial skeleton

13 immovable bones and a movable lower jawbone

maxillae (s. maxilla)

forms upper jaw

contain sockets of the upper teeth

portions of these bones compose the anterior roof of the mouth, floors of the orbit, and the sides and floor of the nasal cavity

palatine bones

L-shaped bones located behind the maxillae

zygomatic bones

form the prominences of the cheeks below

help form lateral walls and floors of the orbits

each bone has a temporal process and a zygomatic process forming a zygomatic arch

lacrimal bones

thin, scalelike structure located in the medial wall of each orbit between the ethmoid and the maxilla

nasal bones

long, thin, and nearly rectangular

lie side by side and fuse at the midline, where they form the bridge of the nose

vomer

thin, flat vomer located along the midline within the nasal cavity

inferior nasal conchae

fragile, scroll-shaped bones attached to the lateral walls of the nasal cavity

support mucous membranes in the nasal cavity

mandible

aka lower jawbone

horizontal, horseshoe-shaped body w a vertical, flat portion projecting upward at each end

characteristics of an infantile skull

relatively small face w prominent forehead and large orbits

jaw and nasal cavity are small, sinuses incompletely formed, frontal bone in two parts

the two bony projections under the ear are the rounded and the pointed ___.

mastoid process; styloid process

identify the process

external acoustic meatus

the bony indentation where the pituitary gland sits is called the

sella turcica or hypophyseal fossa

letter A and letter B

mastoid process; styloid process

ethmoid bone

the cribriform plate is a part of the __ bone

ethmoid

sphenoid bone

crista galli

the two bony projections under the ear are the rounded ____ and the pointed ____

mastoid process; styloid process

the part of the ethmoid bone that extends inferiorly to form the nasal septum is called the

perpendicular plate

what part of the ethmoid bone contains openings (olfactory foramina) that allows for the passage of nerves associated with the sense of smell?

cribriform plate

perpendicular plate

palatine bone

temporal process

what two bones form the nasal septum?

vomer, perpendicular plate of ethmoid

lacrimal bone

vomer bone

what bone is located on the lateral wall of the nasal cavity?

inferior nasal conchae

inferior nasal conchae