Gradually increasing RIF pain, reduced appetite, nausea. Some guarding.
This image is taken transverely scanning down the RIF.
On the left of the image, below the peritoneal surface is the caecum. From this the appendix can be seen. The calssic target sign of the appendix in cross section is evident.
Indications of appendicitis in this case include the echogenci mesenteric ring around the appendix, the enlarged appendix (>6mm across), the small amount of free fluid aroudn the appendix, and the correlation of visualising the appendix with maximal sonographic tenderness.
TECHNIQUE / DISCUSSION
Finding the appendix can be a challenge, as can the assessment of RIF pain.
Before looking for the appendix I would routinely look at the gall bladder, right kidney, and pelvis. In the pelvis I check the bladder, look for ureteric jets and examine the uterus and ovaries if a female. Consider hernias and look for Spegelian, midline, inguinal and femoral hernias if clinically likely.
When trying the find the appendix graded compression and exploring the RIF in a orderly fashion is essential. Use a high frequency linear probe with superficial presents. Set the focal zone about 2cm below the peritoneal surface.
I begin laterally, using the abdominal wall musculature as a guide. With the probe in transverse position I move from the upper abdomen to the lower abdomen following the ascending colon / caecum proximally along the colic gutter. You sometimes see a lateral appendix lying here. Next move the probe slightly medially and repeat, running the probe down again. Go slowly and press firmly. Look for the appendix leaving the ceacum. It often heads medially then runs behind the caecum, or crosses over the psoas and iliac vessels to dive into the pelvis. Repeat the process unitl you have explored the entire right lower quadrant.
You should have identified: External oblique, internal oblique, tranversus abdominus muscles; the paracolic gutter, the ascending colon and caecum, the terminal ilium and small bowel, the rectus sheath and inferior epigastric vessels (following them down to their origin), iliacus and psoas, the iliac vessels, the bladder and hopefully the appendix.
Some authors advocate positioning the patient head down or on their left side, and moving the probe from the pelvis up towards to rib cage when searching for the appendix to increase the pick up rate.
Whatever you do you will occasionally not be able to find the appendix.