Background: Oesophagus is a muscular tube that transports food and liquidsby coordinated contraction of its muscular lining led by stimuli from the nerveplexus. Its muscularis proper layer consists of muscle cells, connective tissue andmyenteric plexus. The aim of our histomorphometric study was to reveal detailedcharacteristics of this layer, cell number, volume, orientation, properties of myentericplexus as well as changes related to aging.

Materials and methods: Oesophagus tissue samples from 17 male cadavers weretaken from the cranial and thoracic parts. Samples were divided in 2 groups: younger(ages 21–45) and older (ages 66–78). The tissue was routinely processed,embedded and serially sectioned. Sections were stained with Masson-Goldner andCresyl-violet dyes. Digital images were analysed with the image analysis software.Statistics were performed with SPSS software.

Results: The average thickness of the cranial part of the oesophageal wall andmuscularis proper was 2590 μm and 1197 μm, respectively in the younger and2453 μm and 1144 μm in the older group. Overall volume of the muscle tissuewas slightly larger in the thoracic part, and in the younger group comparedto the cranial part and the older group. The average number of the striatedmuscle cells per 100 μm in the cranial part was 771.5 and 749.7 in the youngerand the older group, respectively. Striated cells were significantly lesspresent only in the lower thoracic part of the oesophagus. In the older group,smaller striated muscle cells dominated over the larger ones. In the youngergroup, majority of the striated muscle cells were mid-sized. The thickness ofthe circular layer of muscularis proper was more affected by aging than thelongitudinal one. Ganglion cells number was lower in the older group, butplexus area was unchanged.

Conclusions: Aging affects muscularis proper and myenteric plexus of the oesophagus.Major differences can be observed in the striated muscle cells size, volumeof the circular layer and number of the ganglionic cells in the myenteric plexus.