Osteology

Question 1

What is a foramina?

Answer 1

A round-ish hole

Question 2

What is a fissure?

Answer 2

A narrow slit

Question 3

What type of bones are in the neurocranium?

Answer 3

Bones that encase and protect the brain.
Made of calvaria, cranial floor and cranial cavity.
Vaults begin as membranes (intramembranous ossification) and the floor / base begins as cartilage (endochondral ossification)

Question 4

What type of bones are in the viscerocranium?

Answer 4

Bones that make up the facial skeleton and the jaw
They surround the oral cavity, pharynx and upper respiratory passages.
Bones begin as membranes or cartilage and ossify

Question 5

What is the vault / calvaria?

Answer 5

Top bit of the skull

Question 6

What is the cranial floor?

Answer 6

Bottom bit with holes to allow things to pass through

Question 7

What bones does the sagital suture combine?

Answer 7

Two parietal bones

Question 8

What bones does the coronal suture combine?

Answer 8

Frontal and parietal bones

Question 9

What bones does the lamboid suture combine?

Answer 9

Parietal and occipital bones

Question 10

What are fontanelles?

Answer 10

Areas of membrane between bones, that are particularly large

Question 11

What are the purpose of fontanelles?

Answer 11

Alterations of skull size and shape during childbirth

Permits growth of infant brain

Question 12

What is craniosyntosis?

Answer 12

Early fusion of fontanelles and sutures

Question 13

When does the anterior fontanelle usually fuse?

Answer 13

18m-2yrs

Question 14

When does the posterior fontanelle usually fuse?

Answer 14

1-3m

Question 15

What is palpation of the anterior fontanelle used for?

Answer 15

Intercranial pressure and hydration

But, should be taken with other symptoms as could just be a different shape

Question 16

What is the arrangement of the bones in cross section?

Answer 16

Trilaminar - Compact bone on the outside and inside with diploe (spongy bone) in the middle. The compact bone is known as the outer and inner table.

Question 17

Why trilaminar arrangement?

Answer 17

Protective strength without weight

Question 18

What covers the bone?

Answer 18

Periosteum - This covers surface of outer and inner table of skull bones. Strongly adhered at suture line and continuous thought suture and onto inner table of same bone.

Question 19

Why does the periosteum determine the extend of haematoma?

Answer 19

Because the periosteum goes round to the inner table of the same bone so the haemoatoma cannot extend over a suture line to a different bone.

Question 20

What are the different types of skull fractures?

Answer 20

Linear - fairly straight, involve no bone displacement
Comminuted (multiple fracture lines) - fragments may or may not displace inwards towards the brain (depressed vs non-depressed)

Question 21

What is the bregma?

Answer 21

This is the join between the sagittal and coronal suture. This was the site of the anterior fontinelle in infants.

Question 22

What is the lambada?

Answer 22

This is the join between the lamboid suture and the coronal suture.

Question 23

How to skull base (basilar) fractures present?

Answer 23

CSF and blood pooling and accumulate around the eye - present as eye bruising.
Epistaxis if fracture of ethmoid bone
Bleeding through the ear if fracture through petrous bone
Bruising in mastoid area - middle cranial floor fracture
Haemotympanin - when the ear drum goes purple because of blood behind the ear drum.