The Pelvic Girdle and Hip Joint 169fingertips on your buttocks and alternately internally
and externally rotate the hip while maintaining the
arabesque. Note the decrease in contraction of the
gluteus maximus as the leg internally rotates and the
increase as the leg is externally rotated.
Deep Outward Rotators
The deep outward rotators (DOR), or deep external
rotator muscle group, is comprised of the piriformis,
obturator internus, obturator externus (externus, out-
side), gemellus inferior, gemellus superior, and quadra-
tus femoris, as seen in figure 4.9, A and B. This group
of six small muscles is located deep to the gluteus
maximus in the region of the buttocks. The fibers of
this muscle group run primarily horizontally, spanning
from the inside and outside of the pelvis to the greater
trochanter of the femur. The piriformis (L. pirum, pear),
the most superior of the group, is located slightly above
the hip joint, and the quadratus femoris (L. quadratus,
square), the most inferior, is located slightly below it.
The obturator internus and gemelli are located in the
gap between the piriformis and quadratus femoris. As
their names suggest, the obturator internus (internus,
inside) has extensive attachments to the internal sur-
face of the membrane covering the obturator foramen
and adjacent areas, while the obturator externus has
extensive attachments to the external surface of the
obturator membrane and adjacent bones. The obtura-
tor internus is accompanied above by the gemellus
superior (L. geminus, twin, double + superior, above) and
below by the gemellus inferior (L. geminus, twin, double
- inferior, below) to attach via a common, approximately
horizontal, tendon to the greater trochanter; and hence
these three muscles are sometimes referred to as a
three-headed muscle—the triceps coxae (Moore and
Dalley, 1999). The deep outward rotators function
as a group to help hold the head of the femur in the
acetabulum and can help prevent upward jamming of
the femur with hip abduction, making its function very
parallel to the rotator cuff’s function at the shoulder
joint, discussed in chapter 7. However, as their name
implies, this group of muscles is particularly known
for its action of hip external rotation. The ability of the group to produce hip external rotation without
other major accessory motions makes them key in dance for the production and maintenance of turn-
out. When the hip is flexed to 90°, some of these muscles are in an effective position to produce hip
horizontal abduction, making them important in movements such as a passé and rond de jambe in the
air (en l’air) at 90°. Some texts also suggest that the piriformis can assist with hip abduction.
Palpation: Standing on one leg, raise the other leg to the front to a parallel passé (retiré) position.
The uppermost of the deep external rotators, the piriformis, can be felt contracting (under the gluteus
maximus) several inches above and posterior to the greater trochanter as the leg is brought to the side
to a turned-out passé. Then, change positions to standing in parallel first, rock back on the heels, and
externally rotate both legs at the hip to achieve a turned-out first position. The lowest of the DOR, the
quadratus femoris, can be palpated deeply at the base of the buttocks between the ischial tuberosity
and greater trochanter while rotating the legs. The remaining DOR are located between the piriformis and
quadratus femoris and can be palpated as a group by placing the fingertips below the piriformis and
repetitively externally rotating the hip.
FIGURE 4.9 The deep outward rotators (right hip,
posterolateral view). (A) With gluteus maximus removed;
(B) deeper view with quadratus femoris, gemellus
superior, and gemellus inferior removed.