UGI Flashcards
where are the openings in the diaphragm located?
Caval = T8
Oesophageal = T10
Aortic = T12
What passes through the caval opening?
Caval
- IVC
- right phrenic
What passes through the oesophageal opening ?
Oesophageal
- oesophagus
- vagus
- oesophageal branches of left gastric
- lymphatics
What passes through the aortic opening?
Aortic
- aorta
- azygos vein
- thoracic duct
What passes through the ligaments?
Medial
- sympathetic chain
- phrenic
lateral
- quadratus lumborum
- subcostal neurvascular bundle
What is the blood supply to the diaphragm?
- inferior phrenic (first branch of abdominal aorta)
- superior phrenic (branch of thoracic aorta)
- pericardiophrenic (internal thoracic)
- lower 5 intercostal arteries
What is the embryological origin of the diaphragm?
4 structures
- septum transversum - anterior (Morgagni hernia)
- pleuroperitoneal membrane - muscular part
- body wall muscles - muscular part
- mesentry of oesophagus - crura
What is the anatomy of the upper oesophageal sphincter?
Comprised of three muscles
- cricopharyngeus (main)
- thyropharyngeus
- Upper oesophagus
In a state of tonic contraction between swallowing
Prevents reflux of contents into lungs and air into oesophagus (distension)
What is the anatomy of the lower oesophageal sphincter (ie what are factors preventing against GORD)?
The lower esophageal sphincter is a physiological sphincter with a high pressure zone.
MALT are the factors contributing to the sphincter
Muscle
- The muscle in this region normally remains tonically contracted except when swallowing (alcohol relaxes it).
Angle of His
- the angle of entry to the stomach (cardiac incisure; angle of His) can result in a flap-like closure of the lower esophageal entry when the stomach is full.
Length
- the lower 2 cm of the esophagus is in the abdomen, where intra-abdominal pressure can help keep it closed.
Twirl
- Right crus loops around oesophagus
What are the layers of the oesophagus?
- mucosa
- submucosa
- muscularis
There is NO sersoa. Beause of this oesophageal cancer spreads early.
What is the blood supply to the oesophagus?
Oesophagus Part
Arterial
Venous
Parasympathetic
Sympathetic
Upper
Inferior thyroid
Brachiocephalic
Recurrent laryngeal
Middle cervical ganglion
Middle
Thoracic aorta
Azygous veins
Lower
Left gastric
Inferior phrenic
Left gastric vein ® portal vein
Vagus (oesophageal plexus) = motor. LARP.
Greater splanchnic, sympathetic trunks
Where does the oesophagus start and end?
- The oesophagus is a muscular tube measuring approximately 25 cm in length
- Divided into 3 parts - cervical, thoracic and intra-abdominal
- commences at C6 (pharyngo-oesophageal junction)
- enters abdomen at T10 diaphragmmatic hiatus
- ends at about T11
What is the lymphatic drainage of the oesophagus and how is this clinically relevant?
- Upper third = deep cervical nodes
- middle third = mediastinal nodes
- lower third = gastric and coeliac nodes
- There is a RICH SUBMUCOSAL LYMPHATIC NETWORK
- interconnections among these three drainage regions (bi-directional flow)
Clinical relevance
- The bidirectional lymph flow, rich submucosal network and lack of a serosa is responsible for the spread of malignancy from the lower esophagus to the upper esophagus.
Where does the thoracic duct start, cross the midline and end?
starts
- T12 vertebrae as continuation of the cisterna chyli
- ascends posterior to right crus of diaphragm, to right of aorta and oesophagus
crosses midline
- T5 level slopes to the left to cross midline
- ascends superficial to azygos and intercostal arteries
ends
- crosses over dome of left pleura
- passes medial to scalenus anterior
- enters confluence of left IJV and left subclavian
What does the thoracic duct drain?
everything in the body except right head/neck/thorax and upper limb