GIT Flashcards
What are the features of intraperitoneal organs? Give a few examples of intraperitoneal organs.
- Enveloped by visceral peritoneum which covers the organ both anteriorly and posteriorly.
- suspended within abdominal cavity and connects with abdominal wall via mesentery
- mobile
- Stomach, liver, spleen
What are features of retroperitoneal organs? Give a few examples of retroperitoneal organs.
- Only covered in parietal peritoneum which only covers the organ’s anterior surface.
- fixed
- SAD PUCKER
- S: suprarenal (adrenal glands), A: aorta/IVC, D: duodenum (except the proximal 2cm, the duodenal cap), P; pancreas (except the tail), U: ureters, C: colon (ascending & descending parts), K: kidneys, E: esophagus, R: rectum
What is the difference between primary and secondary retroperitoneal organs?
- Primary: develop and remain outside the parietal peritoneum. (oesophagus, rectum, kidneys)
- Secondary: initially intraperitoneal, suspended by mesentery. Became retroperitoneal as their mesentery fused with posterior abdominal wall. (ascending and descending colon)
What is the function of the peritoneum?
- Covers nearly all viscera within the gut and conveys neurovascular structures from the body wall to intraperitoneal viscera.
Describe the structure of the mesentery and its function.
- Double layer of visceral peritoneum.
- Connects an intraperitoneal organ to the posterior abdominal wall.
- Provides a pathway for nerves, blood vessels and lymphatics to travel from body wall to the viscera.
Describe the structure of peritoneal ligaments and its function.
- Double fold of peritoneum that connects viscera together or connects viscera to abdominal wall.
- example is hepatogastric ligament (connects liver to stomach.
What does referred pain mean? What is its significance?
- Pain is referred according to the embryological origin of the organ so pain from foregut structures are referred to the epigastric region, midgut structures are to the umbilical region and hindgut structures to the pubic region of the abdomen.
Where can pain in retroperitoneal organs be referred to?
- back pain
Describe the pathway of referred pain in appendicitis.
- Initially, pain from the appendix (midgut structure) and its visceral peritoneum is referred to the umbilical region.
- As appendix becomes increasingly inflamed, it irritates the parietal peritoneum, causing pain to localise to the right lower quadrant.
What muscles make up the anterior abdominal wall?
- External oblique: superficial, inferomedial fibre direction
- Internal oblique: intermediate, superomedial fibre direction, arise from inguinal ligament
- Tranversus abdominus: innermost, transverse fibre direction, arise from inguinal ligament
- Rectus abdominis
- Pyramidalis muscles
What are the insertions of inferior part of external oblique muscle?
- Lateral part attaches to iliac crest and anterior superior iliac spine
- Central part is free, with no attachments
- Medial part attaches to the pubic tubercle and pubic crest
Where is the inguinal ligament?
- Free inferior border of external oblique muscle
- Thickened as a undercurving fibrous band (curved inwards to the body)
- Extends from anterior superior iliac spine (laterally) to pubic tubercle (medially)
Where are the attachments of the external oblique muscle?
attaches to ribs, linear alba, iliac crest
Where are the insertion and attachments of the internal oblique muscle?
- insert into pubic crest via conjoint tendon
- medially attach to linea alba, superiorly attach to costal margin, posteriorly attach posterior abdominal wall muscle
Where are the insertion and attachments of the transversus abdominus?
- insert into pubic crest via conjoint tendon
- medially attach to linea alba, superiorly attach to costal margin, posteriorly attach to posterior abdominal wall muscle
What are the vertically orientated muscles of anterior abdominal wall?
- Rectus abdominis: principle vertical muscles, intersected by tendons, enclosed by rectus sheath, right next to linea alba, arise inferiorly from the pubic bone and ascend and overlap costal margin attaching to rib cage
- Pyramidalis muscle
What is the function of tendinous intersection?
- Helps rectus abdominus become shorter but stronger
What forms the rectus sheath and what is it’s role?
- Formed by the sponeurosis of EO, IO and TA
- fibrous compartment for rectus abdominis
List the 8 layers of anterior abdominal wall from superficial to deep.
- skin, superficial fascia, external oblique, internal oblique, transversus abdominus, transversalis fascia, extraperitoneal fascia (fat), peritoneum
Describe the pathway of the development of testes.
- Initially developed at posterior abdominal wall in layer 7 (extraperitoneal fat)
- It begins to descend to anterior abdominal wall which is still in layer 7 and punctures a hole in transversalis fascia and goes inferomedially/obliquely.
- It descends beneath the arches fibre of the transversalis abdominus and arches fibre of internal oblique muscles
- It leaves the anterior abdominal wall through the fibrous split of external oblique muscle
- Then it descends obliquely down into scrotum via inguinal canals as spermatogenesis requires lower temperature
- As it descends, it takes each layer and its nerves, vessels and ducts forming the spermatic cord
Which layers of the anterior abdominal wall is not involved in inguinal canal?
- Doesn’t involve skin and superficial fascia layers
What are the features of the inguinal canal?
- Deep (internal) inguinal ring: a circular hole in the transversalis fascia
- Superficial (external) inguinal ring: a triangular split between those fibres of the external oblique aponeurosis
- Superior to the inguinal ligament
What are the boundaries of inguinal canal?
- Floor: inguinal ligament
- Roof: arching fibres of internal oblique and transversus abdominus