188
CHAPTER 17
IOO
)JV
S.M.
loo pv
» V
6 US.
SECS
FIG. 92b. M.S.C. 20 days after injury, no apparent difference between right and left
side. Right diaphragm recovering.
from the intercostal muscle to the act of respiration. They were of small amplitude and
duration and consisted in irregular bursts to maximal inspiration only; moreover, they
were only found anteriorly in the 6th, yth and 8th intercostal spaces. It is likely that the
complete lack of action potentials above the 6th intercostal space is due to the greater
thickness of the tissues overlying the upper part of the chest. It is known that such
electrical inactivity in the upper chest also occurs in normal subjects. Conversely,
Campbell (1958) found that in normal females following radical mastectomy including
removal of the pectoral muscles, and also in dyspnoic patients with very thin chest walls,
the pattern of electrical activity of the intercostal muscles in both upper and lower
intercostal spaces was essentially similar. Once the full reflex activity of the isolated
cord developed, the increase of the electrical response of the intercostals to inspiration
was very conspicuous. The amplitude of the action potentials was larger and they could
2 f
LITRES
7 us.
J/Oc/nfromMt.
100fjy\
- 7 R.I.S.
10cm
1romM.L
sees.
FIG. 93. I.C. i£ months after complete lesion below 05. Reduced activity in 7 R.I.S.
compared with 7 L.I.S. Screening showed greatly reduced function of right diaphragm.
