Emerge Crebrum, brainstemSensory motor n mixedHead n neck function
Pathway between eyball n optccnalFlattened at chaisma to rounded when passes through optic canal.Orbit- forward lateral downwrd to pierc sclera. Torturous course within orbit
Optic tract– homoChaisma- both side
Interpeduncular fossa. Superior and inferior division enters through superior orbital fissure
Incr intracranial pressure
Bends sharply medially AFTER SOF
-arises from the upper part of the trigeminal ganglion as a short, flattened band,which passes forward along the lateral wall of the cavernous sinus, below the oculomotor and trochlear nerves; just before entering the orbit, through the superior orbital fissure, it divides into three branches, lacrimal, frontal, and nasociliary.The frontal branch passes through the orbit superiorly, then reenters the frontal bone briefly before exiting above the orbit through the supraorbital foramen and the supratrochlear notch to provide sensory innervation for the skin of the forehead and scalp. The lacrimal nerve passes through the orbit superiorly to innervate the lacrimal gland. The nasociliary branch gives off several sensory branches to the orbit and then continues out through the anterior ethmoidal foramen, where it enters the nasal cavity and provides innervation for much of the anterior nasal mucosa. It also gives off a branch which exits through the nasal bones to form the external nasal branch.
Anterior to the trigeminal ganglion, the maxillary nerve passes through the cavernous sinus and exits the skull through the foramen rotundum.It begins at the middle of the trigeminal ganglion as a flattened plexiform band, and, passing horizontally forward, it leaves the skull through the foramen rotundum, where it becomes more cylindrical in form, and firmer in texture.It then crosses the pterygopalatine fossa, inclines lateralward on the back of the maxilla, and enters the orbit through the inferior orbital fissure. It traverses the infraorbital groove and canal in the floor of the orbit, and appears upon the face at the infraorbital foramen. There, it is called the infraorbital nerve
The two roots (sensory and motor) exit the middle cranial fossa through the foramen ovale. The two roots then combine.Immediately in the infratemporal fossa beneath the base of the skull, the nerve gives off two branches from its medial side: a recurrent branch (nervusspinosus) and the nerve to the medial pterygoid muscle. The mandibular nerve then divides into two trunks, an anterior and a posterior
Medial part od sof
Maningeal, thyrohyoid n muscular branch Aftr sup bel of omohyodjoind by 2 n 3rd root of ansacervicalis.Branch to genio n thyro supplies by 1cervical spial nerve ligual muscle stylogeniohyoglossus
I YEAR M.D.S
olfactory nerve transmits olfactory impulses
from the olfactory epithelium of the nose to the
It is actually a collection of sensory nerve rootlets
that extend down from the olfactory bulb and
pass through the many openings of the cribriform
plate in the ethmoid bone.
( loss of sense of smell)
(a decreased sense of smell)
(a perversion of the sense of smell)
(awareness of a disagreeable or
offensive odour that does not exist)
testing with pure (non-irritant) odours
should be performed during early recovery
testing should be done in patients with
anosmia : should try ammonia
imaging frequently reveals abnormalities in the
olfactory bulbs and tracts and in the inferior frontal
lobes in patients with posttraumatic olfactory
Sight is dependent not only on cerebral cortex but also on
other six cranial nerve.
Occulomotor ,trochlear nerve and abducent nerve
innervate the extrinsic occular muscle and control
movement of eye ball.
Pain, touch and pressure sensation is carried by the
Facial nerve innervate the orbicularis oculi muscle.
CLINICAL NOTES: Section
of one optic nerve causes blindness in one
Exudates, haemorrhages and abnormalities of
blood vessels may be seen on retinoscopy and
may be signs of generalized disease processes
(e.g. diabetes, rheumatoid arthritis, etc.)
Damage to optic nerve can cause diplopia,
blurring of vision
vision is tested using Ishihara plates which
identify patients who are colour blind.
nerve supplies the superior oblique.
It is the smallest nerve in terms of the number of
axons it contains. It has the greatest intracranial
o trochlear nerve is so called because superior oblique
(which it supplies) is arranged as a pulley (Latin:
trochlea – pulley).
.limiting infero-lateral moment of eye
Injury to the trochlear nerve can cause vertical diplopia on looking
downward which improves with contralateral head tilt and worsens
with ipsilateral head tilt.
transmits sensory fibres from
the skin of the upper face and anterior scalp,
the lining of the upper part of the nasal cavity
and air cells,
and the meninges of the anterior cranial fossa.
maxillary nerve transmits sensory fibres from the
skin of the face between the palpebral fissure and
the mouth, from the nasal cavity and sinuses, and
from the maxillary teeth.
The maxillary division gives off branches in four
In the middle cranial fossa
In the ptreygopalatine fossa
In the infra-orbital groove and canal
On the face ( Terminal branches )
Branches in the middle cranial fossa : middle meningeal nerve.
Branches in pterygopalatine fossa : 1. Zygomatic nerve
2. Pterygopalatine nerve
- Posterior superior lateral
nasal branch .
- Medial or septal branch.
Posterior superior alveolar branches :
Branches in the infraorbital groove and canal :
- Middle superior alveolar nerve.
- Anterior superior alveolar nerve.
- Inferior palpebral branches
- Lateral nasal branches
- Superior labial branches
mandibular nerve is a mixed sensory and
transmits sensory fibres from the skin over the
mandible , side of the cheek and temple, the oral
cavity and contents, the external ear, the
tympanic membrane and temporomandibular
is the largest of all the three divisions.
1 Lingual nerve damage
2 Inferior alveolar nerve and inferior alveolar nerve
3. TRIGEMINAL NEURALGIA:Clinical testing
Test skin sensation of chin and lower lip.
Feel contractions of masseter, temporalis. Open jaw
against resistance (pterygoids, mylohyoid, anterior
Supplies lateral rectus muscle.
Note: the abducent nerve is so called because
lateral rectus abducts the eyeball.
abducent nerve innervates lateral rectus
It emerges from the brain stem between the pons
and the medulla oblongata and usually runs
through the inferior venous compartment of the
petroclival venous confluence in a bow shaped
canal, Dorello’s canal.
DAMAGE TO THE ABDUCENS NERVE :
- In a complete injury of the abducent nerve, the
affected eye is turned medially. In an incomplete
injury, the affected eye is seen at midline at rest,
but the patient cannot deviate the eye laterally.
injuries of the III, IV and/or V nerves are
common and can result in the loss of depth
perception and reading and visual scanning
facial nerve supplies the muscles of facial
taste sensation from the anterior portion of the
tongue and oral cavity.
It is a mixed type of nerve, contains both sensory &
Intracranial course and branches
The most important thing about the intracranial course
of VII is its relationship to the middle ear.
The most important thing about the extracranial
course is its relationship to the parotid gland.
Stapedius: hyperacusis (cannot tolerate sound)
Facial nerve injury in babies- mastoid rudimentry
1. Observe the face. Normal facial movements (lips,
eyelids, emotions) and the presence of normal
facial skin creases indicate an intact nerve.
2. Test strength by trying to force apart tightly closed
eyelids. This should be difficult.
vestibulocochlear nerve is the sensory nerve
for hearing (cochlear) and equilibration
It is also known as the statoacoustic nerve.
Origin and course
Arises laterally in cerebellopontine angle. Passes
with facial nerve into internal acoustic meatus
(temporal bone). Cochlear portion (anteriorly)
and vestibular portion (posteriorly).
Vestibulocochlear nerve does not emerge
A.COCHLEAR NERVE:- CONCERNED WITH HEARING
2.VESTIBULAR NERVE:-CONCERNED WITH BALANCING
1.Lesions- Hearing defects
- IN FRACTURE OF MIDDLE FOSSA
- COMPRESSED BY TUMOUR
The main function of the glossopharyngeal nerve is the sensory supply
of the oropharynx and posterior part of the tongue.
glossopharyngeal nerve has following
Clinical notes: Glossopharyngeal neuralgia
dyskinesia: tardive dyskinesia is
characterized by repetitive, involuntary,
Testing of nerve
Tickling the posterior wall of pharynx
Taste sensibility on the posterior 1/3rd of tongue
main functions of the vagus are phonation
and swallowing. It also transmits cutaneous
sensory fibres from the posterior part Of the
external auditory meatus and the tympanic
It is so called because of its extensive( vague)
course through the head, neck & thorax
The vagus is the most extensively distributed of all
cranial nerves. Its name reflects both its wide
distribution and the type of sensation it conveys
(Latin: vagus – vague, indefinite, wandering)
Palatal elevation – ‘ah’ glossopharyngeal and vagus nerves.
Vagal reflexes: coughing, vomiting, fainting
If speech is normal, the vagus nerves are fine. Tradition and
convention, however, often demand the charade of testing them.
1 Listen to speech.
2 Gag reflex
3 Testing palatal, pharyngeal movements, and listening to speech are
tests of motor components of IX, X and cranial XI .They are thus tests of
the nucleus ambiguss.
The accessory nerve has two parts: cranial and spinal.
Oddly enough, when clinicians refer to the eleventh cranial
nerve, or accessory nerve, they almost always mean spinal
Origin and course of spinal accessory)
• Rootlets from upper four or five segments of spinal cord continue series of rootlets of IX, X and cranial XI.
• Emerge between ventral and dorsal spinal nerve roots, just
behind denticulate ligament.
• Ascends through foramen magnum to enter posterior
• Briefly runs with cranial XI before emerging through jugular
foramen (middle compartment).
• Passes deep to sternocleidomastoid which it supplies.
• Enters roof of posterior triangle of neck. Surface marking in
poste-rior triangle: one third of way down posterior border of
sternocleidomastoid to one third of way up anterior border of
The accessory nerve is vulnerable in the posterior
triangle as it crosses the roof.
Such injuries result in paralysis of trapezius (but not
sternocleidomastoid which it has already supplied) and thus
shoulder abduction beyond 90° involving scapular rotation is
impaired (hair grooming, etc.).
The accessory nerve may be damaged in dissection
Of the neck for malignant disease, in biopsy of enlarged
lymph nodes in and around the posterior triangle, or in
penetrating injuries to this region.
Clinical testing of spinal accessory
Ask the patient to shrug the shoulders (trapezius)
Ask the patient to put hand on head (trapezius:
shoulder abduction beyond 90°).
Ask the patient to move the chin towards one shoulder
against resistance (contralateral sternocleidomastoid).
The hypoglossal nerve supplies the muscles of the tongue.
Movements of the tongue are important in chewing, in the
initial stages of swallowing and in speech. It also conveys
fibres from C1 which innervate the strap muscle
Origin, course and branches
•Originates from medulla by vertical series of rootlets between
pyramid and olive.
•Hypoglossal (condylar) canal in occipital bone.
•Receives motor fibres from C1 and descends to
•Turns forwards, lateral to external carotid artery, hooking
beneath origin of occipital artery. Passes lateral to hyoglossus
and enters tongue from below.
•Gives descendens hypoglossi to ansa cervicalis carrying
fibres from C1 to strap muscles; other C1 fibres remain with XII
to supply geniohyoid.
•Supplies intrinsic muscles of tongue, hyoglossus, genioglossus
1. Hypoglossal nerve lesions
•damage to the hypoglossal nerve in the neck would result in an
ipsilateral lower motor neuron lesion. This would cause the
protruded tongue to deviate to the side of the lesion.
2.Carotid artery surgery, block dissection of neck
•The hypoglossal nerve is vulnerable in surgery (e.g. carotid
endarterectomy, block dissection of the neck for malignant
disease) where it passes under the origin of the occipital artery.
1.Ask the patient to protrude tongue. If it deviates to one side,
the nerve of that side is damaged – the tongue is pushed to the
paralysed side by muscles of the functioning side.
2.Ask patient to push tongue into cheek, then palpate cheek to
feel tone and strength of tongue muscles.
ATLAS OF HUMAN BODY- NETTERS
LASTS ANATOMY – SINNATANBY
MONHEIMS LOCAL ANESTHESIA AND PAIN
CONTROL – C.RICHARD BENNETT
• Hollinshead's Textbook of Anatomy