Anatomy

Skin consists of three layers

• Epidermis
• Dermis
• Subcutaneous

The skin is the largest human organ of the human body and on average consists of 19,000 square cm’s of skin. The human skin is thinner on the eyelids and thicker on the feet.

The Skin has six main functions,

1. Sensation
2. Heat (regulates our temperature)
3. Absorption
4. Protection
5. Excretion
6. Storage

Sensation​– We have sensory nerve endings in the skin and these allow the body tobe able to feel things such as heat, cold, pain, pleasure and so on.

Heat​- Our skin helps the body in many ways and one of these is to regulate ourbodies temperature and it does this in various ways.

• If you are cold, it will tell you by ensuring the blood vessels which lay close to the surface of the skin contract in other words close. It does this to ensure the warm blood is kept closer to the inner organs so they maintain their temperature.

• If the body does need to retain heat it will do this by getting the arrector pili muscles to contract so the hairs raise which in turn allows the warm air to be trapped against the skin.

• Another way of keeping warm is with Adipose (fat) tissue in the epidermis and dermis which will insulate the body against heat loss as well.

• However, if the body needs to cool down then the body will ensure the blood vessels closest to the skin dilate to let the heat escape.

• Heat can also be released from the body via us sweating which also helps us to cool down.

Absorption​– The skin is also capable of absorption and it does this via theepidermis. The skin can absorb Oxygen, fat soluble vitamins, small amounts of water, carbon dioxide and ultraviolet radiation. It can also help convert various chemicals into vitamin D.

Protection​– The skin has what is known as the Acid Mantle this is an antibacterialfilm of sweat and sebum which helps the skin prevent the multiplication of bacteria and mica-organisms which accumulate on the skin’s surface.

You have the subcutaneous layer of our skin which contains our fat cells which help cushion and protect our bodies. Then there is the melanin which helps to protect the body from ultraviolet radiation. Melanin is produced in the basal cell layer.

Finally, we have overlapping cells in the stratum corneum (this is the outermost layer of our skin) and as we said earlier in this chapter helps to protect us from water loss and bacteria.

Elimination​– This is simply where the skin has what we call eccrine glands whichproduce sweat and this helps us to eliminate waste such as urea, uric acid, ammonia and lactic acid through us sweating.

Storage​– Finally, Fat and water are stored in the skin. The subcutaneous layerholds about 15% of our body’s fluid.

The facial muscles are subcutaneous (just under the skin) muscles that control facial expression. They generally originate from the surface of the skull bone and insert on the skin of the face. When they contract, the skin moves in a wave like motion which creates the wrinkles of the face. There are around twenty muscles in the face and we are going to discuss some of the below:

The Frontalis Muscles

The frontalis muscles are also known as the frontal belly of epicranius muscle, with assistance from the occipital belly, pulls the scalp back so that the eyebrows are lifted and the forehead can wrinkle. The epicranius muscle is a wide muscular fibrous layer that wraps around one entire side of the vertex of the skull, from the occipital bone to the eyebrow.

The frontalis muscle takes on a thin, quadrilateral form. This muscle is wider than the occipitalis and its fibres are lighter in colour and longer. There are no bony attachments. The medial fibres relate to those of the Procerus; the corrugator and the orbicularis oculi mix with its immediate fibres. Its lateral fibres also mix with the latter muscle over the zygomatic process of the frontal bone.

At these attachments, the fibres move up and join the galea aponeurotic beneath the coronal suture. The medial margins of the frontalis move together for a while above the root of the nose; however, between the occipitals there is a significant, though changing interval taken up by the galea aponeurotica.

The temporalis muscle

The temporal muscle, also known as the temporalis, is one of the muscles of mastication. It is a broad, fan-shaped muscle on each side of the head that fills the temporal fossa, superior to the zygomatic arch so it covers much of the temporal bone.

Treatment of the Glabella Area (frown)​​The glabella complex consists of seven individual muscles, Frown lines are vertical lines between and above your eyebrow that are the result from frowning and ageing skin. Like forehead lines, as we age these frown lines become more prominent.Treatment of frown lines can be beneficial to patients who are suffering the negative social effects of their frowning, or who

would simply like to reverse the effects of aging. Persistent or deep frown lines often may cause individuals to look angry, stressed, tired, intense or concerned. Elimination of frown lines leads to a more rested, approachable and fresh appearance.

The procerus muscle

​A muscle that arises in the skin over the nose and is connected to the forehead. It acts to draw the eyebrows down.

The ​procerus muscle ​is the pyramid-shaped muscle extending from the lower part of the nasal bone to the middle area in the forehead between the eyebrows.

The corrugator muscle

The corrugator supercilii is a small, narrow pyramidal muscle close to the eye. It is located at the medial end of the eyebrow, beneath the frontalis and just above orbicularis oculi muscle. … The name corrugator supercilii is Latin, meaning wrinkler of the eyebrows. The Corrugator muscle (see diagram)The expression of frowning is mainly caused by the corrugator muscles, but the brow is also depressed by the procerus, the depressor supercilii and by the orbicularis oculi. The entire complex must be understood to assess and treat the area correctly. The corrugators’ origin is deep and becomes superficial as it goes laterally and inserts into the skin. The insertion point is usually visible and is the most lateral point Botox should reach (keeping in mind 1 cm diffusion). This is your guide to the lateral injection point. The bulk of the corrugators and some supercilii fibres usually occur roughly above the inner canthus. Look for where contraction seems strongest. This is usually where the second injection point would go. Looking at the placement of those medial and lateral points, depending on the width of the individual corrugator’s muscle, there may or may not be room for a third injection point in-between.

The Orbicularis Oculi muscles​

The orbicularis oculi muscle is a ring-like band of muscle, called a sphincter muscle, that surrounds the eye. It lies in the tissue of the eyelid and causes the eye to close or blink. At the same time, it compresses the nearby tear gland, or lacrimal gland, aiding the flow of tears over the surface of the eye. Contraction of the muscle also causes the appearance of folds or crow’s feet that radiate out from the outer corner of the eye. Orbicularis oculi (around the eye area)

The orbicularis oculi surrounds the eye and causes lines, holds down the brow, Narrows the eye and helps lift the cheek during a smile. A fabulous result can be gained by relaxing it in a targeted manner using botulinum toxin. (Botox) The orbicularis oculi are, as the name suggests, a circular muscle surrounding the eye. Its bony origin is near the inner canthus via the medial palpebral ligament (MPL) and it has many very superficial insertions all around the dermis surrounding the eye. It is divided into pretarsal, perceptual and orbital sections. Lateral fibres of the orbital section are the primary focus in aesthetics, but the whole complex must be understood to be a competent safe and thoughtful clinician.

Arteries – Nerves – Veins

Below is a picture of where the arteries and veins run in the face which is vital to your understanding of injectables if you are going to practice injectables safely.

It is important that you understand the importance of where you’re injecting in the face and how dangerous this can be.