Trigeminal nerve

Trigeminal Nerve
Tariq Al Fayad M

PRESENTATION LAYOUT
▪ INTRODUCTION
▪ NUCLEI
▪ FUNCTIONAL COMPONENT [ SENSORY & MOTOR]
▪ DISTRIBUTION OFTHE NERVE
▪ DIVISIONS

INTRODUCTION
It is the Largest cranial Nerve
Contains both the Sensory and motor
fibres.
It is sensory from the head, but motor
to the jaw muscles.

The term trigeminal was given byWinslow on
account of its three divisions.
The part of parasympathetic craniosacral
outflow.
It is a mixed nerve ( sensory and motor )
Contains
1,70,000 sensory fibres
7,700 motor fibres
The 3 divisions have approx.
Ophthalmic 26,000
Maxillary 50,000
Mandibular 78,000

NUCLEI
The trigeminal nerve has four
nuclei:
The main sensory nucleus,
The spinal nucleus,
The mesencephalic nucleus, and
The motor nucleus.

SENSORY NUCLEUS
It lies in the upper part of pons lateral to
the motor nucleus.
It is continuous below with the spinal
nucleus and above with the mesencephalic
nucleus.

SPINAL NUCLEUS
▪It descends from the main sensory
nucleus in the pons, through the
whole length of medulla oblongata
▪And into the upper two segments of
the spinal cord.

MESENCEPHALIC NUCLEUS
▪This nucleus is situated in the
lateral part of the central grey
matter of the midbrain.
▪It extends down in the pons up to
the main sensory nucleus.

MOTOR NUCLEUS
This is situated in the upper
part of the pons medial to the
main sensory nucleus.

FUCTIONAL COMPONENT –
SENSORY COMPONENT [GENERAL SOMATIC
AFFERENT] AND CONNECTIONS OFTHE
SENSORY NUCLEI
Sensation from the eyeball, lacrimal gland,
conjunctiva, face, oral and nasal cavities are
carried along the sensory component of the
serve and relayed as below

Pain,temp,light touch touch, pressure proprioception
(relay)
trigeminal gang. Bypasses trigem gang.
main sensory nucleus
descending fibres ascending fibres

descending fibres ascending fibres
Spinal nuc. Principal sen nuc. Mesencephalic
Trigeminal Leminiscus
Thalmus
Post Central Gyrus Cerebral Cortex (areas 3,2,1.)

THE TRIGEMINAL GANGLION :-
Also known as Gasserian ganglion, or semilunar
ganglion, is a sensory ganglion of
the trigeminal nerve that occupies a cavity
(Meckel's cave) in the dura mater, covering
the trigeminal impression near the apex of
the petrous part of the temporal bone.

 It is somewhat crescentic or semilunarin shape, with its convexity directed
anteriomedialy.
 The three divisions of the trigeminal nerve emerges from this convexity.

RELATIONS:-
MEDIALY- Internal carotid artery &
posterior part of cavernous sinus
LATERALY-Middle meningeal artery
SUPERIORLY- Uncus And temporal lobe
INFERIORLY-Motor root of trigeminal nerve,
greater petrosal nerve ,
apex of the petrous temporal bone,
foramen lacerum.

DIVISINS OF 5TH CRANIAL NERVE
Trigeminal nerve
Ophthalmic
(sensory)
Maxillary
(sensory)
Mandibular
(mixed)

OPHTHALMIC NERVE [V1]
It is the smallest of 3 division.
It lies in the Cavernous sinus where the
oculomotor and trochlear nerves are superior
to it and maxillary division is inferior to it.

Before entering the orbit by the superior orbital fissure it
divides into
Lacrimal Nasociliary Frontal
(smallest) (intermediate) (largest)
Internal External Supra Supra
nasal nasal Troclear Orbital
Long Infra Posterior
ciliary Trochlear Ethmoidal

Lacrimal nerve:
 Smallest of main ophthalmic branches
 Enters the orbit through the lateral part of the
superior orbital fissure
 Runs along the upper border of the rectus
lateralis with the lacrimal artery
 Receives a communication from the
zygomaticotemporal branch of maxillary
nerve.which contains lacrimal secretomotor
fibres

FRONTAL NERVE:
Largest branch of the ophthalmic division.
Enters the orbit by the superior orbital fissure.
Divides midway between the apex and the base of the
orbit into two branches:
Supratrochlear Supra orbital
(small) (large)

SUPRATROCHLEAR BRANCH:
Runs anteromedially, passing above the troclear.
Supplies a descending filament to the infratrochlear
branch of naso ciliary nerve.
Then it emerges between the trochlea and the
supraorbital foramen and supplies
- conjunctiva
- skin of the upper eyelid
- skin of the lower forehead near the midline

SUPRA ORBITAl BRANCH:
Emerges from orbit through supraorbital notch or
foramen.
It supplies,
-Conjuctiva
-Central part of the upper eyelid,
-Frontal air sinus
-Skin of the forehead
-scalp up to the vertex or even upto the lambdoid
suture.

Nasociliary nerve:
 Begins in lateral wall of the anterior part of
cavernous sinus.
 Enters the orbit through middle part of superior
orbital fissure.
 Crosses above the optic nerve from lateral to
medial side.

Branches as follows:
o Communication branch to the ciliary ganglion
from sensory root of the ganglion. It is mixed
with sympathetic root.
o Long ciliary nerves run on the medial side of the
optic nerve.
 Supply sensory nerves to cornea, iris ciliary
body.
o Posterior ethmoidal nerve passes through
posterior ethmoidal foramen
 Supplies ethmoidal and sphenoidal air
sinuses.

o Infratrochlear nerve is smallest terminal branch
of Nasocilliary nerve.
o Emerges from orbit below the trochlea and
appears on the face above the medial angle of
the eye.
 Supplies
-Conjunctiva
-Lacrimal sac
-Caruncle
-Medial ends of the eyelids.

o Anterior ethmoidal nerve is the largest terminal
of nasociliary nerve.
o Passes through anterior ethmoidal foramen.
o Appears for short distance, in the anterior
cranial fossa then it descends into the nose
through a slit at the side of anterior part of the
crista galli.

Maxillary Nerve [v2]
After arising from the ganglion passes through the foramen
rotundum and reaches the pterygopalatine fossa.
It has 5 Branches:
 Middle meningeal nerve
 Pterygopalatine nerve
 Posterior superior alveolar nerves
 Zygomatic nerve

Mandibular Nerve [V3]
It is formed by union of tensor trunks, large sensory trunk with motor
root of the trigeminal.
The motor root supplies the muscles of mastication, tensor tympani,
tensor veli palatine , mylohyoid and the anterior belly of the digastric
muscle.

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Trigeminal nerve

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