The purpose of this communication is to present a method that assesses the
sigmoid colon (SC) volume, pressure and compliance both quantitatively and
qualitatively. The response of the SC pressure to SC distension was recorde
d in 12 healthy volunteers. The SC was distended by means of a condom, whic
h was applied to an 8 F tube and inflated with carbon dioxide at a rate of
150 ml/min. The SC pressure was measured by a saline-perfused 8 F tube and
the intra-abdominal pressure by a catheter placed in the urinary bladder. A
curve called 'sigmoidometrogram' could be recorded and assessed qualitativ
ely and quantitatively. The curve had a 'tone limb' representing the SC pre
ssure upon distension and an 'evacuation limb' representing the SC pressure
during balloon expulsion. The former showed insignificant pressure elevati
on (P > 0.05) with increasing volumes of CO2 inflation. It exhibited minor
fluctuations which paralleled those of the intra-abdominal pressure. The 'e
vacuation limb' described a curve with an ascending limb continuous with th
e tone limb and a descending one, which descended vertically to the base li
ne. Quantitatively, the infused CO2 volume and intrasigmoid and intra-abdom
inal pressures could be determined from the curve at each of the distension
and expulsion sensation. Consequently, the SC compliance could be calculat
ed. A normal sigmoidometrogram seems to reflect the normality of the sigmoi
d wall structure, afferent axons and central sensory pathways. Alteration o
f any of the components of this pathway is expected to change the measureme
nts of SC volumes, pressure, compliance and sensation; it would also distur
b the morphometry of the curve.