Lecture 12 - High Yield

Question 1

What do the bones of the base of the skull underlie and what kind of bone are they?

Answer 1

Underlie brainstem and are endochondral bone

Question 2

What do the bones forming the sides and roof of the skull make up and what kind of bones are they?

Answer 2

Make up the bones of the face and are dermal bones

Question 3

What are the components of the chondrocranium?

Answer 3

Neurocranium: cartilage and/or endochondral bone; includes 3 pairs of carilaginous capsules housing special sensory organs (olfactory - most anterior, optic, and otic - most posterior)

Splanchnocranium (Viscerocranium): cartilage and/or endochondral bone

Question 4

What type of bone makes up the dermatocranium?

Answer 4

Dermal bone

Question 5

Describe the floor, posterior wall, and roof of the neurocranium

Answer 5

Floor: formed from 2 pairs of cartilaginous plates, parachordals and prechordals

Posterior Wall: foramen magnum

Roof: usually open, closed in chondrichthyes

Question 6

What is the olfactory, optic, and otic capsules associated with?

Answer 6

Olfactory: associated with sense of smell

Optic: associated with sense of light

Otic: associated with sense of balance

Question 7

What are the 5 bones of the neurocranium/basicranium?

Answer 7

Ethmoid, sphenoid, left/right temporals, and occipital bones

Question 8

What is the only bone that is entirely preformed in cartilage?

Answer 8

Ethmoid

Question 9

What is the sphenoid bone formed from?

Answer 9

Cartilage and dermal elements

Question 10

Describe the parts of the temporal bones

Answer 10

Petrous Part: surrounds ear apparatus; cavity’s connection with pharynx forms eustachian (auditory) tube

Mastoid Process: mass of air-filled outpocketings (air cells) from petrous part

Styloid Process: fuses to petrous portion in front of mastoid; attachment site for muscles and ligaments

Squamous Part: thin sheet of dermal bone forming lateral wall of braincase above auditory meatus

Tympanic Part: forms a ring of dermal bone around the eardrum; expands after birth to become external auditory meatus

Question 11

Describe the parts of the occipital bone

Answer 11

Squamous Part: large dermal bone that forms the lower back of the head

Basilar Part: cartilage-replacement bone formed from anterior vertebral elements; forms from 4 separate bones that fuse around spinal cord to form the foramen magnum for passage of spinal cord, vertebral arteries, and spinal root of XI

Question 12

Describe the frontal bone

Answer 12

Paired in fetus, fused in adult via metopic suture; supraorbital foramina (notches)

Question 13

Describe the maxillary bones

Answer 13

Alveolar processes, infraorbital foramina

Question 14

What are the membrane bones of the skull?

Answer 14

Frontal, maxillary, zygomatic, nasal, parietal bones

Question 15

What are the bones of the anterior skull?

Answer 15

Sphenoid (greater and lesser wings), ethmoid, lacrimal, and vomer