tracheali

Tracheali is a term found in Latin and some modern languages meaning “of the trachea.” In anatomical usage it is most often encountered as part of the name for the trachealis muscle (musculus trachealis), the smooth muscle band that forms the posterior wall of the trachea. The plural or adjectival form tracheali may appear in older texts or in certain language traditions.

Anatomy and structure

The trachealis muscle runs along the back of the trachea, bridging the ends of the C-shaped hyaline cartilage rings that give the trachea its characteristic ringed structure. It constitutes the membranous portion of the trachea’s wall and lies adjacent to the esophagus, within the deep layers of the posterior tracheal wall. The muscle is continuous with the muscularis of the adjacent lower pharynx and upper esophagus and is supplied by the surrounding submucosa and connective tissue.

Function

Contraction of the trachealis muscle reduces the diameter of the tracheal lumen, which can raise airway resistance and enhance the pressure generated during coughing, aiding expulsion of a foreign body or secretions. Relaxation of the muscle increases the lumen size, allowing freer airflow during inspiration. The muscle works in concert with the cartilaginous rings to accommodate changes in airway pressure and volume during respiration.

Innervation and circulation

The trachealis muscle receives autonomic innervation, with parasympathetic and sympathetic fibers mediated by the vagus nerve and thoracic sympathetic pathways, respectively. Blood supply comes from nearby branches, including arteries such as the inferior thyroid and bronchial arteries, with venous drainage to tracheobronchial veins.

Clinical notes

Variations in the thickness or tone of the trachealis can affect airway dynamics, and conditions affecting the posterior tracheal wall (such as tracheomalacia) influence airway stability. Species differences exist in the relative development of this muscular wall.

See also

Trachea, trachealis muscle, esophagus, cartilage rings.