34 Introduction to Medical Terminology
Copyright Goodheart-Willcox Co., Inc.
• Anchoring and movement of muscles—The
bones of the skeletal system act as levers for
muscular action. Muscular movement would
not be possible without tendons, fi brous cords of
tissue that attach muscle to bone, and ligaments,
fi brous cords of tissue that attach bone to bone.
Bone Structure
Bone is a dense connective tissue composed of col-
lagen (KAH-luh-jen) fi bers and minerals. Collagen
fi bers are resistant but fl exible. They are also found
in skin and cartilage. There are 206 bones of vari-
ous sizes and shapes in the adult body (Figure 2.2).
These bones can be classifi ed in several ways.
Long bones are found in the extremities. Short
bones are located in the hands and feet. They
are cube-shaped, and composed of spongy bone,
which allows for fl exible movement. Flat bones
protect vital organs and provide a broad sur-
face area for muscle attachment. Examples of fl at
bones include the cranium (bones of the head),
facial bones, scapulae (shoulder blades), and ster-
num (breastbone).
Sesamoid bones, so named because they resem-
ble large sesame seeds, are embedded within ten-
dons. Sesamoid bones facilitate joint movement
and are found in the patella (kneecap) and in the
hands, wrists, and feet.
Short bones
Long bone
Irregular bone
Sesamoid bone
Flat bone
Figure 2.2 The adult body contains bones of various shapes and sizes.