the dura and over the brain. To differentiate the CT finding from an
epidural hematoma, think about the high-pressure created by the arterial
tear of an epidural that causes the hematoma to expand inward. In con-
trast, the low-pressure venous bleed of a subdural hematoma layers along
the calvarium. (c)Traumatic SAH is probably the most common CT abnor-
mality in patients with moderate to severe traumatic brain injury. (d and e)
Intracerebral hematomas and contusions occur secondary to traumatic
tearing of intracerebral blood vessels. Contusions most commonly occur in
the frontal, temporal, and occipital lobes. They may occur either at the site
of the blunt trauma or on the opposite site of the brain, known as a contre-
coup injury. Examples of each are seen below.
144.The answer is a.(Rosen, p 349.)Central cord syndromeis often
seen in patients with degenerative arthritis of the cervical vertebrae, whose
necks are subjected to forced hyperextension. Typically, it is seen in a for-
ward fall onto the face in an elderly person. This causes the ligamentum
flavum to buckle into the spinal cord, resulting in a contusion to the central
portion of the cord. This injury affects the central gray matter and the most
central portions of the pyramidal and spinothalamic tracts. Patients often
havegreater neurologic deficits in the upper extremities, compared to
the lower extremities, since nerve fibers that innervate distal structures are
located in the periphery of the spinal cord. In addition, patients with central
cord syndrome usually have decreased rectal sphincter tone and patchy,
unpredictable sensory deficits. A diagram of the functional anatomy of the
spinal cord is shown on the next page.
Trauma Answers 161(Courtesy of Adam J. Rosh MD.)