235
CHAPTER SEVEN
Skeletal System
Tibia
The
tibia,
or shin bone, is the larger of the two leg bones
and is located on the medial side. Its proximal end is
expanded into
medial
and
lateral condyles,
which have con-
cave surfaces and articulate with the condyles of the femur
(f
g. 7.52)
. Below the condyles, on the anterior surface, is
a process called the
tibial tuberosity,
which provides an
attachment for the
patellar ligament
(a continuation of the
patella-bearing tendon). A prominent
anterior crest
extends
downward from the tuberosity and attaches connective tis-
sues in the leg.
At its distal end, the tibia expands to form a prominence
on the inner ankle called the
medial malleolus
(mah-le
o-lus),
an attachment for ligaments. On its lateral side is a depres-
sion that articulates with the F bula. The inferior surface of
the tibia’s distal end articulates with a large bone (the talus)
in the ankle.
Patella
The
patella,
or kneecap, is a fl
at sesamoid bone located in
a tendon that passes anteriorly over the knee (see F
g. 7.50).
The patella, because of its position, controls the angle at
which this tendon continues toward the tibia, so it functions
in lever actions associated with lower limb movements.
As a result of a blow to the knee or a forceful unnatural movement of
the leg, the patella sometimes slips to one side. This painful condition
is called a
patellar dislocation.
Doing exercises that strengthen muscles
associated with the knee and wearing protective padding can prevent
knee displacement. Unfortunately, once the soft tissues that hold the
patella in place are stretched, patellar dislocation tends to recur.
Metatarsals
Fibula
Tibia
Tibia
Patella
Femur
Fibula
(c)
Lateral view
Fibula
Tibia
Lateral
condyle
(d)
Posterior view
(b)
Medial
condyle
Femur
Tarsals
Phalanges
Femur
Patella
FIGURE 7.50
Parts of the right lower limb. (
a
) Radiograph of
the knee (anterior view), showing the ends of the femur, tibia, and
F
bula. Thinner areas of bone, such as part of the head of the F
bula
and the patella, barely show in this radiograph. (
b
) Anterior view
of the lower limb. (
c
) Lateral view of the knee. (
d
) Posterior view of
the knee.
(a)
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