The Cranial Nerves are nerves that originate from the brain stem.
Are very specialized and important set of nerves.
There are 12 overall and they control a variety of functions both motor or sensory
Motor is the movement of a muscle [Efferent]
Sensory is the sight, touch or smells of the senses that are transmitted to the brain [Afferent]
Many cranial nerves are either Motor [Efferent] or Sensory [Afferent] but a some are both
Cranial Nerves:
I Olfactory or smell [Afferent]
- Transmits sense of smell
II Optic or vision [Afferent]
- Transmits visual information from eye to brain
III Oculomotor or movement of eyeball [Efferent]
- Innervates levator palprebrae of the eye
- Innervates superior rectus of the eye
- Innervates medial rectus of the eye
- Innervates inferior rectus of the eye
- Innervates inferior oblique of the eye
- Affects the majority of eye movement
- The exceptions are with Cranial nerves IV and VI
IV Trochlear or muscles of eyeball [Efferent]
- Innervates superior oblique muscle of the eye
- Allows for movements of eye including: lateral, depresses, and intorts
V Trigeminal [Afferent] and [Efferent]
- V1 – opthalmic [Afferent]
- V2 – maxillary [Afferent]
- V3 – mandibular [Afferent] and [Efferent]
- Receives sensation from the face.
- Innervates facial muscles for mastication [chewing]
VI Abducens or muscles of eyeball [Efferent]
- Innervates the lateral rectus of the eye
- Affects the abduction of the eye
VII Facial [Afferent] and [Efferent]
- Motor innervation to the muscles of the face
- Allows for facial expressions
- Receives senses of taste from the anterior 2/3 of the tongue
- Affects secretion of the salivary glands [except parotid]
VIII Vestibulocochlear [Afferent]
- Senses Gravity
- Senses Sound
- Senses Rotation
- Essential for balance and movement
IX Glossopharyngeal [Afferent] and [Efferent]
- Receives taste from the posterior 1/3 of the tongue
- Affects secretion of the Parotid gland
- Affects some sensation of the Tonsils
X Vagus [Afferent] and [Efferent]
- Supplies motor innervation to most laryngeal and all pharyngeal muscles
- Controls muscles for voice
- Helps control soft palate
XI Accessory or spinal [Efferent]
- Controls sternocleidomastoid
- Controls trapezius muscles
- Helps with shrugging shoulders
XII Hypoglossal or tongue [Efferent]
- Provides motor innervation to the muscles of the tongue
- Important for Speech
- Important for Swallowing
Below is a Video of the Cranial Nerve Examination
Cranial Nerves,
Spotlight on: Nutrition/Diet
