Home Page Home Article Read Close close

Figures in Case Report by Peter Petros(*) - Michael Swash(**)

(*) Royal Perth Hospital, University of Western Australia
(**) Dept of Neurology, The Royal London Hospital, London, UK

Experimental Study No. 6: Correction of abnormal geometry and dysfunction by suspensory ligament reconstruction gives insights into mechanisms for anorectal angle formation


(Fig. 1)

Acute anorectal angle at rest and straining

Figure 1. – Acute anorectal angle at rest and straining. Transperineal ultrasound. Note excessive forward indentation of the posterior rectal wall at rest. On straining, there is no significant change in the ano-rectal angle; the rectum just above the ano-rectal angle appears to be opened out on straining, rather than narrowed as in Fig. 2.



Close close


(Fig. 2)


Post-operative perineal ultrasound, at rest and straining.
Fig. 2. – Post-operative perineal ultrasound, at rest and straining. Note restoration of normal anatomy. The anorectal angle is now essentially normal at rest. On straining, the rectum narrowed markedly just above the ano-rectal angle, with forward displacement of the anus, and creation of a more acute ano-rectal angle.

 

Close close

(Fig. 3)

 

Simultaneous bladder and EMG measurements
Fig. 3. – Proposed mechanism of an acute anorectal angle. The anorectal angle “A” is formed by balanced backward contraction of levator plate (LP) and longitudinal muscle of the anus (LMA), against forward contraction of m.puborectalis (PRM). PUL and USL laxity will weaken LP/LMA contraction. In relative terms, PRM contracts more strongly. The system becomes unbalanced, and PRM indents the posterior rectal wall, causing an acute anorectal angle. RVF=rectovaginal fascia; PB = perineal body.

 

Close close