Skull Flashcards
Cranium
- protects brain and sensory organs
Formed of two parts:-
- Neurocranium
- Visceocranium
Neurocranium
- formed of a skull cap (CALVARIA),
- a cranial base (BASICRANIUM)
- an intercranial region (inner surface of base of skull)
formed of 8 bones :-
singular bones - Frontal, Ethmoidal , Occipital
paired bones - Temporal, Parietal
Viscerocranium
- comprises the FACIAL BONES in the anterior part of the cranium
Singular bones: - - Mandible and Vomer Paired:- - Maxilla, Inferior Nasal Conchae*, Zygomatic, Palatine, Nasal and Lacrimal *called turbinates in some textbooks
Mandible
Only movable joint of the cranium
articulates with the cranial base : TMJ
- temporomandibular joint
What bones make up the NASAL SEPTUM?
*important exam question
- Perpendicular plate of the ETHMOID BONE
- VOMER
Pterion
Susceptible to fractures
- weak point of the skull
- located two finger breadths superior and lateral to the edge of the orbit
Frontal bone
forms part of the TOP OF THE HEAD
also forms the ROOF OF THE ORBITS
Parietal bones
form lateral walls and roof of the cranium
divided approx mid sagitally
Occipital bone
Posterior region of the skull
Temporal bones
Form the INFERIOR LATERAL WALLS and part of the floor of the cranium
Sphenoid bone
- most complex bone in the body
shaped like a BUTTERFLY
unites the cranial and facial bones
Articulates with every other cranial bone and also the palatine bones, zygomatic bones, maxillae and vomer
Ethmoid bone
- positioned between the orbits
- forms the anteromedial floor of the cranium, roof of the nasal cavity, part of the medial wall of each orbit and part of the nasal septum
Maxilla bone
Forms central part of the facial skeleton
Two unite to form the upper jaw
Palatine bones
Small bones, distinct L shape
Form part of the hard palate, nasal cavity and eye orbit
Zygomatic bones
A.K.A Cheek bones
form lateral wall of each orbit and the cheeks
Lacrimal bone
SMALLEST BONES IN THE SKULL
Form part of the medial wall of each orbit
Have a groove that provides a passageway for the tear duct, which drains into the nasal cavity
Nasal bones
*often fractures by blows to the nose
Forms bridge of the nose
Lateral side articulates with the medial edge of the maxilla.
Vomer bone
Forms interior posterior part of the nasal septum.
Articulates along midline with both the MAXILLAE and the PALATINE bones
“Wings” articulate superiorly with the sphenoid bone and the perpendicular plate of the Ethmoid bone
- forming together the bony NASAL SEPTUM
Inferior Nasal Conchae Bone
located in the lateral wall of the nasal cavity
help create turbulence in inhaled air
has superior and middle counterparts that are part of the ethmoid bone
Mandible bone
Forms the entire lower jaw
Supports the lower teeth and provides attachment for the muscle of MASTICATION.
Rhinorrhae
CSF leaking out after fracture of the nose
Skull air sinuses
- 4 main pairs of cavities in skull
- contains air and mucus which drains through them and out of the nose
- Frontal
- Ethmoid
- Sphenoid
- Maxillary (largest one)
Sutures
FIBROUS JOINTS (synarthroses) between bones of the skull, become increasingly immobile and ossified with age. Everyone has a different suture pattern
Bregma point
Lambda point
Bregma - crossover of coronal and sagittal suture
Lambda- crossover of sagittal and lambdoid suture
Occipital condyle
Articulates with the Atlas
*skull articulates with the cervical spine via the Occipital Condyle
Movements of the Cervical Spine
- Flexion
- Extension
- Lateral flexion (side-to-side)
- Rotation
Cervical spine
Top 7 cervical vertebrae provide support for the neck structures
