Osteology of the Skull Flashcards
What is the skull?
A collective term referring to the complete skeleton of the head
How many bones are in the Skull?
22
Name all the bones of the skull.
Frontal Parietal Temporal Sphenoidal Occipital Ethmoid
Zygomatic
Maxilla
Nasal
Lacrimal
Mandible
What is the only major opening of the box of the head?
Foramen Magnum
How do bones of the skull normally join?
And why?
They form sutures - serrated edged joints
They interlock firmly, making it less likely for them to be easily unlocked.
Name some basic functions of the skull.
Enclose and protect
- The brain
- Special sense organs
Creates a specialised environment in which the brain thrives
Acts as a site of attachment of:
- Muscles
- Meninges
How are the bones of the skull specialised for protection?
They are flat bones.
They are dense, therefore strong.
They are made of two layers of compact bone for resilience.
With a layer of spongy bone in the middle to reduce weight.
How can you divide the cranium?
Into the Calvaria and Facial bones
Describe the mandible
Commonly known as the jaw
Comprised of 2 separate bones
Left and right mandibles join by a midline fibrous joint - the mental symphisis
What is the cranial floor known as, and how can it be further divided?
Also known as the cranial fossa
Divisible into three fossae
- Anterior fossa
- Middle fossa
- Posterior fossa
What enters the cranial cavity through the magnum foramen?
Sensory nerves
Arterial supply
Sympathetic fibres
Venous blood
Describe the frontal bone
It forms the anterior part of the skull vault
Anteriorly and inferiorly it forms the:
-Upper border of the orbital margins
-It also forms the roof of the orbit
Describe the ethmoid bone.
It is found in the midline of the cranial fossa.
When it fractures anosmia is ,likely to occur
It allows for the passage of the olfactory nerve fibres
Describe the sphenoid bone.
It is made up of
- A central part or body
- 2Wings - Greater and lesser
- Pterygoid process
Describe the parietal bone
It has 4 margins
It forms a large part of the side and roof or the cranial cavity
In its internal surface it has:
- Grooves of the middle meningeal artery
- Sagittal sulcus
- Granular pits
- Grooves for the sigmoid sinus
Describe the temporal bone.
It is important in the senses of hearing and balance
There are 6 parts to this bone.
Describe the occipital bone.
Also known as the occiput
Consists of four parts arranged around the foramen magnum:
- Squamous - Forms posterior part
- Condylar - left and right - forms most of the edges of the foramen magnum
- Basilar - Forms anterior part of foramen magnum
