Vascular disorders of the limbs : described for practitioners and students / by Sir Thomas Lewis.

  • Thomas Lewis
Date:
1936
Catalogue details

Licence: In copyright

Credit: Vascular disorders of the limbs : described for practitioners and students / by Sir Thomas Lewis. Source: Wellcome Collection.

    35/136 (page 19)
    continue to spread centripetally in the arm at the rate of about 3 or 4 cm. per minute, until the whole of the ischaemic skin becomes anaesthetic within about a half-hour. Pain sense is dulled and delayed a few minutes after numbness appears, and this change likewise spreads up the limb; actual analgesia follows much later. Sense of cold is lost about the same time or a little earlier than is that of pain, and follows the same course up the limb. Sense of warmth is among the last to dis¬ appear. Motor Nerves.—Conspicuous weakness is found in the muscles of the thenar eminence by the 20th minute; these muscles are paralysed at about the 25th minute, by which time it is usual for the whole hand to have become anaesthetic; the interossei and extensors of the thumb quickly follow suit. The extensors of wrist and fingers are paralysed at about the 30th minute, producing wrist drop; the flexors of the wrist and fingers, and lastly the muscles moving the elbow joint, are paralysed in turn. Thus, the order of muscular paralysis is in general centripetal like that of sensation. Long after voluntary movement has become paralysed the muscles will react directly to electrical stimulation, faradic and galvanic. It is particularly to be stressed that paralysis of a limb arising out of ischaemia does not happen abruptly, but is a very gradual development. Complete paralysis, extending far up the limb, does not occur until a half-hour at least has elapsed from the circulatory arrest. Recovery of Nerves.—Release of the obstructed circulation is followed by very rapid recovery of all the nerve functions provided that circulatory arrest has not been prolonged unduly. Thus it occurs within \ to 1 minute, when arrest has lasted 25 to 35 minutes. Circulatory arrest lasting for hours permanently endangers the functions of the limbs, as will be described later. In the Leg.—The events are comparable, the various forms of sensation are lost in the same order as in the case of the arm and in corresponding times. Similarly the motor loss begins in the toes and ankle and mounts to the knee. The paralysis spreads centri¬ petally. Experiment on animals and occasional cases of thrombosis and embolism in man have shown that if the abdominal aorta is occluded, then the paralysis may take the form of a paraplegia that comes on abruptly within a minute or two of the arrest and includes the sphincters. The rapidity of the event is here due to involvement