Summative 3
Cranial Nerves
Nancy Halliday, PhD
David Ross Boyd Professor
Department of Cell Biology
Learning Objectives
a. Identify the 12 cranial nerves by name, Roman numeral, and anatomical
location.
b. Locate the cranial nerves within the distinct regions of the brainstem.
c. Describe the functions and distribution of each cranial nerve.
d. Trace the path of each cranial nerve through the skull's foramina.
e. Link cranial nerve lesions to their associated clinical functional deficits.
f. Understand the sensory functions of neurons in ganglia related to cranial
nerves.
Cranial Nerves
I
II
III
IV
V
VII
VIII
X
XI
VI
XII
IX
• There are 12 pairs.
• Most emerge directly from the brain.
• Two pairs emerge from the cerebrum (CN I, CN II) and
the remaining pairs arise from the brainstem.
• Cranial nerves are considered part of the peripheral
nervous system (except CN I & CN II).
• Each cranial nerve exits the cranial cavity through
specific foramina (with which you should be familiar).
• With the exception of CN X (Vagus), cranial nerves
innervate structures only in the head and neck.
Midbrain
10 Cranial Nerves emerge from the
midbrain, pons, and medulla of the brainstem
Midbrain: Oculomotor (CN III), Trochlear (CN IV)
III
IV
Pons
V
VIII
VII
VI
Pons: Trigeminal (CN V), Abducens (CN VI),
Facial (CN VII), Cochlear (CN VIII)
IX
X
Medulla
XII
XI
Medulla: Glossopharyngeal (CN IX), Vagus (CN X),
Accessory (CN XI), Hypoglossal (CN XII)
Cranial Nerve Nomenclature
• Cranial nerves are numbered in the order they
have to be cut to take the brain out of the skull!
III
II
IV
I
VI
VII
I
II III
V
IV
VI
XII
VIII
V
VII & VIII
IX, X, XI
XII
XI
Either use their name, or their Roman numeral.
(Olfactory nerve, or CN I, etc.)
X
IX
Things to consider
Cranial nerves can be grouped (chunked) by function:
I
• Cranial nerves I, II and VIII are devoted to
special senses and are related to higher
order brain areas and functions
• Cranial nerves III, IV, & VI are related to eyes
and eye movements
• Cranial nerves V, VII, IX, & X are related to
branchial (pharyngeal) arches
• Cranial nerves X, XI & XII innervate internal
viscera, trapezius & sternocleidomastoid,
and lastly, the tongue
II
VI
III
IV
V
VII
VIII
IX
XII
XI
X
Simple Rules About CN Functions
• Most cranial nerves (7 of the 12) do only one
thing!
• Two cranial nerves have only two functions
I
II
IV
III
– Oculomotor – Visceral Efferent (VE) to smooth
muscles (ciliary muscle and sphincter pupillae),
Somatic Efferent (SE) to extraocular skeletal muscles
– Trigeminal – Somatic Afferent (SA) from face, SE to
Muscles of Mastication (1st arch)
VI
V
• Three cranial nerves have > two functions & all
have the same functions (VII, IX, X)
VII
– VE (Parasympathetics) / VA
– SA from the ear
– Motor for branchial arches
• 2nd Arch (CN VII)
• 3rd Arch (CN IX)
• 4th and 6th Arches (CN X)
– Taste anterior 2/3 of tongue (CN VII)
– Taste posterior 1/3 of tongue (CN IX)
– Taste around the epiglottis (CN X)
VIII
IX
XII
XI
X
What are Pharyngeal Arches?
• The pharyngeal arches, also known as visceral
arches, are structures seen in the early
embryo that are precursors for many structures in
the head & neck.
• They are recognizable in the 4th week of
development.
• Each arch has its own artery (aortic arches), a
nerve that controls a distinct muscle group, and
skeletal elements.
• You will have a separate session on the
pharyngeal arches next week.
4-week-old human embryo
Each Branchial (Pharyngeal) Arch has its Own Cranial Nerve
1. Arch I
maxillary and mandibular divisions of
trigeminal nerve (V2, V3)
Trigeminal Ophthalmic div
Trigeminal
Ganglion
V
2. Arch II
facial nerve (VII)
VII IX
X
Trigeminal
Maxillary div
I
3. Arch III
glossopharyngeal nerve (IX)
I
II III IV VI
Trigeminal
Mandibular div
4. Arches IV and VI
superior and recurrent laryngeal
branches of vagus nerve (X)
Vagus
Facial
Glossopharyngeal
The Details
• The remaining slides introduce each of the cranial
nerves in order.
– Anatomical location
– Specific Functions
– Deficits associated with lesions of the cranial nerves
Olfactory Nerve(s) – CN I
Olfactory Tract
Cribriform Plate
Olfactory Bulb
Olfactory
Nerves
Cribriform Plate
Olfactory Epithelium
Function is sense of smell
(olfaction)
Lesion of the Olfactory Nerves
• Anosmia
• Food tastes funny (loss of smell changes taste perception)
• Nose is running (CSF leaking if due to trauma)
Optic Nerve CN II
Eye Ball
Optic N.
Enters orbit via optic
canal
Optic Chiasm
Function: Vision
CN II actually develops as an extension of
the brain rather than a true “nerve” –
explains why it is surrounded by dura. It
is considered part of the CNS rather than
the PNS.
Optic Tract
Lateral Geniculate
Ganglion
Optic Radiation
Occipital
Cortex
Nasal
Visual
Field
Temporal
Visual
Field
Temporal
Visual
Field
Problems with CN II
(Deficit is based on the
location of the lesion)
Right
Eye
Left
Eye
Nasal
Retinal
Field
Temporal
Retinal
Projection
Nasal
Retinal
Projections
Nerve
Optic Nerve
Lesion
Temporal
Retinal
Field
Tract
Lateral Geniculate Ganglia
Optic
Chiasm
Lesion
Optic
Tract
Lesion
CN III, CN IV, and CN VI
Oculomotor Nerve (CN III)
Trochlear Nerve (CN IV)
Abducens Nerve (CN VI)
Function:
Extraocular (eye)
movements
Enter orbit via superior orbital
fissure
Oculomotor, Trochlear, Abducens
LR6 – SO4
All the rest are 3
& Parasympathetics for the Sphincter Pupillae & Ciliary Muscle
Superior Oblique
Ciliary Ganglion
CNIV
Midbrain
CNIII
Pons
CNVI
Lateral Rectus
CN III, IV, VI in the Brainstem
Cross Section of Brainstem
Visceral
Oculomotor
Nucleus
Ciliary
Ganglion
Ciliary Muscle &
Sphincter Pupillae
CN III
Cranial Nerve III Contains Parasympathetic Fibers (VE) that
Control Lens Shape (for focus) and Pupillary Constriction in
the Iris.
Lesions of CN III, IV and VI
• There may be diplopia with certain eye
movements
• Patients may say they are dizzy
• If the patient’s eye cannot track medially
and the pupil is dilated, think CN III
(oculomotor)
• If the patient’s eye cannot track laterally,
think CN VI (abducens)
Right
Eye
Left
Eye
Normal
Trigeminal Nerve, Sensory Component
Portio Major
Trigeminal
Ganglion
(Location of Sensory cell
bodies)
V1
CNV
V2
V3
Note that the tip of the nose is
V1 – the ophthalmic division
Trigeminal Nerve, Motor Component
Portio Minor
CN V
Motor Root With
Mandibular N.
Mnemonic: MMATT
Muscles of Mastication, Mylohyoid, Anterior belly
of digastric, Tensor tympani, Tensor veli palatini
Trigeminal Nerve in the Brain Stem
(sensory)
Divisions exit the skull via:
V1 Superior Orbital Fissure
V2 Foramen Rotundum
V3 Foramen Ovale
(sensory)
Problems with the Trigeminal
• Loss of muscle tone on the side of the lesion
• Wasting of the Muscles of Mastication
• When asked to open the jaw, the mandible
deviates to the side of the lesion
• Anesthesia over parts of the head – distribution
depends on part of the nerve that is interrupted
• Trigeminal Neuralgia (Tic de le Rue)
Facial Nerve
Motor Branches:
To – Temporal
Zanzibar – Zygomatic
By – Buccal
Motor – Mandibular
Car - Cervical
CN VII
Stylomastoid
Foramen
Most Complex Cranial Nerve!
Cranial
Nerve
VII
Parasympathetic Secretions & Taste
Functions
• Facial Nerve (CN VII) Functions:
• Motor root:
– All Muscles of facial expression
– Stylohyoid
– Posterior belly of digastric
– Stapedius
Greater petrosal
Geniculate ganglion
Pterygopalatine
ganglia
Stapedius
• Parasympathetics to:
– Lacrimal gland, palate glands, and nasal
mucosa (via greater petrosal n &
pterygopalatine ganglion)
– Submandibular and sublingual glands (via
chorda tympani & submandibular
ganglion)
Motor root of VII
• Sensory (Geniculate Ganglion)
– Taste anterior 2/3’s tongue
– Somatic afferents from the ear
Posterior
digastric
Chorda tympani
Stylohyoid
Facial Nerve Nuclei
Enters temporal bone: internal
auditory meatus
(parasympathetic
motor)
Exits skull: stylomastoid foramen
(somatic motor)
(sensory)
Lesions of CN VII
• Symptoms depend on the location of the lesion
• Facial nerve palsy with decreased hearing is really
bad!
• Facial nerve palsy with increase in sound – not as
bad!
• Biggest Parasympathetic Nerve to the head
• Loss of taste to anterior 2/3rd of tongue
• Preservation of upper part of facial muscles – think
CNS!
Vestibulocochlear
Nerve
Functions: Hearing & Balance
CN VIII
Vestibular Portion
Vestibule
Enters skull: internal auditory meatus
Saccule
Ampulla of Semicircular
Canal
Cochlea
Cochlear Portion
Problems with CN VIII
• Vertigo – sensation of movement or spinning and loss of
balance
• Menier’s disease – disorder of the inner ear that can lead to
dizzy spells (vertigo) and hearing loss.
• Saccades – rapid movement of the eye between fixation
points
• Nystagmus – eyes make repetitive, uncontrolled
movements
• Strabismis – Eyes are not aligned properly and point in
different directions
Glossopharyngeal Nerve – CN IX
CN IX
Sensory Functions:
Carotid Body/Sinus
Endodermal portion
of tongue (posterior 1/3),
palate, pharynx
Gag Reflex
Motor Functions:
Stylopharyngeus M.
(3rd Branchial Arch)
Glossopharyngeal VE (Parasympathetic Functions)
O-P
Exits skull: jugular foramen
NOT MUCH!!
Problems with CN IX
• Loss of gag reflex (loss of sensation on posterior tongue and pharynx)
• Glossopharyngeal neuralgia (sharp, stabbing pulses of pain in the back of
the throat and tongue, the tonsils, and the middle ear)
Vagus Nerve – CN X
Parasympathetic to the thorax &
foregut/midgut organs
Visceral Afferents from Carotid
artery, thorax, and foregut/midgut
structures
CN X
Motor Nerves of Pharyngeal
Arches
4th (Superior Laryngeal N.)
6th (Recurrent Laryngeal N.)
Exits skull: jugular foramen
Example Problem with CN X
Side of Lesion
• Uvula and palate do not elevate on the
side of the lesion
• Uvula will deviate away from the lesion
X
Relaxed
Only unaffected muscle contracts
– so uvula points away from the
side of the lesion
Accessory Nerve – CN XI
Exits skull: jugular foramen
Lesion of CN XI
• Loss of shoulder shrug
• Drooping of the shoulder
Hypoglossal Nerve – CN XII
Exits skull: hypoglossal canal
Lesions of the CN XII
• Tongue points toward the side of the lesion
Normal
Lesion
The Charts in the Remaining Slides are
Study Resources.
Superior orbital fissure
Superior orbital fissure
Somatic (general)
sensory
Somatic (general)
sensory
Trigeminal ganglion
Superior orbital fissure
Trigeminal ganglion
Foramen ovale
(Chorda tympani gets to
infratemporal fossa to reach
submandibular & sublingual glands
via petrotympanic fissure)
(Innervation to lacrimal gland, nose, palate is via greater petrosal nerve)
Via lesser petrosal nerve
Anterior Cervical
Triangle & Deep Neck
Mary Moon, Ph.D.
Assistant Professor
Department of Cell Biology
Session Objectives
a. Identify the boundaries and muscles of the anterior triangle of the neck.
b. Recall the contents of the various sub-triangles in the anterior neck.
c. Observe the major divisions of the cervical fascia and list the major structures
contained in each.
d. Describe which cervical fasciae contribute to the carotid sheath.
e. Identify the innervation of the muscles of the anterior triangle of the neck.
f. Trace the vascular supply within the anterior triangle of the neck.
g. Describe the sensory nerves in the anterior triangle of the neck.
h. Identify the large vascular structures, nerves and lymphatic vessels in the deep
neck and root of the neck.
i. Identify the visceral organs in the neck (trachea, larynx, thyroid gland, etc.
• Orientation to the Neck
Lecture Outline
– Review of Cervical Fascia
– Boundaries & Subtriangles
• Skeletal & Cartilaginous Elements
• Muscles of the Anterior Triangle
– Muscular Triangle
– Submandibular Triangle
• Carotid Triangle
– Branches of the External Carotid Artery
• Veins & Lymphatics
• Nerves of the Deep Neck
• Viscera in Anterior Neck
– Thyroid & Parathyroid
– Trachea
– Esophagus
• Root of Neck
– Great Vessel Review
– Thyrocervical trunk
Orientation to the Neck
• Serves as a major conduit for structures passing
between head and trunk/limbs
• C-Spine have characteristics that lend themselves
to motility, i.e. muscle attachments and flattened
articular facets.
• Allows positioning of the head to maximize
efficiency of sensory organs
• Cervical vertebrae are continuous with the
Neurocranium
• Viscerocranium is continuous with viscera in
anterior triangle of the neck
• The attachment of the head to the C-Spine
makes this region vulnerable to acceleration and
deceleration injury acceleration/deceleration
injury
Deep Cervical Fascia
Pretracheal Fascia
Platysma
Larynx
Anterior Triangle
Carotid
Sheath
S
C
M
*
Retropharyngeal Space
Danger Space
Buccopharyngeal fascia
Investing layer of
Deep Cervical
Fascia
Common carotid
Internal Jugular Vein
Vagus Nerve
Prevertebral Muscles
Vertebral Body
Deep Lymph Nodes
Posterior
Triangle
Back muscles
Alar fascia*
Prevertebral
Fascia
Deep Cervical Fascia
Occipital Bone
Mid-sagittal view
Boundaries of the Anterior Cervical Triangle
• Anterior Border of SCM
• Inferior Border of the Mandible
• Midline of the Neck
Hyoid
Clavicle
Subdivisions of the Anterior Triangle
For Descriptive Purposes…
Submandibular
Triangle
Carotid
Triangle
Submental Triangle
Sternocleidomastoid
Muscular
Triangle
Lecture Outline
•
Orientation to the Neck
– Review of Cervical Fascia
– Boundaries & Subtriangles
•
•
Skeletal & Cartilaginous Elements
Muscles of the Anterior Triangle
– Muscular Triangle
– Submandibular Triangle
•
Carotid Triangle
– Branches of the External Carotid Artery
• Veins & Lymphatics
• Nerves of the Deep Neck
• Viscera in Anterior Neck
– Thyroid & Parathyroid
– Trachea
– Esophagus
•
Root of Neck
– Great Vessel Review
– Thyrocervical trunk
Mandible
Submandibular
Fossa
For the submandibular gland
Mylohyoid Line
Attachment point of mylohyoid m
Digastric Fossa
Attachment point of Ant. Belly of Digastric m
Hyoid Bone
Greater Horn
Lesser Horn
Anterior
Lateral View
Posterior
Body
Fracture of they Hyoid may occur with
compression of the throat which leads to
inability to:
• Elevate the hyoid bone
• Move it anterior under the tongue
• Maintain separation between alimentary and
respiratory tracts
Skeletal & Cartilaginous Elements
Hyoid bone
Thyrohyoid
Membrane
Thyroid Cartilage:
Lamina
Laryngeal prominence
Trachea
Emergency
Cricothyrotomy
More Skeletal Elements
Greater Horn
Lesser Horn
Hyoid
Thyrohyoid Membrane
Thyroid Cartilage
Cricothyroid
Ligament
Cricoid Cartilage
First Tracheal
Ring
Lecture Outline
•
Orientation to the Neck
– Review of Cervical Fascia
– Boundaries & Subtriangles
•
•
Skeletal & Cartilaginous Elements
Muscles of the Anterior Triangle
– Muscular Triangle
– Submandibular Triangle
•
Carotid Triangle
– Branches of the External Carotid Artery
• Veins & Lymphatics
• Nerves of the Deep Neck
• Viscera in Anterior Neck
– Thyroid & Parathyroid
– Trachea
– Esophagus
•
Root of Neck
– Great Vessel Review
– Thyrocervical trunk
Muscle of Facial Expression
in the Anterior Triangle of the Neck
Platysma
CN VII
Image from: Ascher et. Al. (2010). See notes for full citation
Muscles of the Anterior Triangle
Thyroid Cartilage
Sternothyroid
Sternohyoid
Infrahyoid
Muscles
Thyrohyoid
Suprahyoid
Muscles
Stylohyoid
Mylohyoid
Mylohyoid Raphe
Digastric:
ant. belly
post. belly
Omohyoid:
sup.
belly
inf. belly
Lateral View
Mylohyoid 1.
4. Stylohyoid
3. Posterior Belly of Digastric
Anterior Belly of
Digastric 2.
9. Thyrohyoid
Sternohyoid 5.
Superior belly 6.
omohyoid
Sternothyroid 8.
7. Inferior belly omohyoid
Infrahyoid Muscles (Muscular Triangle)
Omohyoid (inferior & superior bellies)
Attachments:
1. Sup. Border of scapula (medial to suprascapular notch)
2. Intermediate tendon
3. Body of hyoid bone
Nerve: Ansa cervicalis (C1-C3)
Function: Depresses & fixes hyoid.
Sternohyoid
Attachments:
1. Post. Sternoclavicular joint & manubrium
2. Body of hyoid bone
Nerve: Ansa cervicalis (C1-C3)
Function: Depresses hyoid bone after
swallowing.
Infrahyoid Muscles (Muscular Triangle)
Thyrohyoid
Attachments:
1. Thyroid cartilage (Lamina)
2. Hyoid bone
Nerve: Nerve to thyrohyoid (C1 running with hypoglossal n)
Function: Depresses hyoid.
When hyoid is fixed
raises the larynx.
Sternothyroid
Attachments:
1. Posterior surface manubrium
2. Thyroid cartilage
Nerve: Ansa cervicalis
Function: Draws larynx down.
Cricothyroid Muscle
Attachments:
1. Anterolateral part of cricoid cartilage
2. Inferior margin & inferior horn of thyroid
cartilage
Nerve: External laryngeal branch from Vagus
Function: Stretches & tenses vocal ligament
Anterior
MOTOR
Cervical Plexus (C1-C4)
Posterior
Sensory
Geniohyoid
(C1 via hypoglossal)
Thyrohyoid
(C1 via hypoglossal)
Superior belly
Omohyoid
Sternothyroid
Sternohyoid
Inferior belly
Omohyoid
Loop is called ansa cervicalis (C1-C3)
Submandibular Triangle/ Digastric Triangle
Mandible
Digastric M.
Boundaries
Anterior: anterior belly of digastric
Posterior: posterior belly of digastric
Superiorly: Mandible
Floor: Mylohyoid
Suprahyoid Muscles - Digastric
Anterior Belly
Attachments:
1. Digastric Fossa of Mandible
2. Tendon to hyoid bone
Nerve: CN V3
(Off of Inferior alveolar nerve)
Function: raises hyoid bone,
opens mouth.
Posterior Belly
Attachments:
1. Mastoid process (temporal bone)
2. Tendon to hyoid bone
Nerve: CN VII
Function: pulls hyoid posterosuperiorly.
Suprahyoid Muscles
Stylohyoid
Attachments:
1. Styloid process
2. Lateral hyoid bone
Nerve: CN VII
Mylohyoid
Attachments:
1. Mylohyoid line of mandible
2. Body of hyoid bone
3. Mylohyoid raphe
Function: pulls hyoid bone
posterosuperiorly.
Nerve: Nerve to mylohyoid
(from inferior alveolar of CN V3)
Function: Support the floor of the mouth, elevate the floor and hyoid bone.
Suprahyoid Muscles are Innervated by Cranial
Nerves
Nerve to Mylohyoid
(Branch of Inferior
Alveolar from CN V3)
Mylohyoid
AD
PD
Facial Nerve
(CN VII)
AD = Ant. Digastric
PD = Post. Digastric
Contents of Submandibular Triangle
Facial A & V
Stylohyoid M
Hypoglossal N
Submandibular Gland
Lymph Nodes (not pictured)
Lecture Outline
•
Orientation to the Neck
– Review of Cervical Fascia
– Boundaries & Subtriangles
•
•
Skeletal & Cartilaginous Elements
Muscles of the Anterior Triangle
– Muscular Triangle
– Submandibular Triangle
•
Carotid Triangle
– Branches of the External Carotid Artery
• Veins & Lymphatics
• Nerves of the Deep Neck
• Viscera in Anterior Neck
– Thyroid & Parathyroid
– Trachea
– Esophagus
•
Root of Neck
– Great Vessel Review
– Thyrocervical trunk
The Carotid Triangle – Contents
Tendon of
Digastric m.
Vagus n.
Internal carotid a.
Carotid a. Bifurcation
Transverse cervical n
Hypoglossal n.
Thyrohyoid Branch (C1)
External carotid a.(branches)
Common carotid a.
Ansa cervicalis n.
Omohyoid m.
Carotid Triangle & The Carotid Arterial System
Superficial Temporal A
Maxillary A
Posterior
Auricular A
Occipital A
*Ascending
Pharyngeal A
Lingual A
Facial A
External Carotid A
Superior Thyroid A
Internal Carotid A
with branch Superior Laryngeal A
SALFORMS
External Carotid - Anterior Branches
Superficial Temporal A
Maxillary A
Ascending Pharyngeal A
Facial A
Lingual A
Superior Thyroid A
with superior laryngeal branch
Posterior Branches
&
Carotid Sinus
Posterior Auricular A
CN IX
Occipital A
Carotid Sinus
(Sinus has receptors that sense blood pressure)
(Carotid Body senses oxygen content)
Body Sinus
Carotid Endarterectomy
Carotid occlusion can be relieved by
opening the artery at its origin and
removing plaque. This procedure is known
as the carotid endarterectomy.
Bruits(murmur) in the carotids are a good
indication of carotid artery stenosis.
Lecture Outline
•
Orientation to the Neck
– Review of Cervical Fascia
– Boundaries & Subtriangles
•
•
Skeletal & Cartilaginous Elements
Muscles of the Anterior Triangle
– Muscular Triangle
– Submandibular Triangle
•
Carotid Triangle
– Branches of the External Carotid Artery
• Veins & Lymphatics
• Nerves of the Deep Neck
• Viscera in Anterior Neck
– Thyroid & Parathyroid
– Trachea
– Esophagus
•
Root of Neck
– Great Vessel Review
– Thyrocervical trunk
Major Veins of the Neck
R External Jugular
R Internal Jugular
R Subclavian vein
L Internal Jugular
Anterior Jugular
L Subclavian vein
Right versus Left
Internal Jugular Vein (IJV)
IJV may be accessed for diagnostic
or therapeutic purposes.
(SCM)
Can be found between the sternal
and clavicular head of the SCM
The right IJV is preferable because
it is usually larger and straighter.
Superficial Lymphatics
Lymphatics of the Deep Neck
Lecture Outline
• Orientation to the Neck
– Review of Cervical Fascia
– Boundaries & Subtriangles
• Skeletal & Cartilaginous Elements
• Muscles of the Anterior Triangle
– Muscular Triangle
– Submandibular Triangle
• Carotid Triangle
– Branches of the External Carotid Artery
• Veins & Lymphatics
• Nerves of the Deep Neck
• Viscera in Anterior Neck
– Thyroid & Parathyroid
– Trachea
– Esophagus
• Root of Neck
– Great Vessel Review
– Thyrocervical trunk
Nerves of the Deep Neck
External Br. of Superior Laryngeal N.
Middle Cervical Ganglion
Vagus N (CN X)
Phrenic N (C3-5)
Sympathetic Chain
Left recurrent laryngeal N
Inferior cervical ganglion
Sympathetic Chain (Trunks)
– Bilateral structure located anterior lateral to
the vertebral column
– No white rami
– Preganglionic cell bodies - IML of the upper
thoracic spinal cord.
– 3 Primary Cervical Sympathetic Ganglia
• Superior, Middle, Inferior
Sympathetic Trunks- Cervical Sympathetic Ganglia
Superior cervical ganglia
-to head and neck
Middle cervical ganglia
-to neck and upper limb
Inferior cervical ganglia
-to upper limb
Receive presynaptic fibers from the
superior thoracic spinal levels
Contain postganglionic cell bodies
Ansa Subclavia
Postganglionic cell fibers will leave the
chain via gray rami to pass to cervical
spinal nerves
Sympathetic trunk and Prevertebral Muscles
Superior Cervical
Ganglion
Sympathetic chain
Middle Cervical Ganglion
Inferior Cervical
Ganglion
(Stellate ganglion)*
Longus CApitis M.
Longus Coli M.
Sympathetic Chain sits on top
of these muscles
Innervated by cervical spinal
nerves
Cervical Lesion of the Sympathetic Trunk
Horner Syndrome = ptosis of the eyelid, constriction of the pupil (miosis), dry face
(anhydrosis)
Due to lesion or damage to the cervical sympathetic chain
Where do the Parasympathetics of the deep neck come
from?
Vagus Nerve
But it’s more than just
parasympathetics…
Sympathetic Chain
Subclavian Artery
Common Carotid Artery
Specific Branches of Vagus Nerve
Vagus Nerve (CNX)
Pharyngeal Br. (motor to pharynx & soft palate)
Superior Laryngeal
Internal Branch (sensory to superior larynx)
External Branch (motor to cricothyroid muscle) – that’s it!
R Recurrent Laryngeal
RIGHT loops under subclavian a.
LEFT loops under the aorta
(Motor to intrinsic larynx muscles* and sensory to inferior larynx)
Recurrent Laryngeal Nerves
Right
approaches the
trachea at a
more oblique
angle.
Right
Left
Recurrent Laryngeal Nerves and the Inferior Thyroid Artery
Inferior thyroid artery and Middle thyroid vein
Left Recurrent Laryngeal N
(mixed motor & sensory)
(Becomes inferior laryngeal n inside the larynx)
Laryngeal Nerve Branches
Sup. Laryngeal N.
Internal Branch
Sup. Laryngeal A. & V.
Mucosa being pulled back
Inferior Laryngeal N.
Middle Thyroid V.
Inferior Thyroid A.
Recurrent Laryngeal N.
Lecture Outline
• Orientation to the Neck
– Review of Cervical Fascia
– Boundaries & Subtriangles
• Skeletal & Cartilaginous Elements
• Muscles of the Anterior Triangle
– Muscular Triangle
– Submandibular Triangle
• Carotid Triangle
– Branches of the External Carotid Artery
• Veins & Lymphatics
• Nerves of the Deep Neck
• Viscera in Anterior Neck
– Thyroid & Parathyroid
– Trachea
– Esophagus
• Root of Neck
– Great Vessel Review
– Thyrocervical trunk
Thyroid Gland
• Endocrine Gland
• Located inferior to the thyroid and
cricoid cartilage – moves with the larynx
when swallowing
• Originates as an endodermal proliferation
in the developing tongue and then
migrates inferiorly
• Thyroglossal duct is the passage the gland
takes from the base of the tongue to its
final destination in the anterior neck.
• Two lobes connected by an Isthmus
• Thyroglossal duct remnant may exist as
pyramidal lobe
Ectopic Thyroid
Foramen
Cecum
Blood Supply and Relations
• Two (sometimes three) Arteries
Superior Thyroid Artery
Superior Thyroid
Vein
– Superior Thyroid Artery
– Inferior Thyroid Artery
– Thyroid Ima (not pictured)
• Three Veins
– Superior Thyroid Vein
– Middle Thyroid Vein(another slide)
– Inferior Thyroid Vein
Inferior
Thyroid
Artery
• Surgical relation
– Inferior Thyroid A. to Recurrent
Laryngeal N.
– Cricothyrotomy vs Tracheostomy
Inferior Thyroid Vein
Recurrent Laryngeal Nerve
For Review: Thyroid Ima Artery
Thyroid Ima A.
1.5-12% of population
Venous Drainage of Thyroid Gland
Superior Thyroid
Inferior Thyroid
Middle Thyroid
Internal Jugular
Subclavian
Parathyroid Glands
• Tiny!
• Embedded in the posterior surface of the
thyroid gland
• Separated from thyroid tissue by thick
CT capsule
• Sometimes, parathyroid tissue can be
found independently in the neck or
chest.
Trachea & Esophagus
Relative Positions
Shape of Cartilage Rings
Anatomical Relationships
Cervical Trachea
Trachea
• Consists of C-shaped rings
• Extends from cricoid to bifurcation
• Rigid airway
Why are the tracheal rings C-shaped rather than complete rings?
Esophagus
Esophagus
Cricopharyngeus (Upper Esophageal Sphincter) is normally contracted
to close entry to esophagus. It must relax during swallowing.
Position of Trachea and Esophagus
Position of Trachea and Esophagus
Lecture Outline
• Orientation to the Neck
– Review of Cervical Fascia
– Boundaries & Subtriangles
• Skeletal & Cartilaginous Elements
• Muscles of the Anterior Triangle
– Muscular Triangle
– Submandibular Triangle
• Carotid Triangle
– Branches of the External Carotid Artery
• Veins & Lymphatics
• Nerves of the Deep Neck
• Viscera in Anterior Neck
– Thyroid & Parathyroid
– Trachea
– Esophagus
• Root of Neck
– Great Vessel Review
– Thyrocervical trunk
Root of the Neck
• Junction between the thorax and the neck.
– Superior Thoracic aperture – a passage for all things going from head to thorax
and vice versa.
• Thoracic duct (Already covered)
• Right Lymphatic duct (Already covered)
• L Brachiocephalic Trunk
• Branches off Subclavian Artery
– Thyrocervical Trunk
– Internal Thoracic A.
– Costocervical Trunk
– Vertebral A.
Subclavian A.
Thyrocervical Trunk
Internal Thoracic
R. Subclavian A
R. Common Carotid
Brachiocephalic Trunk
Thyrocervical Trunk Branches*
Ascending Cervical
**Branch of inferior thyroid or
Comes off separately
Transverse Cervical*
Suprascapular*
Inferior Thyroid*
Subclavian Branches in the
Root of the Neck
Costocervical Trunk:
Deep cervical
Superior Intercostal
2
1
Vertebral A
3
Internal thoracic a.
Innervation and Action Infrahyoid and Suprahyoid Muscles
Suprahyoid Muscles
Innervation
Action
Mylohyoid
Nerve to mylohyoid
(Off inferior alveolar from mandibular of CN V)
Elevates hyoid, floor of mouth and tongue
during speaking and swallowing
Geniohyoid
C1 via hypoglossal
Pulls hyoid anterior superiorly
Stylohyoid
Facial nerve CNVII
Elevates and retracts the hyoid
Digastric
Anterior Belly: Nerve to mylohyoid
Posterior Belly: Facial nerve CNVII
Elevates hyoid during speaking and swallowing
Infrahyoid Muscles
Innervation
Action
Sternohyoid
C1-C3 by branch of ansa cervicalis
Depresses hyoid after elevation
Omohyoid
C1-C3 by branch of ansa cervicalis
Depresses and retracts hyoid
Sternothyroid
C2-C3 by branch of ansa cervicalis
Depresses hyoid
Depresses larynx
Thyrohyoid
C1 via hypoglossal nerve
Depresses hyoid
Elevates larynx
Superficial Face
Frederick Miller, Ph.D.
Department of Cell Biology
Department of Family and Preventive
Medicine
9-17-2024
Superficial Face: Learning Objectives
1. Identify the layers of the scalp and recall the clinical significance of
each layer.
2. Identify the location of the parotid gland and trace the duct to its
termination in the vestibule of the mouth and recognize the
importance of parotid anatomy in diseases affecting the gland like
mumps and cancers.
3. Correlate the muscles of facial expression with their actions, their
innervation by the facial nerve and their individual contributions to
facial functions.
4. Trace the arterial supply and venous drainage of the face.
5. Explain the clinical significance of the danger area of the face.
6. Trace the sensory branches of the trigeminal nerve as they supply
touch and pain to the different regions of the face (and parotid
gland) and correlate that with sensory exam, anesthesia of the
face, and the presentation of herpes zoster.
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (branches of CN V)
– Motor innervation of the face (branches of CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Superficial Face: The Cranium
• Neurocranium
-
Brain and meninges
Cranial nerves
Vasculature
• Viscerocranium
- Facial bones
- Orifices
- Viscera
Superficial Face: Osteology
Frontal
• Viscerocranium
Glabella
Supraorbital foramen
– Orbits
– Nose and nasal cavity
Sphenoid
– Oral cavity
• Maxillae
Superciliary arch
Nasal
Infraorbital foramen
• Mandible
– Houses lower teeth
– moveable
Zygoma
Maxillae
– Houses upper teeth
– Fixed
Mental foramen
Orbital part
frontal bone
Mandible
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (CN V)
– Motor innervation of the face (CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Superficial Face: Regions of the Face
Supraorbital Ridge
Superficial Face
Epicanthal fold
• Facial Features
Lateral canthus
– Features are constant
– Lots of variations of each
type of feature from
individual to individual
Root
Medial canthus
Ala
Nasolabial Fold
Labial Commisure
Apex
Nares
Philtrum
Vermilion Border
Mental Protuberance
Superficial Face: Borders and Contents
A. Borders
1. Forehead (hairline)
2. Ant. border of external ear
3. Chin
B. General Contents
1. Eyes
2. Nose
3. Mouth
4. Muscles of Face
5. Buccal Fat Pad
6. Parotid Gland
7. Trigeminal Nerve branches
8. Facial Nerve branches
9. Facial Arteries & Veins
Superficial Face: Parotid Gland
• Para – beside / Otic – ear
• Superficial to masseter
• Innervation:
– Parasympathetic - CN IX
– Sensory: skin and capsule
• Great auricular n. (C2, C3)
• Auriculotemporal n. (CN V3)
• Parotid (Stensen’s) duct
• Found in parotid substance:
– Parotid plexus of CN VII
– External carotid / Superficial
temporal a.
– Retromandibular vein
Parotid duct
Buccinator
Parotid gland
Superficial Face
• Clinical correlation
– Parotitis (Parotiditis)
– Mumps
• Viral infection
(paramyxovirus)
• Manifests as parotitis
– MMR vaccine
• 12-15 months
• 4-6 years
– Frey’s syndrome
Swollen parotid gland
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (CN V)
– Motor innervation of the face (CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Superficial Face - Scalp
SCALP
5 Layers:
1. Skin
2. Connective tissue
Subcutaneous Tissue
3. Aponeurosis
4. Loose Areolar
Connective Tissue
5. Periosteum
Superficial Face - Scalp
Relationship of the scalp to calvaria and meninges
Emissary vein
– Dural sinuses
– Emissary veins Scalp
– Arachnoid granulations
– Foveolae
Dura mater
Arachnoid granulation
Dura mater
Superior sagittal sinus
Superficial Face – Scalp Muscles
Gala aponeurotica
• Epicranial aponeurosis
– Occipitofrontalis
– Temporoparietalis
– Auricularis muscles
• Innervated by motor
branches of CN VII
Frontalis
Auricularis
Occipitalis
Superficial Face
• The temporalis is not
considered a scalp muscle.
• The temporalis is
considered a muscle of
mastication and is deep to
the temporalis fascia.
• The temporalis is
innervated by the deep
temporal nerves (CN V3).
Temporalis
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (CN V)
– Motor innervation of the face (CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Superficial Face – Overview Muscles
• Muscles of Facial Expression
– Orbit of the eye
– Nose and nostrils
– Oris: lips, cheek, mouth
– Also: scalp, neck, external ear
• No deep membranous fascia in the face
• Muscles insert directly into the overlying skin
• Primary function: Sphincters and Dilators
• Derived from: Mesoderm 2nd pharyngeal arch
• Innervation: motor branches of CN VII
Muscles of Facial Expression
• Scalp (aponeurotic) muscles
– Occipitofrontalis
– Temporoparietalis
– Auricularis muscles
• Innervated by motor
branches of CN VII
– Occipitalis: post. auricular
– Frontalis: temporal branches
– TP: temporal branches
Gala aponeurotica
Frontalis
Auricularis
Occipitalis
Muscles of Facial Expression
Associated with:
Orbit
Nose
Oris
Frontalis
Orbicularis oculi ProcerusCorrugator supercillii
Orbital
Palpebral
Attach to the skin
Orbicularis
Orbital part – closes eyelid tightly
Palpebral part – closes eyelid gently
Innervated by motor branches of CN VII
Orbicularis oculi: Temporal / Zygomatic
Corrugator supercillii: Temporal branches
Muscles of Facial Expression
Associated with:
Orbit
Nose
Oris
Nasal muscle group
Attach to the skin
Levator labii superioris Procerus
alaque nasi
Nasalis
Innervated by CN VII
Procerus: Temporal, Zygomatic)
Nasalis: Buccal (some zygomatic)
Muscles of Facial Expression
Associated with:
Orbit
Nose
Oris
Levator labii superioris alaque nasi
Buccolabial group
Attach to the skin
Zygomaticus minor
Zygomaticus major
Levator labii superioris
Risorius
Innervated by CN VII
(see specifics in notes below)
Depressor anguli oris
Depressor labii inferioris
Levator anguli oris
Buccinator
Masseter
Orbicularis oris
Mentalis
Muscles of Facial Expression
Lateral View
Frontalis
Nasalis
Auricularis
Occipitalis
Levator labii superioris alaque nasi
Levator labii superioris
Risorius
Zygomaticus minor
Zygomaticus major
Depressor anguli inferioris
Platysma
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (CN V)
– Motor innervation of the face (CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Overview Innervation of the Face
• Sensory innervation
– Trigeminal Nerve (CN V)
– 3 main divisions
• Motor innervation
– Facial Nerve (CN VII)
• Salivary gland innervation
– Parotid: Glossopharyngeal
Nerve (CN IX)
– Submental and submandibular:
Facial N. (CN VII)
Sensory Innervation of the Face
Branches of the Trigeminal N. (CN V)
Ophthalmic division (V1)
a. Supraorbital
b. Supratrochlear
c. Lacrimal
d. Infratrochlear
e. External Nasal
Ophthalmic division
Maxillary division (V2)
a. Zygomaticotemporal Maxillary division
b. Zygomaticofacial
c. Infraorbital
Mandibular division (V3)
a. Auriculotemporal
Mandibular division
b. Buccal
c. Mental
Great Auricular Nerve (C2,3)
Transverse Cervical Nerve (C2,3)
Trigeminal ganglion
Location of the Trigeminal Ganglion
CN V and Ganglion
V1 - ophthalmic
V2 - maxillary
V3 - mandibular
Sensory Innervation of the Face
Auriculotemporal
Lacrimal
Supraorbital
Supratrochlear
V1
Infratrochlear
Ext. nasal
V2
Zygomatico
temporal
Zygomatico
facial
Infraorbital
Buccal
V3
Posterior cervical rami
Greater Occipital Nerve (C2)
Third Occipital Nerve (C3)
Mental
Anterior cervical rami
Great Auricular Nerve (C2,3)
Lesser Occipital Nerve (C2,3)
Sensory Nerves of the Face – CN V
Supraorbital
Supratrochlear
Anterior ethmoid
Ophthalmic division (V1)
Frontal nerve
a. Supraorbital
b. Supratrochlear
Nasociliary
a. post. ethmoid
b. anterior ethmoid
1. external nasal
c. infratrochlear
Lacrimal
Frontal nerve
Nasociliary
V1
Infratochlear
Lacrimal
Ophthalmic division enters the orbit through the superior orbital fissure
Sensory Nerves
of the Face – CN V
Maxillary Nerve
Trigeminal
ganglion
Maxillary division (V2)
Infraorbital
Nerve
a. Zygomatic nerve
i. Zygomaticotemporal
ii. Zygomaticofacial
b. Infraorbital
Infraorbital
fissure
Infraorbital Nerve
Sensory Nerves of the Face – CN V
Mandibular division (V3)
a. Auriculotemporal
b. Buccal
c. Inf. Alveolar
i. Mental
Trigeminal ganglion
V3
Buccal
Ariculotemporal n.
Note: the auriculotemporal, buccal
branch, and inferior alveolar
Inferior alveolar n.
nerves of the mandibular division
will be seen in the deep face
dissection.
Mental n.
Sensory Nerves of the Face
Cutaneous Nerves emerging onto the face
(anterior view)
Trigeminal Nerve (CN V)
1. Supratrochlear (V1)
2. Supraorbital (V1)
3. Zygomaticotemporal (V2)
Zygomaticofacial (V2)
4. Infraorbital (V2)
5. Buccal (V3)
6. Auriculotemporal (V3)
7. Mental (V3)
2
1
3 6
3
4
5
7
Parotid
duct
Superficial Face
• Clinical Correlation: CN V
• Herpes zoster ophthalmicus
(Shingles)
– Post chicken pox, latent zoster
resides in sensory ganglia
– Reactivation of Varicella
Zoster Virus (VZV)
– What ganglia?
– Distribution of vesicles along
dermatomes
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (CN V)
– Motor innervation of the face (CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Motor Nerves of the Face
Temporal
Posterior auricular
Zygomatic
Facial Nerve (CN VII)
Posterior trunk
Posterior auricular
Anterior trunk
Temporofacial
Buccal
1. Temporal
2. Zygomatic
Marginal mandibular
3. Buccal
Cervicofacial
1. Buccal
2. Mandibular
3. Cervical
To Zanzibar By Motor Car or ……..
Cervical
Exits stylomastoid
foramen
Motor Branches of the CN VII (Facial)
Temporal
Zygomatic
Buccal
Mandibular
Cervical
Superficial Face
• Facial nerve review
• Clinical Correlation:
– Bell’s Palsy
• Unilateral facial paralysis
• Due to inflammation of the facial nerve
• Viral infection, trauma, idiopathic
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (CN V)
– Motor innervation of the face (CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Arterial Supply to Face
Superficial Temporal
Ext. carotid artery
1. Facial artery
a. Inferior labial
b. Superior labial
c. Lateral nasal
d. Angular
2. Superficial temporal
Transverse facial (= X)
3. Posterior auricular
4. Occipital
5. Maxillary
Infraorbital
Mental
Angular
Sup. labial
Inf. labial
Facial
Post. auricular
X
Occipital
Maxillary
Ext. carotid
Int. carotid artery
Ophthalmic artery
1. Supratrochlear
2. Supraorbital
Common carotid
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (CN V)
– Motor innervation of the face (CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Veins of the Face
Supraorbital
Supratrochlear
Superficial temporal
Angular
1. Supraorbital v.
Infraorbital
2. Supratrochlear v.
3. Superficial Temporal v.
Sup. labial
4. Retromandibular v.
5. Facial v.
6. Ophthalmic v. (not labeled) Inf. labial
a. superior
b. inferior
Facial
7. Infraorbital v. (not labeled)
Post. auricular
Occipital
Retromandibular
EJV
IJV
Note: there are many variations for the veins of
the head and neck. Most texts show the external
jugular formed by union of the retromandibular
and posterior auricular veins.
Veins of the Face
Cavernous sinus
Superior ophthalmic v.
Inferior ophthalmic v.
Pterygoid plexus
Retromandibular
Facial v.
Deep facial v.
IJV
Infections of the face and scalp can be
very serious as the superficial veins are in
communication with the deep veins of the
face and cranium at several locations.
Lymphatics of the Face
Mastoid nodes
Parotid nodes
Submental nodes
Occipital nodes
Submandibular nodes
Deep cervical nodes
Right lymphatic trunk
Superficial View
Deep View
Superficial Face
• Lecture Outline
– Osteology
– Facial features and contents
– Scalp
– Muscles of facial expression
– Sensory innervation of the face (CN V)
– Motor innervation of the face (CN VII)
– Branches of the facial artery
– Venous drainage of the face and lymphatics
Dissection of the Superficial Face
Superficial Temporal A&V
Auriculotemporal N
Orbicularis
Oculi
Transverse Facial A
Parotid Gland
Parotid Duct
Branches of the facial N
Greater Auricular N
External Jugular V
Platysma M.
Mentalis M.
Facial A&V
Branch CN V
Nerve
Location
Innervates
Ophthalmic (V1)
Frontal nerve
Supraorbital
Supraorbital notch
Forehead, Scalp
Frontal nerve
Supratrochlear
FH above trochlea
Forehead
Nasociliary /
ant. ethmoid
External nasal
Side of nose
Ala and dorsum of nose;
vestibule
Nasociliary
Infratrochlear
Below eye
Medial lower
eyelid/conjunctiva
Skin side of the nose
Lacrimal
Superolateral orbit
Lateral upper eyelid;lat
conjunctiva, part lacrimal
gland
Infraorbital
Orbital floor
Inf. eyelid, cheek below
eye, ala nose, upper lip
Zygomatic
Zygomaticotemporal Skin from zygomatic
region to anterior
temporal region
Zygomatic
Zygomaticofacial
Skin over cheekbone
Auriculotemporal
Deep to ramus of
mandible
Skin anterior to auricle,
skin of posterior temporal
region
Maxillary (V2)
Mandibular (V3)
Origin
External
carotid
Internal carotid
Branch of carotid
Facial artery
Artery
Location
Supplies
Inferior labial
Deep to orbicularis oris
Lower lip
Superior labial
Deep to orbicularis oris
Upper lip/ala nose
Some - nasal septum
Angular
Along nose to angle of
eye
Cheek, inferior eyelid
Superficial
temporal
Anterior to ear; passes
through parotid
Muscles/skin of
frontal & temporal
scalp
Posterior auricular
Deep to parotid to
mastoid and back of
ear
Scalp posterior,
inferior, and medial
to the ear.
Auricle
Occipital
Runs with C2
Posterior scalp to
vertex
Transverse facial
Runs superficial to
masseter
Parotid gland and
duct; muscles and
skin of face
Maxillary/inferior
alveolar
Mental
Mental foramen
Muscles/skin chin
Ophthalmic
Supraorbital
Supraorbital foramen
Muscles/skin
forehead
Supratrochlear
Supraorbital notch
Muscles/skin
Extra - Central vs. Peripheral CN VII Lesions
• Upper motor neurons
– Cell bodies in cerebral cortex or
brainstem
– Synapse on lower motor
neurons in the midbrain,
brainstem or spinal cord
– Upper motor neurons
decussate (cross over)
• Lower motor neurons
– Cell bodies are in nuclei in the
midbrain, brain stem or the
ventral horn of the spinal cord
– Innervate muscles directly
(SME)
– Lower motor nerves innervate
muscles on the ipsilateral side
of the body
Extra - Central vs. Peripheral CN VII Lesions
• Upper Motor Neurons (UMNs) to Face:
• Upper Face (Upper Eyelid and Forehead):
• UMNs to the upper face split before crossing
over in the brainstem.
• As a result, muscles of the upper face
receive bilateral innervation from the UMNs
of both the left and right cerebral cortices.
• UMNs synapse on lower motor neurons in
both the left and right facial motor nuclei in
the brainstem.
• The lower motor neurons innervate the
muscles of the upper face (e.g., forehead) on
both sides.
• Lower Face (Below the Eyes):
• UMNs to the lower face do not split before
crossing over.
• Muscles of the lower face are controlled by
UMNs from the contralateral cerebral cortex.
• UMNs synapse on lower motor neurons in
Peripheral VII Lesion
the contralateral facial motor nucleus.
• Thus, the lower motor neurons innervate the
muscles of the lower face on only one side.
Central Lesion
Extra - Central vs. Peripheral CN VII Lesions
Lesions of Upper Motor Neurons (UMNs):
• Effects: UMN lesions typically spare
the forehead muscles due to bilateral
innervation.
• Findings:
•
•
•
The patient can wrinkle the forehead on
both sides.
The patient can close both eyes.
Lesion Location: Central lesion, such as
those caused by an ischemic stroke
affecting the motor cortex or its
pathways.
Lesions of Lower Motor Neurons (LMNs):
• Effects: LMN lesions result in ipsilateral
paralysis of both the upper and lower
face.
• Findings:
•
•
•
The patient cannot wrinkle the forehead
on the affected side.
The patient cannot close the eye on the
affected side.
Lesion Location: Peripheral lesion, such Peripheral VII Lesion
as Bell’s Palsy, affecting the facial
nerve.
Central Lesion