Cranial Growth and Ageing Flashcards
How may the centres of ossification in the occipital bone appear?
Fused or separated
When do the centres of ossification fuse by?
School age
What is the sphenoid-occipital synchondrosis?
The cartilaginous union between the sphenoid and occipital bone at the base of the skull
When does the sphenoid-occipital synchrondosis close?
Age 16-25
What is the anterior fontanelle?
Soft diamond shaped part at the front of the skull which allows for cranial growth
When does the anterior fontanelle close?
98% closed by the age of 2
What is the metopic suture?
Connective tissue structure which separates the two halves of the frontal bone of the skull
When does the metopic suture close?
Fuses at around the age of 9 months then disappears at around 6 years old
What is the mastoid process?
Conical prominence projecting from the undersurface of the mastoid portion of the temporal bone
Where is the mastoid process located?
Behind the external acoustic meatus
When can the mastoid process be found?
Distinct at around 2 years old
Describe the tympanic ring
Starts as a tympanic ring but lengthens to a plate
What is the mental symphysis?
Infused centre of the mandible
When does the mental symphysis fuse?
Fused by 7-8 months
What is the angle of the mandible?
Angle between body and ramus which is obtuse
Starts as markedly obtuse and gets less so until teeth are loss
What is a synchondrosis?
An almost immovable joint between bones bound by a layer of cartilage
Where is the sphenoid-occipital synchondrosis?
Between the basisphenoid and basiocciput bones which together form the clivus
What is an ossification centre?
A point at which formation of cartilage begins
How many ossification centres does the occipital bone develop from?
6
What is a fontanelle?
The space between the bones of an infant’s skull where the sutures intersect
Why are fontanelles important stuctures in the developing skull?
They are covered by tough membranes that protect the underlying soft tissues and skull
How many fontanelles are there?
4
When does the anterior fontanelle close?
Between 9 and 19 months
When does the posterior fontanelle close?
By 1 or 2 months, may be closed at birth
