Head and Neck anatomy - face

1. Face
The face is the anterior part of the head, situated between the ears, extending from
the chin to the hairline
Skin of the Face:
1. Contains numerous sweat and sebaceous glands.
2. Varies in thickness, being very thin on the eyelids.
3. Muscles underlying the skin are attached to the dermis.
4. Senile facial wrinkles are perpendicular to the line of muscle pull (horizontal
wrinkles on the brow, 'crow's foot' wrinkles at the lateral canthus, vertical
wrinkles on both lips).
5. No deep fascia is present on the face.
➔ Deep fascia is a dense connective tissue that is commonly
arranged in sheets that form a stocking around the muscles and
tendons beneath the superficial fascia ,
➔ The main function of the deep fascia is to support and protect
muscles and other soft tissue structures. It also provides a barrier
against the spread of infection from the skin and superficial fascia
into muscle compartments.
➔ The absence of a deep fascia in the face allows for greater mobility
and flexibility of the facial muscles, facilitating a wide range of
expressions. Additionally, the lack of a deep fascia contributes to the
relatively thin and pliable nature of facial skin.The face lacks a deep
fascia, which is a dense, fibrous connective tissue layer that is present
in many other regions of the body. In the face, the muscles
responsible for facial expression are organized differently compared
to muscles in other parts of the body. The muscles of facial
expression, such as the orbicularis oris, orbicularis oculi, and other
facial muscles, are more closely associated with the skin and are not
separated from it by a distinct deep fascia.
➔ The absence of a deep fascia in the face allows for greater mobility
and flexibility of the facial muscles, facilitating a wide range of
expressions. Additionally, the lack of a deep fascia contributes to the
relatively thin and pliable nature of facial skin.
➔ While the face doesn't have a deep fascia, it does have a superficial
fascia that connects the skin to the underlying muscles. This
superficial fascia contains fat and other connective tissue elements.
The unique structure of the facial muscles and the absence of a deep

2. fascia are adaptations that allow for the intricate and nuanced
movements involved in facial expression
Muscles of the Face:
1. Muscles of facial expression develop from the mesoderm of the second
pharyngeal arch.
2. They migrate widely to their adult positions and are supplied by the seventh
cranial (facial) nerve.
3. Functionally, they form groups around the orifices (eyes, nose, mouth) to
control these openings.
4. Various expressions on the face are side effects of this muscular control.
Specific Muscles:
1. Levator Palpebrae Superioris:
a. Associated with the orbital muscles.
b. Part of the occipitofrontalis muscle, which is part of the scalp.
2. Occipitofrontalis:
a. Part of the scalp.
3. Orbicularis Oculi:
a. Palpebral Part: Confined to the eyelids.
i. Fibers arise from the medial palpebral ligament, arch across
both lids, and interdigitate laterally.
b. Lacrimal Part: Deeper fibers attached to the lacrimal sac and lacrimal
crest.
c. Orbital Part: Larger part, arises from the frontal bone, anterior lacrimal
crest, and frontal process of the maxilla. Fibers circumscribe the
orbital margin in concentric loops.
Muscles:
● These muscles play a role in the movement and control of the eyelids and
nostrils, contributing to facial expressions and functionality.

3. 1. Orbicularis Oculi:
Nerve Supply: Temporal and zygomatic branches of the facial nerve.
Action:
i. Palpebral Fibers: Gently close the eyelids without burying the
eyelashes.
ii. Orbital and Palpebral Parts: When contracting together,
forcefully close the eyelids, burying the eyelashes. In normal
closing, the lateral part of the upper lid comes down before the
medial part, aiding in spreading lacrimal secretion from the
gland side (lateral) towards the nose.
2. Opponent Muscles:
i. Levator Palpebrae Superioris opposes the upper palpebral
fibers of Orbicularis Oculi.
ii. Occipitofrontalis opposes the orbital part.
3. Muscles of the Nostrils:
Sphincter Muscle of the Nostril (Transverse Part of Nasalis -
Compressor Naris):
i. Forms an aponeurosis over the bridge of the nose with its
counterpart on the opposite side.
ii. Arises from the maxilla.
iii. Opponent Muscle:
1. Alar Part of Nasalis (Dilator Naris): Opposes the
transverse part, inserted into the lateral part of the
ala.(The dilator naris muscle (or alae nasi muscle) is a
part of the nasalis muscle. It has an anterior and a

4. posterior part. It has origins from the nasal notch of
the maxilla and the major alar cartilage, and a single
insertion near the margin of the nostril. It controls
nostril width, including changes during breathing.)
4. Other Contributing Muscles:
i. Levator Labii Superioris Alaeque Nasi: Involved in widening the
nostril.The levator labii superioris alaeque nasi (Latin:
musculus levator labii superioris alaeque nasi) is a muscle
of facial expression that widens the nostril and elevates the
upper lip, thus enabling the facial expression of snarling. It
is classified as the nasal facial muscle.
ii. Depressor Septi: Arises from the maxilla above the central
incisor, attached to the nasal septum.
● Nerve Supply: Buccal branches of the facial nerve.

8. Muscles of the Lips and Cheeks:
1. Sphincter (Constrictor) Muscle of the Lips: Orbicularis Oris
a. Structure:
i. Consists of fibers proper to itself and fibers added from the
dilators.
ii. Divided into four quadrants (upper, lower, right, left), each with
a larger peripheral part and a smaller marginal part in the red
zone of the lips.
iii. Bulk formed by extrinsic fibers, mostly from the buccinator
muscle.
iv. Fibers converge toward the modiolus, forming a chiasma where
middle fibers decussate.
b. Incisivus Labii Superioris and Incisivus Labii Inferioris
They are located under the labial mucosa. They originate near the
incisive alveoli of each jaw, and end on the deep surface of the
orbicular muscle of the mouth, near the labial commissure. The
superior is always more easily separable than the lower.
What is the function of the incisivus labii superioris?
The incisivus labii superioris muscle, situated in the facial region,
serves primarily in retracting the upper and lower lips. 'Incisivus'
derives from the Latin 'incidere' meaning 'to cut through
i. Attached to the incisive fossa of the maxilla and mandible.
ii. Arch laterally, interlacing with fibers of the peripheral part of
orbicularis oris near the modiolus.
iii. Deepest fibers in the lips, attached to the mucous membrane.
c. Nerve Supply: Buccal and marginal mandibular branches of the facial
nerve.
d. Action:
i. Contraction causes narrowing of the mouth.
ii. Lips become pursed into the smallest possible circle, creating a
whistling expression.
2. These muscles play a crucial role in the movement and control of the lips,
contributing to facial expressions and functional activities such as speaking
and smiling.

9. The principal muscle
of the lips is the circumferential orbicularis oris

10. Buccinator Muscle:
The buccinator is an oral muscle of facial expression. It is located between the
mandible and maxilla, deep to the other muscles of the face
1. . Attachments –
Originates from the maxilla and mandible. The fibres run in an
inferomedial direction, blending with the orbicularis oris muscle and the
skin of the lips.
2. Origin:
a. Bony origin from both jaws, horizontally on the maxilla and from the
oblique line of the mandible.
b. Arises between the tuberosity of the maxilla and the hamulus at the
base of the medial pterygoid plate of the sphenoid.
c. Arises from the pterygomaxillary ligament, where the tendon of tensor
palati hooks around the hamulus.
3. Pterygomandibular Raphe:
a. Extends from the tip of the hamulus to the mandible just above the
posterior end of the mylohyoid line.
b. Lingual nerve is in contact with the mandible along this raphe.
4. Insertion:
a. Converges on the modiolus, where its fibers of origin from the raphe
decussate.
b. Maxillary and mandibular fibers pass medially without decussation
into the upper and lower lips, respectively.

11. c. Pierced by the parotid duct.
5. Buccal Fat Pad:
a. Lies on the outer surface of buccinator and is prominent in infants,
contributing to chubby cheeks.
b. Small molar glands beneath the fat pad, with ducts piercing the
muscle to open on the mucous membrane of the cheek.
6. Nerve Supply:
a. Buccal branches of the facial nerve.
b. Buccal branch of the mandibular nerve supplies proprioceptive fibers.
7. Action:
a. Accessory muscle of mastication, assisting in the return of the bolus
from the cheek pouch to the molars.
b. Classified as a muscle of facial expression due to facial nerve supply.
c. Relaxed when the cheeks are puffed out and contracts during forcible
expulsion of air, as in blowing a trumpet.

12. Dilator Muscles of the Lips:
The dilator muscles consist of a series of small muscles that radiate out from
the lips
1. Function:
a. Contraction of these muscles dilates the lips.
b. The contraction may disturb a lower denture.
2. Nerve Supply:
a. Supplied by the marginal mandibular branch of the facial nerve.
3. Nerve Supply of Face Muscles:
4. Motor Supply:
a. The supply from the facial nerve to the muscles is primarily motor.

13. 5. Proprioceptive Input:
a. Proprioceptive impulses from the facial muscles are conveyed
centrally by the trigeminal nerve.
b. Cutaneous branches of the trigeminal nerve connect freely with
branches of the facial nerve.
6. Facial Nerve Pathway:
a. The facial nerve emerges from the base of the skull through the
stylomastoid foramen, near the origin of the posterior belly of
digastric.
b. Branches of the facial nerve include:
i. Posterior Auricular Nerve: Supplies auricularis posterior and
the occipital belly of occipitofrontalis.
ii. Muscular Branch: Supplies the posterior belly of digastric and
stylohyoid.
iii. Temporal and Cervical Divisions: Divide within the parotid gland
into temporofacial and cervicofacial divisions.
iv. Pes Anserinus: A plexiform arrangement of branches emerging
from the parotid gland.
c. The cervical branch passes downward and supplies platysma.
7. Marginal Mandibular Branch:
a. Frequently single, running forwards above, along, or below the lower
border of the mandible.
b. Crosses the inferior border of the mandible to reach the face just
beyond the anterior border of the masseter muscle.
c. Courses superficial to the facial artery and vein.
d. Vulnerable during incisions near the lower border of the mandible.
e. Does not communicate with a buccal branch, and damage causes
detectable paralysis of the depressors of the lower lip and mouth
angle.
8. Cervical Branch:
a. Passes downward from the lower border of the parotid gland.
b. Supplies platysma.
9. Note: The branching pattern of the facial nerve can vary between individuals
and even between the two sides of the face in the same person.

14. Sensory Nerve Supply of the Face:
The trigeminal nerve has three divisions (ophthalmic, maxillary, and mandibular),
each responsible for supplying specific regions of the face.
Ophthalmic Nerve:
1. Lacrimal Nerve:
a. Supplies a small area of skin over the lateral part of the upper lid.
2. Supraorbital Nerve:
a. Indents the bone into a notch or a foramen about a third of the way
lateral to the medial end of the upper margin of the orbit.
b. Passes up and breaks into several branches radiating out to supply
the forehead and scalp up to the vertex.
3. Supratrochlear Nerve:
a. Passes up on the medial side of the supraorbital nerve.
b. Supplies the middle of the forehead up to the hairline.
4. Infratrochlear Nerve:
a. Supplies skin on the medial part of the upper lid.

15. b. Passes above the medial palpebral ligament and descends along the
side of the external nose, supplying skin over the bridge of the nose.
c. Also supplies the conjunctiva of the upper lid.
5. External Nasal Nerve:
a. Supplies the middle of the external nose down to the tip.
b. Emerges between the nasal bone and the upper nasal cartilage.
6. Great Auricular Nerve:
Supplies the skin over the parotid gland and part of the auricle of the
ear.Fibers reach the C2 segment of the spinal cord.
Note:
● The sensory supply of facial skin is divided into three zones by the branches
of the trigeminal nerve, meeting at the lateral margins of the eyelids and the
angle of the mouth.
● The spatial representation of the face in the spinal nucleus of the trigeminal
nerve in the brainstem, particularly with regard to pain sensation, may follow
an 'onion skin' pattern.

16. Maxillary Nerve:
The maxillary nerve arises from the anterior convexity of trigeminal ganglion
between ophthalmic and mandibular divisions of the trigeminal nerve. It is a
medium-sized branch compared to the smaller ophthalmic nerve and the larger
mandibular nerve.
The maxillary nerve gives rise to three cutaneous branches:
1. Infraorbital Nerve:
a. Emerges through its foramen and lies between levator labii superioris
and the deeper-placed levator anguli oris.
b. Branches immediately into a tuft of smaller branches radiating away
from the foramen.
c. Supplies the lower eyelid (including conjunctiva), cheek, nose, upper
lip, and labial gum.

17. 2. Zygomaticofacial Nerve:
a. Emerges from a foramen on the outer surface of the zygomatic bone.
b. Branches supply the overlying skin.
3. Zygomaticotemporal Nerve:
a. Emerges in the temporal fossa through a foramen in the temporal
(posterior) surface of the zygomatic bone.
b. Supplies a small area of temporal skin.
Note:
● The infraorbital nerve is derived from the maxillary nerve.
● The zygomaticofacial and zygomaticotemporal nerves emerge from specific
foramina on the zygomatic bone.
● The course and branching of veins in the neck are also described, including
the retromandibular vein, facial vein, internal jugular vein, and external
jugular vein, as well as their connections and drainage pathways.
Deep Venous Anastomoses:
What is a venous anastomosis?
Arterio-venous anastomoses (AVAs) are direct connections between small
arteries and small veins
1. Medial Angle of the Eyelids:
a. Communication between the angular vein and the ophthalmic veins.
b. Ophthalmic veins drain directly into the cavernous sinus.
c. Important for blood flow in case of facial vein thrombosis, as blood
from the forehead can flow through the orbit to reach the cavernous
sinus.

18. d. Significance in the "danger area" of infection in the upper lip and
nearby cheek.
2. Deep Facial Vein:
a. Passes backward from the facial vein, running between the masseter
and buccinator muscles.
b. Connects to the pterygoid plexus.
c. The pterygoid plexus communicates with the cavernous sinus through
emissary veins passing through the foramen ovale and the foramen
lacerum.
d. The "danger area" of the face is located between the angular and deep
facial veins.
3. Lymph Drainage of the Face:
4. Submental Nodes:
a. Drains a small triangular area, including the chin and tip of the tongue.
5. Submandibular Nodes:
a. Drains a wedge of tissue above the submental nodes, extending
laterally to the facial vessels.
b. Encompasses the central forehead, frontal sinuses, anterior half of
the nose and maxillary sinuses, upper lip, lower part of the face,
tongue, and the floor of the mouth.
6. Preauricular (Parotid) Nodes:
a. Drains the forehead, temple, orbital contents, and cheek.
7. Deep Cervical Nodes:
a. Ultimately receives lymph from all areas of the face.
Note:
● The lymphatic drainage system is organized into three superficial groups
corresponding to specific areas of the face, with eventual convergence into
the deep cervical nodes.