Meso-appendix
Mesoappendix
The small triangular fold of peritoneum that suspends the vermiform appendix from the back of the ileal mesentery.
At a glance
- English
- Meso-appendix
- Latin (TA2)
- Mesoappendix
- System
- Digestive
- Region
- Abdomen
- Side
- Single, on the midline
About the meso-appendix
The mesoappendix is the appendix's own short mesentery. It is a triangular double fold of peritoneum that hangs from the underside of the lower end of the mesentery of the small intestine, close to the ileocaecal junction, and attaches to the appendix along its length. Its free edge usually runs from the base of the appendix towards the tip, although near the tip it often narrows or stops short. Like other mesenteries, it is one of the named parts of the continuous mesocolon.
Between its two layers lie fat, lymphatic vessels running to the ileocolic nodes, and the appendicular artery and vein. The artery is a branch of the ileocolic artery, or of one of its branches, passing behind the end of the ileum to enter the fold and then running along or near its free border to the tip of the appendix. Because the appendix depends almost entirely on this single end artery, its blood supply is easily cut off when the organ swells.
The size and length of the fold help explain why the appendix can lie in so many positions. Where the mesoappendix is long, the appendix moves freely and may hang into the pelvis or lie beside the ileum; where it is short, the appendix is held behind the caecum or curled close against it. The fold also gives a degree of freedom that lets an inflamed appendix stick to nearby loops of bowel or to the greater omentum.
In removal of the appendix (appendicectomy) the surgeon divides and ties the mesoappendix, with the appendicular artery inside it, before dealing with the base of the appendix. Bleeding from a poorly secured vessel in the fold is one of the recognised complications. In appendicitis, inflammation spreading into the fold makes it thick and oedematous, and pus may collect around it to form an appendix mass or abscess.
Function and supply
- Begins at
- Hangs from the posterior (left) layer of the lower end of the mesentery of the small intestine, near the ileocaecal junction.
- Ends at
- Attaches along the vermiform appendix from its base towards its tip.
- Function
- Suspends the appendix and carries its artery, vein, lymphatics and nerves.
- Blood supply
- Carries the appendicular artery, a branch of the ileocolic artery, which runs to the appendix tip in or near its free edge.
Anthromica
See the meso-appendix where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
