324 Dance Anatomy and Kinesiology
Alignment and Common Deviations of the Ankle and Foot
There are numerous alignment problems that can
involve the ankle and foot, including abnormal
positioning of the tibia, arches, rearfoot, and toes.
Some of these problems are described in terms of
the direction of the deviation of the bones; and
similar to the situation with the knee, valgus refers
to a lateral deviation of the distal segment while
varus reflects a medial deviation of the distal seg-
ment. As with some other regions of the body, a
thorough medical evaluation is necessary to distin-
guish between structural and functional alignment
problems. Furthermore, it is important to realize
that ankle and foot deviations are very common in
both dancers and the general population, and that
their significance for injury and the need for correc-
tion are highly controversial.Tibial Torsion
As discussed in the previous chapter, the tibia gen-
erally exhibits external rotation along its length,
termed external tibial torsion, such that in the aver-
age adult the ankle mortise faces about 15° laterally
with the tip of the medial malleoli slightly anterior
and superior relative to the lateral malleoli as seen
in figure 6.27. However, individual variation can be
great, with measures ranging from 4° of internal
tibial torsion to 56° of external tibial torsion being
reported (Smith, Weiss, and Lehmkuhl, 1996). Inter-
nal tibial torsion is associated with walking with the
feet turned inward relative to the knee (toeing-in),
while exaggerated external tibial torsion is associ-
ated with walking with the feet turned out relative
to the knees (toeing-out). Theoretically, an increase
in external tibial torsion might be advantageous
for maximizing turnout of the feet. However, one
study of professional ballet dancers did not show an
increase in average external tibial rotation above
that found in the general population (Hamilton et
al., 1992).Arches of the Feet
The bones of the feet are not arranged in a flat
structure, but rather involve a series of longitudinal
and transverse arches to form a structure similar
to an elastic half-dome as seen in figure 6.28A. You
can better visualize these arches by standing with
your feet side by side and noting that while thelateral margins of both feet stay in contact with
the ground, the inner soles of the feet form a shal-
low dome; the central portion forms an arch that
is generally not in contact with the ground. This
central concavity is due to the medial longitudinal
arch—consisting of the three medial metatarsals,
the cuneiforms, the navicular, and the calcaneus.
The medial longitudinal arch is the higher of the
longitudinal arches and is the arch that people are
generally referring to when talking about the foot.
It is designed to allow accommodation to uneven
surfaces, change in direction, and easy shift of the
body weight from one side of the foot to the other.
In contrast, the lateral longitudinal arch—consist-
ing of the two lateral metatarsals, the cuboid, and
the calcaneus—is designed for stability and weight
bearing and generally is in contact with the ground
during standing.
While the longitudinal arches are responsible for
the doming in a lengthwise direction, the transverse
arch is key for the doming in a medial-lateral direc-
tion. The transverse arch consists of the tarsal bones
in the midfoot (navicular, cuneiforms, and cuboid)
and the metatarsals. This transverse arch can be
further divided into the tarsal, posterior metatarsal,
and anterior metatarsal arches (Magee, 1997). The
height of the tarsal transverse arch, particularly influ-
enced by the cuneiforms, varies markedly between
individuals and is instrumental in creating the high
instep valued in classical ballet. The anterior meta-
tarsal arch is also very important for dancers, and a
loss of this arch is often evidenced by callus forma-
tion under the head of the second metatarsal and
by metatarsal pain.FIGURE 6.27 Tibial torsion (left foot, superior view).