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Summary
Facial muscle evolution in the elderly shows reduced platysma myoides and persistent ear muscles, mirroring primate development. These findings reveal age-related anatomical changes in facial musculature.
Area of Science:
- Anatomy
- Evolutionary Biology
- Gerontology
Context:
- Aging leads to significant anatomical changes, particularly in facial musculature.
- Previous studies noted evolutionary trends in primate facial muscles.
Purpose:
- To investigate the evolutionary mode of facial musculature in the elderly.
- To confirm and elaborate on earlier findings in primate facial muscle evolution.
Summary:
- Dissection of facial muscles in two elderly individuals confirmed evolutionary patterns seen in primates.
- Observed reduction in the platysma myoides (facial muscle) into pars buccalis and pars mentalis.
- Emergence of the chin muscle (m. quadratus) from the platysma myoides' pars mentalis.
- Deep facial muscle arrangements resemble those in Simians, with enhanced verticilization of the canine muscle and separation of zygomatic muscles.
- Extrinsic ear musculature remained well-developed despite lack of function.
Impact:
- Provides insights into age-related anatomical transformations of the human face.
- Contributes to understanding the evolutionary trajectory of facial muscles.
- Highlights the persistence of certain muscle structures even with functional loss in aging individuals.