Week 4 - A - Pituitary gland anatomy Flashcards
What is the other name of the pituitary gland?
The hypophyisis
What are the 3 parts of the brainstem? (superior to inferior) What does the brainstem continue to form? What foramen does this continuation pass through?
Midbrain
Pons
Medulla
Continues to form the spinal cord passing through the foramen magnum
What structures form the diencephalon?
diencephalon = thalamus (T) + hypothalamus (H)
the diencephalon forms the central core of the cerebrum with connections to the right and left cerebral hemispheres & the midbrain
The pituitary gland lies in the pituitary fossa in what depression of which bone?
Lies in the depression called the sella turcica (turkish saddle)
It is in the sphenoid bone
What structure does the pituitary gland lie immediately inferior to? What forms this structure?
Lies immediately inferior to the optic chiasm formed by the right and left optic nerves
What are the two types of photoreceptors found in the the eye? Which part of the eye are these two photoreceptors found in?
Rods & Cones
Found in the retina of the eye (temporal and nasal)
Are rods or cones more responsible for vision at low levels of light? Which is more sensitive?
Rods are responsible for visions at low levels of light and are more sensitive than the cones and do not mediate colour
If damage is cause to the optic chiasm (eg via a pituitary adenoma causing a midline compression), what visual defect most commonly arises?
A bitemporal hemianopia
The temporal side of the visual field refers to the periphery of the eye, does this refer to the inner or outer part of the actual eye itself? How does bitemporal hemaniopia occur?
Refers to the inner part of eye
Due to the fact the axons cross over at the optic chiasm, a midline compression will disrupt the transmission causing no sight in the temporal visual field
What are the two types of surgery carried out to approach the pituitary gland? Which is more commonly carried out?
transcranial approach (subfrontal – under the frontal lobe)
transsphenoidal approach (via nasal cavities & sphenoid sinus) - this is the more commonly carried out approach
What are the structures of the nasal cavities, that increase the surface area of these cavities, thus providing for rapid warming and humidification of air as it passes to the lungs? (they are also known as turbinates)
The nasal concha
What are the nasal concha parts? Which are part of the ethmoid bone?
The superior nasal concha (of the ethmoid bone)
The middle nasal concha (of the ethmoid bone)
The inferior nasal concha
A Le Fort fracture of the skull is a classic transfacial fracture of the midface, involving the maxillary bone and surrounding structures in either a horizontal, pyramidal or transverse direction What type of fracture allows best access to the nasal cavities in more complicated cases?
Le Fort 1 down fractures (speak no evil) allow best access to the nasal cavities
Le Fort 1 (speak no evil) - horizontal maxillary fractures
Le Fort 2 (see no evil) - pryamidal maxillary fractures
Le Fort 3 (hear no evil) - transverse maxiallary fractures
Blood supply to nasal cavities? (3 arteries, names of the cranial nerves)
* facial artery
* ophthalmic artery
* maxillary artery
What are the 12 cranial nerves in order? Which are sensory and which are motor?
- Olfactory (sensory),
- Optic (sensory),
- Oculomotor (motor),
- Trochlear (motor),
- Trigeminal (Opthalmic, maxillary, mandibular) (sensory and motor),
- Abducent (motor),
- Facial (sensory and motor),
- Vestibulocochlear (sensory),
- Glossopharyngeal (sensory and motor),
- Vagus (sensory and motor),
- Spinal accesory (motor),
- Hypoglassal (motor)
What are the foramen of the 12 cranial nerves?
- Olfactory - cribiform plate of ethmoid bone
- Optic - optic canal
- Oculomotor - superior orbital fissure
- Trochlear - superior orbital fissure
- Trigeminal (Opthalmic (superior orbital fissure), maxillary (foramen rotundum), mandibular (foramen ovale))
- Abducent (superior orbital fissure)
- Facial (internal acoustic meatus + stylomastoid foramen)
- Vestibulocochlear (internal acoustic meatus)
- Glossopharyngeal (jugular foramen)
- Vagus (jugular foramen)
- Spinal accesory (jugular foramen)
- Hypoglassal (hypoglassol canal)
Identify the indicated blood vessel. What forms this vessel?
basilar artery
Formed by the right and left vertebral arteries
The basilar artery crosses along the anterior surface of the pons
what is the thick membrane that is the outermost of the three layers of the meninges that surround the brain and spinal cord?(nb. all three meninges layers surround the brain and spinal cord) What are the three meninges layer?
Dura matter
The three layers are: Pia matter Arachnoid matter Dura matter
What is the tough sheet of dura matter that tents over the posterior cranial fossa however has a gap for the brainstem to pass through?
The tenotrium cerebelli
what drains most of the venous blood from the cranial cavity into the internal jugular veins?
The dural venous sinuses
What nerve provides the muscle to give the eye with lateral movement?
What nerve provides the muscle to give the eye with downward and out movement?
The abducent nerve
The trochlear nerve
What structures are at risk of damage in pituitary gland surgery?
optic chiasm
dura mater
Cavernous sinus - cranial nerves 3, 4, 5 (v1, v2), 6 &
internal carotid artery
