Traumatic
Injury to the Thorax
Traumatic injury to the thorax is common, especially as a
result of automobile accidents
Fractured Sternum
The sternum is a resilient structure that is held in
position by relatively pliable costal cartilages and bendable ribs. For these reasons,
fracture of the sternum is not common; however, it does occur in high-speed
motor vehicle accidents. Remember that the heart lies posterior to the sternum
and may be severely contused by the sternum on impact
Rib Contusion
Bruising of a rib, secondary to trauma, is the most common rib
injury. In this painful condition, a small hemorrhage occurs beneath the
periosteum.
Rib Fractures
Fractures of the ribs are common chest injuries. In
children, the ribs are highly elastic, and fractures in this age group are therefore
rare. Unfortunately, the pliable chest wall in the young can be easily
compressed so that the underlying lungs and heart may be injured. With
increasing age, the rib cage becomes more rigid, owing to the deposit of calcium
in the costal cartilages, and the ribs become brittle. The ribs then tend to
break at their weakest part, their angles.
The ribs prone to fracture are those that are exposed or
relatively fixed. Ribs 5 through 10 are the most commonly fractured ribs. The
first four ribs are protected by the clavicle and pectoral muscles anteriorly
and by the scapula and its associated muscles posteriorly. The 11th and 12th
ribs float and move with the force of impact.
Because the rib is sandwiched between the skin externally and
the delicate pleura internally, it is not surprising that the jagged ends of a
fractured rib may penetrate the lungs and present as a pneumothorax.
Severe localized pain is usually the most important symptom of
a fractured rib. The periosteum of each rib is innervated by the intercostal
nerves above and below the rib. To encourage the patient to breathe adequately,
it may be necessary to relieve the pain by performing an intercostal nerve
block.
