Pelvic fascia
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The pelvic fasciae are the
fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organs. ...
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 ...
and can be divided into: * (a) the fascial sheaths of ** the
Obturator internus The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis. It exits the pelvic cavity through the lesser sciatic foramen. The i ...
muscle ( Fascia of the Obturator internus) ** the
Piriformis The piriformis muscle () is a flat, pyramidally-shaped muscle in the buttock, gluteal region of the lower limbs. It is one of the six muscles in the lateral rotator group. The piriformis muscle has its origin upon the front surface of the sacrum, ...
muscle ( Fascia of the Piriformis) ** the
pelvic floor The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus muscle, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the lev ...
* (b) fascia associated with the organs of the pelvis.


Structure


Fascia of pelvic organs

Pelvic fascia extends to cover the organs within the pelvis. It is attached to the fascia that runs along the pelvic floor along the tendinous arch. The fascia which covers pelvic organs can be divided according to the organs that are covered: * The front is known as the "vesical layer". It forms the anterior and lateral ligaments of the
bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine enters ...
. * In males, its middle lamina crosses the floor of the pelvis between the rectum and vesiculæ seminales as the ''rectovesical septum''; in the female this is perforated by the
cervix The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...
and is named the transverse cervical ligament. * At the back, the fascia passes to the side of the
rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the Gastrointestinal tract, gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the s ...
; it forms a loose sheath for the rectum, but is firmly attached around the
anal canal The anal canal is the part that connects the rectum to the anus, located below the level of the pelvic diaphragm. It is located within the anal triangle of the perineum, between the right and left ischioanal fossa. As the final functional segment ...
. This portion is known as the "rectal layer".


Fascia of the pelvic floor

;Superior The part of the pelvic fascia on the pelvic floor covers both surfaces of the
Levatores ani The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of t ...
muscle. The layer covering the upper surface of the
pelvic diaphragm The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus muscle, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the leva ...
follows, above, the line of origin of the Levator ani and is therefore somewhat variable. In front it is attached to the back of the
pubic symphysis The pubic symphysis is a secondary cartilaginous joint between the left and right superior rami of the pubis of the hip bones. It is in front of and below the urinary bladder. In males, the suspensory ligament of the penis attaches to the pubic ...
about 2 cm above its lower border. It can then be traced laterally across the back of the
superior ramus of the pubis In vertebrates, the pubic region ( la, pubis) is the most forward-facing (ventral and anterior) of the three main regions making up the coxal bone. The left and right pubic regions are each made up of three sections, a superior ramus, inferior r ...
for a distance of about 1.25 cm, when it reaches the
obturator fascia The obturator fascia, or fascia of the internal obturator muscle, covers the pelvic surface of that muscle and is attached around the margin of its origin. Above, it is loosely connected to the back part of the arcuate line, and here it is conti ...
. It is attached to this fascia along a line which pursues a somewhat irregular course to the
spine of the ischium The ischial spine is part of the posterior border of the body of the ischium bone of the pelvis. It is a thin and pointed triangular eminence, more or less elongated in different subjects. Structure The pudendal nerve travels close to the isch ...
. The irregularity of this line is because the origin of the Levator ani, which in lower forms is from the
pelvic brim The pelvic brim is the edge of the pelvic inlet. It is an approximately Mickey Mouse head-shaped line passing through the prominence of the sacrum, the arcuate and pectineal lines, and the upper margin of the pubic symphysis. Structure The pel ...
, is in man lower down, on the obturator fascia. Tendinous fibers of origin of the muscle are therefore often found extending up toward, and in some cases reaching, the pelvic brim, and on these the fascia is carried. ;Inferior The diaphragmatic part of the pelvic fascia covers both surfaces of the
Levatores ani The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis. It is attached to the inner surface of each side of t ...
. The inferior layer is known as the
anal fascia The anal fascia is the inferior layer of the diaphragmatic part of the pelvic fascia, which covers both surfaces of the levatores ani. It is attached above to the obturator fascia along the line of origin of the levator ani, while below it is conti ...
. It is attached above to the
obturator fascia The obturator fascia, or fascia of the internal obturator muscle, covers the pelvic surface of that muscle and is attached around the margin of its origin. Above, it is loosely connected to the back part of the arcuate line, and here it is conti ...
along the line of origin of the Levator ani, while below it is continuous with the superior fascia of the
urogenital diaphragm Older texts have asserted the existence of a urogenital diaphragm, also called the triangular ligament, which was described as a layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of t ...
, and with the fascia on the
Sphincter ani internus The internal anal sphincter, IAS, (or sphincter ani internus) is a ring of smooth muscle that surrounds about 2.5–4.0 cm of the anal canal; its inferior border is in contact with, but quite separate from, the external anal sphincter. It is m ...
.


Additional images

File:Gray547.png, The relations of the femoral and abdominal inguinal rings, seen from within the abdomen. Right side.


References


External links

* {{Authority control Pelvis Fascia