The platysma muscle is a thin, subcutaneous, muscular sheet lying under the skin of the neck. It is a paired muscle that arises from the chest, on the level of the second rib. Then it runs upwards and medially. On reaching the border of the mandible, the medial fibers of the platysma intertwine with those of the contralateral muscle as they are inserted into the border of mandible. The lateral fibers, on the other hand, extend to the face, where they interlace with the parotid and masseteric fascia, reaching the angle of the mouth.
Action/function
The platysma muscle tenses the skin of the neck and upper chest, lowering the mandible. It also pulls the angle of the mouth laterally and downwards.
Innervation
This sheet of muscle of the neck is innervated by the cervical branch of the facial nerve, which is the seventh pair of cranial nerves.
Blood Supply
The platysma muscle is supplied by the superficial cervical, which is a branch of transverse cervical artery, and the facial artery, which originates from the external carotid artery.
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| Above, platysma, with other muscles of the neck and face |
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