1. Describe the arrangement of the muscles that make up the anterior and lateral body wall and understand their functions.
- Laterally, the wall of the abdomen is composed of 3 layers of muscles- external, internal and transverse abdominal muscles.
- Anteriorly, the wall consists of a vertical band of muscle, the rectus abdominis, which extends from the xiphoid process to the pubic crest. It is a paired muscle, joined by the linea albea. It is contained in a separate rectus sheath.
- The muscles of the abdominal wall support the abdominal viscera and regulate the pressure within the peritoneal cavity.
- They are important for:
- Respiration, coughing and sneezing
- Micturition, defecation and childbirth
- Lifting heavy objects
2. Be able to distinguish the major segments of the intestinal tract both within a cadaver and in isolation.
- The oesophagus penetrates the diaphragm and opens immediately into the stomach which is followed by the duodenum, forming a c shaped loop towards the upper left hand side of the abdomen.
- The jejunum and ileum then run on a slant from top left to bottom right of the abdomen.
- From here, the large intestine, consisting of the caecum, ascending colon, transverse colon and descending colon form a wide clockwise loop around the outside of the abdomen before giving rise to the sigmoid colon and rectum.
- The appendix is connected to the caecum, and is located in the right iliac fossa.
- The fundus of the stomach often contains gas.
- The jejunum is covered in plicae circularis and folds, whereas the ileum is much fattier.
- The large intestine has fatty tags (appendices epiploica) externally and an outer layer of three bands known as tenae coli that form haustrations.
3. Locate and recognise the superior mesenteric artery and its major branches.
- This artery arises from the aorta and supplies the second part of the duodenum to two thirds along the transverse colon.
- The branches are:
- Jejunal and ileal
- Ileocolic
- Right colic
- Middle colic
4. Locate and recognise the inferior mesenteric artery and its major branches.
- This artery is the third branch of the aorta.
- It supplies the last part of the transverse colon, the descending colon and the sigmoid colon and rectum.
- The branches are:
- Left colic
- Sigmoid
- Superior rectal