Anatomy practical Flashcards
Path of pudendal neurovascular bundle
- Exits greater sciatic foramen below piriformis muscle
- Travels through lesser sciatic foramen to enter the ischioanal fossa
- Travels in the pudendal canal (within the obturator internus fascia)
- Enters the urogenital triangle
Borders of the ischioanal fossa
Lateral: obturator internus muscle
Medial/superior: pelvic diaphragm (mostly levator ani)
Inferior: membranous layer of the superficial layer of the gluteal region
Levator ani muscles
Puborectalis
Pubococcygeus
Iliococcygeus
Puborectalis attachments
Origin: superior pubic rami
Insertion: anococcygeal ligament
Pubococcygeus attachments
Origin: pubis (lateral to puborectalis)
Insertion: anococcygeal ligament, coccyx
Iliococcygeus attachments
Origin: tendinous arch of the levator ani
Insertion: anococcygeal ligament, coccyx
Iliococcygeus innervation
Sacral plexus (S4), pudendal nerve (S2-S4) via inferior rectal nerve
External anal sphincter innervation
Pudendal nerve (S2-S4) via inferior rectal nerve
Inferior rectal nerve functions
- sensory innervation to anal canal inferior to pectinate line
- motor innervation to external anal sphincter
Bulbospongiosus muscle attachments
perineal body and clitoris/penile raphe
Bulbospongiosus muscle innervation
Pudendal nerve (S2-S4)
Bulbospongiosus muscle actions
Females: compresses vestibular glands
Males: assists in erection of penis
Ischiocavernosus muscle attachments
Origin: Ischial ramus
Insertion: crus of clitoris/penis
Ischiocavernosus muscle innervation
Pudendal nerve (S2-S4)
Ischiocavernosus muscle actions
Maintain erection by squeezing blood into penis or clitoris
Colles’ fascia other name
superficial perineal fascia
Where is the perineal membrane found, and what does it look like?
White inferior fascia covering the deep transverse perineal muscle
Deep transverse perineal muscle attachments
Origin: Inferior pubic ramus and ischial ramus
Insertion: perineal body (central tendon), prostate/wall of vagina
External urethral sphincter location
Circular fibers within the deep transverse perineal muscle
External urethral sphincter innervation
Pudendal nerve (S2-S4)
Deep transverse perineal muscle innervation
Pudendal nerve (S2-S4)
Superficial transverse perineal muscle attachments
Origin: ischial ramus (posterior inferior part)
Insertion: perineal body (central tendon)
Superficial transverse perineal muscle innervation
Pudendal nerve (S2-S4)
Neurovascular strucutres on the dorsum of the penis
Deep dorsal penile vein at the midline, with dorsal penile arteries and nerves on either side
Dartos fascia other name
Superficial penile fascia
Buck’s fascia other name
Deep penile fascia
Tunica albuginea location
Surrounding corpora cavernosa; surrounding testicle (below tunica vaginalis); surrounding ovary
Deep penile artery location
Within the corpora cavernosa
Spongy urethra location
Within the corpus spongiosum
The external spermatic fascia is continuous with what muscle?
External oblique muscle
Cremaster muscle is continuous with what muscle?
Internal oblique muscle
Internal spermatic fascia is continuous with what muscle?
Transversalis fascia
Where do scrotum lymphatics drain
Superficial inguinal nodes
Where do lymphatics from testes drain?
Lumbar (para-aortic) nodes
Parts of the broad ligament
Mesometrium- covers the uterus
Mesosalpinx- covers the uterine tube
Mesovarium- connects to the ovary
Between which nervous structures does the superior gluteal artery pass?
Lumbosacral trunk and S1
Visceral motor innervation above the pectinate line
Inferior hypogastric plexus
Good anchor point for sutures during hernia repair and anti-incontinence surgeries
Pectineal (Cooper’s) ligament
Location of pectineal (Cooper’s) ligament
Within the pectineal line, a ridge on the superior pubic ramus
Pelvic floor muscle that attaches to ischial spine
Coccygeus muscle
Coccygeus muscle innervation
Pudendal nerve (S2-S4), sacral nerves (S3-S5, varies)
Lowest part of peritoneal cavity in female; where fluid may accumulate
Pouch of Douglas (rectourterine pouch)
Where would a needle be inserted to drain the pouch of Douglas?
Posterior fornix
Main sympathetic supply to pelvis; continuation of aortic plexus
Superior hypogastric plexus
Indications and location for presacral neurectomy
Women with pelvic pain (e.g. dysmenorrhea). Resection of superior hypogastric plexus.
Connect superior and inferior hypogastric plexuses
Right and left hypogastric nerves
Connect sacral sympathetic trunks to inferior hypogastric plexues
Sacral splanchnic nerves
Pure parasympathetic innervation in the pelvis
Pelvic splanchnic nerves
Main supply to pelvis; mixed sympathetic and parasympathetic fibers
Inferior hypogastric plexus
Structures above the “pelvic pain line.” What is their innervation?
Those in contact with peritoneal covering.
o Male: top of bladder
o Female: top part of bladder, top part of uterus
Follow sympathetics retrograde to T11-L2 spinal levels/dermatomes.
Sensory/pain innervation below “pelvic pain line”
Follows parasympathetics retrograde via pelvic splanchnic nerves to S2-S4 spinal levels/dermatomes.
Exception to “pelvic pain line” rule; where is its pain line?
Colon; pain line is at midpoint of sigmoid colon
Lymphatic drainage of the vagina
- Superior 1/3- external and internal iliac nodes
- Middle 1/3- internal iliac nodes
- Inferior 1/3- superficial inguinal nodes
Lymphatic drainage of the uterus and cervix
- Fundus/upper body- lumbar (para-aortic) and/or superficial inguinal nodes
- Lower body/cervix- external and internal iliac nodes
Lymphatic drainage of the ovaries and uterine tubes
Lumbar (para-aortic) nodes
Lymphatic drainage of the skin of the penis (shaft)
Superficial inguinal nodes
Lymphatic drainage of the glans (penis)
Deep inguinal and external iliac nodes
Lymphatic drainage superior to pectinate line
Internal iliac nodes
Embryonic origin superior to pectinate line
Endoderm
Blood supply and venous drainage superior to pectinate line
Superior rectal artery; superior rectal veins (portal venous system)
Epithelium superior to pectinate line
Cuboidal epithelium
Epithelium inferior to pectinate line
Stratified squamous epithelium (non-keratinized until Hilton’s white line)
Lymphatic drainage inferior to pectinate line
Superficial inguinal nodes
Blood supply and venous drainage inferior to pectinate line
Internal iliac and inferior rectal arteries; inferior rectal veins (caval venous system)
When does the gubernaculum arise?
Week 7 of embryonic development
What pulls down the testis?
Differential growth of the fetus and shortening of the gubernaculum
What causes hydrocyle?
Remnant of tunica vaginalis (NOT patent), made from peritoneum. Serous, peritoneal-like fluid accumulates. Can be idiopathic or caused by infection.
How do you distinguish hydrocele from a tumor?
Transillumination by flashlight (hydrocele lights up)
Pathophysiology and treatment of testicular torsion
The scrotal ligament (a remnant of the gubernaculum) normally holds the testis in place, but becomes loose. This causes the testis to get twisted on itself and ischemic. Should be treated surgically within five hours (both sides sutured for prevention).
What cryptorchidism and what causes it?
Undescended testis. Commonly occurs in premies.
Causes:
-prematurity
-hormonal disorders
-retractile testes (cremaster m.)
-acquired failure of spermatic cord to grow at pace of body
Name of surgery and normal timing for treatment of cryptorchidism
Orchiopexy/Orchidopexy; usually at 9-15 months
5 ways that testes are thermoregulated
1) Hypothalamic control of specialized sweating and panting
2) Countercurrent cooling of blood in testicular artery by the pampiniform plexus
3) Testicular artery is coiled over surface of testis to dissipate heat before entering
4) Dartos muscle can contract or relax
5) Cremaster muscle can pull up testis
Describe the cremaster reflex
Stroking the inner thigh sends sensory info through the femoral branch of the genitofemoral nerve (L1-L2) and the ilioinguinal nerve (L1). Motor fibers of the genital branch of the genitofemoral nerve are activated, causing contraction of the cremaster muscle.
Type of epithelium within seminiferous tubules
Germinal epithelium
When do primordial germ cells migrate to the gonadal ridge? Where do they come from?
Week 5 of embryonic development; from the yolk sac
How many spermatozoa come from one spermatogonoium?
256 spermatazoa
How long does it take for spermatozoa to mature?
72-74 days
Describe homonymous division in the context of sperm development
Spermatogonium (stem cells) divide. One cell goes on to mature into spermatozoa; the other one stays behind to keep dividing
DNA in primary spermatocyte
4N, diploid
DNA in secondary spermatocyte
2N, haploid
DNA in spermatids/spermatozoa
1N, haploid
Organelles that remain in spermatozoa
Mitochondria are packed into the midpiece of the spermatozoan to power the flagellum
Cells with gap junctions to “nurse” the sperm cells
Sertoli cells (epithelial)
What forms the blood-testis barrier? What happens inside/outside? Why is it there?
Formed by occluding junctions of Sertoli cells.
Hormones produced by Sertoli cells
- anti-mullerian hormone
- inhibin (to regulate FSH, which is needed for sperm development)
Where is androgen binding protein produced, and what is it’s function?
Produced by Sertoli cells; maintains high levels of testosterone in the testes for sperm development
Where is luminal fluid produced, and why is it there?
Produced by Sertoli cells; sperm develop motility in the epididymis, so a current in the luminal fluid is required to carry them there
Cause of Sertoli cell only syndrome
There is evidence that Sertoli cell-only syndrome can be caused by interstitial deletions in the ‘azoospermia factor’ (AZF) region on the long arm of the Y chromosome.
