Older texts have asserted the existence of a urogenital diaphragm, also called the triangular ligament, which was described as a layer of the
pelvis
The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton).
The ...
that separates the
deep perineal sac from the upper pelvis, lying between the
inferior fascia of the urogenital diaphragm (perineal membrane) and
superior fascia of the urogenital diaphragm.
While this term is used to refer to a layer of the pelvis that separates the
deep perineal sac from the upper pelvis, such a discrete border of the sac probably does not exist.
While it has no official entry in
Terminologia Anatomica
''Terminologia Anatomica'' is the international standard for human anatomical terminology. It is developed by the Federative International Programme on Anatomical Terminology, a program of the International Federation of Associations of Anatomi ...
, the term is still used occasionally to describe the muscular components of the deep perineal pouch. The urethra and the vagina, though part of the pouch, are usually said to be passing through the urogenital diaphragm, rather than part of the diaphragm itself.
Some researchers still assert that such a diaphragm exists,
and the term is still used in the literature.
The urethral diaphragm is an anatomic landmark used in
radiologic and
urologic classification of
urethral injury
The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra ...
. Specifically, when a retrograde
urethrogram demonstrates extension of contrast from the proximal bulbous urethra into the
perineum
The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis (pubic arch) and the coccyx (tail bone), includi ...
, there is an increase of grading of the injury from a Type 2 to a Type 3 classification.
The term "urogenital diaphragm" is often confused with the pelvic diaphragm (
pelvic floor), which is a true diaphragm supporting many of the pelvic organs.
References
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Perineum