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Origins, insertions, innervation and functions of the platysma.
Hello again everyone! It’s Matt from Kenhub, and in this tutorial, we will be discussing the platysma muscle. The platysma is a paired, flat, superficial neck muscle. It is considered as part of the mimic musculature. The platysma extends from the facial skin slightly above the insertions of the lower jaw to about the height of the second rib. It proceeds upward along the front side of the neck crossing the collarbone and overlaps the sternocleidomastoid.
The platysma is a superficial cutaneous muscle and, unlike other muscles, it is directly connected to the skin. This muscle covers completely both front sides of the neck. Due to the direct insertion to the skin, it can change facial expression along with other facial muscles, playing an important role in human's social behavior. In elderly people when the skin increasingly loses its elasticity, both inner surfaces of the platysma form two longitudinal wrinkles on the neck.
The platysma belongs – as all other facial muscles – to the group of cross-striated musculature. In comparison to humans, the equivalent of the platysma in animals has a much more important function. For example, the platysma in horses helps them get rid of insects by contracting the skin muscles.
The platysma is highly innervated, similar to what we find on the tongue and eye muscles. The platysma receives its innervation from the facial nerve. Damage to the platysma may lead to dysfunction of the facial expression in terms of paralysis.