B E N J A M I N K E L L E Y

Transcription

1 B E N J A M I N K E L L E Y The foramen magnum is a threshold, a three- dimensional aperture that resides at the base of the skull, a protected anatomical position. The foramen magnum is a hole, a passageway from the postcranial to the cranial. A gateway from the physical to metaphysical chambers. A void. To observe its geometry, to ascertain its physical dimension is an attempt to further define the human form, mechanically, anatomically. 1

2 Foramen Magnum (for the measure of) Pelican 1200 case, rubber, gigli saw, inside calipers, scalpel, clipboard 4.87 x x 9.68 (closed) 2013 edition of three A collection of instruments selected for the specific task of measuring the Foramen Magnum. fo- ra- men mag- num: noun Definition: the opening in the skull through which the spinal cord passes to become the medulla oblongata. Origin: New Latin, literally Large opening First known use: 1857 (Merriam Webster Dictionary) The instruments are housed within a waterproof, crush proof, pressure regulated case, the Pelican Instruments: Gigli Saw a wire bone saw, compact and versatile. Inside Calipers to gauge dimensions. Scalpel - #3 scalpel with removable #11 blade. Clipboard Data recording 2

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4 Method of Measurement: Maximum length of the foramen magnum (LFM) measured in an anteroposterior direction along the principal axis of the foramen. Maximum width of the foramen magnum (WFM) measured approximately perpendicular to the LFM and recorded at the widest transverse diameter of the foramen. Circumference of the foramen Magnum (FMC) measured by pressing a narrow strip of calibrated paper along the inner margin of the foramen magnum. The paper strip is then unrolled and measured with calipers. Formulae: The LFM, WFM and FMC can be inserted into on the three formulae to estimate the area of the foramen magnum. The first method is a formula pub;ished by Routal et al., which is based on the height (h) and width (W) of the foramen magnum. Area = ¼ x PI x W x h The second method is a formula derived by Teixeira, which also uses width height of the foramen magnum. Area = PI x ((h=w)/4)2 Ventral view of human skull. Photograph by Benjamin Kelley. The third method is a formula published by Gapert, Black, and Last and uses the circumference (C) to estimate the radius (r) of the foramen magnum, assuming it to be circular. This radius is then applies to the formula for the area of the circle. C = 2 x PI x r Area = PI x r2 (Black, Gapert, Last. P1-9). Cranial base demonstrating the foramen magnum measurements: dashed line FMC, vertical arrow LFM and horizontal arrow WFM (Black, Gapert, Last. P1-9). 4

5 Works Cited: Black, Sue. Gapert, Rene. Last, Jason. Sex determination from the foramen magnum: discriminant function analysis in an eighteenth and nineteenth century British sample. Int J Legal Med. : n. pag. Web. Foramen Magnum. Def. 1. Merriam Webster Online, Merriam Webster, n.d. Web. 12 Nov Works Consulted: Matthews, Washington. On Measuring the Cubic Capacity of Skulls. National Academy of Sciences. Thirteenth Memoir. Volume III. Part 2. Washington Government Printing Office (1886): Print. Howells, W.W. Cranial Variation in Man: A Study By Multivariate Analysis of Patterns of Difference Among Recent Human Populations. Papers of the Peabody Museum of Archeology and Ethnology, Harvard University, V. 67. Cambridge : Harvard University Press, Print. Consultants: Eric W. Boyle, Ph.D. Archivist Laura E. Cutter Archivist (Contractor, American Registry of Pathology) David R. Hunt, Ph.D., D- ABFA Physical/Forensic Anthropologist Smithsonian Institution National Museum of Natural History Washington D.C. Brian F. Spatola Collections Manager, Anatomical Division 5