NETTER - Neuroscience Flash Cards

Hematomas
1. Tentorium cerebelli
2. Herniation of temporal lobe
3. Skull fracture affecting middle meningeal artery
4. Midline shift of falx cerebri and third ventricle
5. Compression of cerebral peduncle
6. Herniation of cerebellar tonsil in foramen magnum
7. Compression of CN III
Comment: A skull fracture that tears the middle meningeal artery
can result in an arterial bleed into the epidural space. This bleed,
or any space-occupying mass in the supratentorial space, can
displace the brain and cause it to shift midline structures (subfalcial)
or compress downward, herniating the temporal lobe across the
tentorium cerebelli (transtentorial herniation). The herniating brain
often compresses CN III, causing an ipsilateral fixed, dilated pupil
and oculomotor palsy, and it compresses the adjacent cerebral
peduncle, causing contralateral hemiparesis and contralateral
drooping lower face (central facial palsy). A space-occupying mass
in the posterior fossa can herniate the cerebellar tonsil through the
foramen, compressing the brain stem, altering vital visceral functions
such as blood pressure and respiration, and can result in death.
Overview of the Nervous System