Human Development Anatomy Flashcards
What is the lumbrosacral trunk?
Where fibres from L4 and all of L5 join, this emerges medial to psoas major and runs inferiorly over the pelvic brim and joins the sacral plexus
What type of outflow is present in the parasympathetic nervous system?
Cranio-sacral: cranial (CN III, VI, IX and X) and sacral (S2,3,4; pelvic splanchnic nerves)
Where do the ovarian arteries originate?
Branches from the abdominal aorta and arise from L2 region
What is the blood supply to the uterus and vagina?
Uterine and vesicular arteries (branches of the internal iliac)
What is the inguinal canal?
Space that passes obliquely through the abdominal wall in the inguinal region, and is found over the medial half of the inguinal ligament
What are the openings at each end of the inguinal canal?
Deep (internal) ring and the superficial (external) ring
Describe the deep (internal) ring of the inguinal canal
An opening in the transversalis fascia and is located at the midpoint of the inguinal ligament. This is the point halfway between the ASIS and the pubic tubercle.
Describe the superficial (external) ring of the inguinal canal
An opening in external oblique aponeurosis. It is located above the pubic tubercle.
What does the inguinal canal contain in males?
Vas deferens, testicular vessels and ilioinguinal nerve
What does the inguinal canal contain in females?
Round ligament of the uterus and ilioinguinal nerve
What forms the walls of the inguinal canal?
Anterolateral muscles of the abdominal wall (external oblique, internal oblique and transversus abdominis) and their aponeuroses
What are the boundaries of the urogenital triangle?
Roof = pelvic diaphragm (levator ani and coccygeus muscles) Walls = narrow walls of the pelvic cavity below the attachment of the levator ani muscle. Posterior = perineal body
What are the two divisions of the perineum?
Urogenital and anal triangles
What does the deep perineal pouch contain in females?
Proximal part of the urethra, mass of smooth muscle and dorsal neurovasculature of the clitoris
Where does the superficial perineal pouch lie?
Between the perineal membrane and the membranous layer of the superficial fascia is the superficial perineal pouch, which contains the erectile tissues of the clitoris and associated skeletal muscles
What are the contents of the superficial perineal pouch in women?
Clitoris and associated muscle (ischiocavernosis), bulbs of the vestibule and surrounding muscle (bulbospongiosis), greater vestibular glands, deep perineal branch of internal pudendal vessels and nerve, superficial transverse perineal muscle
What is the anorectal ring?
the junction of the rectum, anal canal, the internal sphincter, the deep part of the external sphincter and the puborectalis muscle form the anorectal ring
Describe the internal anal sphincter
Involuntary sphincter
Describe the external anal sphincter
Voluntary sphincter and the puborectalis fibres of the levator ani blend with the deep fibres of the external sphincter
Describe the descent of the testes in development
Testes develop high on posterior abdominal wall –> descend through the inguinal canal in the anterior abdominal wall and into the scrotum of the perineum.
What is the tunica vaginalis?
The serous covering of the testis
What is the tunica albuginea?
The fibrous covering of the testis, superficial to the tunica vaginalis
Which artery supplies the testis and from which vessel does it branch?
Testicular artery from the abdominal aorta
Which vein drains the testis, and into which vessels does this then drain?
Testicular vein and this drains into the IVC on the right side and the left renal vein on the left side
How is the pampniform plexus involved in regulating the testicular temperature?
It’s a network of very small veins in the spermatic cord which act as a heat exchanger too cool blood in adjacent arteries
Describe the path of the vas deferens
Begins at tail of epididymis (superior pole) –> ascends testis medial to epididymis –> spermatic cord –> inguinal canal –> crosses external iliac vessels –> passing between ureter and bladder –> medial to seminal vesicles –> joins seminal vesicle duct to form ejaculatory duct –> urethra
Describe the 3 coverings of the peritoneal outpouching formed by the tunica vaginalis
Transversalis fascia (deepest), musculature of internal oblique, aponeurosis of external oblique (superficial)
Describe the gubernaculum
Helps descent of testis and extends from the inferior border of the developing gonads to the labioscrotal swellings
Why are there no parasympathetic fibres in the spermatic cord?
Because only sympathetic innervation is used in ejaculation
Describe the pouch of Douglas in females
Deep recto-uterine pouch (posteriorly between the uterus and rectum), and is the lowest point in the female pelvis
What is the trigone in the bladder?
Smooth triangular area between the openings of the ureters and urethra on the inside of the bladder
Describe the structure of the bladder
Apex directed towards top of pubic symphysis, base of bladder shaped like inverted triangle (faces posteroinferiorly)
Which muscles ‘cradle’ the inferolateral surfaces of the bladder?
Cradled between the levator ani muscles of the pelvic diaphragm and the adjacent obturator internus muscle
What is the infundibulum?
Expanded trumpet-shaped end of uterine/Fallopian tube
What is the fimbriae?
Finger-like projections on the end of the Fallopian tube
What is the ampulla of the ovary?
The stem of the Fallopian tube that carries eggs to the uterus
Describe the broad ligament
Peritoneal fold that suspends the uterus and the uterine tubes