Resource Paper: Turnout for Dancers - Hip Anatomy and Factors Affecting Turnout

Introduction
Turnout describes the position of the legs, used in many forms of dancing, in which each leg is rotated in the opposite direction from the other and facing away from the midline of the body as observed from the front. "Ideal" turnout traditionally has been identified as 180 degrees of outward rotation (also called external rotation and lateral rotation) of both legs combined. An awareness of basic anatomy will help in the understanding of the limitations of this expectation.

The paper is divided into several sections: (1) Bones of the hip joint, (2) Structure of the hip joint: the ball and socket, (3) Capsule and ligaments of the hip joint, (4) Muscles of the hip that create turnout, (5) Factors affecting turnout, and (6) Individual anatomical variations. It is important to begin with an understanding of the bones, so that the perception of turnout is structurally clear. Dancers can safely execute the skills requiring external rotation only if they have a sound knowledge of optimal individual skeletal and soft tissue range of motion capabilities . It is from ideas or images of movement tasks that the dancer can achieve the most efficient dynamic movement, and not by trying to coordinate and control individual muscle activation, or to achieve some ideal of perfection that is anatomically unrealistic. For those readers unfamiliar with the movement terminology used in this paper, there is an appendix of terms at the end.

Bones of the Hip Joint
The pelvis is made up of two halves, the innominate bones, or hip bones. Each innominate bone is formed from the fusion of three bones: ilium, pubis, and ischium. Each of the three bones contributes to the hip socket or acetabulum, like a pie with three slices. Fusion of these three bones, forming one solid bone, does not occur until about the 16th year of life. The pubic bones connect in front by way of the symphysis pubis, a joint that connects these bones with a small disc made of cartilage (see Figures 1 and 2).

Figure 1: Pelvis, front view

Figure 2: Pelvis, side view

Between the two innominate bones is the foundation for the pelvis, the sacrum (see Figure 3). The sacrum is a triangular-shaped bone that comprises five fused bones at the lower end of the spinal column. Lower still is the coccyx, four fused bones, often referred to as the tailbone. Dense ligaments hold the pelvis to the sacrum at junctions known as the sacroiliac joints, which are slightly moveable. Note in Figure 3 how the sacrum has a deep forward angulation relative to the final or 5th lumbar vertebra. This angle is almost 30 degrees on average.

Figure 3: Lumbosacral joint

Figure 4: Femur (thigh bone)

The femur is more commonly known as the thigh bone (see Figure 4). Although all femurs share certain structural characteristics and landmarks, each person's anatomy is unique. The femur consists of the round head, the neck, the shaft and two condyles (lateral and medial) at the base of the femur. The femur is the longest bone in the body, and though it has movement in all three planes like the shoulder joint, it has much more limited range of motion.

This paper may be reproduced in its entirety for educational purposes, provided acknowledgement is given to the "International Association for Dance Medicine and Science."

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