Femur As the femur is the only bone in the thigh, it serves as an attachment point for all the muscles that exert their force over the hip and knee joints. Some biarticular muscles – which cross two joints, like the gastrocnemius and plantaris muscles – also originate from the femur. In all, 23 individual muscles either originate from or insert onto the femur. In cross-section, the thigh is divided up into three separate fascial compartments divided by fascia, each containing muscles. These compartments use the femur as an axis, and are separated by tough connective tissue membranes (or septa). Each
Vertical clinging and leaping phalangeal index, low intermembral index, femurs with cylindrical head and high, narrow patellar grooves, and fused fibula and tibia. The high phalangeal index is the elongation of the phalangeal finger bones, which helps vertical clingers who require increased prehensile power in their hands to support their large bulk. The low intermebral index is the total length of the humerus and radius in percentage of total length of the femur and tibia. The features of the femur is part of an evolution of elongated femurs that helps the primates' extreme range of flexion and extension, which allows them to perform their