Applying the muscles of the face

When carrying out a facial reconstruction, there is some variation in the order in which experts apply the muscles to the skull. Some experts include the large muscle of the forehead, the Occipito Frontalis, whereas some omit this muscle as it’s thin and they feel it does not contribute significantly to the overall contours of the face. Whichever approach is taken, the fundamental principle that deep muscles are applied first, with superficial muscles being applied latterly, remains constant. Usually the first group of muscles to be applied to the skull in a facial reconstruction are those that are involved in the movement of the jaw. These muscles lie directly on the skull with no other structures beneath them and so are applied first.

The thickness of each muscle is determined using tissue depth markers, which have previously been attached to the skull. These markers are placed at specific points on the skull and simulate the average tissue depth for that area. The first muscle in this group is the Temporalis. The Temporalis is a thick fan-shaped muscle that closes the mouth and assists the jaw to move side to side to grind up food. If you touch the side of your head above your ears while it’s clenching your teeth, you will easily feel the Temporalis muscle. The second muscle to be applied is the Buccinator.

The Buccinator is sometimes known as the ‘trumpeter muscle’ as its role is to puff out the cheeks and prevent food from passing to the outer surface of the teeth during chewing. This is followed by the final muscle involved in chewing, the Masseter. This runs from the cheek bone to the lower jaw and brings the teeth back together to grind up food. The Masseter is the strongest muscle in the human body. The remaining muscles located around the mouth are predominantly involved in facial expression. Contraction of the Mentalis muscle makes us pout, while Depressor Labii Inferioris pulls down the bottom lip allowing us to sulk.

The circular muscle around our mouth is Orbicularis Oris and this muscle brings our lips together so we can pucker up for a kiss! Levator Anguli Oris is the happy muscle making the corners of our mouth turn upwards into a smile. Whilst in contrast, Levator Labii Superioris is the muscle that deepens the furrows, either side of our nose, and top lip when we feel sad. This muscle works in conjunction with Depressor Anguli Oris which lowers the corners of your mouth into a frown. Levator Labii Superioris Alaeque Nasi dilates the nostrils and raises the upper lip. In animals, it’s associated with snarling, and in humans it’s often used when expressing discontentment.

It is sometimes referred to as the ‘Elvis muscle’ in tribute to Elvis Presley. There are two muscles associated with the cheekbones, Zygomatic Major and Zygomatic Minor. Both muscles are involved in elevating the upper lip to generate a smile, with the minor muscle allowing us to curl our top lip which usually demonstrates smugness. The muscle encircling the eyes is one of the latter ones to be applied during the facial reconstruction process. The Orbicularis Oculi is a distinctive muscle that is constructed of two parts, the palpebral and the orbital. The palpebral area lies at the centre of the sphincter muscle and forms the eyelids with the orbital region encasing it concentrically.

The Orbicularis Oculi muscle opens and closes the eyelids thus allowing us to blink, wink or squint in bright sunlight. The parotid gland is layered on top of one of the first muscles applied to the skull, the Masseter muscle. This salivary gland provides the anchor point for the final and most superficial muscle in the facial reconstruction, Risorus. Risorus is a very thin and delicate muscle that pulls the lips horizontally, creating a large if not insincere smile. The final stages in the reconstruction process are to apply facial fat to give the face the appropriate contours, followed by the application of a uniform flat layer of clay to form the skin.

Any information previously obtained from the skull, such as gender and ethnicity, is then used to influence how the remaining features of the face, such as the ears and hair, are constructed.