The trochlear nerve is the fourth cranial nerve (CN IV) and one of the ocular motor nerves that controls eye movement. The trochlear nerve, while the smallest of the cranial nerves, has the longest intracranial course as it is the only nerve to have a dorsal exit from 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 longest cranial nerve?
The vagus nerve (cranial nerve [CN] X) is the longest cranial nerve in the body, containing both motor and sensory functions in both the afferent and efferent regards.
What is the smallest nerve?
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.
What does hypoglossal nerve do?
The hypoglossal nerve is mainly a somatic efferent (motor) nerve to innervate the tongue musculature. The nerve also contains some sympathetic postganglionic fibers from the cervical ganglia, which innervates tongue vessels and some small glands in the oral mucosa.
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 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 side of the neck is the vagus nerve on?
On the right side, it arises from the trunk of the vagus as it lies beside the trachea. On the left side, it originates from the recurrent laryngeal nerve only.
What is the strongest nerve in human body?
Sciatic nerve, largest and thickest nerve of the human body that is the principal continuation of all the roots of the sacral plexus.
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.
Which is the sixth cranial nerve?
Cranial nerve six (CN VI), also known as the abducens nerve, is one of the nerves responsible for the extraocular motor functions of the eye, along with the oculomotor nerve (CN III) and the trochlear nerve (CN IV).
What happens if the trigeminal nerve is damaged?
Trigeminal nerve injuries not only causes significant neurosensory deficits and facial pain, but can cause significant comorbidities due to changes in eating habits from muscular denervation of masticator muscles or altered sensation of the oral mucosa.
Does Trochlear nerve cross?
The trochlear nucleus gives rise to nerves that cross (decussate) to the other side of the brainstem just prior to exiting the brainstem. Thus, each superior oblique muscle is supplied by nerve fibers from the trochlear nucleus of the opposite side.
Can nerve damage affect the tongue?
There are many different reasons for changes in the tongue’s function and appearance. Tongue movement problems are most often caused by nerve damage. Rarely, problems moving the tongue may also be caused by a disorder where the band of tissue that attaches the tongue to the floor of the mouth is too short.
What nerves affect the tongue?
The hypoglossal nerve is the twelfth cranial nerve, and innervates all the extrinsic and intrinsic muscles of the tongue, except for the palatoglossus which is innervated by the vagus nerve. It is a nerve with a solely motor function.
What causes damage to the hypoglossal nerve?
Hypoglossal nerve disorders may be caused by tumors, strokes, infections, injuries, or amyotrophic lateral sclerosis. People with hypoglossal nerve disorder have difficulty speaking, chewing, and swallowing. Doctors usually do magnetic resonance imaging and/or a spinal tap to identify the cause. The cause is treated.