Modiolus (face)

The modiolus is a complex, fibromuscular structure located at the angle of the mouth. It represents a crucial point of convergence and interlacing of numerous facial muscles. This chiasma of muscles contributes significantly to facial expression, particularly those expressions involving smiling, frowning, and puckering of the lips.

Anatomically, the modiolus is situated lateral and slightly superior to the corners of the mouth. It's not a bone or cartilage, but rather a dense knot of connective tissue that serves as an anchor point for muscles including, but not limited to, the orbicularis oris, zygomaticus major, buccinator, risorius, depressor anguli oris, levator anguli oris, and platysma. The specific muscular attachments can vary slightly between individuals.

The integrity and function of the modiolus are essential for proper oral competence and facial aesthetics. Weakness or damage to the modiolus can lead to drooping of the corner of the mouth, difficulties with speech articulation (particularly involving labial sounds), and challenges with tasks like whistling or holding liquids in the mouth. Trauma, stroke, or surgery affecting the facial nerve can compromise the function of muscles attached to the modiolus, leading to noticeable changes in facial expression and oral function.

Clinical examination often involves assessing the symmetry and strength of the modiolus muscles during various facial movements. Rehabilitation strategies, such as facial exercises, may be employed to improve muscle tone and coordination following injury or paralysis affecting the modiolus.