A standard nomenclature for the axes and planes of vertebrate eyes

A standard nomenclature for the axes and planes of vertebrate eyes There is a general problem in naming the axes and planes of vertebrate eyes. The problem arises from the fact that both the position of the head relative to the body and the position of eyes relative to the head show great variability in vertebrates. Thus the standard vertebrate axes (dorso-ventral, antero-posterior, and left–right or medio-lateral) and orthogonal planes (saggital, coro-nal or frontal, and transverse, axial or cross sectional) cannot unambiguously be applied simultaneously to the lateral eyes of fishes with a horizontal body axis, the lateral eyes of chickens with a vertical body axis and those of a frontal eyed primate. One might think that such problems had been solved by the comparative anatomists; however this does not appear to be so. In the 5th edition of Nomina Anatomica Veterinaria (Anonymous, 2005) of the six planes and axes, only the transversalis plane is defined for a body part as ''.. .a plane perpendicular to the long axis of a body or part. " Because the longest axis of an eye may be either parallel or perpendicular to the plane of a pupil, even this single definition is not helpful. The situation is not much better in the special terminology of birds. In Nomina Anatomica Avium in the bird eye, of all its planes and axes only the axis bulbi is defined for the eye (Evans, 1979; Evans & Martin, 1993) as ''A line passing through the central point[s] of the cornea and the lens which thus passes from the anterior to the posterior pole of the bulbus oculi. " Perhaps because English, and not Latin, has become the lingua franca of science, most writers on the anatomy of the eye in the last hundred years have used English terms to define the planes and axes of the eye. For the human eye Oyster (1999) has defined the planes of the eye as the ''horizontal " , ''saggital " , and ''coronal " (where the vertical saggital plane divides the eye in more or less symmetrical halves), and the axes that are perpendicular to these planes, respectively as ''Superior-inferior " , ''Nasal-temporal " and ''Antero-posterior ". The famous comparative anatomists of the eye, Walls (1967), Polyak (1957) and Rochon-Duvigneaud (1943) have used ''horizon-tal section " or ''vertical section " , or their French equivalents, when describing an entire vertebrate …