Corpus: Trachealis muscle

The term trachealis muscle refers to the bundles of smooth muscle cells in the dorsal wall of the trachea (paries membranaceus).

The trachealis muscle consists of two layers;

• a clearly defined inner ring muscle layer
• an only partially present, weakly developed outer longitudinal muscle layer

The circular fibres of the ring muscle layer attach to the perichondrium of the cartilage clasps (cartilagines tracheales) of the trachea in the area of the paries membranaceus. The longitudinal muscle layer is limited to the cartilage-free, ventral and lateral wall sections of the trachea. It is absent in the area of the paries membranaceus.

The trachealis muscle is innervated by the recurrent laryngeal nerve from the vagus nerve.

The trachealis muscle can reduce the lumen of the trachea through contraction. This is particularly beneficial when coughing up foreign bodies, as the reduction in the tracheal cross-section increases the flow velocity in the trachea.

Harjeet, Sahni D, Jit, Development of the human trachea, J.Anat.Soc.India 53 (1) 1-3 (2004)