The skeletal system includes all of the bones, cartilages, and ligaments of the body. It serves to support the body, protect the brain and other internal organs, and provides a rigid structure upon which muscles can pull to generate body movements. It also stores fat and the tissue responsible for the production of blood cells. The skeleton is subdivided into two parts. The axial skeleton forms a vertical axis that includes the head, neck, back, and chest. It has 80 bones and consists of the skull, vertebral column, and thoracic cage. The adult vertebral column consists of 24 vertebrae plus the sacrum and coccyx. The thoracic cage is formed by 12 pairs of ribs and the sternum. The appendicular skeleton consists of 126 bones in the adult and includes all of the bones of the upper and lower limbs plus the bones that anchor each limb to the axial skeleton.
appendicular skeleton
all bones of the upper and lower limbs, plus the girdle bones that attach each limb to the axial skeleton
axial skeleton
central, vertical axis of the body, including the skull, vertebral column, and thoracic cage
coccyx
small bone located at inferior end of the adult vertebral column that is formed by the fusion of four coccygeal vertebrae; also referred to as the “tailbone”
ear ossicles
three small bones located in the middle ear cavity that serve to transmit sound vibrations to the inner ear
hyoid bone
small, U-shaped bone located in upper neck that does not contact any other bone
ribs
thin, curved bones of the chest wall
sacrum
single bone located near the inferior end of the adult vertebral column that is formed by the fusion of five sacral vertebrae; forms the posterior portion of the pelvis
skeleton
bones of the body
skull
bony structure that forms the head, face, and jaws, and protects the brain; consists of 22 bones
sternum
flattened bone located at the center of the anterior chest
thoracic cage
consists of 12 pairs of ribs and sternum
vertebra
individual bone in the neck and back regions of the vertebral column
vertebral column
entire sequence of bones that extend from the skull to the tailbone
1. Which of the following is part of the axial skeleton?
A) shoulder bones
B) thigh bone
C) foot bones
D) vertebral column
D
2. Which of the following is a function of the axial skeleton?
A) allows for movement of the wrist and hand
B) protects nerves and blood vessels at the elbow
C) supports trunk of body
D) allows for movements of the ankle and foot
C
3. The axial skeleton ________.
A) consists of 126 bones
B) forms the vertical axis of the body
C) includes all bones of the body trunk and limbs
D) includes only the bones of the lower limbs
B
1. Define the two divisions of the skeleton.
The axial skeleton forms the vertical axis of the body and includes the bones of the head, neck, back, and chest of the body. It consists of 80 bones that include the skull, vertebral column, and thoracic cage. The appendicular skeleton consists of 126 bones and includes all bones of the upper and lower limbs.
2. Discuss the functions of the axial skeleton.
The axial skeleton supports the head, neck, back, and chest of the body and allows for movements of these body regions. It also gives bony protections for the brain, spinal cord, heart, and lungs; stores fat and minerals; and houses the blood-cell producing tissue.