The Ankle and Foot 309Bursae
There are many bursae in the region of the ankle
and foot. Some of these bursae can become inflamed
and painful in dancers. For example, the bursa
located between the attachment of the Achilles
tendon onto the heel and the overlying skin (super-
ficial calcaneal bursa—figure 6.11) can easily become
irritated by ill-fitting ballet or street shoes, while the
deeper bursa is at greater risk for inflammation when
there is a prominent upper angle of the calcaneus
(Mercier, 1995). A heel lift, padding, use of a ballet
shoe that ends lower on the heel, or modification
of dance shoes to reduce pressure to the area can some-
times afford relief for the more superficial bursa.
Muscles
In addition to the many ligaments and joint cap-
sules of the ankle-foot complex, many muscles act
to provide stability as well as produce the complex
movements of the many joints in this region. Some
of these muscles play a vital role in shifting the body
weight to the desired position relative to the foot,
as well as absorbing the large forces associated with
impact during weight-bearing movements such as
walking, running, and jumping.
Description and Functions of Individual Muscles of the Ankle and Foot
There are 24 muscles of the ankle and foot. Twelve
of these muscles are located entirely within the foot
and are called intrinsic muscles (L. intrinsecus, on the
inside). The remaining 12 muscles have distal tendon
attachments on the foot but otherwise lie outside the
foot. Hence, these muscles are called extrinsic muscles
(L. extrinsecus, from without). The extrinsic muscles
of the foot can be grouped by location into anterior,
posterior, posteromedial, and lateral crural muscles.
Each of these groups has at least one shared action
at the ankle-foot, and each is located in the same
osseofascial compartment of the leg (figure 6.9).
All of these extrinsic muscles cross at least two
joints and so have actions at more than one joint.
However, for purposes of simplicity, the actions at
the ankle, subtalar, and midtarsal joints and other
relevant joints are not differentiated here. Instead,
dorsiflexion and plantar flexion are listed relative to
the ankle-foot, while, since the ankle cannot contrib-
ute to other movements, inversion and eversion are
listed only relative to the foot. Also, for purposes of
simplicity and in keeping with many anatomy texts, the
actions of foot abduction and adduction will not be
included on charts. However, in general, the muscles
with the action of foot inversion can also produce foot
adduction, while the muscles with the action of foot
eversion can also produce foot abduction. Many of
the names of the muscles of the ankle and foot reflect
the action that the given muscle performs, making it
easier to learn these muscles. (See Individual Muscles
of the Ankle and Foot, pp. 310-323.)FIGURE 6.10 Examples of retinaculum and tendon
sheaths (right foot, lateral view).FIGURE 6.11 Bursae of the heel (left foot, lateral view).