Final answer:
The sacral index is a calculation used in anthropology and physical anthropology to help determine the relative degree of curvature in the sacrum bone. By measuring the sacral index, anthropologists can gain insights into the locomotion, posture, and biomechanics of different human populations.
Step-by-step explanation:
The sacral index is a calculation used in anthropology and physical anthropology to help determine the relative degree of curvature in the sacrum bone. The sacrum is a triangular bone at the base of the spine that connects to the hip bones. The sacral index is calculated by dividing the maximum width of the sacrum by the maximum length and multiplying by 100.
By measuring the sacral index, anthropologists can gain insights into the locomotion, posture, and biomechanics of different human populations. For example, an index below 60 is considered a low sacral index, which indicates a straighter sacrum and upright posture. A higher index, above 70, typically indicates a curved sacrum and a more efficient upright posture for walking and running.