Anatomy – Exam 2 (Part 2)

·  Pelvis (Viscera)

○  Objectives

§  Describe the surfaces of the urinary bladder and the viscera which contacts them

§  Describe the pelvic course of the ureters

§  Define the bladder trigone

§  Describe the pelvic course of the vas deferens

§  Describe the position and gross anatomical structure of the seminal vesicles

§  Discuss the route of a sperm cell during emission and ejaculation

§  Describe the anatomy of the posterior wall of the prostatic urethra

§  Define the lobes of the prostate and understand how enlargement effects urine flow and retention

§  Describe the accessory reproductive glands of the male and define the contribution of each to semen

§  Describe the peritoneal reflections on the pelvic viscera in both sexes

§  Define the parts of the broad ligament

§  List the structures that lie between the lamellae of the broad ligament

§  Delineate the parts of the uterus and vagina

§  Define the normal position of the uterus and the terms anteversion/anteflexion and retroversion/retroflexion

§  Define the ligamentous supports for the uterus

§  Explain the relationships and importance of the pelvic peritoneal pouches

§  Distinguish between false and true pelvis and understand which organs are located in each

§  Explain the relationships of the vaginal fornices to surrounding structures

○  Reminder

  • False Pelvis – pelvic brim to top of ilium
  • True Pelvis – pelvic brim to levator ani

○  Male Stuff

  • No major organs between bladder and rectum in male
  • Prostatic Venous Plexus – unique to males; on anterior bladder surface
  • Prostate – has three lobes defined by the urethra and ejaculatory duct
  • Anterior Lobe – in front of the urethra
  • Posterior Lobe – behind the urethra and ejaculatory duct
  • Median Lobe – in between urethra and ejaculatory duct

○  Most susceptible to benign enlargement

○  Benign Prostatic Hyperplasia – almost all males over 50 have it, but only bad if it encroaches

§  Upward Encroachment – creates bump in urinary bladder and urine can become trapped and stagnant leading to bladder infection

§  Urethral Encroachment – impedes flow of urine causing weak stream, urgency to urinate (often at night), hard to start urinating, urinating in small amounts, trouble stopping urination

§  Simple surgery can treat this

  • Arterial Supply to Prostate

○  Prostatic Artery – a terminal branch of the inferior vesical artery

  • Seminal Glands – on posterior bladder surface
  • Does not actually contain semen, just a component of it

§  Ductus Deferens – travels superior to the union of the ureter to the bladder

·  The two sides do not unite

§  Ampulla of the Ductus Deferens – unites with the seminal gland of the same side to form the ejaculatory duct

·  This union occurs right at surface of prostate gland

  • Note – peritoneum is loose at anterior wall to urinary bladder junction
  • Rectovesical Pouch – lowest point in peritoneal cavity; is the only recess down there in males
  • Note – best place to enter pelvis surgically is just above the pubic symphysis because then you don’t get into the peritoneal cavity
  • Bladder

·  Internal Urethral Sphincter – made of circular muscle extensions of detrussor muscle

○  Closes during sexual arousal, especially during emission and ejaculation to prevent retrograde flow of semen

○  Only in males

  • Involuntary Urinary Continence – Both Sexes

○  The neck region of the bladder creates a passive sphincter that is normally closed due to the CT and elastic tissue in that region

  • Urethra

○  Pelvic part becomes the prostatic part and is longer in males

○  Membranous part goes from superior part of UG diaphragm to perineal membrane; least distensible

○  Penile/spongy part is everything after the perineal membrane

  • Prostatic Part of Urethra
  • Urethral Crest – a ridge along the posterior portion
  • Seminal Colliculus – highest point on urethral crest
  • Prostatic Utricle – embryonic remnant of the vagina; no function
  • Two openings of the ejaculatory duct – just below prostatic utricle
  • Prostatic Ducts – around 30 of them; just little openings in the prostatic sinus
  • Emission - delivery of contents of ejaculatory ducts and prostatic ducts into urethra

·  When these substances are combined you get semen

  • Caused by peristaltic waves from epididymus, ductus deferens, and contraction of smooth muscle in seminal gland and prostate gland
  • Feels good; Ejaculation will occur right after
  • Male Accessory Reproductive Organs
  • Seminal Gland – contributes 60% of semen

○  Creates mucoid substance to help keep semen in vagina

○  Contents

  • Fructose, citric acid and other nutrients for sperm
  • Prostaglandins – react with cervical mucous to make the environment more conducive to sperm movment

○  Reverse peristalsis especially in uterine tube to move sperm toward egg

○  Note – sperm in upper vagina can reach ampulla in 5 minutes

  • Fibrinogen – clotting factor that maintains the mucoid consistency to hold semen in upper vagina
  • Prostate – contributes 30% of semen

○  Creates alkaline, thin and milky substance

○  Citrate, phosphate, calcium for sperm

○  Profibrinolysin – converted to fibrinolysin which, after a delay, causes the lysis of the mucoid clot of semen

  • Sperm make 10% of the semen

○  Note – sperm cells mature in epididymus and can live for 40 days there

  • Bulbourethral Gland – produces contents only during sexual stimulation and does not store secretion

○  Secretions are typically not mixed with semen, they are released ahead of it

○  Male Sex Response

§  Erection – engorgement of erectile tissue due to contraction of perineal muscles

  • Controlled by parasympathetic nervous system
  • Helicine arteries – blood vessels curled in helix and contain smooth muscle

○  Under parasympathetic stimulation the smooth muscle relaxes and causes arterial blood to be dumped into venous erectile tissue

  • Emission
  • Contraction of smooth muscle in ductus deferens, prostate and seminal vesicles
  • Contraction of internal urethral sphincter
  • Release of secretions from testes, prostate gland, seminal vesicles, and bulbourethral glands
  • Mediated by sympathetic nervous system
  • If emission occurs, ejaculation will occur
  • Ejaculation – rhythmic, spasmodic contraction of the perineal muscles, levator ani, external anal sphincter and gluteal muscles causes propulsion of semen along penile urethra
  • Initiated by secretions entering penile urethra
  • Mainly somatic innervation
  • Detumescense/Resolution – return of erectile tissues to flaccid state
  • Involves refractory period which is age dependent
  • Sympathetic nerves cause helicine arteries to contract

○  Female Sex Response

§  Arousal

·  ↑ secretions (vestibular and vaginal)

○  No glands in the wall of the vagina and thus the secretions are a watery transudate from the wall

○  Cervix secretes mucoid substance

  • Erection of clitoris – same as in males, due to parasympathetic stimulation of helicine arteries
  • Plateau – can last minutes to hours
  • General vascular engorgement (clitoris, labia, breast, lower vagina)
  • Erection of nipples
  • “Sex flush” – reddish vascular flushing of skin over breasts and chest
  • Dilation of upper vagina
  • Uterine Tenting – uterus elevated up higher in pelvis so that vagina is longer
  • Orgasm – if orgasm then probably a greater chance of fertilization
  • Rhythmic contractions of perineal muscles (1 second intervals)

○  Number and intensity of rhythmic contractions is highly variable

  • Dilation of cervix
  • Uterine contractions (due to release of oxytocin) helps move sperm to fallopian tubes
  • Uterine Dipping – uterus drops into vagina and pushes vaginal cervix into the semen
  • Resolution – return to pre-excitement stage
  • No refractory period

○  Pelvis

  • Piriformis muscle – goes through greater sciatic foramen
  • Obturator Internus muscle –
  • Tendinous Arch –
  • Urogenital Diaphragm – urinary and genital structures go through; on a flat plane
  • Muscles of Pelvic Diaphgram – no clear distinction
  • Note - Levator Ani is just the iliococcygeus and pubococcygeus
  • Iliococcygeus – originates on tendinous arch over obturator internus and goes to coccyx
  • Ischiococcygeus – ischial spine to coccyx
  • Pubococcygeus – anterior pubic area to coccyx

○  Puborectalis - Medial-most fibers of pubococcygeus meet posterior to rectum (don’t connect to coccyx)

§  Are in constant tension and pull anal-rectal junction anteriorly to create the 80º anorectal junction

○  Are essential for fecal continence

§  During defecation, this muscle is relaxed

  • Note – same in males and females
  • Female Specific Things

○  Rectoceole – rectum not supported by pelvic diaphragm and encroaches on vagina

○  Urethrocoele – same thing, but with bladder

○  Kegal Exercises – retone muscles of pelvic floor to support weight of pelvic organs (leading to prolapsed uterus or bladder etc.)

  • Do these after vaginal birth because they get stretched
  • Nerves of the Pelvis

·  Branches of Sympathetic Trunk

○  Gray Rami Communicantes – joins the ventral rami of S2-S4 and goes to lower limb

○  Sacral Splanchnic – come off in sacral region and stay in the pelvis to supply sympathetic innervation to the pelvis

○  Pelvic Splanchnic Nerves – split off of S2-S4 and provide parasympathetic innervation to organs in pelvis and perineum

§  Feed into the Inferior Hypogastric Plexus

  • The only part or this that leaves the pelvic cavity the part for the external genitalia (nerves for erection)

○  ‘S2, 3 and 4 keep the penis off the floor’

·  Sacral Plexus – plexus that forms from ventral rami of S2-S4 and the lumbar plexus

○  Goes through greater sciatic foramen to supply lower limb

  • Superior Hypogastric Plexus – entirely sympathetic nerve plexus that feeds to hypogastric nerves
  • Hypogastric Nerves – right and left and heads down into inferior hypogastric plexus
  • Inferior Hypogastric Plexus – receives innervation also from pelvic splanchnics and thus contains parasympathetics and sympathetics

○  Is posterior to the rectum

○  Gives off innervation for a bunch of named plexi (ie uterovaginal plexus)

  • Vessels of the Pelvis

·  Supplied by branches of Internal Iliac

○  Lots of variation in these branches

○  Posterior Division of Internal Iliac

§  Iliolumbar artery – leaves true pelvis and goes to false pelvis

§  Lateral Sacral arteries – multiple branches go to wall of true pelvis and cauda equina

§  Superior Gluteal Artery – largest branch; leaves pelvis between lumbrosacral trunk and S1 ventral ramus and goes into greater sciatic foramen

○  Anterior Division of Internal Iliac

§  Obturator artery – links with obturator nerve and leaves pelvis through obturator foramen

○  40% of the time it actually comes from the inferior epigastric artery

§  Umbilical artery – gives off superior vesicle arteries and becomes patent (goes to umbilicus as the medial umbilical fold)

○  Superior Vesicle Arteries – for urinary bladder

§  Uterine Artery – typically gives off Vaginal Artery

§  Inferior Vesicle Arteries – for neck region of bladder

○  Can give off Vaginal Artery

  • Middle Rectal Artery – often shares a common trunk with the inferior vesicle arteries
  • Internal Pudendal artery – leaves through greater sciatic foramen

§  Inferior Gluteal artery – leaves through greater sciatic foramen

  • Note – ureter crosses underneath the uterine artery at junction of vagina and cervix

○  ‘water flows under the bridge’

  • Lymphatics of the Pelvis
  • They basically just follow vessels

·  Perineal drainage (including most of the genitalia) goes to inguinal nodes

○  Exception – testicular lymph drains into nodes around the aorta because its lymph goes through inguinal canal and along testicular vessels

○  Ways to Give a Pudendal Nerve Block

  • Ischioanal fossa - Bathe pudendal nerve through ischioanal fossa associated with ischial spine
  • Transvaginally – palpate ischial spine through vagina and inject there
  • Note – mons pubis and anterior labia won’t be affected because they are from ilioinguinal nerve

·  Gluteal Region and Posterior Thigh

○  Objectives

§  Describe the dermatome pattern for the lower limb

§  Demonstrate the sacrotuberous and sacrospinous ligaments and describe how they contribute to the formation of the sciatic foramina

§  Review the anatomy of the bones of the pelvis and the femur

§  Demonstrate the surface anatomy of the sciatic nerve

§  Demonstrate the large gluteal muscles and understand their role in gait as well as their nerve and blood supply

§  Describe the course structures take from the pelvic cavity to the gluteal region

§  Demonstrate the six lateral rotator muscles of the hip

§  Understand the course structures take from the gluteal region to the perineum

§  Define the hamstring muscle group and delineate their actions, nerve supply, and blood supply

○  Review three parts of the hip bone and note that they only fuse completely by 22 years

○  Review bones and ligaments of the pelvis

Femur / Tibia / Fibula
Greater Trochanter –
Lesser Trochanter –
Head, Neck and Shaft
Intertrochanteric line – just outside lateral border of the neck
Intertrochanteric crest –
Gluteal Tuberosity – on posterior side
Linea aspera – ridge; starts around gluteal tuberosity
Medial and Lateral Supracondylar ridge – continuous with linea aspera
Popliteal surface – between the suprachondylar ridges
Adductor Tubercle –
Medial and Lateral Condyles – smooth surface where it articulates with tibia
Intercondylar fossa – between the condyles / Intercondylar eminence –
Medial and Lateral Chondyle
Tibial tuberosity –
Anterior Border – subcutaneous
Medial malleolus - / Head, Neck and Shaft –
Lateral Malleolus –
Note – is buried in muscle
Note – is lateral
Note – doesn’t articulate with femur

○  Angle of Inclanation – long axis of femur vs head and neck

  • Normal – around 135º; variation between sexes

§  Coccsa Valgus - ↑ angle; causes lateral deviation; ‘bow-legged’

§  Coccsa Varus - ↓ angle; causes medial deviation; ‘knock-kneed’

○  Callipygous – a wonderful ass

○  Gluteal Region – bounded by iliac crest and gluteal fold

  • Gluteal Fold – lower edge of gluteus maximus where dermis is attached to deep fascia
  • Dermatome – basically just S1 (lateral) and S2 (medial)
  • Nerves and Veins of Cutaneous Region
  • Most subcutaneous blood drains into saphenous veins
  • Inferior cluneal nerves – sensory innervation to lower gluteal area
  • Dorsal rami supply medial portion
  • Ventral rami supply lateral portion
  • Muscles
  • Fascia Lata – deep fascia of the gluteal region and thigh

○  Iliotibial Tract – thickening of fascia lata laterally