Appendicitis- appendix

 WHAT IS APPENDICTIS?

Appendicitis begins with the obstruction of the appendix lumen

with a fecal concretion (fecalith) and lymphoid hyperplasia followed by distention of the appendix.

Clinical findings include initial pain in the umbilical or epigastric region (later pain localizes to the

right lumbar region), nausea, vomiting, anorexia, tenderness to palpation, and percussion in the right

lumbar region. Complications may include peritonitis due to rupture of the appendix. McBurney

point is located by drawing a line from the right anterior superior iliac spine to the umbilicus. The

midpoint of this line locates the root of the appendix. The appendix is suspended by the mesoap-

pendix (i.e., intraperitoneal) and is generally found in the retrocecal fossa (although its position is

variable).

What is appendix?
This is a worm-like diverticulum arising from the posteromedial wall, of the caecum, about 2 cm below

the ileocaecal orifice. The appendix  is a narrow, muscular tube with a large amount of lymphoid tissue

in its wall. It is attached to the posteromedial surface of the cecum approximately 1 in.

(2.5 cm) below the ileocecal junction. It has a complete peritoneal covering, which is attached to the

mesentery of the small intestine by a short mesentery of its own called

the mesoappendix.

A. General Features

● The appendix is an intraperitoneal (mesoappendix), narrow, muscular tube attached to the postero-

medial surface of the cecum.

● The appendix is located ≈2.5 cm below the ileocecal valve.

● The appendix may lie in the following positions: Retrocecal (65%), pelvis (32%), subcecal (2%),

anterior juxta-ileal (1%), and posterior juxta-ileal (0.5%).

What is mesoappendix?

The mesoappendix contains the appendicular vessels and nerves. The base of the appendix can be

located inside the abdomen by tracing the teniae coli of the cecum and then following them to the

appendix, where they converge to form a continuous muscle coat.

VARIABILITY OF POSITION OF APPENDIX AND

THE DIAGNOSIS OF APPENDICITIS

The inconstancy of the position of the appendix should be borne in mind when attempting to diag-

nose an appendicitis. A retrocecal appendix, for example, may lie behind the cecum, and it may be

difficult to elicit tenderness on palpation in the right iliac region. An appendix hanging down in the

pelvis

may result in absent abdominal tenderness in the right lower quadrant but deep tenderness may be

experienced just above the symphysis pubis. Rectal or vaginal examination may reveal tenderness of |

the peritoneum in the pelvis on the right side.

Positions of the appendix according to the clock.

1. The appendix may pass upwards and to the right. This is the paracolic or 11 O'clock position.

2. It may lie behind the caecum or colon, known as retrocaecal or 12 O'clock position. This is the

commonest position of the appendix, about 65%.

3. The appendix may pass upwards and to the left. It points towards the spleen. This is the splenic or 2

O'clock position. The appendix may lie in front of the ileum (preileal) or behind the ileum (postileal).

4. It may pass horizontally to the left (as if pointing to the sacral promontory called promontoric or 3

O'clock position.

5. It may descend into the pelvis called pelvic or 4 O'clock position. This is the second most common

position about 30%.

6. It may lie below the caecum (subcaecal) and may point towards the inguinal ligament called as

midinguinal or 6 O'clock position.

Blood Supply of appendix

Arteries

Appendicular artery is a branch of the posterior cecal artery

Veins

The veins drain into the posterior cecal vein.

The appendicular artery is a branch of the lower division of the ileocolic artery. It runs behind the

terminal part of the ileum and enters the mesoappendix at a short distance from its base. Here it gives a

recurrent branch which anastomoses with a branch of the posterior caecal artery.The main artery runs

towards the tip of the appendix lying at first near to and then in the free border of the mesoappendix.

The terminal part of the artery lies actually on the wall of the appendix (Fig. 20.19). Blood from the

appendix is drained by the appendicular, ileocolic and superior mesenteric veins, to the portal vein.

Lymph Drainage of appendix

The lymph drains into nodes in the mesoappendix and

eventually into the superior mesenteric lymph nodes.

Nerve Supply of appendix

The appendix is supplied by the sympathetic and vagus

nerves from the superior mesenteric plexus.

Sympathetic nerves are derived from thoracic nine and

ten segments through the coeliac plexus.

Parasympathetic nerves are derived from the vagus.

Referred pain of appendix is felt at umbilicus, similar to

that of small intestine and testis.

WHAT IS PAIN OF APPENDICITIS?

Visceral pain in the appendix is produced by distention of its lumen or spasm of its muscle. The afferent

pain fibers enter the spinal cord at the level of the tenth thoracic segment, and a vague referred pain is

felt in the region of the umbilicus. Later, the pain shifts to where the inflamed appendix irritates the

parietal peritoneum, and then the pain is precise, severe,

and localized.

What are Appendicular Orifice?

1. The appendicular situated on the posteromedial aspect of the caecum 2 cm below the ileocaecal

orifice.

2. The appendicular orifice is occasionally guarded by an indistinct semilunar fold of mucous

membrane, known as 'valve of Galactic.

3. The orifice is marked on the surface by a point situated 2 cm below the junction of the trans-

tubercular and right lateral planes.

4. McBurney's point is the site of maximum tenderness in appendicitis. The point lies at the junction

of lateral one-third and medial two-thirds of the line joining the right anterior superior iliac spine to the

umbilicus.