Week 3 - Osteology of the Skull Flashcards
(25 cards)
How is the cranium divided up?
- Neurocranium - bones that encase the brain
- Viscerocranium - bones of the face
What are the 3 major functions of the skull?
1) encloses and protects brain and special sensory organs
2) creates a specialised env for the brain
3) attachment site for muscles and meninges
Describe the layers of the cranium
2 plates of compact bone with a layer of spongy bone (the Diploe) in between
What 4 bones meet at the pterion?
- Frontal
- Parietal
- Greater wing of sphenoid
- Squamous area of temporal bone
What sort of bone is the mandible?
An innominate bone
How is the Neurocranium divided up?
Into the calvaria (roof) and cranial floor
Which bones make up the calvaria?
- Frontal
- Parietal x2
- Temporal x2
- Occipital
What suture binds the frontal and parietal bones?
Coronal suture
What suture joins the two parietal bones in the midline?
The sagittal suture
What is the junction of the coronal and sagittal sutures known as?
The Bregma
What suture joins the parietal and occipital bones?
The Lambdoidal suture
Where is the Lambda found?
At the junction of the sagittal and Lambdoidal sutures
List the 3 cranial fossae which make up the cranial floor, and their constituent bones
1) Anterior - frontal, ethmoid and sphenoid
2) Middle - sphenoid and temporal x2
3) Posterior - occipital and temporal X2
Which cranial nerves lie in which fossae?
Anterior - CN I and II
Middle - CN III - VII
Posterior - CN VIII - XII
Which bone allows passage of the olfactory nerves?
The Cribriform plate of the ethmoid
Which bone houses the pituitary gland?
The sella turcica of the sphenoid
Which bone contains both the EAM and IAM?
Temporal bone
The mastoid process and styloid process are features of which bone?
The temporal bone
State the 4 regions of the occipital bone
Squamous
Condylar - X 2
Basilar
What enters the cranial cavity via the foramina of the cranial floor?
- Sensory nerves
- Arteries to brain/meninges
- Sympathetic fibres
What leaves the cranial cavity via the foramina of the cranial floor?
- Motor nerves
- Venous blood and lymph
- Parasympathetic outflow
What are fontanelles?
Wide membranous islands between the cranial bones in the neonate
What develops from the anterior and posterior fontanelles respectively?
- Bregma
- Lambda
What happens to the baby’s skull during birth?
Why is this beneficial
- Head smaller - birthing easier
- Bones interlock - protects brain
