Masticatory muscle transposition in primates: effects on craniofacial growth.

The effects of early transposition of the masticatory muscles on the craniofacial growth and development of infant primates are documented with the aid of serial cephalometry, EMG's, and dry-skull preparations. The bilateral posterior transposition of the insertion of the masseter and temporalis muscles was followed by a significant superior and anterior rotation of the midfacial growth pattern as well as by marked skeletal morphological changes. The study documents the ability to change skeletal craniofacial growth patterns by altering muscle attachments.