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CHAPTER 22
synchronously. One of my patients, a young soldier with a complete lesion below T3
whose paraplegia since his injury in 1944 gradually developed from a flexion into an
extension synergy, showed interesting rhythmic synchronous contractions occurring
simultaneously only in the tibialis posterior on both sides (Fig. 109). These rhythmic
contractions occurred spontaneously at rest in bed, but the intensity and rate could be
increased by various stimuli including change of posture. Rhythmic continuous contrac
tions also may occur, although rarely, in the extensor group of the trunk erectors in
complete and incomplete cervical lesions. They may become very troublesome to the
patient and make his life miserable. In one of the writer's tetraplegics, these rhythmic
contractions of the trunk erectors leading to spasmodic retroversion movements (opistho-
tonic reflex response) of the body could be eliminated following intra-thecal alcohol
block at the level of the thoraco-lumbar junction, thus eliminating a considerable amount
of volleys of afferent impulses to the heightened reflex activity of the isolated cord.
Superficial (cutaneous) reflexes
In cord transection above T5, abdominal and cremaster reflexes are, as a rule, abolished.
However, this is by no means consistent, and in several complete lesions at high level
these reflexes, although greatly diminished and easily exhaustible, were found to be
present.
Failure of reflex return
Failure of reflex return will occur if the transverse lesion is associated with a lesion in
the vertical plane. This may involve either only those muscle groups supplied by certain
segments or all muscles below the level of the lesion, according to the extent of the longitu
dinal lesion. The areflexia will persist and involve the entire paralysed region and the
muscle groups will show all signs of a lower motor neuron damage indicated by atrophy
and reaction of degeneration to electrical test. In such instances, the grey matter of the
isolated cord has sustained a definite damage either through haematomyelia or ischaemic
necrosis, as a result of vascular occlusion.
As already mentioned, septic and toxic conditions leading to anoxia, in particular due
to severe infection of the urinary tract or pressure sores, may profoundly affect the reflex
activity of the isolated cord and may lead to hypo- and even areflexia, the latter in the
final stages of life. On the other hand, it must be remembered that the onset of toxic
conditions may lead first to an increase of spasticity. This was not infrequently found
as the first symptom of a recurrence of urinary infection or even of an infected ingrowing
toenail.
Clinical significance of paraplegia-in-flexion or -extension
FACTORS INFLUENCING REFLEX-SYNERGIES
Riddoch (1917), studying the activities of the flexor and extensor reflex arcs of the
paralysed lower limbs advanced the theory that it is frequently possible to say whether
