muscular layer
Last reviewed 01/2018
The muscular layer of the oesophagus is divided into two parts:
- outer longitudinal layer
- inner circular layer
In the upper third, skeletal muscle predominates. In the inferior two thirds, smooth muscle is more common. There is a transition between the two sets of fibres.
Functionally, the skeletal muscle may be present superiorly to increases the transit rate of a food bolus through this section. This permits more rapid reopening of the larynx so that breathing may be resumed.
There is no anatomical thickening of the muscular layers within the inferior oesophageal wall i.e. there is no true intramural sphincter.