The research part of this work is focussed on the macroscopic and microscopic evaluation of the insertional area of the diaphragm into the intercostal area of the anterolateral part of the lower thoracic apertuře. Dissection and histological processing of tissue was performed, according to the presented proceduře, on 3 cadavers (2 females, 1 male, 6th and 7th decennium). It was discovered that the diaphragm's muscle fascicles, which are directed into the intercostal space of the area of interest, continually cross-over into the muscle fascicles of the transversus abdominis muscle. No transitional fibrous area of tendinous or aponeurotic character was observed macroscopically between the two muscles. Similarly, no fibrous insertion or intersection between the two muscles was observed microscopically in the mentioned area. The crossover of the two aforementioned muscles was impossible to differentiate both macroscopically and microscopically. The results of this work support the repeatedly proven fact of functional interpiay between the diaphragm and the transversus abdominis muscle. The structural character of the mechanical attachment of both muscles in the area of interest reflects their inseparable participation in respiratory and postural tasks.

        Key words: diaphragm, m. transversus abdominis