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The Perineum
The Anatomy of the Perineum
Question | Answer |
---|---|
* What borders the perineum: anteriorly, inferiorly, anteriorly, anterior and laterally, posterior and laterally, posteriorly | Pelvic diaphragm, skin of the perineal region, pubis symphisis, ischiopubic ramus, sacrotuberous ligament, coccyx |
* What are the two pouches contained by the urogenital triangle? | The superficial perineal pouch, and the deep perineal pouch |
What two layers contain the superficial perineal pouch? | The membranous layer of superficial fascia (inferior border) and the perineal membrane (superior border) |
The ____ layer of the superfical fascia of the abdominal wall (____ fascia) extends into the perineal region and over the penis and the scrotum. | membranous; Scarpa's |
What is Scarpa's fascia called hwne it enteres the perineum? | Colle's fascia |
What two structures is the membranous layer of the superficial fascia attached to firmly? | Ischiopubic rami and ischial tuberosities |
Posteriorly, along a line drawn between two ischieal tuberosities, the membranous layer of the superficial fascia fuses to the _____ membrane | Perineal |
What is the perineal membrane? | A fibrous membrane found in the perineum that is attached to the inferior rami of the pubis and ischium (also known as the inferior fascia of the urogenital diaphragm) |
What is the superficial perineal pouch? | It is the space between the membranous layer of the superficial fascia and the perineal membrane |
* Superficial perineal pouch is continuous superiorly onto the anterior abdominal wall as the potential space between _____ fascia and the ___ fascia covering the abdominal musculature (i.e. external oblique musculature) | Scarpa's; deep |
* The superficial perineal pouch extends posteriorly only as far as the boundary between the ____ and ____ triangles. Therefore, it does NOT extend into the ____ triangle. | Urogenital; anal; anal |
Limited laterally in the perineum by the fusion of the ____ fascia to the ____ _____. | Perineal fascia; ischiopubic rami |
The ____ ____ ____ extends as a potential space within the scrotum and penis. It extends into the thigh where it fuses with the deep fascia of the thigh (the fascia ____) along a line just below and parallel to the ____ ligament. | superficial perineal pouch; lata; inguinal |
Posteriorly, the fusion of the ____ layer of the superficial fascia and the _____ membrane form the posterior boundary. | membranous; perineal |
* * What are the contents of the superficial perineal pouch? | Root (erectile tissue), bulb/vestibular bulb, the crura of the penis/clitoris; bulbospongiosus muscle, ischiocavernous muscles, superficial transverse perinei muscles, and the greater vestibular glands |
What structure splits the vestibular bulb into to in females? | The Vagina |
The bulb is attached to the undersurface of what diaphragm? | The urogenital diaphragm |
This structure encloses the entire length of the penile (spongy) urethra | Bulb of the penis |
The bulb is continue forward into the body of the penis and forms ____ ____. It is invested by a thin sheath of ____ muscle. | Corpus spongiosum; bulbospongiosus m |
Where is the crura of the penis/clitoris located? What structure do they join to form? | In the superficial perineal pouch; each crus is attached to the ischiopubic ramus; join the corpus spongiosum in the region of the pubic arch. Come to lie side by side forming corpora cavernosa |
The ____ muscles invest the crura of the corpora cavernosa. These are thin sheath of skeletal muscles arise from the ischial rami at the base of the crura | ischiocavernosus muscles |
What muscles cover the bulb of the penis/vestibular bulb? What is its function? | Bulbospongiosus muscle; compresses the penile part of the urethra, emptying it of urine/semen; compresses deep dorsal vein of the penis impeding the venous drainage (for erection) |
What do the ischiocavernous muscles do? | Cover the crura of the penis/vestibular bulb; compresses the crura to assist in the process of the erection |
What do the superficial transverse perinei muscles do? | Fix the perineal body in the center of the perineum |
What do the greater vestibular glands do? | In females, secrete a lubricating fluid |
Where is the deep perineal pouch located? | Space superior to the perineal membrane. It is between the perineal membrane and the superior fascia of the urogenital diaphragm. Laterally, bounded by the perineal membrane and superficial fascia of the urogenital diaphragm (fused to ischiopibic rami) |
What is the posterior border of the deep perineal pouch? | Both superior fascia of the urogenital diaphragm and the perineal membrane are fused along a line between the two ischial tuberosities (border between urogenital and anal triangles) |
What are the contents of the deep perineal space/pouch in males? Muscles, glands, and notable nerve branches | Sphincter urethrae muscle, deep transverse perineal muscle, internal pudental artery and vein, branches of the perineal nerve, and bulbourethral glands in male |
What does the sphincter urethrae muscle do? Where is it? | Compresses membranous part of urethra / relaxes during micturation; arises from pubic arch on both sides, passes medially to encircle urethra, supplies perineal branch of pudendal nerve |
What does the deep transver perineal muscle do? | Located posterior to the sphincter urethra muscle; each muscle arises from the ischial ramus and passes medially to be inserted in the perineal body |
What do the bulbourethral glands do (in male)? | Lie beneath sphincter urethrae muscles; pierce perineal membrane and enter penile urethra; homologous to greater vestibular glands in female |
What are the contents of the deep perineal pouch in females? | Same as men, but greater vestiblar glands are absent, vagina passes through, and sphincter urethrae pierced by urethra and vagina |
On the superior surface of the sphincter urethrae and the deep transverse perineal muscles, the fascia is called the ___ ___ of the ___ ____. | Superior fascia of the urogenital diaphragm |
Where is the deep space? | Between the superior fascia of the urogenital diaphragm and the perineal membrane (which is also called the inferior fascia of the urogenital diaphragm) |
What is the urogenital diaphragm? Where is it located? | It is a triangular musculo-fascial diaphragm filling the gap of the pubic arch |
The urogenital daphragm consists of ___ ____ and deep ___ ___ muscles along with the fasciae covering them | Sphincter urethrae; transverse perenei |
What are the components of the urogenital diaphragm? | Superior fascia of the urogenital diaphragm, the sphincter urethrae muscle, the deep transverse perinei muscle, and the perineal membrane (inferior fascia of the urogenintal diaphragm) |
* If a patient suffers a urethral rupture within the __ ___ pouch, urine will extravasate into superficial perineal pouch when the patient attempts to urinate. Where will urine accumulate? | superficial perineal; figure it out : | |
What are the borders of the anal triangle? | Tip of coccyx to the ischial tuberosities; imaginary line drawn between two ischial tuberosities; anal triangle triangle extends from the skin inferiorly to the pelvic diaphragm superiorly |
What structure lies in the middle of the anal triangle? | The anal canal opening |
The spaces on either side of the anal canal are called the ___ ___ ____. | Ischioanal (ischiorectal) fossae |
What are the ischioanal fossa filled with? | Fat between the skin and the pelvic diaphragm |
Do the left and right ischioanal fossa communicate with one another? Why is this important? | Yes, they make contact; this means an infection in one can extend to the other fossa |
What are the boundaries of the ischioanal fossa? Anterior, posterior, lateral, superomedial, inferior? | Anterior: transverse perinei. Post: gluteus maximus muscle and sacrotuberous muscle. Lateral: fascia covering obturator internus muscle. Superomedial: external anal sphincter and levator ani. Inferior: skin covering anal triangle |
What are the contents of the ischioanal fossa? | Fat (liquid at body temp.); inferior rectal nerve and vessels; internal pudental vesels and pudental nerve; perineal branches of posterior femoral cutaneous nerve |
The ischioanal fossa extends as a potential space between what two diaphragms? What is this space called? How far can infections here extend? | Pelvic and urogenital; anterior recess of the ischiorectal fossa; can extend anteriorly to the pubic bone |
What is the perineal body? | Thickening of fascia that lies at the midpoint of a line drawn between the two ischial tuberosities. Perineal body may be damaged during parturation |
What are the muscles attached to the perineal body? | Superficial transverse perineal muscles; deep transverse perineal muscle; bulbospongiosus muscle; levator ani |
Where does the pudental nerve originate? (Cord segments) | S2-S4 |
What nerve supplies the perineal structures? What artery? What vein? | Pudental nerve; internal pudental artery; internal pudental vein parallels course of artery and drains all structures that it supplies EXCET Penis/clitoris, which travles to pelvic venous plexus |
Describe the course of the internal pudental vessels and pudental nerve from the pelvis to the perineum | Exit pelvis via greater sciatic foramen; wrap around ischial spine; pass through lesser sciatic foramen, enter perineum; lie in pudental canal; leave pudental canal and branch out to specific structures |
Where is the pudental canal? | lies against the obturator internus muscle; sleeve of obturator internus fascia that encloses internal pudental vessels and pudental nerve |
What nerve is annastesized if you want to relieve perineal pain during childbirth? | The pudental nerve; close to ischeal spine, which provides useful landmark |
Name the structures found in the deep perineal piuch of the male | Deep transverse perineal muscle, sphincter urethrae, membranous urethra, internal pudental vesssl, perineal nerve branches, dorsal nerve of the penis, bulbourethral galnds |
Name the structures found in the deep perineal piuch of the female | Deep transverse perineal muscle, sphincter urethrae, membranous urethra, internal pudendal vessels, perineal nerve branches, dorsal nerve of the clitoris, portion of vagina; greater vestibular glands are found in SUPERFICIAL PERINEAL POUCH |