J Korean Soc Coloproctol.  1998 Jun;14(2):217-224.

Anal Endosonographic Findings of Internal Anal Sphincter in Normal Adult Korean

• Kim KJ
• Kim CY
• Jang JH
• Kim KC
• Min YD

Abstract

PURPOSE: To describe the appearance and average thickness of the internal anal sphincter with anal endosonography in healthy Korean adults. MATERIAL AND METHODS: 184 subjects(male: 96, female: 88) with no history of anorectal disease or surgery were studied with anal endosonography. The average thickness of internal sphincter was meas ured at the mid-anal canal. For the internal sphincter, which is often asymmetric, the thickness of each 4 part(12, 3, 6 and 9 o'clock direction) were measured in left lateral decubitus position.
RESULTS
The anal wall was well visualized in 5 layers(mucosa, submucosa, internal anal sphincter, intersphincteric plane, external anal sphincter) with anal endosonography. The anal endosonogram showed the internal anal sphincter as a homogenous, well-defined, hypoechoic, circular band, and slightly asymmetric. The average thickness of the internal anal sphincter in the area of mid-anal portion was 2.0 0.3 mm(range: 1~3 mm). There was no sexual difference; however, a significant positive correlation with age was found in average thickness of the internal anal sphincter. The correlation with lean body mass was not found.
CONCLUSION
The internal anal sphincter is well-visualized, best defined structure by anal endosonography. Average thickeness of the sphincter in Korean appeared to be the same as in the Western.

Keyword

Internal anal sphincter; Anal endosonography

MeSH Terms

Adult*
Anal Canal*
Endosonography
Female
Humans