Week 3 - Floor of Skull

Question 1

Which bone forms the posterior boundary of the anterior cranial fossa?

Answer 1

Lesser winds of sphenoid bone

Question 2

What bones form the floor of the middle cranial fossa?

Answer 2

Greater wings of sphenoid bone and temporal bone

Question 3

What bones forms the posterior border of the middle cranial fossa?

Answer 3

Petrous part of the temporal bone

Question 4

Which 4 bones make up the pterion of the skull?

Answer 4

Frontal, parietal, temporal and sphenoid bone

Question 5

What bones make up the anterior and posterior border of the posterior cranial fossa?

Answer 5

Anterior - dorsum sellae of sphenoid bone
Posterior - occipital bone

Question 6

What is the foramen of the anterior cranial fossa?

Answer 6

Foramina of the cribriform plate

Question 7

What passes through the foramina of the cribriform plate?

Answer 7

Axons of olfactory cells in olfactory epithelium that form olfactory nerves (CNI)

Question 8

What are the foramen of the middle cranial fossa?

Answer 8

Optic foramen, superior orbital fissure, inferior orbital fissure, foramen rotundum, ovale, spinosum, lacerum and carotid canal

Question 9

What passes through the optic foramen?

Answer 9

Optic nerves and ophthalmic arteries

Question 10

What passes through superior orbital fissure?

Answer 10

Ophthalmic veins, oculomotor nerve, trochlear nerve, abducent nerve, and sympathetic fibres

Question 11

What passes through the foramen rotundum?

Answer 11

Maxillary nerve

Question 12

What passes through the foramen ovale?

Answer 12

Mandibular nerve and accessory meningeal nerve

Question 13

What passes through the foramen spinosum?

Answer 13

Middle meningeal artery and vein
Meningeal nerve

Question 14

What passes through the foramen lacerum?

Answer 14

Is closed by cartilage
ICA, accompanying sympathetic and venous plexuses

Question 15

What passes through the carotid canal?

Answer 15

ICA, accompanying sympathetic and venous plexuses

Question 16

What foramen are in the posterior cranial fossa?

Answer 16

Internal acoustic foramen, jugular foramen, hypoglossal foramen and foramen magnum

Question 17

What passes through the internal acoustic foramen?

Answer 17

Vestibulocochlear nerve, facial nerve and labyrinth artery

Question 18

What passes through the jugular foramen?

Answer 18

Glossopharyngeal nerve, vagus nerve and accessory nerve.
Meningeal branches of ascending pharyngeal and occipital arteries

Question 19

What passes through the hypoglossal foramen?

Answer 19

hypoglossal nerve (CNXII)

Question 20

What passes through the foramen magnum?

Answer 20

Medulla, meninges, vertebral arteries, CNCXI, dural veins, anterior and posterior spinal arteries

Question 21

What is the groove just lateral to the foramen spinosum?

Answer 21

Middle meningeal artery - ECA

Question 22

Where does the superficial temporal artery cross on skull?

Answer 22

Pterion suture of the skull

Question 23

What stops a bleed between periosteum of skull and dura mater from spreading?

Answer 23

Sutures and dura mater have connection which is tightly bound so stops spread

Question 24

Describe the transverse sinus

Answer 24

Grooves caused by intracranial venous sinus
Laterally from internal occipital protuberance
Continue as S shaped groove for sigmoid sinus

Question 25

Into what foramen does the groove for the sigmoid sinus lead?

Answer 25

Jugular foramen - IJV emerges from here

Question 26

What is the sella turcica?

Answer 26

Turkish saddle Is a deep depression in the midline of the middle cranial fossa which houses the pituitary gland

Question 27

In body of which bone is the sella turcica found?

Answer 27

Body of sphenoid bone

Question 28

What are the parts of the sells turcica?

Answer 28

Hypophysial fossa Dorsum sellae Tuberculum sellae

Question 29

What do the anterior and posterior clinoid processes give attachment to?

Answer 29

Fold of dura mater called the tentorium cerebelli

Question 30

What is on either side of the sella turcica?

Answer 30

Cavernous venous sinus

Question 31

What foramen is immediately anterior to the cavernous sinus?

Answer 31

Superior orbital fissure

Question 32

What are the finger like projections on skull cap?

Answer 32

From arachnoid mater into superior sagittal sinus which help CSF to be reabsorbed into systemic circulation

Question 33

What bones make up the floor of the skull?

Answer 33

Medial and lateral plate of the pterygoid processes Palatine process of maxilla Horizontal plate of the palatine bone Vomer Temporal Occipital

Question 34

What is the pterygoid hamulus?

Answer 34

Hook like process at lower extremity of medial pterygoid plate of sphenoid bone

Question 35

Name the muscle which attached to the medial pterygoid late of sphenoid bone

Answer 35

Tensor veli palatini

Question 36

Name the muscles which attach to the lateral pterygoid plate of the sphenoid bone

Answer 36

Medial and lateral pterygoid muscles

Question 37

Describe the neonatal skull

Answer 37

Not fully ossified Less rigid and more flexible

Question 38

What are the advantages of a neonate having a comparatively flexible skull?

Answer 38

During childbirth - head can leave the birth passage During infancy - lets the brain grow with the skull Also helps in events of accidents and falls

Question 39

What type of ossification occurs in the flat bones of vault of skull?

Answer 39

Intramembranous

Question 40

What type of ossification occurs in the irregular bones of base of skull?

Answer 40

Condro-membranous

Question 41

What age do the anterior and posterior fontanelles fuse?

Answer 41

Anterior - 4-26 months Posterior - 1-2 months