The rectal muscularis is a crucial layer of the rectal wall, composed of smooth muscle fibers that facilitate the movement and expulsion of fecal matter during defecation. It consists of an inner circular layer and an outer longitudinal layer, both of which are essential for maintaining rectal tone and coordinating peristaltic activity.

Rectal Muscularis

Rectal wall

Smooth muscle fibers are non-striated, involuntary muscles found in the walls of hollow organs, such as the intestines and blood vessels, responsible for regulating internal movement and flow. Unlike skeletal muscle, they contract slowly and can sustain contractions for extended periods without fatigue, playing a crucial role in maintaining physiological homeostasis.

Smooth Muscle Fibers

Movement and expulsion of fecal matter

Defecation is the final act of digestion, involving the expulsion of waste material from the digestive tract through the anus. It is a complex process regulated by both voluntary and involuntary control mechanisms, essential for maintaining homeostasis and overall health.

Defecation

Inner circular layer

Outer longitudinal layer

Rectal tone refers to the natural tightness and elasticity of the rectal muscles, which is crucial for maintaining continence and facilitating defecation. It is assessed during physical examinations to evaluate the integrity of the nervous system and the health of the pelvic floor muscles.

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