Week 3 - Floor of Skull Flashcards
Which bone forms the posterior boundary of the anterior cranial fossa?
Lesser winds of sphenoid bone
What bones form the floor of the middle cranial fossa?
Greater wings of sphenoid bone and temporal bone
What bones forms the posterior border of the middle cranial fossa?
Petrous part of the temporal bone
Which 4 bones make up the pterion of the skull?
Frontal, parietal, temporal and sphenoid bone
What bones make up the anterior and posterior border of the posterior cranial fossa?
Anterior - dorsum sellae of sphenoid bone
Posterior - occipital bone
What is the foramen of the anterior cranial fossa?
Foramina of the cribriform plate
What passes through the foramina of the cribriform plate?
Axons of olfactory cells in olfactory epithelium that form olfactory nerves (CNI)
What are the foramen of the middle cranial fossa?
Optic foramen, superior orbital fissure, inferior orbital fissure, foramen rotundum, ovale, spinosum, lacerum and carotid canal
What passes through the optic foramen?
Optic nerves and ophthalmic arteries
What passes through superior orbital fissure?
Ophthalmic veins, oculomotor nerve, trochlear nerve, abducent nerve, and sympathetic fibres
What passes through the foramen rotundum?
Maxillary nerve
What passes through the foramen ovale?
Mandibular nerve and accessory meningeal nerve
What passes through the foramen spinosum?
Middle meningeal artery and vein
Meningeal nerve
What passes through the foramen lacerum?
Is closed by cartilage
ICA, accompanying sympathetic and venous plexuses
What passes through the carotid canal?
ICA, accompanying sympathetic and venous plexuses
What foramen are in the posterior cranial fossa?
Internal acoustic foramen, jugular foramen, hypoglossal foramen and foramen magnum
What passes through the internal acoustic foramen?
Vestibulocochlear nerve, facial nerve and labyrinth artery
What passes through the jugular foramen?
Glossopharyngeal nerve, vagus nerve and accessory nerve.
Meningeal branches of ascending pharyngeal and occipital arteries
What passes through the hypoglossal foramen?
hypoglossal nerve (CNXII)
What passes through the foramen magnum?
Medulla, meninges, vertebral arteries, CNCXI, dural veins, anterior and posterior spinal arteries
What is the groove just lateral to the foramen spinosum?
Middle meningeal artery - ECA
Where does the superficial temporal artery cross on skull?
Pterion suture of the skull
What stops a bleed between periosteum of skull and dura mater from spreading?
Sutures and dura mater have connection which is tightly bound so stops spread
Describe the transverse sinus
Grooves caused by intracranial venous sinus
Laterally from internal occipital protuberance
Continue as S shaped groove for sigmoid sinus
Into what foramen does the groove for the sigmoid sinus lead?
Jugular foramen - IJV emerges from here
What is the sella turcica?
Turkish saddle
Is a deep depression in the midline of the middle cranial fossa which houses the pituitary gland
In body of which bone is the sella turcica found?
Body of sphenoid bone
What are the parts of the sells turcica?
Hypophysial fossa
Dorsum sellae
Tuberculum sellae
What do the anterior and posterior clinoid processes give attachment to?
Fold of dura mater called the tentorium cerebelli
What is on either side of the sella turcica?
Cavernous venous sinus
What foramen is immediately anterior to the cavernous sinus?
Superior orbital fissure
What are the finger like projections on skull cap?
From arachnoid mater into superior sagittal sinus which help CSF to be reabsorbed into systemic circulation
What bones make up the floor of the skull?
Medial and lateral plate of the pterygoid processes
Palatine process of maxilla
Horizontal plate of the palatine bone
Vomer
Temporal
Occipital
What is the pterygoid hamulus?
Hook like process at lower extremity of medial pterygoid plate of sphenoid bone
Name the muscle which attached to the medial pterygoid late of sphenoid bone
Tensor veli palatini
Name the muscles which attach to the lateral pterygoid plate of the sphenoid bone
Medial and lateral pterygoid muscles
Describe the neonatal skull
Not fully ossified
Less rigid and more flexible
What are the advantages of a neonate having a comparatively flexible skull?
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
What type of ossification occurs in the flat bones of vault of skull?
Intramembranous
What type of ossification occurs in the irregular bones of base of skull?
Condro-membranous
What age do the anterior and posterior fontanelles fuse?
Anterior - 4-26 months
Posterior - 1-2 months
