body weight. The lateral malleolus articulates with the ankle
and protrudes on the lateral side.
The foot is made up of the ankle, the instep, and the toes.
The ankle or
sus) is composed of seven
One of these bones, the
lus), can move
freely where it joins the tibia and F
bula, forming the ankle.
The other tarsal bones are firmly bound, supporting the
name the bones of the tarsus.
The largest of the tarsals, the
or heel bone, is below the talus where it projects backward to
form the base of the heel. The calcaneus helps support body
weight and provides an attachment, the
for muscles that move the foot.
The instep or
sus) consists of
F ve elongated
which articulate with the tar-
sus. They are numbered 1 to 5, beginning on the medial side
is a long, slender bone located on the lateral side
of the tibia. Its ends are slightly enlarged into a proximal
and a distal
(F g. 7.52)
The head artic-
ulates with the tibia just below the lateral condyle; however,
it does not enter into the knee joint and does not bear any
The skeleton is particularly vulnerable to injury during the turbu-
lent teen years, when bones grow rapidly. Athletic teens sometimes
develop Osgood-Schlatter disease, which is a painful swelling of
a bony projection of the tibia below the knee. Overusing the thigh
muscles to straighten the lower limb irritates the area, causing the
swelling. Usually a few months of rest and no athletic activity allows
the bone to heal on its own. Rarely, a cast must be used to immobilize
Right femur. (
) Anterior surface. (
) Posterior surface.
Bones of the right leg, anterior view.