Principles of anatomy and physiology for physical training instructors in the Royal Air Force.

Date:
1946
Catalogue details

Licence: Public Domain Mark

Credit: Principles of anatomy and physiology for physical training instructors in the Royal Air Force. Source: Wellcome Collection.

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    6. Muscles of, the Pelvis (Figure 54) There are four pairs of muscles forming the floor of the pelvis; only the levatores ani will be described. FiGure 54—Section through pelvis viewed from the side showing the right levator ani (male) A—Opening for anal canal B—Opening for urethra The Jevator ani (the elevating muscle of the anus) has a name which does not do full justice to its function ; each is a broad thin muscle on either side of the floor of the pelvis ; together they form what is called the pelvic diaphragm ; the two muscles plug the gap in the pelvis and prevent the descent of the abdominal contents which would occur in their absence. Origin : from the front, sides, and back of the pelvis. Insertion : each muscle unites in the midline of the pelvic cavity with its fellow on the opposite side, leaving a gap for the anal canal and urethra* in the male and for the vagina, urethra and the anal canal in the female. Action : in addition to their important function of supporting the abdominal] contents, they constrict the anal canal and raise the pelvic floor thus controlling defecation. * The urethra is the passage through which urine is expelled from the bladder.
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