In Depth
- Author
- Rhys Evans PH
- Address
- Head and Neck Unit, Royal Marsden Hospital, London.
- Title
- The paranasal sinuses and other enigmas: an aquatic evolutionary
theory.
- Source
- Journal of Laryngology & Otology 1992 Mar;106(3):214-25
- Abstract
- The functional role of the paranasal sinuses in man has long
been in dispute and as yet no satisfactory explanation has been
offered for these 'unwanted' spaces. An answer may be found by
study of the comparative evolutionary development of the sinuses
in man and other higher primates. Several unique physical
characteristics of man not seen elsewhere in the ape family, or
indeed in other terrestrial mammals, including some relating to
the upper aerodigestive tract, are not satisfactorily explained
by the traditionally held theory of evolutionary development of
early man directly from the arboreal ape. It is argued that these
developmental differences are much more logically explained by a
period of aquatic adaptation at a crucial period in the
evolution of pre-hominid man. A new theory is proposed which
might explain the importance of the sinus air cavities as
buoyancy aids for protection of the upper airway tract in such
an aquatic environment. Further evidence is offered relating to
a pathological condition of the external ear canal which
supports this theory that man at some stage in his early
development acquired an affinity for an aquatic environment.
Explanation of these unique hominid characteristics in terms of
an aquatic evolutionary theory may help to resolve some of the
enigmatic inconsistencies between man and other higher primates,
and may account for man's eventual emergence as the dominant
extant species, and perhaps an explanation for the 'missing
link'.
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