Anatomy and Physiology of the lip

To give the best treatment outcome for your client, you should first have a thorough understanding of the lip anatomy and what makes them appear youthful. The lips are defined by the vermillion border, the juncture where the lips meet the surrounding skin. The portion of the upper lip border that forms the double curve is called the cupid’s bow, named after the ancient Roman god of love. The peaks of this bow are called the glogau-Klein points, which coincide with the philtral columns, the raised vertical ridges connecting the bottom of the nose meeting at the upper lip. The fleshy protuberance located at the centre of the upper lip is called the labial tubercle, and the corners of the mouth are called the oral commissures. In youthful lips, the ideal ratio of the vertical height of the upper lip to that of the lower lip is 1:618; this is referred to as the golden ratio.

The golden ratio was a mathematical equation devised by the Greeks in an attempt to measure beauty. While this ratio can be applied to anything, it was used by Leonardo Da Vinci for the perfect human body, and it can also be applied to the human face.

The golden lip ratio us for the lower lip to be 1.618 times the height of the upper lip.

One aspect that should be taken into account prior to treatment is the proportion of the upper lip to the lower lip. A narrow upper lip is associated with an aggressive facial expression, and the demand for balancing the lips will need to be taken into consideration during the procedure.

Lips are a combination or oral membranes and facial skin.

The skin and oral mucosa of the lips show a demarcation by the vermilion border. The inner mucosa is wet and non-keratinised and the outer mucosa is dry and keratinised.

Lips are:

• Very Vascular
• Dry
• Prone to Cold Sores and Cancer
• Sensitive to dryness
• Have numerous nerve endings
• Have little sun protection
• Have no saliva glands
• Have no sebaceous glands
• Sensitive to pain

The colouring in the lips is due to blood showing through from the underlying capillaries and melanocytes.

Lip colour can fade by up to 70% after micro-pigmentation and this needs to be taken into account when choosing your colours.

Chronological lip ageing 

• Upper lip loses volume, lengthens and inverts.
• Lower lip starts to become thinner and roll inwards.
• The intercommissural width becomes smaller.
• Commissures drop.
• Decreased display of the maxillary anterior teeth.
• Exposure of mandibular anterior teeth increases.
• Philtrum columns flatten and ‘splay’ as they approach the upper vermillion border.
• Vermillion border becomes thinner.
• Partial loss of cupids bow.
• Perioral rhytids, nasolabial folds and labiomental folds become more noticeable.
• Curves of the lips are lost.
• Lips become drier.