CHAPTER 24
DISTURBANCES OF SENSIBILITY
(a) Disturbances below the transverse lesion
Distinction has to be made between the sensory disturbances in the immediate and early
stages of complete transverse lesion and those in the later stages. In complete lesions, the
conduction of all afferent impulses subserving the various modalities of superficial and
deep sensibility mediated by the posterior columns, anterior and lateral spino-thalamic
or ventro- and dorso-spinocerebellar tracts are interrupted at the level of the transection.
The resulting loss of sensibility in the paralysed areas involves appreciation of touch,
superficial and deep pressure, pain, itching as well as pleasurable sensations, temperature,
position and movement (kinaesthesia), vibration (pallaesthesia), two-point discrimina
tion, and appreciation of writing figures or letters on the skin (graphaesthesia). The
border line between the sensitive and insensitive parts of the body is at first sharp to all
forms of sensation. However, once the spinal segments above the transverse lesion nearest
to the transection assume their compensatory overlapping sensory function, the areas of
anaesthesia, analgesia and thermo-anaesthesia become dissociated, and the area of
analgesia, unlike its distribution in peripheral nerve lesions, exceeds the area of anaes
thesia (Fig. 113). The photographs also show the relationship between disturbances of
sensibility and sweating (see chapter on Sweating).
(b) Disturbances above the level of the lesion due to tendinous or articular
contractures
Pain and parasthesia are especially conspicuous in shoulders and arms in complete lesions
of the cervical cord. Although the traumatized cervical roots may have initially produced
some root irritation, there is no doubt that the pain above the level of the lesion in most
of the cases we have seen was caused by tendinous or articular contractures in shoulders,
elbows and fingers, due to faulty positioning of the upper limbs in the early stages
following injury. In particular, in complete lesions below C6 where the triceps is para
lysed, flexion contractures of the elbow as the result of overaction of the normal biceps
are relatively common and are produced by continuous flexion of the forearms. Fig. 8
shows the agony in the face of a young soldier, who was admitted 4 months after a
cervical injury below C6, when the sister tried to extend the forearm. Articular contrac
tures in the hips, also in the small joints of the vertebra caused by long fixation in plaster
casts and plaster beds, were also found to be the cause of nerve irritation above the lesion
in cauda equina injuries. It was most striking that in those patients where these contrac
tures were the only or main cause of pain the pain gradually disappeared commensurate
with the relief of the contractures by regular passive and active movements as shown in
Fig. 8.
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