326 Dance Anatomy and Kinesiology
problems (Conti and Wong, 2001; Hamilton, 1982;
McCrory et al., 1999; Yakut et al., 1997).Rearfoot Valgus and Varus
Another important consideration for foot align-
ment is the position of the calcaneus. Because the
calcaneus is part of the medial longitudinal arch,
the subtalar joint, and one of the transverse tarsal
joints, its position will influence the position of the
rearfoot, midfoot, and forefoot.
Rearfoot position can be estimated by the inter-
section at the subtalar joint of a line running down
the back of the lower third of the tibia and a line
bisecting the back of the calcaneus as seen in figure
6.30 (Kreighbaum and Barthels, 1996). A line that
bisects the calcaneus would ideally be approximately
perpendicular to the floor during standing and when
the dancer is viewed from behind (Kreighbaum and
Barthels, 1996). This would be considered a neutral
position of the rearfoot (figure 6.30A). If the line that
bisects the calcaneus deviates outward distally more
than 2° (Levangie and Norkin, 2001), creating an
everted foot, this condition is termed rearfoot valgus
(L. turned outward) (figure 6.30B). This condition
is commonly associated with excessive pronation
during gait and requires midtarsal inversion to bring
the lateral toes down to the ground in the same plane
with the hallux during standing. A dancer with rear-
foot valgus will find it easy to “roll in,” or place too
much of the body weight on the inside of the foot
and tend to lift the outside toes off the floor.
If the line that bisects the calcaneus deviates
inward versus outward distally, this malalignmentthe general population (Omey and Micheli, 1999)
and is common in dancers.
Individuals with flatfeet have been shown to have
more firing of muscles during standing, probably to
try to prevent further flattening of the arches and
offer stability to the intertarsal joints. There is some
evidence that pes planus and its associated exces-
sive pronation increase the risk for certain types of
injuries such as shin splints, plantar fasciitis, and
metatarsal stress fractures. However, the general
proposed association of flexible pes planus with
increased injury risk is controversial and complex,
perhaps because the additional undesired stress to
the structures working to support the medial arch
may at least in part be counterbalanced by the ben-
eficial shock absorbency offered by this foot type.Pes Cavus (High-Arched Foot)
The condition opposite to pes planus is pes cavus.
Pes cavus (L. pes, foot + cavus, hollow) involves an
abnormally high arch (figure 6.28C), and a footprint
would show less area of contact than for a normal
foot or flatfoot (figure 6.29, A and C). How much
of pes cavus is congenital and how much it can
be developed is controversial, but in the author’s
experience, dancers can increase their arch to some
degree with supplemental conditioning and dance
training. Although the aesthetic of this cavus foot
type is valued in most forms of dance, this foot type
is generally a more rigid foot type, allowing limited
pronation for shock absorbency. Hence, it may
increase the risk for certain types of injuries such
as stress fractures, tarsal sprains from going over
the foot on pointe, plantar fasciitis, and metatarsalFIGURE 6.29 Footprint associated with (A) normal foot, (B) pes planus, (C) pes cavus.