Anatomy Flashcards
What makes up the diencephalon?
Thalamus and hypothalamus
What bony structure does the pituitary lie in?
The pituitary fossa in sella turcica of the sphenoid bone
What is the progression of the visual system?
Optic nerves > optic chiasm > optic tracts > thalamus > optic radiation > visual cortex of the occipital lobe
What is the clinical effect of a pituitary tumour on the visual pathway?
It disrupts the transmission of APs from the nasal retina bilaterally. This means the patient lists the ability to see structures in the temporal side of the visual field bilaterally > bitemporal hemianopia
What is responsible for each hemifield?
The temporal left retina and the nasal right retina are responsible for the right hemifield, whereas the nasal left retina and the temporal right retina are responsible for the left hemifield.
What is involved in a transcranial approach?
Sub frontal approach - under the frontal love
What is involved in a transsphenoidal approach?
Via nasal cavities and sphenoid sinus (involves the surgical fracture of the nasal septum, floor and roof of the sphenoid sinuses)
In which bone is the cribriform plate?
Ethmoid bone
In which bone is the conchae?
Ethmoid bone
**What are the 4 paranasal sinuses?
Frontal, maxillary, ethmoid and sphenoid
What lines the paranasal sinuses?
Mucous-secreting respiratory mucosa
What are the 3 possible functions of the sinuses?
1) Make mucous and drain it into the nasal cavities through ostia
2) Reduce the weight of the skull
3) Add resonance to the voice
What approach can be used to access the nasal cavities to provide better surgical access in more complicated cases?
Le Fort I down-fracture
What is the tentorium cerebelli?
A tough sheet of dura mater “tenting” over the cerebellum within the posterior cranial fossa but with a central gap to permit the brainstem to pass through)
What is the diaphragm sellae?
A tough sheet of dura mater forming a roof (diaphragm) over the pituitary fossa
What are the dural venous sinuses?
Venous channels within the dura mater that drain most of the venous blood from the cranial cavity (including the brain) into the internal jugular veins (not histologically veins but function like veins)
What sinuses surround the pituitary gland?
The cavernous and intercavernous sinuses
Where do the dual venous sinuses drain into the internal jugular veins?
The jugular foraminae in the floor of the posterior cranial fossa
Where do the lobes of the thyroid gland attach?
Lateral aspects of the thyroid and cricoid cartilages and to the trachea
What does the isthmus lie anterior to?
2nd and 3rd cartilages of the trachea