(d) The sacrum, which is a bony fusion of five sacral vertebrae.
(e) The coccyx (pronounced COCK-sicks, "tail"), with 3-4 coccygeal
(3) The vertebrae are held together in two ways:
(a) The intervertebral disc holds the bodies of adjacent vertebrae
together. The intervertebral disc is a fibrous ring with a soft center. This disc allows
the vertebral bodies to move on one another. This joint between the vertebral bodies is
a plane-type joint.
(b) The various parts of adjacent vertebrae are held together by
ligaments. A ligament is a dense FCT structure which extends from bone to bone.
These ligaments extend along the vertebral column from the base of the skull all the
way down to the coccyx.
(4) The spine has four curvatures in the adult human. In the cervical (neck)
region and the lumbar (low back) region, the spine curves forward. In the thoracic
(chest) region and the sacro-coccygeal (pelvic- sacrum and coccyx) region, the spine
(5) When one examines the back of a person by sight and feel (palpation),
certain landmarks are observed.
(a) At the upper shoulder region in the midline, a knob can be seen and
felt. This is the tip of the spinous process of the seventh cervical vertebra. Since this is
the first vertebra from the top that can be easily palpated, this bony landmark is called
the vertebra prominens (the "prominent vertebra").
(b) From the vertebra prominens down to the beginning of the sacrum,
one can feel the tip of the spinous process of each vertebra.
b. The Thoracic (Rib) Cage. The rib cage (figure 4-5) forms a protective
enclosure for the vital organs contained within the thorax (chest) such as the heart and
lungs. It also allows the movements of breathing to take place.