Chapter 7: The Skull Flashcards
How many bones does the skull have?
22
How many cranial bones are there
8
What are the cranial bones?
-frontal
- parietal(2)
- temporal (2)
- occipital
- sphenoid
- ethmoid
How many facial bones are there?
14
What are the facial bones
- zygomatic bones (2)
- lacrimal (2)
- nasal(2)
- vomer
- inferior nasal conchae (2)
- palatine (2)
- maxillae (2)
- mandible
Orbital cavity
Eye socket
Oral cavity
Mouth
Nasal cavity
Nose
Paranasal sinuses
Functions:
- lighten skulls mass
- increase surface area of nasal mucosa to most in and cleanse inhaled air
- serve as (echo) resonating chambers that intensify and prolong sounds
Suture
Immovable fibrous joint in an adult skull
Coronal suture
Untuned the frontal and parietal bones
Sagittarius suture
Unites the two parietal bones
Squamous suture
Unite the parietal and temporal bones
Lambdoid suture
Unites the two parietal bones to the occipital bone
What are Fontanells
Soft spots
- areas of cartilage and unossified mesenchyme that are arranged in thin plates around the developing brain
Fontanels functions
- flexibility to the fetal skull
- allow skull to change shape through the birth canal
- permit rapid growth of the brain
Where is the frontal bone located
- forms the anterior roof of the cranium ( forehead) , nasal cavity, and orbital arches
Important features of frontal bone
- squamous part
- glabella
- siperciliary arches
- supraorbital margin
- zygomatic process
- frontal crest
- suborbital foramen
- frontal sinuses
Frontal crest
Attachment site for meninigies to help stabilize the brain within the skull
Is the frontal bone paired or unpaired?
Unpaired
Frontal sinuses
lighten bone, moisten inhaled air, and give resonance to voice
Orbital part
Forms roof of the orbit
Squamous part
Attachment of scalp muscles
Supraobital
Forms the protective superior border of orbit
Where is the parietal bone located?
- forms side and roof of cranial cavity
Features of the parietal bone
- paritetal eminence
- parietal foramina
- superior and inferior temporal lines
Inferior and superior temporal lines
Attachment site for temporal is muscle
Parietal eminence
Forms the rounded prominence on each side of the skull
Is the parietal bone paired or unpaired
Paired
Is the temporal bone pair or unpaired
Paired
Where is the temporal bone located
- forms zygomatic arch
- forms inferior- lateral part of the cranial floor plus part of the lateral wall near the ear
What two processes make up the zygomatic arch
Zygomatic process and temporal process
Features of the temporal bone
- mandibular fossa
- air cells
- Petronius part
- styloid process
- squamous part
- zygomatic process
Madibular fossa
Articulate with the mandible mastoid
Air cells
Lighten the mastoid process
Mastoid process
Attachment site of some neck muscles to extend or rotate the head
Petrous portion
In the temporal bone
- located at the base of the skull between the sphenoid and occipital bone
Houses the internal ear, internal acoustic meats and groove for the sigmoid sinus
Mastoid portion
Temporal bone
Contains the
- external auditory meatus
- mastoid process
- carotid process
- styloid process
- stylomastoid process
External auditory meatus
Conducts air to the middle ear
Carotid canal
Internal carotid artery
Styloid process
Attachment for hyoid and tongue muscles
Stylomastoid foramen
The passage for the facial nerve and stylomastoid artery
Squamous portion of the temporal bone
- zygomatic process
- temporal process
- mandibular fossa
- articulate tubercle
- mastoid process
- carotid canal
Is the occipital bone paired or unpaired?
Unpaired
Occipital bone prodominate features
- squamous part
- basilar part
- foramen mangnum
- hypoglossal canal
- occipital condoles
- external occipital protuberance
- jugular notch
- ligamentum nuchae
- superior and inferior nuchal line
Foramen magnum contains
Spinal cord, vertebra,, spinal arteries, and the accessory nerve
Occipital condyles
First cervical vertebra ( atlas) and Atlanto-occipital joints
External occipital protuberance
Midline projection
Ligamentum nuchae
Ligament helps support the head
Is the sphenoid bone paired or unpaired
Unpaired
What shape is the sphenoid bone
Butterfly
Main features of the sphenoid bone
- body
- sphenoid turcica
- sphenoid sinus
- tuberculin sellae
- hypophyseal fossa (pituitary gland)
- Doris. Sallae
Body of sphenoid bone
Houses sphenoid sinuses
Medial and lateral pterygoid plates
Attachment site for two muscles of mastication (chewing muscles)
Lesser wings
Part of the anterior cranial fossa; contains the optic canal
Greater wings
Form part of middle cranial fossa and orbit
Superior orbital fissure
For the ophthalmic, trigeminal, ocular, trochlear, and abducens nerves
Foramen rotundum
Maxillary nerve
Foreman ovale
Mandibular nerve
Foreman spinosum
Internal carotid and pharyngeal artery
Is the ethmoid bone paired or unpaired?
Unpaired
What shape is the ethmoid bone?
Irregular shaped with numerous paranasal sinuses
Ethmoid bone main features
- ethmoidal cells ( becomes ethmoidal sinus)
- cribiform foramina
- superior and middle nasal conchae
- crista galli
Cribiform foramina
Passes oldfactory nerve
Superior and ,idle nasal conchae
- Mucous membranes increases vascular and mucous membrane surface area
- warms and humidifies air
- involved in sense of smell
Crista galli
A point of attachment for the Falx cerebri (brain membrane)
Is the zygomatic paired or unpaired
Paired
Zygomatic bone features
- zygomatic arch
- maxillary, frontal, and orbital process
- zygomaticofacial
Is the lacrimal paired or unpaired
Paired
What is the lacrimal bone
- smallest bone of the face
- forms the anterior portion of the eye socket
Feature of the lacrimal bone
Lacrimal groove
What is the lacrimal groove
Honey depression into the maxilla
- passes tears from the eye into the nasal cavity
Is the nasal bone paired of unpaired?
Paired
What does the nasal bone do?
- forms the bridge of the nose
- supports cartilage
- supports thin musck3s of facial expression
What is a common site for facial injuries
Nasal bone
Is the vomer bone paired or unpaired?
Unpaired
Features of the vomer bone
Ala
Vertical plate
What does the vomer do?
Divided the nasal cavity into the left and right
- forms the nasal septum
Is the inferior nasal conchae paired or unpaired
Paired
What does the inferior nasal conchae do?
Helps to swirl and filter the air before is passes to the lungs
Superior nasal conchae
Ethmoid bone
- increases surface area and aids in sense of smell
Is the palatine paired or unpaired
Paired
What does the palatine do?
Separates the nasal and orbital cavity
Is the maxillae paired or unpaired
Paired
What are the feature of the maxillae
- Infraorbital margin
- Orbital surface
- alveolar process
- Infraorbital foramen
Infraorbital foramen
Allows blood vessels, and triennial nerve to pass
What does the maxillae do?
Fuse at the midline to form the upper jaw
Is the mandible paired or unpaired
Unpaired
What is the only movable facial bone
Mandible
What are the structural features of the mandible
- body
- rami
- angle
- mental protuberance
- condylar process
- consider process
- mandibular notch
- mental foramen
What bones is the orbit of the eye formed by
- frontal
- zygomatic
- sphenoid
- ethmoid
- lacrimal
- maxilla
Is the humour bone paired or unpaired?
Unpaired
What does the hyoid bone do?
- serves as an attachment site for the muscles of the tongue, neck, and pharynx
