The trigeminal nerve (cranial nerve V) leaves the side of the pons at mid-pons level, as a large sensory root with a small motor root beside it. Its three divisions leave the skull by three openings: the ophthalmic (V1) through the superior orbital fissure, the maxillary (V2) through the foramen rotundum and the mandibular (V3) through the foramen ovale. [1][2][3]
The 3D brain needs JavaScript. The text below still says where the trigeminal nerve is and what it does.
Opens cut by a side (sagittal) slice through the pons, which the trigeminal nerve leaves the brain from. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Not a separate shape in this atlas; lit: the part it leaves the brain from. Lit: the whole pons, the part the trigeminal nerve leaves the brain from. The nerve’s roots, its ganglion and its three main divisions have no shape in the BodyParts3D atlas; the atlas draws only fine branches of the ophthalmic division inside each eye socket (the frontal, lacrimal and nasociliary nerves and their twigs), and those are not part of this site’s brain model, so nothing is drawn for the nerve. [4][1]
Where it leaves the brain: the pons. The large sensory root enters the side of the pons at mid-pons level, and the smaller motor root comes out just above and inward of it. [1][2][5]
Lit here: the pons, the part the trigeminal nerve leaves the brain from — see it on its own page.
From the pons the roots run forward to the trigeminal ganglion (also called the semilunar or Gasserian ganglion), which sits in a pocket of dura called Meckel’s cave and holds the cell bodies of the sensory fibres. The motor fibres pass through it without stopping. [1]
Its three divisions fan out from the ganglion and leave the skull separately: the ophthalmic nerve (V1) through the superior orbital fissure into the eye socket, the maxillary nerve (V2) through the foramen rotundum and the mandibular nerve (V3) through the foramen ovale. [1][3]
On its way to the eye socket the ophthalmic division runs through the cavernous sinus, alongside the oculomotor, trochlear and abducens nerves. [3]
Its sensory nucleus runs the whole length of the brainstem, from the midbrain through the pons and medulla into the top of the spinal cord, in three parts (mesencephalic, principal sensory and spinal trigeminal); its motor nucleus lies deep in the pons. [1]
What it does
It carries touch, pain and temperature from the face: the skin of the face and front of the scalp, the surface of the eye (cornea and conjunctiva), the inside of the nose and mouth, and the teeth and gums. [1][5]
Each division covers its own band of the face: V1 the forehead, upper eyelid and the nose down to its tip; V2 the lower eyelid, cheek, upper lip and upper teeth; V3 the lower lip, lower teeth, chin and jaw, except the angle of the jaw. [1]
Only the mandibular division carries motor fibres. It works the four chewing muscles (the masseter, the temporalis and the medial and lateral pterygoids) and four more: the tensor veli palatini, the mylohyoid, the front belly of the digastric and the tensor tympani in the middle ear. [1]
The ophthalmic and maxillary divisions are purely sensory; the trigeminal and facial nerves split the face between them, the trigeminal for its feeling and the facial for its movement. [1][5]
Connections
From the face, mouth and teeth to the trigeminal nuclei of the brainstem; from there the signals cross the midline and rise in the trigeminothalamic tracts to the thalamus, which passes them on to the cerebral cortex. [1]
Other names
Cranial nerve V (CN V), fifth cranial nerve; nervus trigeminus (Latin). “Trigeminal” is from Latin tri- (three) and geminus (twin), after its three divisions: ophthalmic (V1), maxillary (V2) and mandibular (V3). [1]
Size
The model has no shape for the trigeminal nerve, so it is not measured here. The pons, lit as the part it leaves the brain from, measures about 34 mm front to back, 29 mm top to bottom and 42 mm side to side on this model (the box it fits in, not its volume). [4]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.