Final answer:
The term used for muscles that move the leg away from the body is 'abductors.' Adductors bring the leg towards the body. The erector spinae group is essential for supporting the vertebral column and maintaining upright posture.
Step-by-step explanation:
The organization of back muscles - extrinsic includes various types of muscle actions. Among these, muscles that move the leg away from the body are known as abductors. In contrast, muscles that perform the opposite action, bringing the leg toward the body, are called adductors. The extrinsic back muscles are typically involved in movements of the shoulder girdle and are essential in controlling arm movements relative to the body's main axis.
In addition to these, the back is supported by the intrinsic muscles, which also help move the vertebral column. The erector spinae group is a key intrinsic muscle group that contributes to the extension, lateral flexion, and rotation of the vertebral column. It consists of the iliocostalis, longissimus, and spinalis groups. These muscles together maintain the lumbar curve and are paramount in supporting upright posture.