Gross anatomy of Oesophagus (British English) or Esophagus(American English)

Well it is a known fact that most of the portion of Oesophagus lies in thoracic cavity but a little bit of distal portion of oesophagus do exist in abdominal cavity

Yeah , a little portion of oesophagus.

So let's trace oesophagus and find out how it enters in abdominal cavity.

So what actually separates the thoracic cavity from the abdominal cavity ?

It's the diaphgram, it's a big muscle but tissues and many structure do cross this big muscle to enter from the upper cavity to abdominal cavity like oesophagus, vagal trunks, aorta and vena cava but how they do so?

As you might be knowing that the diaphgram has many opening and passage ways through it for different structure and one of the passage is - "oesophagus hiatus"

Oesophagus hiatus :- is nothing but an opening in right crus (if you are not aware of crus see the next paragraph) of diaphgram through which oesophagus passes when it enters from thoracic to abdominal cavity.

Note :- For those who does not know what crus is:-

"Actually diaphgram is a very big dome shaped muscle and for its proper support and functioning it needs a wide connection to structure so that when this big muscle contracts these connections stabilize it" and crus is one of them, a crus is an extension of diaphgram which connects the diaphgram to lower vertebrae giving the muscle a stability factor.

See the image below showing the crus of the diaphgram :-

So now you are clear with crus, see in above picture, the right crus has a hole in it (see that hole carefully) that hole is - "esophagus hiatus" (hiatus-opening in a solid structure)

See the image below for more clear concept :-

So the oesophagus enters in the abdominal cavity via this esophagus hiatus and it is not the esophagus alone which passes through it

What else passes through " esophagus hiatus "

Oesophagus is not the only structure which passes through this opening

Vagal trunks also passes through this opening. There are two vagal trunks :-"Anterior" and "Posterior", These vagal trunks also accompany the esophagus during his journey

So you find on the:-

Anterior side of esophagus - "Anterior vagal trunk"

Posterior side of esophagus - "Posterior vagal trunk"

Note:- As you might be knowing that foregut undergoes a clockwise rotation so it's all contents also get rotated clockwise that's why the Anterior vagal trunk was once used to be on the left side in embryonic period and posterior vagal trunk used to be on the right side during embryonic times

That's why Anterior vagal trunk (Embryonic left sided) has fibres from left vagal nerve nucei and Posterior vagal trunk (Embryonic right sided) has fibres from right vagal nerve nucei.

Now when esophagus enters through his hiatus from right crus of the diaphgram, it turns slightly on the left side to merge with cardiac portion of stomach. ( we will read it about in gross anatomy of stomach)

Blood supply of Esophagus

We wil read about it in detail when we will talk about the thoraco-abdominal blood circulation as of now just to complete the concept let's talk about it.

1. Upper Abdominal Esophagus (just crossed the hiatus) :- Supplied by "Oesophagal branches of left inferior phrenic artery".
2. Lower Abdominal Esophagus (after its left turn proximal to stomach) :- Supplied by "Oesophagal branches of left gastric artery" (which arises from celiac trunk)

See image below for more clearance :-

Medical science is a visual science especially the anatomy :- so I suggest you to watch "acland video atlas" they are the best, no one can take their place, you can find them online.

Signing off

Bhavesh saini (Author)

¤Student of Knowledge¤