Changes with Advance of Age of the Human Maxillomandibularis, Zygomaticomandibularis and Superficial Temporalis

Abstract

Investigations were made into changes of the maxillomandibularis, zygomaticomandibularis and superficial temporalis in human adults aged from the 30s to 100s, except for the 90s. Great changes with advance of age were found in the maxillomandibularis and superficial temporalis. The maxillomandibularis gradually came to have a tendon in the original part. In specimens of persons in their 40s, its terminal tendon elongated downwards to the attached portion of the second layer of the pars superficialis of the masseter, avoiding the terminal portion of the intermediate masseter and the tendon of the first layer of the deep masseter. The elongated tendon ceased elongation when it reached the tendon of the second layer of the superficial masseter approximately in specimens of persons in their 50s. The superficial temporalis in specimens from the 30s to 50s was sufficiently developed in its muscular substance and had a strong tendon above the zygomatic arch. However, in specimens of persons over 60 years of age, its muscular substance moved downwards and only a little could be seen slightly above the zygomatic arch or at the same level as the arch. The zygomaticomandibularis underwent fewer changes than the maxillomandibularis or superficial temporalis.