What is the trigeminal root entry zone?
The root entry zone, i.e. the zone where peripheral myelination transitions to central myelination, was defined as the area from the site of entry of the trigeminal nerve into the pons to 7 mm peripherally along the nerve (Peker et al., 2006).
What is the boundary between the CNS and the PNS?
The Redlich–Obersteiner’s zone, also known as the root entry zone, is a boundary between the central nervous system (CNS) and the peripheral nervous system (PNS). The Redlich–Obersteiner’s zone is located at the point of entry of either between cranial nerves and the brain or spinal nerves and the spinal cord.
What is the root exit zone?
The root exit zone (REZ) of the seventh cranial nerve has been the target of microvascular decompression surgery (MVD) while searching the neurovascular conflict for treatment of hemifacial spasm for long time. Recently, increasing cases regarding the offending vessel beyond the REZ have been reported.
What is neurovascular compression?
Neurovascular compression syndrome (NVCS) is defined as a direct contact with mechanical irritation of cranial nerves (CNs) by blood vessels.
What is the cisternal segment of trigeminal nerve?
The cisternal segment of CN V arises from the anterolateral aspect of the pons (Figure 1), and consists of a large sensory root comprising the main bulk of the nerve, and of one or more smaller motor roots arising superomedial to the sensory root (4).
What type of MRI is used for trigeminal neuralgia?
Magnetic resonance image (MRI) with high resolution on the pons demonstrating the trigeminal nerve root. In this case, the patient with trigeminal neuralgia has undergone gamma-knife therapy, and the left-sided treated nerve (arrow) is enhanced by gadolinium.
Where does the CNS become the PNS?
The CNS is made up of the brain and the spinal cord components. The PNS is all the nerves that branch out from the CNS components and extend to other parts of the body – to the sense organs, muscles, and glands. The PNS connects the CNS to the rest of the body.
How is vascular compression diagnosed?
If a vascular compression syndrome is suspected, testing may include a audiogram (hearing test), VNG (balance test), ECOG (test for Meniere’s disease), and ABR (brainstem hearing test). An MRI is always ordered. These tests are to look for other causes as much as they are to diagnose vascular compression.
What causes neurovascular compression?
Neurovascular compression syndromes — hemifacial spasm, glossopharyngeal neuralgia, and trigeminal neuralgia — are generally caused by compression of a cranial nerve due to a redundant or aberrant vascular structure.
What causes an artery to compress a nerve?
Compression can be due to vascular abnormalities such as an aneurysm or arteriovenous malformation [8], and demyelination due to multiple sclerosis has been described [6].
What is the Meckel’s cave?
Meckel’s cave is a natural mouth-shaped aperture in the medial portion of the middle cranial fossa that acts as a key conduit for the largest cranial nerve, the trigeminal nerve (CN V). It connects the cavernous sinus to the prepontine cistern of the posterior fossa.
What is Cisternal segment?
What are the 2 divisions of the efferent PNS?
The efferent division of the PNS can be divided into two components – the autonomic nervous system and the somatic nervous system.
How is vascular compression treated?
How are vascular compressive syndromes treated? Trigeminal neuralgia is treated with daily medications. These may include medications for nerve pain (gabapentin), antiseizure medications (tegretol, valproic acid, phenytoin), or relaxing medications (clonazepam, baclofen).
Why does vascular compression happen?
Vascular compression syndromes are a group of conditions that occur when a person’s blood vessels are under abnormal pressure, limiting the size of the blood vessel and the amount of blood that flows through it.