Anal Canal Anatomy

The upper two thirds of the anal canal is supplied with blood mainly from the superior rectal artery a branch of the inferior mesenteric artery and drains into the superior rectal veins. The anatomy of the anal canal is also key to understanding the spread of neoplastic disease based on its origin in the upper or lower anal canal.

Radiotherapy Dictionary Anorectal Anatomy

The anal canal is surrounded by internal and external anal sphincters which play a crucial role in the maintenance of faecal continence.

Anal canal anatomy. The anal canal is the short terminal portion of the rectum through which wastes from the large intestine are excreted from the body. Define and describe the internal features of the anal canal. Anatomically the anal canal extends from the level of the upper aspect of the pelvic diaphragm to the anus.

Structure of rectum serous muscular ouer longitudinal inner circular submucous mucous 4. The upper region has 5 to 10 rectal columns each column containing a small artery and vein. The internal anal sphincter is permanently contracted through the sympathetic tonus and relaxes under parasympathetic influence.

It has a narrower diameter than that of the rectum to which it is joined. Levator anus muscles components 3. The anal canal is an important part of the continence organ.

It is encircled by a muscle called sphincter which controls intestinal movements. Describe the anal sphincters internal and external and provide a comparison between. Triangles pelvic outlet 2.

The anal canal is between 25 and 5 in length and is guarded by two muscles that control the release of waste from the rectum. Anal canal anatomy it is about 1 15 inches long. Internal anal sphincter surrounds the upper 23 of the anal canal.

This part differs from the part above the pectinate line in several respects including innervation venous and lymphatic drainage and possibly lining epithelium. It is formed from a thickening of the involuntary circular smooth muscle in the bowel wall. In surgical usage however the anal canal is frequently limited to that part of the intestine below the pectinate line.

The external anal sphincter surrounds the anal canal like a clamp. The ring at the terminal portion of the anal canal is called the anus. Pectinate line anal columns valves and sinuses.

Anatomy of anal canal 1. The anal canal connects with the rectum at the point where it passes through a muscular pelvic diaphragm. The anal canal is the most terminal part of the lower gi tractlarge intestine which lies between the anal verge anal orifice anus in the perineum below and the rectum above.

It is surrounded by a muscular sphincter system which tightly closes the lumen.

Anatomy And Embryology Of The Colon Rectum And Anus