12 CRANIAL NERVES

• There are 12 pairs of cranial nerves that supply the structures in the Head, Neck, Thorax, and abdomen.
• A cranial nerve can be made up of a mixture of functions which are called modalities or may be made up of a single modality
• A modality is SENSORY, MOTOR, SPECIAL SENSORY, etc.

1.OLFACTORY NERVE (Cranial nerve l)

• Component- Sensory
• Function    - Smell
• Origin        - Olfactory receptor nerve cells
• Opening to the skull- Openings in the cribriform plate of the ethmoid.

2. OPTIC NERVE (cranial nerve ll)

• Component - sensory
• Function - vision
• Origin - Back of the eyeball
• Opening of the skull - Optic canal

3.OCCULOMOTOR NERVE (Cranial nerve lll)

Component- Motor
• Functions - 

1. Raises upper eyelid
2. Turns eyeball upward, downward and Medially
3. Constricts pupil
4. Accommodates the Eye

• Origin - Anterior surface of the midbrain
• Opening of the skull - Superior orbital fissure

4.TROCHLEAR NERVE (Cranial nerve lV)

• Component - Motor
• Function- Assisting in turning eyeball downward and laterally
• Origin - Posterior surface of the midbrain
• Opening to the skull - Superior orbital fissure

5.TRIGEMINAL NERVE (cranial nerve V)

      V1. Ophthalmic nerve

      V2. Maxillary nerve

      V3.Mandibular nerve

V1. Ophthalmic nerve

• Components - sensory
• Functions - 

1. Cornea
2. Skin of forehead
3. Scalp
4. Eyelids and Nose
5. Mucous membranes of paranasal sinuses and nasal cavity.

• Origin - anterior aspect of the pons
• Opening of the skull - Superior orbital fissure

V2. Maxillary nerve

• Components- Sensory
• Functions - 

1. The skin of the face over the maxilla
2. Teeth of the upper jaw
3. The mucous membrane of the nose, the maxillary sinus, and the palate

• Origin - anterior aspect of the pons
• Opening to the skull - Foramen ovale

V3. Mandibular nerve

• Components - accessory motor
• Function - 

1. Muscles of mastication
2. Mylohyoid
3. Anterior belly of digastric
4. Tensor veli palatine
5. Tensor tympani

• Origin- anterior aspect of the pons
• Opening to the skull - Foramen Rotundum

6.ABDUCENT NERVE (cranial nerve Vl)

• Component - Motor
• Function - Lateral rectus muscle turns eyeball laterally
• Origin - Medulla oblongata
• Opening to the skull - Superior orbital fissure

7.FACIAL NERVE (cranial nerve Vll)

• Component - Mixed
• Functions -

(I) MOTOR

1. Muscles of the face and scalp
2. Stapedius muscle
3. Posterior belly of digastric
4. Stylohyoid muscles

(ll) Sensory

1. Taste from anterior 2/3rd of the tongue, from the floor of the mouth and palate.

8.VESTIBULOCOCHLEAR NERVE (cranial nerve Vlll) (Auditory/Acoustic nerve)

• Component - Sensory
• Function - 

1. Vestibular - Saculae, Saccule , Semicircular canals- Position of the head.
2. Cochlear - Organ of Corti - Hearing

• Origin - Medulla oblongata
• Opening to the skull- Internal acoustic meatus

9.GLOSSOPHARYNGEAL NERVE (cranial nerve lX)

• Component - Mixed
• Function - 

(I) Motor

1. Stylopharyngeus muscle- assists swallowing

(ii) Sensory

1. General sensation and taste from posterior 1/2 of the tongue and pharynx.
2. Cortis sinus and carotid body.

(iii) Secretomotor

          Parotid gland

• Origin: Medulla Oblongata
• Opening to the skull: Jugular Foramen

10.VAGUS NERVE( Cranial nerve X)

• Component - Motor
• Function

1. Heart and great thoracic blood vessels
2. Larynx, Trachea, Bronchi, and lungs
3. Alimentary tract from the pharynx to the splenic flexure of the colon
4. Liver, kidney, Pancreas

• Origin - Medulla Oblongata
• Opening to the skull - Jugular foramen

11.ACCESSORY NERVE( cranial nerve Xl)

• Component-Motor
• Function

(I) cranial root

• Muscles of the soft palate
• muscles of pharynx
• muscles of larynx

(ii) Spinal root

• Sternocleidomastoid
• Trapezius muscle

• Origin - Medulla oblongata
• Opening to the skull - Jugular foramen

12.HYPOGLOSSAL NERVE(Cranial nerve Xll)

• Component - Motor
• Functions- Muscles of the tongue
• Origin- Medulla oblongata
• Opening to the skull- Hypoglossal canal