Cranial Nerves: Introduction

by Darren Salmi, MD, MS

My Notes
  • Required.
Save Cancel
    Learning Material 2
    • PDF
      Slides Anatomy Cranial Nerves Introduction.pdf
    • PDF
      Download Lecture Overview
    Report mistake

    00:01 Let's take an overview of the cranial nerves.

    00:05 The cranial nerves will be discussed in greater detail as they come up throughout the head anatomy portion, but I think it's worth looking at all of them together to give you an idea of what they're doing overall.

    00:18 To start, let's look at how they're numbered.

    00:22 They're generally numbered from anterior to posterior, as they come off of the brain.

    00:29 For example, cranial nerve one is actually very far anterior, and it's actually made up of many small nerves.

    00:37 It's actually a bunch of tiny nerves that sit in the olfactory mucosa of the upper nasal cavity.

    00:44 And they're going to carry out smell.

    00:48 A little bit further back, we have the optic nerves, and they're carrying vision from the retina.

    00:56 Cranial nerve III is the oculomotor nerve, so named because it innervates muscles that move the eyeball.

    01:04 Cranial nerve IV called the trochlear nerve has to do with a tiny little pulley thing called the trochlea that's related to another one of the extra ocular muscles.

    01:14 Similarly abducens, innervates a muscle that abducts the eye hence its name.

    01:23 Cranial nerve V, the trigeminal nerve is so named because it has three separate branches ophthalmic maxillary and mandibular.

    01:33 And it carries out both sensory and motor functions.

    01:37 Cranial nerve VII innervates the muscles of facial expression and that's called the facial nerve.

    01:45 Cranial nerve VIII, vestibulocochlear has both vestibular and cochlear functions meaning they're related to equilibrium and hearing.

    01:55 Cranial nerve nine glossopharyngeal has areas of the tongue and pharynx that interacts with, it has both motor and sensory innervation as well hence its name the glossopharyngeal nerve.

    02:10 The vagus nerve does a little bit of everything, sensation, parasympathetic, it has motor innervation and it goes all the way down to the colon.

    02:22 So it's called vagus because it wanders like a Vega bond.

    02:28 Cranial nerve XI, the accessory nerve is a little bit of a misnomer in the sense that it actually originates in the spinal cord, but it does enter the cranial cavity so that actually ends up exiting.

    02:39 So that is really what makes it a cranial nerve because it exits the cranium, but it innervates two muscles that move the head, neck and shoulders.

    02:51 Finally cranial nerve XII, hypoglossal, provides motor innervation to the tongue or glossus hence its name.

    03:01 The cranial nerves can kind of be summarized here in terms of what they do most generally.

    03:07 So we have somatic versus visceral, meaning sort of the body and things you can control versus organs.

    03:15 That's what's meant by visceral.

    03:17 We also have special senses that are carried out by the cranial nerves.

    03:22 Those are things like vision or smell.

    03:25 And as you can see, we have a nice summary here of which things are done by which nerves.

    About the Lecture

    The lecture Cranial Nerves: Introduction by Darren Salmi, MD, MS is from the course Neurovasculature of the Head.

    Included Quiz Questions

    1. II
    2. VII
    3. I
    4. X
    5. XII
    1. V
    2. VI
    3. II
    4. XI
    5. XII
    1. XI
    2. X
    3. IX
    4. VII
    5. VI

    Author of lecture Cranial Nerves: Introduction

     Darren Salmi, MD, MS

    Darren Salmi, MD, MS

    Customer reviews

    5,0 of 5 stars
    5 Stars
    4 Stars
    3 Stars
    2 Stars
    1  Star