Face

The Face

extends superiorly from the adolescent position of hairline, inferiorly to the chin and the base of the mandible, and on each side to the auricle.

The forehead is, therefore, common to both the face and the scalp.

SKIN

1 The facial skin is very vascular. Rich vascularity makes the face blush and blanch. Wounds of the face bleed profusely but heal rapidly. The results of plastic surgery on the face are excellent for the same reason.

2 The facial skin is rich in sebaceous and sweat glands. Sebaceous glands keep the face oily, but also cause acne in young adults. Sweat glands help in regulation of the body temperature. 

3 Laxity of the greater part of the skin facilitates rapid spread of oedema. Renal oedema appears first in the eyelids and face before spreading to other parts of the body.

4 Boils in the nose and ear are acutely painful due to fixity of the skin to the underlying cartilages.

5 Facial skin is very elastic and thick because the facial muscles are inserted into it. The wounds of the face, therefore, tend to gape.

SUPERFICIAL FASCIA

It contains:

(i) The facial muscles, all of which are inserted into the skin,

(ii) the vessels and nerves, to the muscles and to the skin, and

(iii) a variable amount of fat.

Fat is absent from the eyelids, but is well developed in the cheeks, forming the buccal pads that are very prominent in infants in whom they help in sucking.

(iv) The deep fascia is absent from the face, except over the parotid gland where it forms the parotid fascia, and over the buccinator where it forms buccopharyngeal fascia. 

FACIAL MUSCLES

The facial muscles, or the muscles of facial expression, are subcutaneous muscles. They bring about different facial expressions. These have small motor units.

Embryologically, they develop from the mesoderm of the second branchial arch, and are, therefore, supplied by the facial nerve.

Morphologically, they represent the best remnants of the panniculus carnosus, a continuous subcutaneous

muscle sheet seen in some animals. All of them are inserted into the skin.

Topographically, the muscles are grouped under the following six heads.

Functionally, most of these muscles may be regarded primarily as regulators of the three openings situated on the face, namely the palpebral fissures, the nostrils and the oral fissure. Each opening has a single sphincter, and a variable number of dilators. Sphincters are naturally circular and the dilators radial in their arrangement. These muscles are better developed around the eyes and mouth than around the nose 

Muscle of the Scalp

Occipitofrontalis

Muscles of the Auricle

Situated around the ear

1.  Auricularis anterior

2.  Auricularis superior

3 . Auricularis posterior

These are vestigeal muscles

Muscles of the Eyelids/Orbital Openings 

1. Orbicularis oculi

2.  Corrugator  supercilii

3.  Levator palpebrae superioris (an extraocular muscle, supplied by sympathetic fibres and the third cranial nerve) 

Muscles of the Nose

1. Procerus

2. Compressor naris.

3. Dilator naris

4. Depressor septi

Muscles around the Mouth

1. Orbicularis oris

2. Buccinator

3. Levator labii superioris alaeque nasi 

4. Zygomaticus major

5. Levator labii superioris

6. Levator anguli oris

7. Zygomaticus minor

8. Depressor anguli oris

9. Depressor labii inferioris

10.Mentalis (Latin chin)

11. Risorius (Latin laughter)

Muscles of the Neck

Platysma (Greek broad) 

A few of the common facial expressions and the muscles producing them are given below: 

1. Smiling and lauglting: Zygomaticus major

2. Sadness: Levator labii superioris and levator anguli oris.

3. Grief: Depressor anguli oris.

4. Anger: Dilator naris and depressor septi.

5. Frowning: Corrugator supercilii and procerus. 

6. Horror, terror and fright: Platysma

7. Surprise: Frontalis

8. Doubt: Mentalis

9. Grinning: Risorius

10. Contempt: Zygomaticus minor.

11. Closing the mouth: Orbicularis oris

12. Whistling: Buccinator, and orbicularis oris. 

Motor Nerve Supply

The facial nerve is the motor nerve of the face.

Its five terminal branches, temporal, zygomatic, buccal, marginal mandibular and cervical emerge from the parotid gland and diverge to supply the various facial muscles as follows.

Temporal- frontalis, auricular muscles, orbicularis oculi.

Zygomatic- orbicularis oculi.

Buccal- muscles of the cheek and upper lip 

Marginal mandibular- muscles of lower lip. 

Cervical- platysma. 

The facial nerve is examined by testing the following facial muscles.

a. Frontalis; Ask the patient to look upwards without moving his head, and look for the normal horizontal wrinkles on the forehead

b. Dilators of mouth: Showing the teeth.

c. Orbicularis oculi: Tight closure of the eyes.

d. Buccinator: Puffing the mouth and then blowing forcibly as in whistling.

Infranuclear lesion of the facial nerve, at the styiomastoid foramen is known as Bell's

palsy, upper and lower halves of the face on the same side get paralysed.

• The face becomes asymmetrical and is drawn up to the normal side.
• The affected side is motionless.
• Wrinkles disappear from the forehead.
• The eye cannot be closed.
• Any attempt to smile draws the mouth to the normal side.
• During mastication, food accumulates between the teeth and the cheek.
• Articulation of labials is impaired. 

In supranuclear lesions of the facial nerve; 

usually a part of hemiplegia, with injury of corticonuclear fibres only the lower part of the opposite side of face is paralysed.

The upper part with the frontalis and orbicularis oculi escapes due to its bilateral representation in the cerebral cortex 

The sensory distribution of the trigeminal nerve explain why headache is a uniformly common symptom in involvements of the nose (common cold, boils), the paranasal air sinuses (sinusitis),

infections and inflammations of teeth and gums, refractive errors of the eyes, and infection of the  meninges as in meningitis.

Trigeminal neuralgia may involve one or more of the three divisions of the trigeminal nerve. lt causes attacks of very severe burning and scalding pain along the distribution of the affected nerve.

Pain is relieved either: (a) By injecting 90% alcohol into the affected division of the trigeminal

ganglion, or (b) by sectioning the affected nerve, the main sensory root, or the spinal tract of the trigeminal nerve which is situated superficially in the medulla. The procedure is called medullary tractotomy. 

Arteries of Face

Features

The face is richly vascular. 

It is supplied by:

1. The facial artery,

2. The transverse facial artery, and 

3. Arteries that accompany the cutaneous nerves.

These are small branches of ophthalmic, maxillary and superficial temporal arteries. 

Facial Artery (Facial Part)

• The facial artery is the chief artery of the face.
• It is a branch of the external carotid artery given off in the carotid triangle just above the level of the tip of the greater cornua of the hyoid bone.
• In its cervical course, it passes through the submandibular region and finally
• enters the face.

Course

1.It enters the face by winding around the base of the mandible, and by piercing the deep cervical fascia, at the anteroinferior angle of the masseter muscle. It can be palpated here and is called 'anaesthetist's

artery'.

2. First it runs upwards and forwards to a point 1.25 cm lateral to the angle of the mouth. Then it ascends by the side of the nose up to the medial angle of the eye, where it terminates by supplying the lacrimal

sac; and by anastomosing with the dorsal nasal branch of the ophthalmic artery.

3. The facial artery is very tortuous. The tortuosity of the artery prevents its walls from being unduly stretched during movements of the mandible, the lips and the cheeks.

4. It lies between the superficial and deep muscles of the face. 

Branches

The anterior branches on the face are large and named.

They are:

1. lnferior labial, to the lower lip.

2. Superiorlabial, to the upper lip and the anteroinferior part of the nasal septum.

3. Lateral nasal, to the ala and dorsum of the nose. The posterior branches are small and unnamed. Anastomoses

1. The large anterior branches anastomose with similar branches of the opposite side and with the mental artery. In the lips, anastomoses are large, so that cut arteries spurt from both ends.

2. Small posterior branches anastomose with the transverse facial and infraorbital arteries.

3. At the medial angle of the eye, terminal branches of the facial artery anastomose with branches of the ophthalmic artery. This is, therefore, a site for anastomoses between the branches of the external and internal carotid arteries. 

Transverse Facial Artery

This small artery is a branch of the superficial temporal artery.

After emerging from the parotid gland, it runs forwards over the masseter between the parotid duct and the zygomatic arch, accompanied by the upper buccal branch of the facial nerve. It supplies the parotid gland and its duct, masseter and the overlying skin, and ends by anastomosing with neighbouring arteries 

Veins of the Face

1. The veins of the face accompany the arteries and drain into the common facial and retromandibular veins. They communicate with the cavernous sinus.

2. The veins on each side form a 'W-shaped' arrangement. Each corner of the'W' is prolonged upwards into the scalp and downwards into the neck.

3. The facial vein is the largest vein of the face with no valves. 

It begins as the angular vein at the medial angle of the eye. 

It is formed by the union of the supratrochlear and supraorbital veins. 

The angular vein continues as the facial vein, running downwards and backwards behind the facial artery, but with a straighter course. 

It crosses the anteroinferior angle of the masseter, pierces the deep fascia, crosses the submandibular gland, and joins the anterior division of the retromandibular vein below the angle of the mandible to form the common facial vein. 

The latter drains into the internal jugular vein.

4. Deep connections of the facial vein include:

a. A communication between the supraorbital and superior ophthalmic veins.

b. Another connection with the pterygoid plexus through the deep facial vein which passes backwards over the buccinator. 

Dangerous Area of Face

The facial vein communicates with the cavernous sinus through emissary veins.

Infections from the face can spread in a retrograde direction and cause thrombosis of the cavernous sinus.

This is specially likely to occur in the presence of infection in the upper lip and in the lower part of the nose. This area is, therefore, called the dangerous area of the face

The facial veins and its deep connecting veins are devoid of valves, making an uninterrupted passage of blood to cavernous sinus.

Squeezing the pustules or pimples in the area of the upper lip or side of nose or even the cheeks may cause infection which may be carried to the cavernous sinus leading to its thrombosis. 

Lymphatic Drainage of the Face

The face has three lymphatic territories:

1. Upper territory, including the greater part of the forehead, lateral halves of eyelids, conjunctiva, lateral part of the cheek and parotid area, drains into the preauricular / parotid nodes.

2 Middle territory, including a strip over the median

part of the forehead, external nose, upper lip, lateral part of the lower lip, medial halves of the eyelids, medial part of the cheek, and the greater part of lower jaw, drains into the submandibular nodes.

3 Lower territory, including the central part of the lower lip and the chin, drains into the submental nodes 

Watch lectures on YouTube:

The Face | The Muscles, Nerves, Arteries, Veins and Lymphatics.