Transcript Cavernous Sinus Anatomy

Can you identify the
midbrain, pons and
medulla on this midsagittal sequence.
Pons
Medulla
Can you identify the
pituitary gland? Note its
relationship to the
sphenoid sinus
Pituitary
S
Can you identify the
corpus callosum and the
cerebellum?
Corpus callosum
cerebellum
This is a coronal T1 weighted
sequence through the brain.
Can you identify the lateral
ventricles?
What are these glandular
structures noted laterally
(red arrows)?
Parotid glands
What is this bony structure
(red arrow)? See the
adjacent muscular
attachments.
Mandible
What are these
circular low signal
structures (yellow
arrows). Hint
flowing blood can
look like low signal,
sometimes called
“flow voids”.
Cavernous carotids
What is this large are of
signal void, in the middle of
the image (arrows)?
Hint, air produces no signal.
Sphenoid sinus
What is this muscular
structure (yellow arrows)?
This is the tongue. Do you see
the areas of high signal in the
muscle. We always see fat
(high signal on T1) in the tongue
Can you identify the
maxillary sinuses?
Hint, air filled sinuses will
produce no signal
Can you identify the nasal
turbinates?
Now let’s take a look at the
orbits. Try and pick out the
optic nerve, superior rectus,
superior oblique, medial, lateral
and inferior rectus extra-ocular
muscles. The inferior oblique
muscle is note seen on these
images.
Review the innervation of the
these muscles. Which 2
muscles are not innervated by
the oculomotor nerve (III)
Superior oblique– trochlear
nerve (IV)
Lateral rectus– Abducens
nerve (VI)
Blue=optic nerve, White=inferior rectus
Red=medial rectus, Yellow=superior oblique
Green=superior rectus, Pink=lateral rectus
What is the signal void
over the orbits (arrow)?
Frontal sinuses
These are coronal contrast enhanced images, do you see the carotid arteries in the
cavernous sinuses.
Note the venous blood in the sinuses is slow flowing and in bight on these images
but the blood in the carotid arteries is fast flowing and it shows up as signal void.
Cavernous
sinuses
Carotids
Now we are out of the cavernous sinus. Do you see the abnormal enhancing
lesion in this case?
Can you identify the mandible?
Masseter muscle
Medial pterygoid muscle
What are the muscles
attached to the inside and
the outside of the mandible?
Do you see the right parotid gland?
Why don’t you see the left parotid
gland? (was he born without one)
Unlikely, his head is just tiled in
the MRI scanner so the left one
is out of the plane
Can you identify the air filled spaces (areas of signal void) on this image?
Mastoid air cells
Nasopharynx
Maxillary Sinuses
What is this blood filled normal venous structure?
Transverse sinuses
What extra-ocular muscles do you see
on this image?
Inferior rectus on the right (yellow
arrow)
Lateral rectus on the left (red arrow)
This is the lesion, adjacent to the
cavernous extending to the orbital
apex
Do you see any areas of
abnormal enhancement?
What extra-ocular muscles can you
identify on the right?
Do you see the optic nerve?
Medial rectus blue arrow
Lateral rectus red arrow
Optic nerve pink arrow
Can you identify the frontal sinuses
and the sylvian fissures.
Frontal sinuses pink arrows
Sylvian fissures blue arrows