a combining form with the meanings âheight,â âtip end,â âextremities of the body,â used in the formation of compound words: acrophobia. Also, especially before a vowel, acr-. Origin of acro-. < Greek, combining form of Ã¡kros topmost, highest; akin to Latin Äcer sharp.
â¢ CANTUS FIRMUS (noun) The noun CANTUS FIRMUS has 1 sense: 1. a melody used as the basis for a polyphonic composition. Familiarity information: CANTUS FIRMUS used as a noun is very rare. Dictionary entry details.
The muscularis externa (muscularis for short) is the muscular wall of the GI tract, deep to (surrounding) the submucosa. The tongue and the muscularis of the upper esophagus consists of striated muscle. Along the rest of the tract, the muscularis consists of two distinct layers of smooth muscle.roceeding from the inside (i.e., ab luminally from the lumen): 1  Mucosa -- innermost layer (closest to the lumen), the soft, squishy lining of the tract, consisting of epithelium, lamina propria, and muscularis mucosae. 2  Submucosa -- connective tissue supporting (outside, deep to) the mucosa.