Cranium

Layers of head

• Skin
• Subcutaneous fat
• Skull
  • Outer table
  • Diploe
  • Inner table
• Dura mater
  • Fused to periosteum
• Brain

Cranial nerves

For anatomical path, see 'nerves' under 'Neck' section

No.	Name	Sensory/motor	Origin/target	Exit path	Function	Exam
I	Olfactory	Sensory			Smell from nasal cavity	Smell
II	Optic	Sensory	Retinal ganglion cells	Optic canal	Vision from retina to brain	VA, visual fields
III	Oculomotor	Mainly motor	Anterior midbrain	Superior orbital fissure	EOM except LR and SO; pupillary constriction	EOM
IV	Trochlear	Motor	Dorsal midbrain	Superior orbital fissure	SO (depress, abduct and intort the eyeball)	EOM
V	Trigeminal	Both	Pons	V1 - ophthalmic - SOF. V2 - maxillary - foramen rotundum. V3 (and lingual nerve) - mandibular - foramen ovale.	Sensation from face, mouth and nasal cavity, muscles of mastication	Sensation
VI	Abducents	Motor	Pons	Superior orbital fissure	LR - abducts	EOM
VII	Facial	Both	Pons	Stylomastoid foramen	Motor to facial expression, posterior digastric, stylohyoid, stapedius. Chorda tympani: taste from anterior 2/3 tongue and secretomotor innervation to lacrimal glands and submandibular/lingual glands.	Expression
VIII	Vestibulocochlear	Sensory		Internal acoustic canal	Sensation of sound, rotation and gravity.	Hearing
IX	Glossopharyngeal	Both	Medulla	Jugular foramen	Taste from posterior 1/3 tongue, secretomotor to parotid, motor to stylopharyngeus.	Afferent for gag reflex
X	Vagus	Both	Posterolateral sulcus of medulla	Jugular foramen	Most laryngeal/pharyngeal muscles and sensation. PNS to nearly all thoracic and abdominal viscera.	Efferent for gag reflex
XI	Spinal accessory	Motor		Jugular foramen	SCM and trapezius	Movement
XII	Hypoglossal	Motor	Medulla	Hypoglossal canal	Motor innervation to muscles of tongue.	Stick tongue out