2. EL-BADAWI 2
FUNCTIONAL COMPONENTS OF THE CRANIAL NERVES
EFFERENT (MOTOR) AFFERENT (SENSORY)
SOMATIC VISCERAL VISCERAL SOMATIC
GENERAL SPECIAL GENERAL GENERAL SPECIAL GENERAL SPECIAL
1 2 3 4 5 6 7
Accordingly, there are seven columns of cranial nerve nuclei arranged
from medial to lateral in the brain stem as shown above.
3. 3
1 2 3 4 5 6 7
OCULOMOTOR N.
EDINGER WESTPHAL N.
SUPERIOR COLLICULUS
MESENCEPHALIC N.
INFERIOR COLLICULUS
MAIN SENSORY N.
SUPERIOR SALIVATORY N.
MOTOR N. OF V
ABDUCENT N.
MOTOR N. OF FACIAL
VESTIBULAR N.
INFERIOR SALIVATORY N.
HYPOGLASSAL N.
NUCLEUS AMBIGUUS
SPINAL N. OF TRIGEMINAL
DORSAL VAGAL N.
TROCLEAR N.
1-GSE
2-GVE
3-SVE
4-SVA
5-GVA
6-SSA
7-GSA
MID-BRAIN
PONS
MEDULLA
CRANIAL NERVES NUCLEI
4. 4
WHAT IS MENT BY THESE TERMS?
1- General Somatic Efferent (GSE): Fibers supplying the muscles which does
not develop from the pharyngeal arches (muscles of the eye and of the
tongue).
2- Special Visceral Efferent (SVE): Fibers supplying Muscles developing from
the pharyngeal arches.
3- General Visceral Efferent (GVE): Fibers supplying structures developing
from the splanchnic mesoderm and from endoderm (PARASYMPATHETICS).
4- General Visceral Afferent (GVA): Fibers carrying sensations from different
organs and mucous membranes developing from splanchnic mesoderm
and from endoderm (Interoceptives).
5- Special Visceral Afferent (SVA): Fibers carrying smell and taste
sensations as these organs are covered by endodermal mucous
membranes.
6- General Somatic Afferent (GSA): Fibers carrying sensations from
structures developing from somatic mesoderm and from ectoderm
(Exteroceptives).
7- Special Somatic Afferent (SSA): Fibers carrying sensations from organs
developing from ectoderm; Vision and Hearing.
5. EL-BADAWI 5
CRANIAL NERVES UNDER EACH COLUMN:
1. GSE: III, IV, VI, XII.
2. SVE: V(1ST arch), VII (2nd arch), IX (3rd arch) and X & XI (cranial part) for (4th& 6th arch).
3. GVE: III, VII, IX, X.
4. GVA: VII, IX, X.
5. SVA: I,- VII, IX, X.
6. GSA: V, IX, X.
7. SSA; II, VIII.
NUCLEI RELATED TO EACH COLUMN:
1. GSE: Each nucleus takes the name of the nerve i.e., motor nucleus of
oculomotor nerve e.t.c,.
2. SVE: Motor nucleus of trigeminal for V, motor n. of fascial for VII and nucleus
ambiguous for IX, X, and cranial part of XI.
3. GVE: Edinger-Westphal nucleus for III, superior salivary nucleus for VII,
inferior salivary nucleus for IX, and dorsal motor nucleus of the vagus for X.
4. GVA: Nucleus of tractus solitarius for VII, IX AND X.
5. SVA: Nucleus of tractus solitarius receives also taste fibers carried by VII, IX
and X. Those for smell (I) has its pathway.
6. GSA: Nucleus of the spinal tract for V, IX and X, main sensory nucleus for V
and mesencephalic nucleus for V also.
7. SSA: Both have their own pathways.
7. EL-BADAWI 7
Deep origin of III, IV and VI nerves
Functions and nuclei:
•The oculomotor: GSE , GVE
Motor nucleus of III
Edinger-Westphal nucleus.
•The trochlear: GSE
Motor nucleus of IV.
•The abducent: GSE
Motor nucleus of VI
VI nucleus
VII nucleus
IV nucleus
IIIIVVI
7
9. EL-BADAWI 9
Abducent n.
Trochlear n.
Oculomotor n.
Trigeminal n
2
Dura at the Clivus of the skull
Free border
and
Attached border
Of the Tentorium
cerebelli
Relation of the III, IV and VI nerves to the dura matter
10. EL-BADAWI 103
Temporal lobe
I C A
I C A
Sphenoidal air sinus
Hypophysis cerebri
Abducent n. Mandibular n.
Maxillary n.
Ophthalmic n.
Trochlear n.
Oculomotor n.
The cavernous
sinus
Relation of III, IV and VI nerves to the cavernous sinus
11. EL-BADAWI 114
Lacrimal n.
Frontal n.
Trochlear n.
Nasociliary n.
Inferior division of III n.
Abducent n.
Inferior ophthalmic vein
Lateral rectus Inferior rectus
Ophthalmic artery
Optic nerve
Medial rectus
Superior division of III n.
Superior ophthalmic vein
Superior rectus Common tendinous ring
Relations of the III, IV and VI nerves in the superior orbital fissure
12. EL-BADAWI 125
Trochlear n.
Lacrimal n.
Frontal n.
Lateral rectus
Superior division
of III n.
Nasociliary n
Inferior division of III n.
Abducent n.
Inferior rectus
Medial rectus
Superior rectus
Inferior oblique
Superior oblique
Levator palpebrae superioris
Lacrimal gland
Optic nerve
Relations of the III, IV and VI nerves in the orbit
14. EL-BADAWI 14
The Oculomotor nerve
a. Functions:
• GSE .GVE
b. Deep origin:
• Motor nucleus of III (GSE) . Edinger-Westphal nucleus (GVE) (both in the midbrain)
c. Superficial origin: To the interpeduncular fossa of the midbrain
d. Course and relations:
• It arises from the interpeduncular fossa of the midbrain on the medial side
of the cerebral peduncle between the superior cerebellar and the posterior
cerebral arteries (1)
• it pierces the pia and arachnoid then it pierces the dura matter in front of
the point of decussation between the free and the attached borders of the
tentorium cerebelli (2)
• it then passes within the lateral wall of the cavernous sinus above the
trochlear nerve (3)
• as it leaves the sinus, it divides into two divisions, superior and inferior.
Both will enter the orbital cavity through the superior orbital fissure
between the two heads of the lateral rectus (within the common tendinous
ring) having the nasociliary nerve in between (4)
• in the orbit (5),
The superior division passes above the optic nerve and ends by supplying:
. The superior rectus . The levator palpebrae superioris
The inferior division passes below the optic nerve and ends by supplying:
. The inferior rectus . The medial rectus . The inferior oblique
. Branch from the nerve to inferior oblique to the ciliary ganglion
15. EL-BADAWI 15
The Trochlear nerve
a. Function:
• GSE
b. Deep origin:
• The motor nucleus of the trochlear nerve in the midbrain
c. Superficial origin:
• From the back of the midbrain below the inferior colliculus on the sides of
the frenulum veli(1)
d. Course and relations:
• The nerve will curve around the lateral side of the cerebral peduncle
between the posterior cerebral and superior cerebellar arteries and
pierces the pia and the arachnoid, the dura matter at the point of
decussation between the free and the attached borders of the tentorium
cerebelli(2)
• It passes in the lateral wall of the cavernous sinus below the oculomotor
and above the ophthalmic nerves(3)
• It then enters the orbit through the superior orbital fissure outside the
common tendinous ring medial to the frontal nerve(4)
• In the orbit it passes medially to enter the orbital surface of the superior
oblique muscle(5)
16. EL-BADAWI 16
The Abducent nerve
a. Function:
• GSE
b. Deep origin:
• Motor nucleus of the abducent nerve in the pons
c. Superficial origin:
• From the pontomedullary angle above the pyramid (1)
d. Course and relations:
• It pierces the pia and the arachnoid then the dura matter at
the clivus of the skull (2)
• It then, enters the floor of the cavernous sinus lying lateral
to the internal carotid artery (3)
• It enters the orbit through the medial end of the superior
orbital fissure (4) within the common tendinous ring to
end by supplying the lateral rectus (5)
17. EL-BADAWI 17
Functions and deep origin of the Trigeminal nerve
Functions:
•GSA to
Mesencephalic nucleus of V
Main sensory nucleus
Spinal nucleus of V
•SVE from
Motor nucleus of V
19. EL-BADAWI 19
The Trigeminal nerve
a. Functions:
• GSA . SVE
b. Deep origin:
• The mesencephalic nucleus, in the midbrain (GSA)
• The principal (main) sensory nucleus, in the pons (GSA)
• The spinal nucleus of the trigeminal nerve, in the medulla (GSA)
• The motor nucleus of the trigeminal in the pons (SVE)
c. Superficial origin:
• From the ventral surface of the pons at the origin of the middle
cerebellar peduncle (1)
d. Foramen: foramen ovale
e. Course and relations:
• It is the largest and shortest cranial nerve, its short trunk is formed
of small motor and large sensory roots. The sensory root is a
branch of the semilunar ganglion which lies near the apex of the
petrous part of the temporal bone covered by the cavum
trigeminal.
• To the convex surface of the ganglion its three branches are
attached:
1. The ophthalmic nerve
2. The maxillary nerve
3. The mandibular nerve (which is joined with the motor root)
21. EL-BADAWI 21
Nasociliary n.
Frontal n.
Lacrimal n.
Lacrimal gland
Palpebral branch
Ciliary ganglion
Supratrochlear n.
Supraorbital n.
Infratrochlear n.
Anterior ethmoidal n.
Posterior ethmoidal n.
Short ciliary nn.
Long ciliary nn.
The Ophthalmic nerve
22. EL-BADAWI 22
The Ophthalmic nerve
a. Function:
• GSA (pure sensory)
b. Course and relations:
• It is the smallest of the three branches, passes forwards in the lateral wall of the cavernous sinus below the
trochlear nerve and above the maxillary nerve
• Just before it enters the orbit through the superior orbital fissure, it divides into three branches, lacrimal, frontal
and nasociliary.
1. The lacrimal nerve
• Enters the orbit through the lateral part of the superior orbital fissure outside the tendinous ring
• Passes along the lateral wall of the orbit, above the lateral rectus with the lacrimal artery
• Receives communication (parasympathetic) from the zygomaticotemporal nerve which carries secretory
fibres to the lacrimal gland
• It supplies the lacrimal gland, and gives a palpebral branch to the upper eyelid
2. The frontal nerve
• Is the largest branch of the ophthalmic nerve
• Enters the orbit through the superior orbital fissure outside the common tendinous ring medial to the
lacrimal nerve
• In the orbit, it runs below the roof above the levator palpebrae superioris
• It ends by dividing into:
• Supratrochlear nerve: to the forehead and the scalp
• Supraorbital nerve: to the frontal air sinus, face and the scalp
3. The nasociliary nerve
• Enters the orbit through the superior orbital fissure inside the common tendinous ring between the two
divisions of the oculomotor
• It crosses above the optic nerve from lateral to medial below the superior oblique above the medial rectus
• It ends by giving the following branches:
• Sensory branch to the ciliary ganglion
• Long ciliary nerves : to the eye ball
• Posterior ethmoidal nerve: through the posterior ethmoidal canal to the ethmoidal and sphenoidal
air sinuses
• Infratrochlear nerve: to the lower eyelid and the face
• Anterior ethmoidal nerve: passes to the anterior ethmoidal canal to the cranial cavity then to the
nasal cavity through a slit on the lateral side of the cribriform plate of ethmoid to be called the
internal nasal which supplies the nose and ends as the external nasal to the skin of the nose.
23. EL-BADAWI 23
Maxillary nerve
Zygomatic n.
Zygomaticotemporal n.
Zygomaticofacial n.
Communication with
Lacrimal n.
Infraorbital n.
Deep petrosal n.
Great petrosal n.
Pterygopalatine ganglion
Posterior superior
alveolar n.
Middle and anterior
superior alveolar nn.
Palpebral br.
Nasal br.
Labial br.
Maxillary nerve
Nerve to pterygoid canal
24. EL-BADAWI 24
The maxillary nerve
a. Function: GSA (pure sensory)
b. Course and relations:
• It passes in the lateral wall of the cavernous sinus below the ophthalmic nerve
• Leaves the cranial cavity through the foramen rotundum to the pterygopalatine fossa,
then through the pterygomaxillary fissure to the infratemporal fossa to the inferior orbital
fissure
• It continues as the infraorbital nerve which passes through the infraorbital groove and
canal in the floor of the orbit, it appears in the face through the infraorbital foramen
c. Branches:
• In the cranial cavity: meningeal branch to the outer layer of the dura matter
• In the pterygopalatine fossa:
• Ganglionic: sensory branch to the pterygopalatine ganglion
• Zygomatic nerve: divides into zygomaticotemporal and zygomaticofacial nerves to
the face and scalp (the zygomaticotemporal nerve carries secretory fibers to the
lacrimal gland from the ganglion to the lacrimal nerve)
• Posterior superior alveolar nerve; pierces the infratemporal surface of the maxilla to
supply the maxillary sinus and the molar teeth, it give branches to the cheek and
gum
• In the infraorbital canal (branches of the infraorbital nerve):
• Middle superior alveolar: to the upper premolar teeth
• Anterior superior alveolar nerve: to the incisor and canine teeth, it sends a nasal
branch to the nose and the nasal septum
• In the face: to supply the face
• Palpebral
• Nasal
• Superior labial
25. EL-BADAWI 25
Nervous spinosus
Foramen spinosum
To lateral pterygoid m
Buccal nerve
To medial pterygoid m
Otic ganglion
Tensor tympani m
Tensor palati m
Lingual nerve
Sbmandibular ganglion
Inferior alveolar nerve
Mental nerve
To masseter
Auriculotemporal nerve
To temporalis m
The Mandibular nerve
27. 27
The mandibular nerve
a. Functions: GSA, SVE (mixed nerve)
b. Course and relations:
• Is the largest branch of the trigeminal nerve, formed of two roots a large sensory and small
motor
• It leaves the skull through the foramen ovale to the infratemporal fossa where the two roots
unite to form the nerve trunk
• The trunk lies medial to the lateral pterygoid muscle
• It is very short trunk which divides into anterior and posterior divisions
c. Branches:
From the trunk
• Nervus spinosus (meningeal): it passes up to the cranial cavity to supply the outer layer of the
dura matter in the middle cranial fossa
• Nerve to medial pterygoid: is the motor branch to the medial pterygoid muscle, it give a branch
which passes through the otic ganglion without relay to supply the tensor palati and tensor
tympani muscles
From the anterior division
• Deep temporal nerves: to the temporalis muscle
• Nerve to lateral pterygoid: supplies the muscle
• Masseteric nerves: pass through the mandibular notch to supply the masseter
• Buccal nerve: passes between the two heads of the lateral pterygoid to the face to supply the
skin over the cheek
From the posterior division
1. The auriculotemporal nerve:
• Arise by two roots which surrounds the middle meningeal artery
• Passes deep to the neck of the mandible within the substance of the parotid gland to leave
the gland through its upper end of the gland to the scalp, it carries postganglionic
secretormotor fibres from the otic ganglion to the parotid gland
• It is sensory to the external acoustic meatus, articular to the temporomandibular joint and
superficial temporal to the scalp
28. EL-BADAWI 28
The mandibular nerve (cont.)
2. The lingual nerve:
• It is joined by the chorda tympani branch of the facial nerve in the infratemporal
fossa
• It descends downwards between the medial pterygoid muscle and the ramus of
the mandible, then it lies behind the root of the third molar tooth where is
covered by the mucous membrane of the mouth (dangerous position).
• In the submandibular region, it passes between the mylohyoid laterally and the
hyoglossus muscles deep to the submandibular gland
• It curves around the duct of the gland (lateral, below and then medial to it)
• Its terminal branches carries sensations from the mucous membrane of the
mouth, the gum, the anterior 2/3 of the tongue.
• The chorda tympani through it, supplies the submandibular and the sublingual
glands and carries taste fibres from the anterior 2/3 of the tongue
3. The inferior alveolar nerve:
• It descends deep to the lateral pterygoid, then between the ramus of the
mandible and the sphenomandibular ligament to enter the mandibular canal
• It runs in the canal as far as the mental foramen where it divides into mental and
incisive branches
• Before it enters the mandibular canal it gives its mylohyoid branch which
pierces the sphenomandibular ligament and descends in a groove on the
medial side of the ramus of the mandible to end by supplying the mylohyoid
and the anterior belly of digastric
29. EL-BADAWI 29
FACIAL NERVE
Functions and deep origin:
•SVE from
•Motor nucleus of VII
•GVE (parasympathetic) from
•Superior salivary nucleus
•SVA
•GVA both to
•Nucleus solitarius
VI nucleus
32. EL-BADAWI 32
Great petrosal n Nerve to pterygoid canal
Pterygopalatine ganglion
Lacrimal
gland
Deep petrosal n.
Lingual n.
Submandibular ganglion
Sublingual gland
Submandibular gland
Nerve to stapedius m
Chorda tympani n.
Temporal br.
Buccal br.
Zygomatic br.
Mandibular br
Cervical br
To Stylohyoid m
To posterior belly of digastric m
Parotid gland
Facial nerve
Tympanic memb.
Stylomastoid foramen
Internal acoustic meatus
Auricularis superior
Auricularis inferior
Occipitalis
34. EL-BADAWI 34
The Facial nerve
a. Functions: SVA GVA SVE GVE
b. Deep origin:
• Nucleus solitarius (SVA, GVA)
• Motor nucleus of facial nerve (SVE)
• Superior salivatory nucleus (GVE)
c. Internal course: the motor fibres passes dorsally and medially forming a loop around the
abducent nucleus in the floor of the fourth ventricle forming the facial colliculus
d. Superficial origin: at the pontomedullary angle above the inferior cerebellar peduncle
e. Course and relations:
The intrapetrous course
• The nerve passes laterally with the vestibulocochlear nerve to the internal acoustic
meatus
• At the bottom of the meatus the nerve enters the facial bony canal where it runs
laterally above the vestibule and reaching the medial wall of the middle ear it bends
sharply backwards above the promontory (forming its genu where the genicular
ganglion is found), it then arches downwards in the medial wall of the middle ear to
reach the stylomastoid foramen
Extracranial course
• As it emerges from the foramen, it runs forwards in the substance of the parotid
gland crosses the styloid process, the retromandibular nerve and the external
carotid artery and divides behind the neck of the mandible into its terminal
branches which come out of the anteromedial surface of the gland
35. EL-BADAWI 35
The Facial nerve (cont.)
f. Branches:
1. Within the facial canal
• Nerve to stapedius: supplies the stapedius muscle
• Greater petrosal nerve: arises from the genicular ganglion (contains parasympathetic
fibres to the pterygopalatine ganglion and taste fibres to the mucous membrane of the
palate), it reaches the cranial cavity through a hiatus on the anterior surface of the petrous
part of the temporal bone to the foramen lacerum. It is joined by the deep petrosal nerve
from the sympathetic plexus on the internal carotid artery to form the nerve of the
pterygoid canal which passes through the pterygoid canal to the pterygopalatine fossa
and ends in the pterygopalatine ganglion.
• Chorda tympani nerve: arises from the facial nerve 6 mm above the stylomastoid foramen
and runs upwards to perforate the posterior bony wall of the tympanic cavity. It then
passes forwards on the medial surface of the tympanic membrane between its fibrous and
mucous layers crossing the handle of the malleus. It comes out of the tympanic cavity
through the petrotympanic fissure to the infratemporal fossa where it joins the lingual
nerve. Through the lingual nerve, it supplies both the submandibular and sublingual
salivary glands by secretomotor fibres and taste fibers from the anterior 2/3 of the tongue
2. At the exit from the stylomastoid foramen
• Posterior auricular nerve: to the auricularis posterior and the occipital belly of the
occipitofrontalis muscle
• Digastric branch: to the posterior belly of digastric muscle
• Stylohyoid branch: to the stylohyoid muscle
3. On the face
• Temporal Zygomatic Buccal Mandibular Cervical
to supply the muscles of the face, buccinator and platysma muscles
36. EL-BADAWI 36
Auricularis superior
Auricularis inferior
Great petrosal n
Nerve to stapedius m
Chorda tympani n.
Occipitalis
To posterior belly of digastric m
To Stylohyoid m
Cervical br
Mandibular br
Buccal br.
Zygomatic br.
Temporal br.Lingual n.
Parotid gland
Pterygopalatine ganglion
Middle ear cavity
Facial nerve
37. EL-BADAWI 37
Ansa cervicalis
Vagus nerve
Hypoglossal nerve
Accessory nerve
Styloid apparatus
Posterior belly of digastric m
Internal carotid a
External carotid a
Glossopharyngeal nerve
Lingual a
Common carotid a
Internal jugular v
Occipital a
Common relations of the last four cranial nerves
38. EL-BADAWI 38
Common Relations of the Last Four Cranial Nerves
•The IX, X, XI leave the cranial cavity through the middle part of the
jugular foramen
• At the base of the skull, they lie between the internal carotid artery
and the internal jugular vein deep to the styloid process and the
structures attached to it and posterior belly of the digastric muscle.
•The XII nerve leaves the skull through the hypoglossal canal where
it lie deep to the internal jugular vein then it joins the other nerves
39. EL-BADAWI 39
Spinal nucleus of V
(GSA)
Nucleus solitarius
(SVA&GVA) Inferior salivatory n
(GVE)
Nucleus Ambiguus
(SVE)
Dorsal motor nucleus of X
(GVE)
GLOSSOPHARYNGEAL NERVE
GVA
SVA
GSA
SVE
GVE
VAGUS NERVE
GVA
SVA
GSA
SVE
GVE
Functions and Nuclei of IX and X nerves
IX
X
40. 40
Carotid br
Tympanic br
Tympanic plexus
Lesser petrosal n
Auditory tube
Otic ganglion
Parotid gland
Tonsillar branches
Lingual branches
Pharyngeal branches
On the middle constrictor
To stylopharyngeus
Glossopharyngeal nerve
41. 41
The Glossopharyngeal nerve
a. Functions: GSA GVA SVA GVE SVE
b. Deep origin: in the medulla oblongata
• Spinal nucleus of trigeminal nerve (GSA)
• Nucleus of tractus solitarius (GVA SVA)
• Inferior salivatory nucleus (GVE)
• Nucleus ambiguus (SVE)
c. Foramen: middle of the jugular foramen
d. Course and relations:
• At the base of the skull the nerve lies between the internal jugular vein and the internal carotid
artery deep to the styloid process and structures attached to it and the posterior belly of
digastric
• The nerve passes between the internal and external carotid arteries to reach the posterior border
of the hyoglossus muscle.
• It then curves forwards lying on the muscle to pass between the superior and middle constrictor
muscles to end by breaking into its terminal branches
e. Ganglia:
• Superior ganglion: has no branches and considered a detached part of the inferior ganglion
• Inferior ganglion: its branches carry general sensations from the pharynx, soft palate and tonsils
as well as general and taste fibres from the posterior 1/3 of the tongue
f. Branches:
• Tympanic nerve: is a branch of the inferior ganglion reaches the tympanic cavity through the
tympanic canaliculus to form the tympanic plexus on the medial wall of the cavity, out of the
plexus , the lesser petrosal nerve arises to the cranial cavity and through the foramen ovale to
relay into the otic ganglion. Postganglionic fibres supplies the parotid gland
• Carotid branch: to the carotid sinus and body, it carry stimuli about blood pressure changes
• Pharyngeal branches: is the sensory root of the pharyngeal plexus, carry the general sensations
from the pharynx
• Muscular branch: to the stylopharyngeus muscle
• Tonsillar branches: carry sensory branches from the palate and the tonsils
• Lingual branches: carry general and taste fibres from the posterior 1/3 of the tongue
42. EL-BADAWI 42
Meningeal br
External laryngeal n.
Internal laryngeal n.
To Carotid body
Superior laryngeal n.
Cardiac br
Recurrent laryngeal n.
Auricular br
Pharyngeal br
Cranial part of XI
The Vagus nerve
43. EL-BADAWI 43
The Vagus nerve
a. Functions: GSA GVA SVA GVE SVE
b. Deep origin: in the medulla oblongata
Spinal nucleus of trigeminal nerve (GSA)
Nucleus of tractus solitarius (GVA SVA)
Dorsal motor nucleus of the vagus (GVE)
Nucleus ambiguus (SVE)
c. Superficial origin: from the side of the medulla between the olive and the ICP
d. Foramen: middle part of jugular foramen
e. Course and relations:
• At the base of the skull the nerve lies between the internal jugular vein and the internal
carotid artery deep to the styloid process and structures attached to it and the posterior
belly of digastric
• The nerve descends vertically within the carotid sheath between the common carotid
artery and the internal jugular vein until it reaches the root of the neck, it crosses in
front of the first part of the subclavian artery to the thorax
f. Ganglia:
• Superior ganglion: its branch is the auricular nerve
• Inferior ganglion: its branches carries general sensations from the larynx, trachea,
bronchial tree, lungs, and the alimentary tract down to the junction between the right 2/3
and left 1/3 of the transverse colon. It also carries taste fibres from the root of the
tongue and the epiglottis
g. Branches in the neck:
1. In the jugular foramen
• Meningeal branch: to the dura matter of the posterior cranial fossa
• Auricular branch: it passes through the mastoid canaliculus to supply the floor and the
posterior wall of the external auditory meatus and the outer surface of the drum
44. EL-BADAWI 44
The Vagus nerve (Cont.)
2. In the neck
• Pharyngeal: (consists principally of the cranial part of XI), is the motor part of the
pharyngeal plexus through which it supplies all muscles of the pharynx except the
stylopharyngeus (by XI) and all muscles of the palate except the tensor palati (by
mandibular nerve)
• Branch to the carotid body
• Superior laryngeal nerve: passes deep to the internal carotid artery on thee lateral wall of
the pharynx, it divides into:
Internal laryngeal nerve: pierces the thyrohyoid membrane with the superior
laryngeal vessels, it carries sensations from the larynx, epiglottis above the vocal
cords
External laryngeal nerve: supplies the cricothyroid muscle
• Cardiac branches: superior and inferior branches to the cardiac plexuses
• Right recurrent laryngeal nerve: arises from the right vagus where it crosses in front of the
right subclavian artery, it curves around the artery and ascends upwards in a groove
between the trachea and oesophagus close to the medial surface of the thyroid gland . It
supplies all the intrinsic muscles of the larynx except the cricothyroid muscle (by external
laryngeal) and sensations from the larynx below the vocal cords
3. In the thorax
• Cardiac
• Left recurrent
• Pulmonary
• Oesophageal
4. In the abdomen
• Gastric
• Coeliac
• hepatic
45. EL-BADAWI 45
THE ACCESSORY NERVE DEEP ORIGIN
Nucleus Ambiguus
Upper 5 spinal segments
Cranial part
Vagus Nerve
Spinal part
46. EL-BADAWI 46
The Accessory nerve
a. Functions: SVE (cranial root), GSE (spinal root)
b. Deep origin:
• Nucleus ambiguus (SVE)
• Upper 5 cervical segments
c. Superficial origin: the cranial part from the side of the medulla, the spinal part
from the side of the spinal cord
d. Internal course: the spinal part ascends in the vertebral canal then through the
foramen magnum to join the cranial root and both leave the cranial cavity through
the middle part of the jugular foramen
e. Course and relations:
• Just below the base of the skull the cranial part separates to join the vagus
nerve
• The spinal part lies between the internal jugular vein and the internal carotid
artery deep to the styloid process and structures attached to it and the
posterior belly of digastric
• It curves laterally and backwards posterior or sometimes anterior to the
internal jugular vein
• it then passes through the upper part of the sternocliedomastoid muscle to
the posterior triangle lying on the levator scapulae and ends into the
trapezius muscle
f. Branches:
• The cranial part is distributed through the pharyngeal and laryngeal
branches of the vagus nerve
• The spinal part supplies the sternocleidomastoid and trapezius muscles
47. EL-BADAWI 47
Vagus nerve
Cranial part of XI
Spinal part of XI
Trapezius m
Sternomastoid m
Foramen magnum
Jugular foramen
The Accessory Nerve
49. EL-BADAWI 49Omohyoid
(inferior belly)
1C
2C
3C
Hyoglossus m
Genioglossus m
Geniohyoid m
Thyrohyoid m
Sternohyoid m
Sternothyroid m
Omohyoid
(superior belly)
Descending hypoglossi
(superior limb)
Descending cervicalis
(inferior limb)
Ansa cervicalis
Hypoglossal canal
The Hypoglossal Nerve
50. EL-BADAWI 50
The Hypoglossal nerve
a. Functions: GSE
b. Deep origin: the motor nucleus of the XII in the medulla oblongata
c. Superficial origin: from the side of the medulla between the olive and the pyramid
d. Foramen: the hypoglossal canal
e. Course and relations:
• The XII nerve leaves the skull through the hypoglossal canal where it lie deep
to the internal jugular vein then it joins the other nerves (IX, X, XI)
• it lies between the internal jugular vein and the internal carotid artery deep to
the styloid process and structures attached to it and the posterior belly of
digastric
• In the carotid triangle, it curves medially crossing anterior to the internal and
external carotid arteries and the loop formed by the lingual artery
• It then ascends upwards behind the common tendon of the digastric muscle
• In the submandibular region it lies on the lateral surface of the hyoglossus
muscle deep to the mylohyoid muscle and the submandibular gland
• In the interval between the hyoglossus and mylohyoid it lies below the deep
part of the submandibular gland, the submandibular duct and the lingual nerve
• It passes next on the lateral aspect of the genioglossus and continue in its
substance where it breaks into its terminal branches
f. Branches: it supplies all the intrinsic and extrinsic muscles of the tongue except
the palatoglossus (by the cranial part of XI through the pharyngeal branch of X from
the pharyngeal plexus)
