Pelvis Flashcards
What is the origin of the obturator internus muscle?
Anterolateral wall of the true pelvis (deep surface of obturator membrane and surrounding bone)
What is the insertion of obturator internus?
Medial surface of the greater trochanter of the femur
What is the function of the obturator internus muscle?
Lateral rotation of the extended hip joint
Abduction of the flexed hip
What is the innervation of the obturator internus muscle?
Nerve to obturator internus (L5, S1)
What is the origin of piriformis?
Anterior surface of sacrum between anterior sacral foramina
What is the insertion of piriformis?
Medial side of the superior border of the greater trochanter of the femur
What is the function of piriformis?
Lateral rotation of the extended hip
Abduction of the flexed hip
What is the innervation of piriformis?
Branches from L5, S1 and S2
Which muscles form the pelvic diaphragm?
Levator ani: iliococcygeus, pubococcygeus and puborectalis (from lateral to medial)
Coccygeus
What are the borders of the urogenital triangle?
Pubic symphysis, ischial tubersoties and perineal body
What are the borders of the anal triangle?
Perineal body, ischial tuberosities and coccyx
What is the function of the pelvic diaphragm?
Pelvic floor, supports the pelvic viscera, maintains an angle between the rectum and anal canal, reinforces the external anal sphincter, functions as a vaginal sphincter in women, pulls coccyx forward after defecation
What are the four parts of the male urethra?
Preprostatic, prostatic, membranous and spongy
Briefly describe the preprostatic urethra
It is about 1cm long, extends from the base of the bladder to the prostate and it is associated with the internal urethral sphincter which prevents retrograde movement of semen during ejaculation
Where do the ducts of the prostate empty in to?
The prostatic urethra - the lumen is marked by a longitudinal midline fold of mucosa (the urethral crest). The depression on each side of the crest is the prostatic sinus; the ducts of the prostate empty in to here.
What is the seminal colliculus?
An enlargement of the urethral crest midway along its length to form a somewhat circular elevation. The prostatic utricle opens on to the centre of the seminal colliculus
What might you find on each side of the prostatic utricle?
The opening of the ejaculatory duct
Briefly describe the membranous part of the urethra
It is narrow and passes through the deep perineal pouch. During its transit through this pouch, it is surrounded by skeletal muscle of the external urethral sphincter.
Briefly describe the spongy part of the male urethra
It is surrounded by erectile tissue (corpus spongiosum). It is enlarged at its base and at the end to form the navicular fossa. The two bulbourethral glands open in to the bulb of the spongy urethra. The external urethral orifice is the sagittal slit at the end of the penis.
Where is the trigone?
It is the smooth triangular area between the openings of the ureters and the urethra on the inside of the bladder. Stretch receptors are located here.
Where is the median umbilical ligament and what is it a remnant of?
From the apex of the bladder it continues superiorly up the anterior abdominal wall to the umbilicus. It is a remnant of the embryological urachus that contributes to the formation of the bladder.
What is the urachus?
A fibrous remnant of the allantois, a canal that drains the urinary bladder of the fetus that joins and runs in the umbilical cord
What is the interureteric crest?
The horizontal line that extends between the two urethral orifices inside the bladder
Where is the scrotal ligament found and what is it a remnant of?
Attaching the inferior pole of the testis to the scrotum and it is a remnant of the gubernaculum
What is the lymph drainage of the testes?
Lateral aortic or lumbar nodes and preaortic nodes. Due to descent of testes from abdomen carrying vessels and lymphatics.
What are the sides and anterior part of the testis covering by?
A closed sac of peritoneum - the tunica vaginalis
What structures are within the testis?
Seminiferous tubules and interstitial tissue
What encloses the seminiferous tubules and interstitial tissue?
A thick connective tissue capsule, the tunica albuginea
What do the seminiferous tubules connect to?
They become straight tubules and connect to a collecting chamber, the rete testis
Where is the rete testis located?
In a thick, vertically orientated linear wedge of connective tissue, the medistinum testis, projecting from the capsule into the posterior aspect of the gonad
What are the two distinct components of the epididymis?
The efferent ductules and the true epididymis
What do the efferent ductules form?
They form an enlarged coiled mass that sits on the posterior superior pole of the testis and forms the head of the epididymis
What is the true epididymis?
A single, long coiled duct into which the efferent ductules all drain, and which continues inferiorly along the posterolateral margin of the testis as the body of the epididymis and enlarges to form the tail of epididymis at the inferior pole of the testis
When does the ductus deferens become the ejaculatory duct?
When it is joined by the duct of the seminal vesicle
Where is the ampulla of the ductus deferens?
Between the ureter and ejaculatory duct, the ductus deferens expands to form the ampulla of the ductus deferens
Where are the seminal vesicles located?
It is immediately lateral to and follows the course of the ductus deferens at the base of the bladder
Where are the bulbourethral glands located?
There is one of each side, they are small, pea-shaped mucous glands situated within the deep perineal pouch. They are lateral to the membranous part of the urethra.
Where do the ducts of the bulbourethral glands open in to?
They open in to the bulb of the spongy urethra at the root of the penis