which cranial nerve has the longest course

What are the 8 cranial nerves?

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 most anterior origin?

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.

What is the longest cutaneous nerve in the human body?

Nov 25, 2020 · Accessory nerve is a motor nerve that controls the muscles in your neck. Hypoglossal nerve is the 12th cranial nerve which is responsible for the movement of most of the muscles in your tongue. Among these cranial nerves, Xth cranial nerve, Vagus, is …

What is the longest and largest nerve?

Nov 29, 2021 · Of all the cranial nerves, the abducens nerve has the second 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. This will be of clinical significance later.

Which cranial nerve has the longest intradural course?

The trochlear nerve (CN IV) is the only cranial nerve in which all the fibers cross to the opposite side. 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 longest route in periphery?

Vagus nerve (CN X) Cranial nerve 10 is also a multimodal nerve, It originates from multiple nuclei in the brainstem, and exits the skull through the jugular foramen. It is the longest cranial nerve and the only one to leave the head and neck region.

Which cranial nerve has the shortest course?

The trochlear nerve- The trochlear nerve is the smallest cranial nerve. It is the fourth cranial nerve. Emerging from the brain, it has the shortest course as it terminates by innervating a muscle present in the eye.

What has the longest course and most extensive distribution of all cranial nerves?

The vagus nerve has the most extensive distribution of the cranial nerves.

Is the vagus nerve the longest nerve in the body?

Gross Anatomy. The vagus nerve is the longest cranial nerve. It contains motor and sensory fibers and, because it passes through the neck and thorax to the abdomen, has the widest distribution in the body. It contains somatic and visceral afferent fibers, as well as general and special visceral efferent fibers.Dec 8, 2017

What is the largest of the cranial nerves and the most important sensory nerve of the face?

The largest of the cranial nerves and most important sensory nerve of the face is the trigeminal nerve (letter C).

What is the longest nerve in the human body?

Sciatic NerveSciatic Nerve and Sciatica. The sciatic nerve is the longest, largest nerve in your body. Your sciatic nerve roots start in your lower back and run down the back of each leg.Jun 15, 2021

Which is the thickest cranial nerve?

Thickest Cranial Nerve---> Trigeminal.

Which is the largest and smallest cranial nerve?

Largest Cranial Nerve – Trigeminal nerve (5th Cranial nerve) Smallest cranial nerve – Trochlear Nerve (4th Cranial nerve)

What is the course of the vagus nerve?

Course. The vagus nerve runs from the brain through the face and thorax to the abdomen. Exits the brain from the medulla oblongata of the brainstem and travels laterally exiting the skull through the jugular foramen.

Is the vagus nerve afferent or efferent?

mixed nerveThe vagus nerve is a mixed nerve, as it contains both afferent (sensory) and efferent (motor) fibers. This means it is responsible for not only carrying motor signals to the organs it innervates, but it also carries sensory information from these organs back to the central nervous system.

Which is the most anterior cranial nerve quizlet?

CN 1 located most anterior and cranial nerve XII located most posterior.

Which cranial nerve has the longest intracranial course?

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.

What nerve innervates the ipsilateral lateral rectus muscle?

The abducens nerve functions to innervate the ipsilateral lateral rectus muscle and partially innervate the contralateral medial rectus muscle (at the level of the nucleus - via the medial longitudinal fasciculus). Physiologic Variants. A few physiologic variants of abducens nerve anatomy have been documented.

What is the CN VI?

Last Update: November 19, 2020. Introduction. 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). Structure and Function. Unlike the oculomotor nerve and the trochlear nerve, ...

What is the abducens nerve?

Unlike the oculomotor nerve and the trochlear nerve, the abducens nerve is a purely motor nerve, meaning the nerve has no sensory function. Its main function is to carry general somatic efferent nerve axons to innervate the lateral rectus muscle, which then abducts the eye on the ipsilateral side. It is also secondarily involved in innervation ...

What causes abducens nerve palsy?

Of those, the most common cause of abducens nerve palsy is diabetic neuropathy. Damage to the abducens nerve can result from anything compresses it.

Can a lumbar puncture cause meningitis?

In fact, a lumbar puncture (LP) for cerebrospinal fluid (CSF) analysis is completed to exclude meningitis in patients who have no history of diabetes or hypertension and who have a head CT scan negative for other pathology.

Which nerve has the longest course?

The vagus nerve has the longest course of all the cranial nerves, extending from the head to the abdomen. Its name is derived from the Latin ‘ vagary’ – meaning wandering. It is sometimes referred to as the wandering nerve.

Which nerve passes through the neck?

In the neck, the vagus nerve passes into the carotid sheath, travelling inferiorly with the internal jugular vein and common carotid artery. At the base of the neck, the right and left nerves have differing pathways:

What is the sensory function of the vagus nerve?

Sensory Functions. There are somatic and visceral components to the sensory function of the vagus nerve. Somatic refers to sensation from the skin and muscles. This is provided by the auricular nerve, which innervates the skin of the posterior part of the external auditory canal and external ear.

Which nerve innervates the larynx?

The internal laryngeal provides sensory innervation to the laryngopharynx and superior part of the larynx. Recurrent laryngeal nerve (right side only) – Hooks underneath the right subclavian artery, then ascends towards to the larynx. It innervates the majority of the intrinsic muscles of the larynx.

What happens if you have a lesion to the CN X?

As CN X innervates the Palatopharyngeus and Salpingopharyngeus muscles a lesion here will cause the Palatoglossal arch to drop leading to Uvula deviation away from the affected side. The CN IX is sensory to the oropharynx and laryngopharynx with CN X being the motor efferents involved in the Gag reflex therefore a lesion in this area will cause a loss of the Gag reflex.

Which nerve forms the posterior vagal trunk?

In the thorax, the right vagus nerve forms the posterior vagal trunk, and the left forms the anterior vagal trunk . Branches from the vagal trunks contribute to the formation of the oesophageal plexus, which innervates the smooth muscle of the oesophagus.

Which nerve is responsible for innervation of the oesophagus, stomach, and most of the

The vagus nerve provides parasympathetic innervation to the majority of the abdominal organs. It sends branches to the oesophagus, stomach and most of the intestinal tract – up to the splenic flexure of the large colon.

Which cranial nerve has the longest intracranial course?

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. It has a purely somatic motor function. In this article, the anatomical course, motor functions and clinical relevance of the nerve will be examined.

Which nerve innervates the superior oblique muscle?

The trochlear nerve innervates a single muscle – the superior oblique, which is a muscle of oculomotion. As the fibres from the trochlear nucleus cross in the midbrain before they exit, the trochlear neurones innervate the contralateral superior oblique.

Where does the trochlear nerve originate?

The trochlear nerve arises from the trochlear nucleus of the brain, emerging from the posterior aspect of the midbrain (it is the only cranial nerve to exit from the posterior midbrain).