It is also the only cranial nerve to emerge from the dorsal side of the brainstem and, consequently, has the longest intradural (intracranial) course of any cranial nerve.
Which cranial nerve has the longest course?
The fourth cranial nerve (trochlear nerve) has the longest intracranial course; it is the only cranial nerve that has a dorsal exit from the brainstem (figure 1). It begins in the midbrain at the level of the inferior colliculus as fascicles extending from the fourth nerve nuclei.
Which cranial nerve has the longest intracranial route?
Of all the cranial nerves, the abducens nerve has the longest intracranial course. It is located in the pons at the floor of the fourth ventricle, at the same level as the facial colliculus. In fact, the axons of the facial nerve loop around the posterior aspect of the abducens nucleus.
Which of the following is the longest cranial nerve?
The vagus nerve is the longest cranial nerve as it starts in the medulla and extends to the abdomen.
Which cranial nerve has shortest intracranial course?
The trochlear nerve is unique among the cranial nerves in several respects: It is the smallest nerve in terms of the number of axons it contains. It has the greatest intracranial length. It is the only cranial nerve that exits from the dorsal (rear) aspect of the brainstem.
What is the shortest cranial nerve?
The trochlear nerve is the fourth paired cranial nerve. It is the smallest cranial nerve (by number of axons), yet has the longest intracranial course.
Which is the thickest cranial nerve?
The largest cranial nerve is trigeminal nerve. The smallest cranial nerve is abducens nerve. The thinnest cranial nerve is trochlear nerve.
How do you test for cranial nerve 4?
Trochlear nerve (CN IV)
Cranial nerve IV acts as a pulley to move the eyes down—toward the tip of the nose. To assess the trochlear nerve, instruct the patient to follow your finger while you move it down toward his nose.
Which cranial nerve is commonly affected by increase in intracranial pressure?
As the abducens nerve enters the subarachnoid space, other etiologies may arise resulting in palsy. In these cases, the palsy is primarily because of the increased intracranial pressure. As such, other symptoms such as a headache, nausea, vomiting, and papilledema may be noted.
Where is the cranial nerve located?
The cranial nerves are a set of 12 paired nerves that arise directly from the brain. The first two nerves (olfactory and optic) arise from the cerebrum, whereas the remaining ten emerge from the brain stem.
How do you test for cranial nerve 10?
The motor division of CN 9 & 10 is tested by having the patient say “ah” or “kah”. The palate should rise symmetrically and there should be little nasal air escape. With unilateral weakness the uvula will deviate toward the normal side because that side of the palate is pulled up higher.
What is the largest nerve in human body?
The sciatic nerve is the largest nerve in your body. It begins in your lower back and travels all the way down to the heel of your foot. You may have heard of a condition called sciatica in which painful sensations radiate from your lower back and down your leg.
How long does 6th cranial nerve palsy last?
Sixth nerve palsy caused by viral illness generally goes away completely while cases due to trauma may have residual symptoms. The greatest improvement generally occurs in the first 6 months. Most people with idiopathic sixth nerve palsy (of unknown cause) completely recover.
What cranial nerve does the nose connect to?
The olfactory nerve (CN I) is the first and shortest cranial nerve. It is a special visceral afferent nerve, which transmits information relating to smell.