Bones of the Cranium

Question 1

2 parts of the skull

Answer 1

Cranium and Face

Question 2

Sutures

Answer 2

Immovable junction where two bones meet

Exception: moveable temporomandibular joint (Jaw)

Question 3

Sinuses

Answer 3

Air filled cavities within bones that decrease weight of the skull

Question 4

Forms anterior portion of cranium, anterior floor, and superior part of face

Answer 4

Frontal bone

Question 5

Bone that forms the roof and lateral sides

Answer 5

Parietal bone

Question 6

Bone that forms the floor and lateral sides

Answer 6

Temporal bone

Question 7

Bone that forms the posterior portion of the cranium and posterior floor

Answer 7

Occipital bone

Question 8

Foramen magnum is found in the inferior aspect of which bone

Answer 8

Occipital bone

Question 9

3 portions of the sphenoid bone

Answer 9

Body (houses the pituitary gland in the depression called sella turcica)

Lesser wings project from the anterior aspect of the body

Greater wings project from lateral aspects of the body

Question 10

4 portions of the Ethmoid bone

Answer 10

1. Vertical perpendicular plate (forms the nasal septum)
2. Horizontal cribriform plate (where olfactory nerves pass through)
3. Labyrinths x2 (house ethmoid sinuses)

Question 11

Palatine bone

Answer 11

Extends from the hard palate in the back of the mouth to the orbital floor

Question 12

Lacrimal bone

Answer 12

Located along the medial wall of the orbit.

Question 13

What is the orbit shaped as

Answer 13

A 4 sided pyramid with the apex of the pyramid posteriorly and slightly nasal.

Question 14

What is the roof of the bony orbit formed by

Answer 14

Frontal bone and lesser wing of the sphenoid bone

The frontal bone makes up the majority of the roof

Question 15

What is the floor of the bony orbit formed by

Answer 15

The floor is formed by the palatine bone, zygomatic bone, and maxillary bones.

Question 16

What part of the bony cavity is the weakest and why

Answer 16

The floor is the weakest due to the infraorbital groove/canal in the maxillary bone and infraorbital foramen. There is also an air-filled maxillary sinus beneath the floor.

Question 17

What is the lateral wall of the bony cavity formed by

Answer 17

Formed by the zygomatic and greater wing of the sphenoid bone. The rim or margin is the strongest area in the orbit because it is most exposed to possible injury.

Question 18

What is the medial wall of the bony orbit formed by

Answer 18

Ethmoid, maxillary, lacrimal and body of the sphenoid bone

The majority of it is the ethmoid bone, which is the thinnest wall in the orbit.

Question 19

The ethmoid bone is paper thin, which can also be referred to as

Answer 19

Lamina papyracea

Question 20

If someone has an infection in their orbit, where did the infection likely spread from?

Answer 20

The infection likely spread from an infection in the ethmoid sinus and travel through the medial wall (thinnest wall).

Question 21

Maxillary bone is apart of which two sides of the orbit

Answer 21

Medial and floor

Question 22

The ___ bone is medial to the ethmoid bone

Answer 22

Lacrimal

Question 23

What are the four paranasal sinuses and their purpose

Answer 23

1. Frontal- superior to orbits
2. Ethmoid- Medial and posterior to orbits
3. Sphenoid- Medial and posterior to orbits
4. Maxillary- inferior to orbits/under the floor

All connect to the nose
purpose to reduce weight of the skull and filter air we breathe.

Question 24

Superior to inferior order of the 4 sinuses

Answer 24

FESM

• Frontal
• Ethmoid
• Sphenoid
• Maxillary

Question 25

If patient complains of pressure behind eye

Answer 25

Could be due to sinusitis (infected air cavities)

Question 26

What are the largest sinuses

Answer 26

Maxillary