Yasuo Nakajima1,2, Satoru Muro1, Hisayo Nasu1, Masayo Harada1, Kumiko Yamaguchi1, Keiichi Akita3. 1. Department of Clinical Anatomy, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan. 2. Tokatsu-Tsujinaka Hospital, Shimbashi, Tokyo, Japan. 3. Department of Clinical Anatomy, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan. akita.fana@tmd.ac.jp.
Abstract
PURPOSE: The anterior bundle of the longitudinal muscle in the region anterior to the anal canal in males has been described, although the anatomical details remain unclear. The present study was undertaken to clarify the precise morphology of the anterior bundle of the longitudinal muscle and its relationship to the surrounding structures, and to visualize the anterior bundle of the longitudinal muscle via transanal ultrasonography. METHODS: Histological examination was carried out using seven male cadavers; an additional three male cadavers were used for transanal ultrasonography, and the ultrasonography images were compared with the actual sagittal sections. In addition, transanal ultrasonography images of 50 male patients at Tokatsu-Tsujinaka Hospital were studied. RESULTS: The region anterior to the anal canal consisted of smooth muscles and skeletal muscles. The anterior bundle of the longitudinal muscle was situated between the bulbospongiosus and the external anal sphincter, and consisted of smooth muscle. The bundle was identified in the transanal ultrasonography of cadavers by comparison with the actual sections. Transanal ultrasonography images of living bodies showed the anterior bundle of the longitudinal muscle as a hypoechoic layer of approximately 17.7 mm in length. CONCLUSIONS: The detailed anatomical findings of the anterior bundle of the longitudinal muscle suggested "an alternate arrangement of smooth muscles and skeletal muscles" in the region anterior to the anal canal and facilitated the visualization of the anterior bundle of the longitudinal muscle in transanal ultrasonography.
PURPOSE: The anterior bundle of the longitudinal muscle in the region anterior to the anal canal in males has been described, although the anatomical details remain unclear. The present study was undertaken to clarify the precise morphology of the anterior bundle of the longitudinal muscle and its relationship to the surrounding structures, and to visualize the anterior bundle of the longitudinal muscle via transanal ultrasonography. METHODS: Histological examination was carried out using seven male cadavers; an additional three male cadavers were used for transanal ultrasonography, and the ultrasonography images were compared with the actual sagittal sections. In addition, transanal ultrasonography images of 50 male patients at Tokatsu-Tsujinaka Hospital were studied. RESULTS: The region anterior to the anal canal consisted of smooth muscles and skeletal muscles. The anterior bundle of the longitudinal muscle was situated between the bulbospongiosus and the external anal sphincter, and consisted of smooth muscle. The bundle was identified in the transanal ultrasonography of cadavers by comparison with the actual sections. Transanal ultrasonography images of living bodies showed the anterior bundle of the longitudinal muscle as a hypoechoic layer of approximately 17.7 mm in length. CONCLUSIONS: The detailed anatomical findings of the anterior bundle of the longitudinal muscle suggested "an alternate arrangement of smooth muscles and skeletal muscles" in the region anterior to the anal canal and facilitated the visualization of the anterior bundle of the longitudinal muscle in transanal ultrasonography.
Authors: R G Beets-Tan; G L Morren; G L Beets; A G Kessels; K el Naggar; E Lemaire; C G Baeten; J M van Engelshoven Journal: Radiology Date: 2001-07 Impact factor: 11.105
Authors: Felix Aigner; Andrew P Zbar; Barbara Ludwikowski; Alfons Kreczy; Peter Kovacs; Helga Fritsch Journal: Dis Colon Rectum Date: 2004-02 Impact factor: 4.585