Elbow taken as six handbreadths; three to the elbow and three from the elbow to the shoulder. Another measure was the "cubit" (from "cubital"). This was taken to be the length of a man's arm from the elbow to the end of the middle finger. Though the elbow is similarly adapted for stability through a wide range of pronation-supination and flexion-extension in all apes, there are some minor differences. In arboreal apes such as orangutans, the large forearm muscles originating on the epicondyles of the humerus generate significant transverse forces on the elbow joint. The structure to resist these forces is
Bird measurement that the bill point to the tail tip can be measured. This can however vary with the handling and can depend on the age and state of shrinkage in the case of measurements taken from preserved skins in bird collections. The wing length usually defined as the distance between the bend of the wing and the longest primary can also vary widely in some large birds which have a curved wing surface as well as curved primaries. The measurement can additionally vary depending on whether a flexible tape measure is used over the curve or if measured with a rigid