Bones of the Skull and Face Flashcards
Bones of the skull divided into 2 groups:
- Bones of the facial skeleton
- Bones of the Cranial Skeleton
they are often referred as the craniofacial skeleton
22 bones
some paired, some unpaired
ALL are attached by IMMOVEABLE joints called sutures, EXCEPT the MANDIBLE
Sutures are what kind of joint?
Synarthrodial joint
Immoveable
In infants and very young children however these joints do permit some movement
The temporomandibular joint
The temporomandibular joint, or TMJ, is classified as synovial joint [highly moveable].
Is is similar to a ball and socket joint
This joint connects the mandible (lower jaw) to the temporal bone that is a part of the cranial skeleton
How many bones are in the facial skeleton? viscerocranium
14 bones
What are the paired bones of the facial skeleton?
- Maxillae - paired
- Nasal bones - paired
- Palatine bones - paired
- Lacrimal bones - paired
- zygomatic bones - paired
- inferior nasal conchae - paired
What are the unpaired bones of the facial skeleton?
Mandible
Vomer
Mandible
Forms the lower jaw
begins as a paired bone with mental symphysis [juncture of 2 bones]
it becomes fused into a single bone early in life
What are the parts of the mandible?
Body
Alveolar Arch
Angle
Ramus
Coronoid + Condylar Processes
Alveolar Process
Maxillae
Paired bone that forms the UPPER JAW
It helps to form the following structures:
Roof of the oral cavity
Floor + lateral walls of the nasal cavity
Floor of the orbits
What are the four processes of the Maxillae?
- Zygomatic process
- alveolar process
- palatine process
- frontal process
Maxillae - Zygomatic Process
Located between the anterior + posterior surfaces on the lateral aspect of the bone
The process is directed superiorly + laterally to articulate with the zygomatic bone
Frontal process
superiorly directed plate of bone on the anterior surface
It articulates with the FRONTAL bone
Maxillae: Palatine + alveolar processes
Palatine Process:
Horizontal plate of bone, directed medially
Articulates with the opposite side to form the anterior 2/3-3/4 of the hard palate
Alveolar process:
houses the TEETH
Nasal bones
Form the bridge of the nose
Bones are comprised of two small oblong plates of bone
nasal bones lie medially to the frontal process of maxilla
How do the nasal bone articulate?
They articulate with the following:
frontal bone
maxillae
other bones of the nose
Palatine bones
Located in the posterior nasal cavity
Situated posteriorly to the palatine process of the maxilla
TOGETHER, the palatine bones and the palatine process of the maxilla make up the hard palate
What landmark do the palatine bones contain?
posterior nasal spine
posteriorly directed bony projection that is used as the landmark in imaging
What structures do the palatine bones contribute to?
Posterior floor + lateral wall of the nasal cavity y
Posterior 1/4 of the hard palate
The floor of the orbit
What is the function of the horizontal, superior, and vertical parts of the palatine bones?
horizontal part, with an inferior surface that forms the posterior portion of the hard palate
superior part that helps form the posterior portion of the nasal cavity
Vertical portion contributes to the lateral wall of the nasal cavity
Lacrimal Bones
Smallest of the facial bones
Form part of the medial wall of the orbital cavity
(inner eye socket location in images)
What bones do the zygomatic bones articulate with?
Maxillae
Frontal bone
Temporal bone
TOGETHER, these bones make up the LATERAL ORBIT
What are the 4 processes of the zygomatic bones?
Maxillary
Frontal or frontosphenoidal
Orbital
Temporal
Inferior Nasal Conchae
make up most of the inferior part of the lateral nasal walls
Articulate with the maxillae posteriorly and with the palatine bones
Vomer
Forms the inferior half of the bony nasal septum
Articulates inferiorly with the maxillae and the palatine bones
Anterior border of vomer articulates with the cartilaginous septum of the nose
How many bones make up the cranial skeleton?
8
What are the unpaired bones of the cranial skeleton?
Ethmoid
Frontal
Occipital
Sphenoid
What are the paired bones of the cranial skeleton?
Parietal
Temporal
Ethmoid
UNPAIRED
Separates nasal cavity from brain
considered to be a cranial bone, but also contributes to facial skeleton
consists of a number of parts + articulates with 15 bones
Ethmoid articulates with several bones
Frontal (1)
Inferior nasal concha (2)
Sphenoid (1)
Zygomatics (2)
Nasals (2)
Lacrimals (2)
Palatines (2)
Vomer (1)
Maxillae (2)
What are the 4 parts of the Ethmoid (unpaired bones of cranium)?
- Cribiform Plate
- Crista Galli
- Ethmoid Labyrinth
- Conchae
Cribiform plate (part of the ethmoid bones)
Horizontal plate that separates the oral + nasal cavities forms the roof of the nasal cavities
Crista Galli (ethmoid bones)
Superior projection from the cribiform plate
triangular process that separates the cerebral hemispheres
Ethmoid labyrinth (ethmoid bones)
a thin walled section of bone that has air pockets that vary in size
Conchae (ethmoid bones)
Forms the medial surface of the ethmoid labyrinth
it is comprised of 2 lateral plates that house the superior + medial nasal conchae
forms the lateral walls of the nasal cavities
Frontal Bone
unpaired bone + forms the ANTERIOR part of the BRAIN CASE
Contains a vertical plate (forehead) and a horizontal aspect that contributes to the roof of the orbit + nasal cavities
What are the 4 parts of the FRONTAL BONE
- Ethmoid notch
located at midline that articulates with the ethmoid bone
- Zygomatic process
Articulates with the zygomatic bone + is situated laterally to the orbital surface
- Frontal or nasal spine
bony projection found medially on the frontal bone + that articulates with the nasal bones and ethmoid
- Supraorbital rim
forms the superior surface of the orbits
Parietal bone
Is paired bone that is joined at the sagittal suture
Forms the rounded roof of the cranium
Roughly quadrilateral in shape
Articulation of the parietal bone
Articulates with several bones
Frontal bone at the coronal suture
Temporal bone at the squamous or lateral suture
Occipital bone at the lambdoidal suture
Occipital Bone
UNPAIRED bone that forms the inferior and posterior portions of the cranium
Articulates with the parietal bone at the lambdoid suture
FORAMEN MAGNUM is situated at the skull based + allows passage of the spinal cord
LATERAL CONDYLES are situated laterally to the FORAMEN MAGNUM + PERMIT C1 [atlas] articulation
Temporal Bone
PAIRED BONE that forms the LATERAL BASE + part of the lateral aspect of the cranium
3 parts of the temporal bone
Squamous portion
Petrous portion
Tympanic portion
Squamous portion of the temporal bone
forms the lateral, anterior, and superior aspects of the temporal bone
includes ZYGOMATIC PROCESS that articulates with the TEMPORAL PROCESS of the zygomatic bone
Petrous portion of the temporal bone
Found at the base of the skull
It houses the essential organs of hearing + balance and includes the mastoid process [a point of attachment for some muscles]
Tympanic Portion of Temporal bone
Anterior to the mastoid process + inferior to the squamous + petrous portions of the temporal bone
Forms part of the external auditory meatus [EAM] + includes the styloid process [point of attachment for some muscles]
Sphenoid - temporal bone
COMPLEX BONE that articulates with ALL BONES of the CRANIAL SKELETON + 3 BONES of the FACIAL SKELETON
Vomer
Palatine bones
zygomatic bones
Where is the sphenoid bone situated?
Situated at the skull base, anterior to the foramen magnum
Shaped like a bat
4 parts of the sphenoid
- Body
Anterior surface that forms the posterior wall of the nasal cavity
- LESSER WING (2)
Laterally directed plates that contribute to the superior walls of the orbits
- Greater Wings (2)
Laterally directed, curve superiorlyy + posteriorly
They form the posterior 1/2 of the lateral orbital wall
4.Pterygoid processes:
For the attachment of the pterygoid muscles
- lateral pterygoid process
- medial pterygoid process
- pterygoid hamulus
Sphenoid - Pterygoid processes
- Lateral pterygoid process
Attachment for some muscles - Medial pterygoid process
Attachment for some muscles
- Pterygoid hamulus
Termination point of the medial pterygoid process