Abdominal Viscera 1 Flashcards
Length of oesophagus
25cm
Path of oesophagus
Starts at C6. Descends in midline behind trachea, deviates to the left and pierces muscular diaphragm at T10.
Why is the oesophagus constricted on inspiration?
Right and left cruses form sleeves around oesophagus which form a sphincter around oesophagus when diaphragm contracts.
Cellular feature of junction between oesophagus and stomach
Sharp line of demarcation between simple squamous cells of oesophagus and gastric lining of stomach
Narrowings of oesophagus 1 2 3
1) Upper oesophageal sphincter in neck 2) Aortic arch and left main bronchus in thorax 3) Diaphragmatic orifice in abdomen
Arterial supply of cervical oesophagus
Inferior thyroid artery
Arterial supply of thoracic oesophagus
Oesophageal branches of descending aorta
Arterial supply of abdominal aorta
Left gastric artery from aorta
Venous drainage of cervical oesophagus
Brachio-cephalic system
Venous drainage of thoracic oesophagus
Azygous and systemic
Venous drainage of abdominal oesophagus
Left gastric portal overlaps systemic
Lymphatic drainage of cervical oesophagus
Deep cervical nodes
Lymphatic drainage of thoracic oesophagus
Mediastinal nodes
Lymphatic drainage of abdominal oesophagus
Pre-aortic nodes
Two types of oesophageal herniations
1) Paraoesophageal histal hernia 2) Sliding hiatal hernia
Paraoesophageal histal hernia
Only ~5% of oesophageal hernias. Where proximal stomach pushes through oesophageal hiatus, enters thorax beside oesophagus.
Sliding hiatal hernia
Most common form of oesophageal hernia (~95% of cases). Where oesophagus pulls into the thorax, bringing some of the stomach with it.
Quadrant where stomach is
LUQ
*Stomach in situ
*Components of stomach
Angular notch
A notch on the lesser curvature of the stomach, separating the body from the pylorus
Stomach after the angular notch
Pyloric antrum narrows to the pyloric canal and pyloric sphincter.
How does the stomach relate to the liver?
Tethered to the liver by the lesser omentum. Lesser omentum is a serous membrane stretching between the lesser curvature of the stomach and the visceral surface of the liver
Name for ridges lining interior of the stomach
Rugae
Blood supply of the stomach
Gastric vessels overlie lesser curvature. Gastroepiploic vessels overlie greater curvature. These come from the right and left inferior phrenic arteries, which comes from the aorta.
Is the duodenum retro- or intraperitoneal?
Retroperitoneal
Primary function of duodenum
Absorption, digestion
Name for very first structure in the duodenum
Duodenal cap
Significance of duodenal cap
Can get peptic ulcers, because of proximity to gastric acid
Parts and lengths of duodenum
1st - 2’ 2nd - 3’ 3rd - 4’ 4th - 1’
1st part of duodenum 1 2
1) Arches upwards, backwards to posterior abdominal wall. 2) Associated with right crus, right psoas, medial to right kidney
2nd part of duodenum 1 2 3 4
1) Head of pancreas is to the left. 2) Right kidney is to the right. 3) Posteromedial wall has major duodenal papilla about halfway down 4) Mesentary of mesocolon passes over here
3rd part of duodenum 1 2 3
1) Passes over right and left psoas 2) Travels over the front of IVC, aorta 3) Superior mesenteric artery and vein travel from aorta, IVC over the top of duodenum
4th part of duodenum 1 2
1) Turns upwards, forwards, joining the jejunum in the duodenal-jejunal flexure 2) Attached to left psoas with fibrous tissue
Proportions of small intestine that are jejunum and ileum
Jejunum is 1st 40%. Ileum is last 60%
Differences between jejunum and ileum 1 2 3 4 5
1) Location - Jejunum is mostly LUQ, ileum is mostly RLQ 2) Lumen of jejunum is wider than ileum 3) More mucosal folds in jejunum (more absorption takes place here) 4) Mesentery of jejunum has less fat than that of the ileum, so vessels are easier to see in the jejunal mesentery 5) Lots of arcadesm short vasa recta in ileum. Shorter arcades and more vasa recta in jejunum
Name for where the small intestine becomes the large intestine
Ileo-caecal junction
Where does the appendix always begin?
Where the tenia choli join at the caecum
Differences between small and large intestines 1 2 3
1) Size 2) Position 3) Small intestine has a continuous longitudinal muscle coat. Large intestine has three discontinuous tenia coli 4) Large intestine has omental appendicies (fat tags)
Parts of large intestine 1 2 3 4
1) Caecum 2) Transverse colon 3) Descending colon 4) Sigmoid colon
Caecum
Blind pouch hanging below ileo-caecal junction Appendix hangs from here, where tenia coli join
Appendix 1 2 3
1) Narrow tube of variable length (~7-10cm) 2) Base is always attached to where the 3 tenia coli join at the caecum. 3) The position of the apex is variable (~25% of the time is pelvic appendix, most of the time is retro-caecal)
Transverse colon 1 2
1) Has right colic/hepatic flexure and left colic/splenic flexure. 2) Travels right to left
Path of the tenia coli at the rectum
Become continuous
