“The Face” extends from the rots of hair

 

FACE

“The Face” extends from the rots of hair above to the chin below and from one auricle to the other auricle at the sides. The forehead stands therefore common to the face and scalp; but for the sake of convenience the incisions are made in the dissection of face excluding the forehead.

N.B. Before staring the dissection, see that the lips, cheeks and eyelids and distended by placing cotton wool inside the vestibule of month and the conjunctival sacs and the margins of the lips & eyelids are stitched up. 

  

Skin Incisions

1.       A longitudinal incision in the median plan from the root of the nose to the symphysis menti.

2.       A slight curved incision from the root of the nose to the upper & front part of the auricle passing along superciliary arch.

3.       An oblique incision from the symphysis menti along the lower border of the body of the mandible to its angle.

4.       One semicircular incision along the muco-cutaneous junction of the upper and lower lips.

5.       One circular incision along the margin of the upper and lower eyelids.

Skin

To be retlected as a single flap laterally over the auricle. It is not uniform all over the face; thin & lax over the eyelids but fairly thick elsewhere. On the tip and the alae of the nose the skin is fused with the underlying cartilage in such a way that some portion of the cartilage is inevitable taken away with the skin.

After removal of the skin fibres of the Superficial Muscles of the face will come into view but as most of them are inserted into the skin, their surfaces become somewhat lacerated in appearance.

Skin of the Face is very vascular, so wounds bleed freely but heal quickly.

                        

 

Superficial Fascia

Very than and is generally taken away with the skin. Carefully clean the sub-cutaneous fat and areolar tissue without injury to the vessels & nerves.

Then note the position of the Facial muscles and define their outlines as clearly as possible. Preserve some portion of the Buccal pad of fat  at about the middle of the cheek.

Deep Fascia

There is no deep fascia in the face except posteriorly over the parotid gland and the Masseter where it is known as the Parotido Masseteric Fascia. It is derived from the deep fascia of the neck and after ensheathing the parotid gland, is attached above to the zygomatic arch. It has to be reflected backwards avoiding injury to the vessels & nerves. Facial expression has become easy due to the absence of deep fascia in the face.

Vessels & Nerves of the Face

A)      Nerves of the face: 13 in number on each side, of which only one is motor and twelve are sensory. Motor Nerve of the face is the facial nerve and the Sensory Nerves are all derived from the trigeminal nerve except one which is derived from the cervical plexus.

          a)       Sensory Nerves: Are the following :

                   Derived from the ophthalmic division of the trigeminal nerve.

                   1.       Supra orbital.

                   2.       Supra trochlear.

                   3.       Infra trochlear.

                   4.       Lacrimal.

                   5.       External nasal.

                   Derived from the maxillary division of the trigeminal nerve.

6.                 Zygomatico facial.

7.       Zygomatic temporal.        

                   8.       Infra orbital.

                   Derived from the mandibular divison of the trigeminal nerve.

                   9.       Buccal.

                   10.     Mental.

                   11.     Auriculo temporal

                   Derived from the cervical plexus.

b)       Motor Nerve: It the Facial nerve with its following terminal branches:

                   1)       Temporal.    

                   2)       Zygomatic.

                   3)       Buccal.

                   4)       Mandibular.

                   5)       Cervical.

B)       Arteries of the face

          1)       Facial artery with its branches.

          2)       Transverse facial artery, a branch of the superficial temporal artery.

          3)       Smaller arteries that usually accompany the cutaneous branches of the trigeminal nerve having identical names such as supra-orbital, infra orbital, mental etc, being derived from the external carotid and ophthalmic arteries.

          They freely anastomose with one another, so that a network of arteries is formed in the face.

C)                Veins of the face

They form a plexus in the superficial fascia & muscles of the face and are drained by the veins which accompany the arteries. Facial vein is important of these veins. It has no valves.

DISSECTION NOTE: In dissecting the vessels and nerves of the face, firs of all the nerves (motor then sensory) have to be traced, then followed by the arteries & veins. Clean the outer surface and the anterior border of the parotid gland, that trace The branches of the facial nerve which emerge from its deep surface in a radiating manner to the muscles of their supply. Cervical branch of the facial nerve goes downwards behind the angle of the mandible to the neck to supply the Platysma.

     Then trace all the twelve sensory nerves with great care as they are very delicate: of them the following Nerves are more or less stronger and must be detected at their respective sites: (a) Supraorbital, (b) Infra orbital, (c) Zyomatico temporal, (d) Zygomatico facial, (e) Mental, (f) Auriculo temporal.

   In the dissection of the face, only small proximal parts of the supratrochlear, Surpaorbital, Zygomatyico temporal and Auriculotemporal nerves are exposed but their terminal parts are distributed to the Scalp & Temporal region, where those four sensory nerves have been described.

 

Other Eight Sensory Nerves are distributed as follows:

1)     Infra trochlear nerve :  Is a branch of the nasociliary, which is a branch of the ophthalmic division of Trigeminal nerve. It comes out of the orbit above the medial angle of the eye and supplies the skin and conjunctiva of the medial part of the eyelids. skin of the root of the nose, lacrimal sac and caruncul lacrimalis.

2)     External nasal nerve: Is the continuation of the Anterior ethmoidal nerve, which is continued behind with the nasociliary. It emerges out of the nasal cavity between the lower border of the nasal bone and the upper nasal cartilage and supplies the skin of the lip & vestibule of the nose.

3)     Lacrimal nerve: Is the smallest branch of the ophthalmic division of Trigeminal nerve. It enters the orbit through the superior orbital fissure and supplies the larcimal gland and conjunctiva, then piercing the orbital septum it ends by supplying the skin of the upper eyelid. Sometimes this nerve may be absent.

4)     Zygomatico facial nerve: Is a branch of the zygomatic branch of the maxillary nerve. It comes out of the zygomatico facial foramen of the zygomatic bone and supplies the skin over the prominence of the cheek (malar prominence).

5)     Infra orbital nerve:  Is the continuation of the maxillary nerve. It traverses the infra orbital groove, then infra orbital canal and appears in the face through the infra orbital foramen under cover of the Levator labii superiors and ends by dividing into three sets of branches:

a)Palperbral branches: Supply the skin and conjunctiva of the lower eyelid

b) Nasal branches: Supply the skin of the side of the nose.

c) Supply the skin and mucous membrane of the cheek and upper lip.

These branches communicate with the zygomatic and upper deep buccal branches of the facial nerve. forming a network, called the infra orbital plexus.

6)     Buccal nerve : Is a branch of the anterior trunk of the mandibular nerve. It passes between the two heads of the lateral pterygoid muscle and appears in the face from under cover under cover of the masseter to the outer surface of the Buccinators where it supplies the skin and mucous membrane for the cheek.

7)     Mental nerve: Is one of the terminal branches of the inferior dental nerve. It appears in the face through the mental foreman

8)      and under cover of the Depressor anguli oris divides into branches which supply the skin & mucous membrane of the lower lip and the skin over the body of the mandible.

9)     Anterior branch of the great auricular nerve: It supplies the skin of the face over the parotid gland. The great auricular nerve is formed by the anterior primary rami of the 2nd and 3rd cervical spinal nerves.