Facial asymmetry

Genes play a big role in how our faces look. Most differences in face size and shape—such as the width and height of the nose and its prominence, lip fullness, and the distance between the eyes—are likely influenced by genetics. Genetic factors can also contribute to facial asymmetry, affecting how balanced or uneven our features appear.

Facial asymmetry can result from injuries that damage the bones, soft tissues, or muscles of the face, causing uneven features or lasting changes in appearance.

Facial asymmetry can happen when something goes wrong with the nerves in the face. These problems can start from birth (developmental disorders) or happen later in life. For example, Bell’s palsy, brain tumors, and stroke are conditions that can cause one side of your face to droop.

Myopathies are conditions that weaken muscles. When facial muscles are affected, it can lead to uneven expressions and an asymmetrical appearance. For example, facioscapulohumeral muscular dystrophy is a condition that can cause weakness in facial muscles. Temporomandibular joint (TMJ) disorders are a common musculoskeletal problem that can produce an uneven bite and asymmetrical facial expression.

Some congenital (present at birth) conditions and developmental disorders can lead to facial asymmetry, including:

• Cleft palate
• Hemifacial microsomia
• Skull base abnormalities
• Congenital muscular torticollis
• Unilateral coronal craniosynostosis
• Positional plagiocephaly

Dental issues like disease, tooth extractions, dentures, and orthodontic treatments can change the shape of the face and jaw. Some dental work may lead to noticeable asymmetry. For example, crooked or crowded teeth can shift the jaw’s position. Tooth extractions may alter how facial muscles look, and dentures or veneers can change facial contours. A misaligned bite can also impact jaw alignment.

Facial asymmetry typically increases as we age, especially in the bottom two-thirds of the face. This happens due to several changes in our facial skin, bones, and muscles:

• Sagging skin: Aging reduces skin elasticity, causing sagging that makes one side of the face look droopier.
• Losing plumpness: Fat beneath the skin diminishes, making unevenness more noticeable.
• Weaker bones: Thinning jawbones alter the face’s shape, reducing symmetry.
• Weaker muscles: Muscle weakness leads to drooping and a more uneven appearance.

Lifestyle choices like smoking, which can cause gum disease, weakens the bones supporting the teeth and may lead to a misaligned bite.

Everyday habits, like sleeping on one side or on your stomach, chewing mostly on one side, or resting your face on your hand, can lead to muscle imbalances and facial asymmetry. Poor posture can also affect the alignment of your neck and jaw, changing the balance of your facial features.