Metacarpal Essay

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Summarization: Terrestriality was suggested to have been more common in the past than it is today, according to primate fossil records obtained from many museums around the country. This terrestriality is more prominent amongst cercopithecoid primates. Preference of habitually terrestrial substrates was based on primate forelimb anatomy. Extant large-bodied terrestrial cercopithecine monkeys favor digitigrade hand postures during locomotion. Being able to recognize if a fossil primate habitually adopted digitigrade postures would be most apparent in the terrestrial group. The functional morphologies of primate metacarpals …show more content…
Their scientific name is Cercopithecidae and they are in the clade, Catarrhini (Check 2004). Digitigrade means the metacarpals are oriented almost vertical relative to the ground and the metacarpal joints extend to the wrist in a neutral position. It is relatively rare to see digitigrade amongst the extant primates, because the majority of primates are arboreal. Palmigrade is when the metacarpals are oriented almost parallel with the ground and the metacarpal joints are in a neutral position with the wrist extended (Check 2004). Primates that are arboreal live in trees and those that are terrestrial live on the ground. Terrestrial primates have shorter “fingers” in comparison to the total hand length. This does not completely distinguish between habitually digitigrade and habitually palmigrade primates. Terrestriality can be determined by reconstructing the shoulder, elbow, and wrist joint morphologies, as well as hand proportions. The first recognizable old world monkeys are known as Victoriapithecids (Patel …show more content…
Of these adult individuals, 39 were cercopithecine and 20 were colobine, or old world, leaf-eating primates. An adult was defined as “individuals with a complete epiphyseal fusion of all forelimb long bones, including metacarpal heads” (Patel 2016). Museum records and canine size provided the distinction between male and female primates. Approximately 81% of the individuals were wild-shot and 19% came from captivity. Their linear measurements were obtained, as well as their status of “adulthood”. Linear measurements of the humerus and three middle metacarpals (second, third, and fourth) were used for this study. Humerus length is equal to the maximum length from the most proximal aspect of the humeral head to the distal-most aspects of capitulum (Patel 2016). Taxa classified as digitigrade have shorter metacarpals relative to body mass and humerus length (HL) when compared to palmigrade taxa. Humerus length was measured using a portable osteometric board (Patel 2016). This tool is a board with measurements on it to size the lengths of human or animal skeleton (Patel 2016). Digitigrade taxa also have smaller joint diameters joining dorsal and ventral surfaces relative to the product of body mass and metacarpal length. Metacarpal head size and shape do not differ significantly between digitigrade and palmigrade hand posture

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