F- CLINICAL ASPECTS OF SPINAL CORD INJURIES
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pain of sciatic type before disturbances of bladder, bowels and sexual functions as well
as numbness or weakness in certain muscles become manifest. Angiomatous malforma
tions involving the conus and cauda equina may also produce a symptomatology of
dissociated type. A classical example of incomplete cauda equina lesion of specific involve
ment of posterior root resulting in their degeneration occurs, of course, in tabes dorsalis,
leading to ataxy and dribbling incontinence due to distension of the bladder as a result
of the sensory loss.
Great varieties of incomplete conus-cauda equina involvement also result from
traumatic lesions due to fracture dislocations of the lumbar vertebrae. The abnormality
of the gait, as a result of the paralysis of the gluteal muscles especially gluteus medius,
has already been described in the section on complete conus-cauda equina lesions. In a
certain type of incomplete lesion due to polio or fracture of the lumbar spine, the paralysis
may involve the quadriceps while the gluteal muscles are more or less intact, enabling
the patient to stand and walk, although the abnormality of the gait is of different type as
compared with that of cauda equina lesions affecting the gluteal muscles.
The stabilization of the knee joint in patients with paralysis of the quadriceps is
ensured by the function of the gluteus maximus in combination with that of the soleus;
therefore, the walking capability is maintained. The stabilization of the knee joint is
only in danger when the line of gravity falls behind the knee joint axis. Per contra, the
characteristic feature of the gait in patients with paralysis of the gluteus maximus, but
intact quadriceps, is the backward thrust of the trunk causing the line of gravity to fall
behind the joint centre and thus preventing the jack-knifing of the hip joint (see chapter
on Physiotherapy).
