Avoiding obstetrical injury to the anal sphincter is the single biggest factor in preventing anal incontinence among women. Any form of instrument delivery has consistently been noted to increase the risk of obstetric anal sphincter injury and altered fecal continence by between 2- and 7-fold. Routine episiotomy is not recommended. Episiotomy use should be restricted to situations where it dire...

Muscular hypertrophy of the internal anal sphincter in association with proctalgia was first described a few years ago, but has remained largely unnoticed (1-4). In some cases autosomal-dominant inheritance has been demonstrated. Physical examination identifies an enlarged anal sphincter, which sometimes the patient has already noticed. This muscular mass may mimic an anal tumor and even hamper...

PURPOSE This study was designed to determine whether functional variations of internal sphincter activity occur in order to differentiate between patients with anal fissures from those with hemorrhoids. METHODS Thirty patients with chronic anal fissure (median age, 28 years; 12 females), 22 patients with hemorrhoids (median age, 37 years; 7 females), and 33 control volunteers (median age, 48....

The function of the anal sphincters has been studied by obtaining continuous recordings of the pressure in the anal canal and the electromyographic activity in the striated sphincter muscles during expansion of the ampulla recti by means of an air balloon. Ten healthy subjects were examined before and after the striated muscles had been entirely paralysed by bilateral pudendal block, making it ...

OBJECTIVE The purpose of this study was to assess the correlation between internal and external anal sphincter volumes and manometric anal pressures. STUDY DESIGN Ten healthy nulliparous women underwent anal sphincter magnetic resonance imaging and anal manometry measurement. A 3-dimensional reconstruction of magnetic resonance images was accomplished with the use of 3-dimensional slicer. Sph...

It is well known both by clinical examination and by objective measurement that a high pressure zone is to be found in the anal canal, due to the action of the anal sphincteric muscles. Division of part of the internal anal sphincter in the operation of internal sphincterotomy resulted in a diminution in this pressure zone (Bennett and Duthie, 1964). The pressure remaining after internal sphinc...

The internal and sphincter receives its parasympathetic nerve supply from the sacral outflow and its sympathetic supply from the thoracicolumbar outflow of the spinal cord. In order to investigate the influence of the tonic discharge of these nerves, eight healthy subjects receiving high spinal anaesthesia (T 6-T 12) and five receiving low spinal anaesthesia (L 5-S 1) were examined. Continuous ...

We report a 20-year-old female with generalized, severe, recessive dystrophic epidermolysis bullosa who developed secondary chronic anal fissures. This resulted in anal sphincter spasm and severe, disabling pain. She was treated with five botulinum toxin A injections into the internal anal sphincter over a period of 2 years and gained marked improvement in her symptoms. This case demonstrates t...

The anal sphincter is made up of the internal and external sphincter, which are arranged concentrically around the anal canal; they overlap except in the most distal part of the anal canal in the region of the superficial part of the external sphincter. Continuous electromyographic (EMG) activity may be recorded in the external anal sphincter at rest (Floyd and Walls, 1953) but the external sph...

The isolated internal anal sphincter from cats shows a myogenic spontaneous rhythmic activity. Basal tension and frequency of contraction waves from internal anal sphincter strips are inhibited by muscarinic and beta-adrenergic receptors and excited by alpha-adrenergic receptors. Isoprenaline in high doses had an alpha-adrenoceptor-stimulating activity in strips from the internal sphincter. The...