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Chapter 2 The Skeletal System 41
Pelvic Girdle
The pelvic girdle is made up of bones that sup-
port attachment of the lower extremities to the
axial skeleton (Figure 2.10). The bones that com-
prise the pelvic girdle are as follows:
• The ischium (IS-kee-um) is the posterior part of
the pelvic bone.
• The ilium is the broad, blade-shaped bone that
forms the upper part of each side of the pelvis.
• The pubis (PYOO-bis) is the anterior part of the
pelvic bone.
Lower Extremities
The bones that make up the lower extremities,
shown in Figure 2.1, are as follows:
• The femur, or thighbone, is the upper leg bone.
It is the longest bone in the human body.
• The patella, or kneecap, is the bone that forms
the anterior part of the knee.
• The tibia, or shinbone, is the larger, more medi-
ally located lower leg bone.
• The fi bula, located laterally to the tibia, is the
smaller of the two lower leg bones.
• Seven tarsal bones make up the ankle. The larg-
est of these bones, called the calcaneus (kal-
KAY-nee-us), is known as the heelbone. The
next largest is the talus (anklebone).
• Five metatarsals (MET-uh-TAR-suhlz) com-
prise the bones of the foot.
• Each foot contains 14 phalanges. There are two
phalanges (proximal and distal) in the big toe.
There are three phalanges in each of the other four
toes: proximal, medial, and distal phalanges.
The longest bone in your body is your femur
(thighbone). The femur is about one-quarter of your
total height. The smallest bone in your body is the
stirrup bone, or stapes (STAY-peez). Located inside
the ear, the stapes can measure one-tenth of an
inch. This tiny bone carries sound vibrations to the
cochlea, a spiral-shaped structure in the inner ear
that generates nerve impulses in response to the
vibrations.
Fascinating Fact
Iliac crest
Pubis
Ischial spine
Ischial tuberosity
Pelvis Coxal bone, right lateral view
Coxal bone
Ischium
Acetabulum
Ilium
Sacroiliac
joints
Obturator
foramen
Coccyx
Sacrum
Pubis
symphysis
Figure 2.10 The bones of the pelvic girdle.