Sievert: Anal Triangle Flashcards
What does the sacrospinous ligament connect?
the sacrum to the ischial spine
What does the sacrotuberous ligament connect?
the sacrum to the ischial tuberosity
Above the ischial spine is a large notch, the (blank), which is converted into a foramen by the sacrospinous ligament
greater sciatic notch
Final segment of vertebral column
coccyx
Why are the greater and lesser sciatic foramen important?
They allow for nerves and vessels to leave the pelvis and enter the perineum without puncturing the pelvic floor.
The obturator foramen is filled with the (blank)
obturator membrane
What two muscles arise from the obturator membrane and act on the hip joint?
the obturator externus and the obturator internus
How does the obturator internus leave the pelvis to attach to the femur?
It passes through the lesser sciatic foramen
The area inferior to the pelvic diaphragm between the coccyx and the pubis and including all the structures in the two triangles
perineum
Pyramidal fibromuscular mass in the middle line of the perineum at the junction between the urogenital triangle and the anal triangle
perineal body
Perineal body is found in both males and females. In males, it is found between the (blank) and the anus; in females, is found between the (blank) and anus
bulb of the penis; vagina
Two muscles that make up the pelvic floor
levator ani and coccygeus
T/F: There is a dense connective tissue membrane over the obturator internus that forms a tendinous arch
True
The anal triangle in the female is identical to that of the male, but the UG triangle in the female has an additional opening for the (blank)
vagina
How do you get nerves and blood vessels out of the pelvis?
Through the greater sciatic foramen
Vessels and nerves can leave the pelvis through the greater sciatic foramen and then pass into the perineum by running superficial to the (blank) lig. but deep to the (blank) lig
sacrospinous; sacrotuberous
What is the purpose of the vessels leaving the pelvis through the greater sciatic foramen to enter the perineum?
Does not compromise the integrity of the pelvic floor
Boundaries of the ischio anal fossa
Medial: external anal sphincter and Pelvic diaphragm
Lateral: obturator muscle and ischium
Superior: pelvic diaphragm
Posterior: sacrotuberous lig. and gluteus maximus Inferior: Skin
Anterior boundary extends all the way forward to the pubis as the anterior recess
3 things in the anal triangle
- anal canal
- ischioanal fossa
- pudendal nerves and vessels as they pass thru on their way to the UG triangle
As the pudendal nerves pass through the anal triangle toward the UG triangle, what is the first branch they give off?
inferior rectal vessels and nerves
THis muscle is key, because superior gluteal nerves and vessels enter the gluteal region superior to the muscle, while inferior gluteal nerves and vessels enter inferior to this muscle
piriformis muscle
The pudendal nerve exits the pelvis via the greater sciatic foramen, passes superficial to the (blank) ligament, and enters the perineum passing deep to the (blank) ligament
sacrospinous; sacrotuberous
Once in the ischioanal fossa, the pudendal nerve gives off the (blank) and then enters the pudendal canal to travel anteriorly towards the UG triangle.
inferior rectals
The pudendal nerve supplies (blank) innervation to the external sphincter and UG triangle muscles, and (blank) innervation to the perineum.
motor; sensory
The internal pudendal artery and vein follow the (blank) into the canal giving off similar branches.
pudendal nerve
Rectum is approximately 10 cm in length and begins at the (blank) vertebra and extends to the (blank).
S3; rectoanal junction
Where does the anal canal begin? Where does it end?
At the superior limit of the pelvic diaphragm-where the rectal ampulla narrows; anus
The pectinate line marks the point where (blank) motor and sensory above give way to (blank) motor and sensory below
viscero; somatic
The pectinate line is also the point of junction between the embryonic (blank) and the proctodeum.
hindgut
Three blood supplies to the anal canal Which vessel(s) are a branch of the IMA? Which vessel(s) are a branch of the common iliacs?
superior, middle, and inferior rectals
Superior rectal from the IMA
Middle and inferior from the pectinate, which comes off of the common iliacs
Three vessels drain the anal canal with anastomoses, two return to the (blank) and one to the (blank). What can portal hypertension cause?
systemic; portal; varices in the venous plexuses
Above the pectinate line, where do lymph nodes drain? Below the pectinate line, where do lymph nodes drain? Where does all of the lymph ultimately go?
iliac nodes; inguinal nodes; cysterna chyli and thoracic duct
What nerves supply the anal canal above the pectinate line?
hypogastric plexus
What maintains the tone of the internal sphincter? What inhibits tone and evokes peristalsis?
sympathetics; parasympathetics
Above the pectinate line, where do afferents to the spinal cord travel? Below the pectinate line?
S2-4 pelvic splanchnics; inferior rectal nerves
Below the pectinate line, afferent nerves are somatosensory. What does this mean?
They are sensitive to all normal stimuli
This muscle serves an important function in preventing untimely flatulence and defecation during relaxation of the involuntary internal anal sphincter
puborectalis
What innervates the external anal sphincter?
inferior rectals off of the pudendal (S2-4)
What innervates the levator ani?
small branches off the sacral plexus (S4) and some from the inferior rectal
The UG triangle extends from the ischial tuberosities to the (blank) and is filled in by the (blank).
pubis; UG diaphragm
Does the urethra pass through the UG triangle? What else passes through in the female? What is contained in the UG triangle?
yes; vagina; muscles and erectile tissues of the external genitalia
Two muscles of the UG diaphragm in males
deep transverse perineal
sphincter urethrae
The two muscles of the UG diaphragm are encased above and below by a dense connective tissue envelope-the superior and inferior fascia. The inferior fascia is very thick and is referred to as…?
perineal membrane
The perineal membrane serves as the major attachment site of the (blank)
external genitalia
These glands are located in the UG diaphragm. The ducts of the glands enter the urethra more superiorly.
bulbourethral glands
Discuss the barriers of the “deep pouch”
extends superiorly from the perineal membrane to the investing fascia of the pelvic diaphragm
What are the equivalent glands in the female to the bulbourethral gland? Where are these glands located? Where do they drain to?
Bartholin’s glands; located entirely within the superficial pouch; drain to vagina
What are the three bodies of erectile tissue attached to the perineal membrane?
two crura laterally and one midline bulb housing the urethra
What covers the erectile tissues directly? What then covers the deep layer, and binds the tissues together to form the penis?
dense CT called tunica albuginea; deep perineal fascia (Buck’s fascia)
mushroom shaped cap of erectile tissue covered over by foreskin in the uncircumcised male.
glans
This surrounds the corpus spongiosum of the penis
corpus cavernosum
What do the crura of the penis become?
corpora cavernosa
What does the bulb of the penis become?
corpus spongiosum
What layer of fascia is continuous with the deep perineal fascia? What layer of fascia lines the scrotum and ultimately blends with the membranous layer of the abdominal wall?
Buck’s fascia; Dartos fascia
In the female external genitalia, the bulb is split into two and is separated by the vestibule of the vagina. It does not contribute to the formation of the (blank)
clitoris
What forms the glans of the clitoris?
extensions of the crura on either side
The female external genitalia are contained in a dense connective tissue called the (blank)
tunica albuginea
Two muscles of superficial perineal pouch
bulbospongiosus
ischiocavernosus
In males, what are the two muscles of the external genitalia? What covers all three muscles? This layer is continuous with the investing fascia of the anterior abdominal wall muscles.
bulbospongiosus
ischiocavernosus
deep perineal fascia called Gallaudet’s (same as Buck’s on the penis)
Nerves of the perineum: After the pudendal gives off the inferior rectals, it gives off (blank) branches to the muscles, (blank) branches to the skin, and the (blank) nerve to the penis.
deep perineal; superficial perineal; dorsal nerve
This nerve is entirely sensory to the penis
dorsal nerve
Blood flow to the perineum is similar to nerve supply, with the addition of two arteries.
An artery to the bulb and one deep artery running through each crura of the penis
The internal pudendal artery gives off (blank) branches, an artery to the (blank), a (blank) artery to each crura and the (blank) artery of the penis
perineal; bulb; deep; dorsal
Venous return is similar to arterial flow with one exception
dorsal vein of the penis drains to the prostatic plexus no the internal pudendal vein
T/F: The pudendal nerve in the female follows the exact pattern as that in the male
True
T/F: The arterial supply and venous draining in the female is identical to that in the male
True
Internal pudendal artery first gives off inferior rectal artery, then (blank) branches, then an artery to the (blank), (blank) arteries to the crura, and a (blank) artery of the clitoris.
perineal; bulb; deep; dorsal
This fascia replaces the fatty layer and has smooth muscle in the scrotum
Dartos fascia
This fascia is the membranous layer of the superficial fascia
Colles’ fascia
This is an investing layer on the penis and is continuous with Gallaudet’s over the muscles of the genitalia and the UG diaphragm
Buck’s fascia
(blank) fascial layers extend into the anal triangle, but the (blank) fascial layers stop at the posterior border of U-G diaphragm. Both stop at the (blank).
superficial; deep; fascia lata
The (blank) of the vagina is the space between the labia minora. What openings does it contain?
vestibule; urethra, vagina, and greater and lesser vestibular glands
This is the area of skin that overlies the pubic symphysis
mons pubis
Empty into the urethral orifice and secrete a watery fluid similar to that secreted by the prostate
Paraurethral (Skene’s) glands
Three components of the male urethra
prostatic urethra (runs through prostate gland) membranous urethra spongy urethra (longest and lengthiest portion)
The pelvic cavity of the true pelvis has the pelvic floor as its inferior border. The perineum has the pelvic floor as its superior border.
Some sources do not consider “pelvic floor” and “pelvic diaphragm” to be identical, with the “diaphragm” consisting of only the levator ani and coccygeus, while the “floor” also includes the perineal membrane and deep perineal pouch.[2] However, other sources include the fascia as part of the diaphragm.[3] In practice, the two terms are often used interchangeably.
Yep.
