Chapter 10- Bones of the Skull (BOOK)

what are the functions of the skull?

Onions makes patrica cry ... she will turn into a skull from how much she is crying RIP 1. protective cavity for the brain

2. cavities to house sensory organs

3. opening for air and food passage

4. mastication

how many bones does the skull have?

22

are the skull bones paired or unpaired?

both paired and unpaired

how are the skull bones grouped?

cranial bones and facial bones

where are most of the skull bones joined?

at immovable joints called SUTURES

-which bone is not joined at immovable joints (sutures)?

-what type of joint does it have?

-mandible (jaw bone)

-has a synovial (movable) joint

how many CRANIAL bones? what are they?

8 bones

-occipital (1)

-parietal (2)

-frontal (1)

-temporal (2)

-sphenoid (1)

-ethmoid (1)

what is the function of cranial bones?

encase and protect the brain

what is the superior portion of the cranium called?

calvaria

how many occipital bones?

1 bone

from latin, occipitium means what?

back of the head

from latin, occipio means what?

I begin or commence

at birth, what portion of the skull is "born" first?

the occipital portion

what/where is the occipital bone?

-flat bone

-located at the posterior inferior aspect of the cranium

what/where is the foramen magnum?

a large foramen at the BASE OF THE SKULL near the ANTERIOR ASPECT of the occipital bone through which the SPINAL CORD enters the cranium

what are the structures on the occipital bone?

Olivia eats some olives in bed 1. external occipital protuberance

2. superior nuchal line

3. inferior nuchal line

4. occipital condyles

5. basilar part

external occipital protuberance (aka ____) is what/located where?

-occiput

-a large, prominent eminence on the posterior midline of the occipital bone

what/where is the superior nuchal line?

a curved ridge extending laterally from the occiput

what/where is the inferior nuchal line?

a curved ridge that parallels the superior nuchal line and extends laterally from the occiput

what/where are the occipital condyles?

prominent OVAL PROJECTIONS at the ANTEROLATERAL aspects of the FORAMEN MAGNUM

what do the occipital condyles articulate with?

first cervical vertebrae

where does the basilar part of the occipital bone lie?

ANTERIOR to the FORAMEN MAGNUM

what does the basilar part articulate with?

sphenoid bone

what is the superior surface of basilar part called?

clivus

how many parietal bones?

2 bones

from Latin, parietalis means what?

pertaining to walls

what do the parietal bones form?

a large part of the walls of the skull

where are the parietal bones located?

at the LATERAL and SUPERIOR aspects of the cranium

how many frontal bones?

1 bone

from latin, frons means what?

a brow or forehead

what is the frontal bone?

the bone of the forehead

where is the frontal bone located?

at the ANTERIOR and SUPERIOR aspect of the CRANIUM, ANTERIOR to the PARIETAL BONES

what does the frontal bone form?

the roof of the orbits (eye sockets)

what are the structures on the frontal bone?

1. supraorbital margin

2. supraorbital notch or foramen

3. squamous part

4. frontal sinus

what is the supraorbital margin?

part of the frontal bone that forms the SUPERIOR BORDER of the ORBIT

what/where is the supraorbital notch or foramen?

a small notch or hole that is found at the medial third of the supraorbital margin

what is the squamous part of the frontal bone?

forms the forehead

where is the frontal sinus?

a space that lies between the orbital and squamous parts of the frontal bone

how many temporal bones?

2 bones

from latin, tempus means what?

time

why are the temporal bones named so?

bc the hair of this region turns gray first, revealing the effects of age and time

where do the 2 temporal bones lie?

the LATERAL aspects of the cranium, INFERIOR to the parietal bones

which bone is the weakest cranial bone?

temporal bone

what are the structures on the temporal bone?

1. squamous part

2. zygomatic process

3. mandibular fossa

4. mastoid process

5. external auditory meatus

6. styloid process

7. petrous portion of the temporal bone

what is between the styloid and mastoid process

a deep hole called the stylomastoid foramen

what passes through the styloid mastoid foramen

CN VII, facial nerve

what/where is the squamous part of the temporal bone?

a thin, scalelike (from Latin squama=scale) SUPERIOR extension of the temporal bone forming part of the LATERAL CRANIAL WALL

what/where is the zygomatic process of temporal bone?

a long, thin process that extends ANTERIORLY from the ANTEROINFERIOR ASPECT of the squamous part to articulate w the ZYGOMATIC BONE

what is the zygomatic arch formed by?

formed by the zygomatic process of temporal bone and the temporal process of the zygomatic bone

from Greek, zygoma means what?

a yoke or bar connecting 2 parts

what is the mandibular fossa?

oval depression for articulation with the mandible, specifically the CONDYLOID PROCESS of the mandible

what is the location of the mandibular fossa?

temporomandibular joint

from Greek, mastos means what?

a breast

from Greek, oeides means what?

shape

what/where is the mastoid process?

the breast-shaped projection extending inferiorly from the posterior aspect of the mastoid part

what is the external auditory meatus?

a large canal POSTERIOR to the mandibular fossa that OPENS TO THE EAR

what/where is the styloid process?

a long, slender, pencil-like process ANTEROMEDIAL to the external auditory meatus that extends INFERIORLY

what/where is the petrous portion of the temporal bone?

hard (like a rock) wedge-shaped portion between the occipital and the sphenoid bones that houses the middle and inner ear

from latin, petrosus means what?

rocky/stony

how many sphenoid bones?

1 bone

from greek, sphen means what?

a wedge

from greek, oeides means what?

shape

why is the sphenoid named so?

bc it is located, or wedged, between the cranial and facial bones

-where is the sphenoid bone?

-what does the sphenoid bone form?

-the base of the cranium ANTERIOR to the temporal and occipital bones

-forms part of the FLOOR and LATERAL WALLS of the orbit

what are the structures on the sphenoid bone?

1. body

2. sella turcica

3. greater wings

4. lesser wings

5. pterygoid process

what/where is the body of the sphenoid?

cubical portion of the sphenoid in the midline of the base of the cranium ANTERIOR to the occipital bone

why is the sphenoid body hollowed out?

to form TWO SPHENOID AIR SINUSES

what is the sella turcica?

a deep depression on the SUPERIOR ASPECT of the sphenoid body

from Latin, sella turcica means what?

Turkish saddle, a saddle with a high back

what is the posterior border of the sella turcica formed by?

dorsum sellae

what does the sella turcica contain?

hypophyseal fossa

what does the hypophyseal fossa house?

the pituitary gland

what are the greater wings?

two broad LATERAL EXTENSIONS from the body

what openings do the greater wings contain?

-foramen rotundum

-foramen ovale

-foramen spinosum

what passes through the foramen spinosum?

middle meningeal artery

what are the lesser wings? what do they form?

-thin triangular projections that extend into the POSTERIOR wall of the orbit

-form the ANTERIOR aspect of the SUPERIOR surface of the body

where is the pterygoid process located?

extends INFERIORLY from the junction of the GREATER WING and BODY

what does the pterygoid process consist of?

medial and lateral pterygoid plate

what/where are the medial and lateral pterygoid plate separated by?

posteriorly by an oval fossa called PTERYGOID FOSSA

where does the medial pterygoid plate lie?

lateral to the choanae

how many ethmoid bones?

1 bone

from Greek, ethmos means what?

a sieve

from Greek, oeides means what?

shape

what/where is the ethmoid bone?

a sievelike bone at the anterior base of the cranium BETWEEN THE TWO ORBITS

what are the structures of the ethmoid?

1. cribriform plate (aka horizontal plate)

2. perpendicular plate

3. lateral mass

4. middle nasal concha (turbinate)

5. superior nasal concha (turbinate)

what does the cribriform plate (aka ____) form/what does it contain?

-horizontal plate

-forms the ANTERIOR aspect of the cranium

-has numerous FORAMINA for the passage of nerve fibers

what does the cribiform plate surround?

the base of the vertical CRISTA GALLI

where is the perpendicular plate? what does it form?

thin; PERPENDICULAR TO and extends INFERIORLY from the cribiform plate to form the SUPERIOR ASPECT of the nasal septum

what does the lateral mass consist of?

consists of lateral aspects of the ethmoid made of large air cells (ETHMOID SINUSES)

what does the lateral mass form part of?

the ORBIT

what is the middle nasal concha (turbinate)?

free, convoluted inferior margin of the medial plate of the lateral mass

what is the superior nasal concha (turbinate)?

part of the lateral mass SUPERIOR to the middle nasal concha

where is it difficult to see the superior nasal concha?

anterior view of the skull

how many bones make up the skeleton of the face (facial bones)?

14

what are the facial bones?

1. Maxilla

2. Mandible

3. Zygomatic (cheek bone)

4. Nasal

5. Lacrimal

6. Inferior nasal conchae (turbinates)

7. Palatine

8. Vomer

how many maxilla bones?

2 bones

what does the maxilla form?

the upper jaw

from Latin, maxilla means what?

jaw bone

what are the structures in the maxilla?

1. body

2. alveolar process

3. palatine process

4. infraorbital foramen

-what is the shape of the body of the maxilla?

-what does the body of the maxilla contain?

-pyramidal in shape

-contains a large air sinus called the MAXILLARY SINUS