300 Dance Anatomy and Kinesiology
in front of the navicular and are called the first,
second, and third cuneiform going from medial to
lateral. These cuneiforms are each in line with the
three medial metatarsals, while the two lateral meta-
tarsals are in line with the cuboid. Each metatarsal
consists of a base (proximally), a body, and a head
(distally). While the bases of the metatarsals articulate
with the cuboid and cuneiforms, the heads articulate
with their respective phalanges. The heads of the
metatarsals can be easily palpated on the underside
of the foot (plantar surface) at the base of the toes
when the toes are repetitively flexed and extended.
The metatarsals and toes are numbered 1 through
5, from medial to lateral. There are three phalanges
in each of the toes except the great toe. These are
termed the proximal, middle, and distal phalanges
for toes 2 through 5 (the lesser toes). The first toe
is termed the hallux (L. hallux, great toe), and it
contains only two phalanges, the proximal and distal
phalanges. Located directly below the head of the
first metatarsal are two small sesamoid bones called
the medial and lateral sesamoid (figure 6.2A).
Due to the large number of bones in the foot and
the complexity of the joints, it is customary to refer
to segments of the foot rather than individual bones
for some descriptions of motion or mechanics. The
segments of the foot are the rearfoot, midfoot, and
forefoot (figure 6.2A). The rearfoot, or hindfoot, is
composed of the talus and calcaneus. The midfoot is
composed of the navicular, cuboid, and cuneiforms.
The forefoot is composed of the metatarsals and
phalanges.Joint Structure and Movements of the Ankle and Foot
There are 34 joints in the ankle-foot complex (Smith,
Weiss, and Lehmkuhl, 1996). The ankle, subtalar,
and transverse tarsal joints are particularly key
for desired functioning of this region, and their
movements are intimately linked. Other more
distal joints are important for subtle adjustments
of the foot and movements of the toes. A sum-
mary of the primary joints of the ankle and foot
is provided in table 6.1. Most of these joints are
named according to the bones that compose the
joints (e.g., tarsometatarsal), making learning the
names easier and logical. Many joint capsules and
approximately 100 ligaments provide stability for
these joints and provide constraints for movements
of the ankle-foot complex. For purposes of simplicity,
this text will cover only selected primary ligaments
of the rearfoot.Ankle Joint Classification and Movements
Because the “ankle joint” is formed between the
bones of the lower leg and the upper portion of the
talus, its technical name is the talocrural (L. crus, leg)
joint. The ankle joint is classified as a hinge joint and
is more specifically formed by the articulation of the
superior dome of the talus with the distal tibia and
fibula (figure 6.3). The tibia is the primary weight-
bearing bone of the lower leg, and it translates most
of the weight between the femur and the talus, while
the medial malleolus extends to provide medial sup-
port for the ankle. The fibula serves as a lateral strut,
providing additional stability by helping to form a
slot or mortise into which the talus can fit. The fibula
has also been estimated to transmit about 6% to 7%
of the load when the ankle is in a neutral position,
but up to one-sixth of the load of the leg when the
ankle-foot is in a position of dorsiflexion and ever-
sion (DiFiori, 1999; Sammarco, 1980).
The distal tibia and fibula form a fibrous joint
(distal tibiofibular joint), and the very strong interos-
seous membrane and adjacent ligaments (including
the anterior and posterior tibiofibular ligaments)
allow the tibia and fibula to function as a structural
unit like a mortise. This mortise fits over the convex
superior portion of the talus, gripping it tightly along
its flattened sides to provide much-needed stability
for this joint, while still allowing for small move-
ments of the fibula relative to the tibia—necessary to
accommodate the changes in contact area with the
talus accompanying ankle joint movement. A cast of
this mortise would closely replicate the shape of the
talus, making it the most congruent joint found in
the human body.
Due to this mortise architecture, with the medial
and lateral malleolus extending downward, only
small side-to-side movements and rotation are
permitted at this joint; and consistent with its clas-
sification as a hinge joint, the fundamental motions
allowed are flexion and extension. The specialized
terms of ankle dorsiflexion and plantar flexion are
used because there is lack of agreement as to which
movement would be considered flexion and which
extension: Functional and anatomical perspec-
tives would suggest opposite answers. So as seen
in figure 6.4, a neutral or anatomical position is
when the foot forms a 90° angle with the tibia, and
dorsiflexion refers to bringing the top of the foot
(dorsum) and the shin closer together such as in
“flexing the foot.” Conversely, plantar flexion refers
to the opposite motion of bringing the bottom or
sole of the foot (plantar surface) and the shin away
from each other such as in “pointing the foot.” The