Understand the organization of pelvic viscera, and examine the peritoneum of the pelvic cavity

Find these structures:

• Viscera

  • Urinary bladder

  • Uterus (female)

  • Uterine tubes (female)

  • Ovaries (female)

  • Rectum

• Peritoneum

  • Female:

    • Vesico-uterine pouch

    • Recto-uterine pouch (posterior cul-de-sac)

    • Suspensory ligament of ovary

    • Broad ligament of uterus

  • Male:

    • Recto-vesical pouch

2.) Identify the viscera (bladder, uterus, uterine tubes, ovaries, & rectum) of the pelvic cavity. 

Note: In males and females, the bladder is positioned anteriorly and the rectum posteriorly. In females, the uterus is positioned in an intermediate position between the bladder and rectum. The uterine tubes and ovaries are positioned superolaterally to the uterus.

Photo 3. Female: organization of viscera

Photo 4. Male: organization of viscera

3.) Locate the peritoneum in the abdomen, and follow into the pelvis. Visualize the peritoneum (broad ligament and suspensory ligament of ovary) as it reflects onto pelvic viscera and neurovasculature, and locate the peritoneal pouches (vesico-uterine and recto-uterine in females; recto-vesical pouch in males). Elevating the uterus slightly may provide a better view of the vesico-uterine pouch.

Note: The broad ligament of uterus is composed of 2 layers of peritoneum and serves to divide the true pelvis of females into an anterior part (containing the bladder) and a posterior part (containing the rectum), in addition to attaching the uterus to the lateral pelvic walls. The uterine tubes and ovaries are attached or suspended within the superior-most portion of the broad ligament (mesosalpinx). Superolaterally, the broad ligament is attached to the fibrous suspensory ligament of ovary, which contains the ovarian neurovasculature. The inferior portion of the broad ligament (mesometrium) is continuous with the parietal peritoneum of the pelvis.

Note: With the presence of the uterus and vagina in females, this creates two peritoneal pouches (vesico-uterine, recto-uterine), whereas there is a single peritoneal pouch between the bladder and rectum (recto-vesical) in male pelvic cavities.

Note: The vesico-uterine pouch is the inferior-most extension of peritoneum between the bladder and the uterus. The recto-uterine pouch is a deep pocket of peritoneum between the uterus & vagina and rectum. The vaginal wall of the posterior fornix is in contact with the recto-uterine pouch and offers access to the peritoneal cavity.

Photo 5. Peritoneum of pelvic cavity, female 

Photo 6. Peritoneum of pelvic cavity, male

Examine the interior of the urinary bladder

Find these structures:

• Urinary bladder

  • Ureteric orifices

  • Internal urethral orifice

  • Uvula of bladder (male)

• Urethra

4.) Incise the peritoneal covering of the urinary bladder where the superior surface meets the base (vesico-uterine pouch in females and recto-vesical pouch in males), and carefully reflect the peritoneum from the base of the bladder.

5.) Identify the ureters as they enter the base of the bladder, and coronally incise (with scissors) the wall of the base, superior to the ureters. If necessary for a more complete view, the superior surface of the bladder can be completely removed. Examine structures of the internal posterior wall. Be aware that urine may be present in the bladder, and can be removed with paper towels. To obtain a clear view of the urethra, observe a sagittally-sectioned plastinated specimen. 

Photo 7. Procedural: Bladder incision

Photo 8. Female bladder

Photo 9. Male bladder 

Note: The trigone of the bladder consists of three orifices: two superolateral ureteric orifices and a single internal urethral orifice. In males, the prostatic median lobe of the prostate gland creates an elevation in the internal urethral orifice, the uvula of bladder. If the uvula is hypertrophied, this can obstruct the flow of urine.

Examine the female genital tract

Find these structures:

• Broad ligament of uterus

  • Mesovarium

  • Mesosalpinx

  • Mesometrium

• Uterus

  • Round ligament of uterus

• Uterine tubes

  • Infundibulum

    • Abdominal ostium

    • Fimbriae

  • Ampulla

  • Isthmus

6.) Locate the ligament of ovary (ovarian ligament) and round ligament of uterus in the broad ligament of uterus. Locate the three constituent mesenteries of the broad ligament.

Note: The ligament of ovary (ovarian ligament) and round ligament of uterus are remnants of the gubernaculum, are continuous, and are located in the broad ligament of the uterus. The ligament of ovary connects the ovary to the uterus, and is located posteroinferior to the uterine tubes. The round ligament of uterus is more anterolaterally placed and connects the uterus to the labium majus by traversing the inguinal canal. Recent research suggests the round ligament in some individuals ends just medial to the superficial inguinal ring without full extension to the labium majus (Gray’s Anatomy, 41st edition).

Note: Three mesenteries combine to form the broad ligament. They include the mesovarium (ovary), mesosalpinx (uterine tube), and mesometrium (body of uterus). 

Photo 10. Ligament of ovary and round ligament

Photo 11. Broad ligament

7.) Locate the uterine (Fallopian) tubes and ovaries. Identify the various parts of the uterine tube.

Note: The uterine tubes are open to the abdominal cavity via the abdominal ostia. The ostium leads into the infundibulum, which is the trumpet-shaped, distal-most portion of the uterine tube. Fimbriae surround the proximal infundibulum, which appear as finger-like extensions of ciliated mucosa. These fimbriae aid in the movement of an oocyte released from the ovary into the uterine tube. The infundibulum, the widest and longest portion of the uterine tube, is continuous with the ampulla. The ampulla is the most typical site of fertilization. The ampulla is continuous with the short and muscular isthmus of uterine tube that leads into ostia that open into the uterus. In other words, the uterine tube parts are organized in this manner (lateral to medial): abdominal ostium → infundibulum → ampulla → isthmus → uterine ostium.

Note: Ovaries are located in the pelvic cavity suspended with the mesovarium portion of the broad ligament. It is closely associated with the uterine tube, particularly the infundibulum and fimbriae. The ovaries appear dull white, and may appear atrophied, particularly in postmenopausal individuals.

Photo 12. Uterine tube and ovary close-up

Identify the external and internal iliac aa. & vv.

Find these structures:

• Common iliac a. &. v.

  • External iliac a. & v.

  • Internal iliac a. & v.

8.) Locate the common iliac aa. & vv. at the bifurcation of the abdominal aorta and formation of the inferior vena cava by the junction of the common iliac vv. at approximately the level of the L4 vertebra.

9.) The common iliac aa. bifurcate into the external and internal iliac aa. at the pelvic brim, just anterior to the sacro-iliac (SI) joints. Remove any peritoneum or connective tissue, in addition to moving (without removing) any viscera, to obtain a better view of this bifurcation. The veins may be removed to better visualizing the branching pattern in this area.

Note: The external iliac aa. are larger than the internal iliac aa., and supply the lower limb. The internal iliac aa. supply structures associated with pelvic and gluteal regions.

Photo 13. Abdominal aorta bifurcation and inferior vena cava formation 

10.) Follow the external iliac a. as it traces the pelvic brim to enter the lower limb (beyond the inguinal ligament) as the femoral a. Identify the inferior epigastic a. branch of the external iliac a. Note the arteries’ relationships with the ureters, gonadal vessels, and round ligament of uterus/ductus deferens.

Note: The external iliac a. only has two, named branches in association with the pelvis: deep circumflex iliac a. and inferior epigastric a.

Photo 14. External iliac and inferior epigastric a.

Dissect and conceptualize the autonomic nerves & plexuses superior to the pelvic cavity

Find these structures:

• Peripheral autonomic plexuses

  • Superior hypogastric plexus

    • Hypogastric nn.

11.) Locate the superior hypogastric plexus anterior to the aortic bifurcation. Dissect the hypogastric nn. (derived from the fibers connecting the superior hypogastric and inferior plexuses) as they pass anterior to the common iliac aa. & vv. and descend into the pelvic cavity.

Note: The superior hypogastric plexus lies within extroperitoneal connective tissue in the midline, anterior to the abdominal aortic bifurcation. It is derived from three sources: lumbar splanchnic nn. (sympathetic), pelvic splanchnic nn. (parasympathetic), and the aortic plexus (sympathetic and parasympathetic). The organization of this plexus is widely variable, with possible presentations ranging from a web-like appearance to distinct nerve trunks.

Note: The typically paired hypogastric nn. are located between the superior & inferior hypogastric plexuses, medial to internal iliac vasculature and lateral to the anterior sacral foramina.These nerves consist of both sympathetic (from superior hypogastric plexus) and parasympathetic (from inferior hypogastric plexus) fibers.

Photo 15. Superior hypogastric plexus and hypogastric nn.

Note: Medial and parallel to the labia majora, the labia minora extend posteriorly from the clitoris to encircle the vestibule. The anterior region of each labium minus divides to form two structures: anteriorly (superficial to the clitoris) the prepuce, and posteriorly the frenulum of the clitoris.

Note: Labia minora surround the vestibule, the medial cavity that contains the external urethral meatus (the final anatomical point of the urine conduction pathway) and the vaginal orifice (the external opening of the vagina). 

Photo 17. Vulva

Note: As you will see, the clitoris is an extensive structure. The glans clitoris (also known as the glans of clitoris, the glans, or colloquially as the clitoris) is nestled beneath the prepuce of clitoris and supported by the frenulum of clitoris (both are of the labia minora). The clitoris is a richly vascularized and innervated (particularly the glans) structure that is an important mediator of sexual response. 

Photo 18. Glans clitoris

Examine male external genitalia

Find these structures:

• Penis

  • Body (shaft) of penis

  • Dorsum

  • Glans penis

    • Corona of glans

  • Prepuce (foreskin)

    • Frenulum

  • External urethral meatus

• Scrotum

  • Raphe of scrotum

  • Septum of scrotum

13.) Examine the penis, and locate its parts. 

Note: The penis consist of a root (that anchors the penis to the perineum, within the superficial perineal space) and body (the serves as the intromittent organ). Three tubes of erectile tissue internally traverse the penis: laterally paired corpora cavernosa and corpus spongiosum. In standard anatomical position (SAP), the penis stands in its erect state. The side of the penis in SAP that may contact the anterior abdomen is the dorsum (dorsal surface) of the penis. Opposite from the dorsum is the urethral surface. 

Photo 19. Penis

Note: The distal end (tip) of the body is the glans penis, a bulbous, skin-covered elaboration of corpus spongiosum. The rounded, circumferential border of the glans penis is the corona of glans. While the penis is in a flaccid state, an elaboration of the skin surrounding the body, the prepuce (foreskin), covers the glans penis. A slight reflection of prepuce on the urethral surface proximal to the glans penis, the frenulum, connects the prepuce to the glans. 

Note: The spongy (penile) urethra is transmitted by the corpus spongiosum and terminates at the external urethral meatus of the glans penis. 

Photo 20. Glans penis 

14.) Examine the scrotum. 

Note: The scrotum is a cutaneous expansion suspended from the perineum and inferior portion of the proximal body of the penis. The scrotum contains the testes and distal spermatic cords. The layers of the scrotum and spermatic cord are homologous and contiguous with many of the layers of the anterior abdominal wall. 

Note: The scrotum consists of two major layers: skin & subcutaneous layer. The subcutaneous is also known as the dartos proper (consisting of smooth muscle and fascia). Deep to the dartos is the spermatic cord and its coverings. The dartos divides to form the septum of scrotum which separate the testes. Superficial to the septum, and continuous with the raphe of the penis is the raphe of the scrotum. The raphe of the scrotum runs from the raphe of the penis to the anus. 

Note: The scrotum is homologous with the labia majora. 

Photo 21. Scrotum

Examine the spermatic cord and testis

Find these structures:

• Spermatic cord

  • External spermatic fascia (= external oblique m. fascia)

  • Cremaster m. & fascia (= internal oblique m. & fascia)

  • Internal spermatic fascia (= transversalis fascia)

  • Ductus (vas) deferens

  • Testicular a.

  • Pampiniform plexus (of veins)

• Testis

  • Convoluted seminiferous tubules

  • Epididymis

    • Head

    • Body

    • Tail

15.) On a male donor, unilaterally follow the spermatic cord from the superficial inguinal ring into the testes. Use sharp dissection with scissors to incise the skin and dartos to reveal the spermatic cord and testis.

Note: The spermatic cord consists of three layers of tissues that envelop contents. The three basic layers of the sheath portion of the spermatic cord (and associated homologs) are the:

• external spermatic fascia (= external oblique m. fascia),

• cremaster m. & fascia (= internal oblique m. & fascia), and

• internal spermatic fascia (= transversalis fascia).

The major contents of the sheath are the: 

• ductus (vas) deferens,

• testicular a., and

• pampiniform plexus (of veins).

The contents also include the:

• artery of ductus deferens (from the inferior vesical a.),

• cremasteric a. (from the inferior epigastric a.),

• genital br. of the genitofemoral n., 

• autonomic fibers:

  • sympathetics follow the arteries,

  • parasympathetics follow the ductus deferens,

• lymphatics, and

• processus vaginalis vestige (a thread-like connection that may connect the tunica vaginalis of the testis to the peritoneum).

Note: External to the spermatic cord, you may observe anterior scrotal nn. which are continuations of the ilio-inguinal n. On a female donor, these are known as the anterior labial nn., and they accompany the round ligament. 

Photo 22. Spermatic cord 

16.) Using blunt dissection, carefully open the spermatic cord to reveal its contents.

Photo 23. Spermatic cord contents

17.) Gently open the internal spermatic fascia surrounding the testis to reveal the testis and its features. 

Note: The testis is enveloped by the tunica vaginalis. The tunica vaginalis is comprised of two layers: a parietal layer (which adheres to the internal spermatic fascia) and a visceral layer (which invests the spermatic cord and testis). Between the parietal and visceral layers of the tunica vaginalis is a dynamic potential space (cavity). This dynamic potential space allows the testes to move within the scrotum. 

Photo 24. Testis

18.) Using a combination of blunt and sharp dissection, open the visceral layer of the tunica vaginalis to reveal the testis and epididymis.

Note:  The male gonads, the testes, are each encapsulated by the tunica vaginalis and (deep to the tunica vaginalis) the tunica albuginea. The tunica albuginea is a dense, white layer which surrounds and compartmentalizes segments of the seminiferous tubules. Spermatozoa travel from the coiled seminiferous tubules through straight tubules into the rete testis. From the rete testis, spermatozoa move into the epididymis before traveling to the ductus deferens. 

Note: The epididymis is comprised of a head and body (which receive spermatozoa from the rete testis) and tail. Spermatozoa travel from the head → body → tail of the epididymis. 

Photo 25. Epididymis

Section the penis

Find these structures:

• Erectile tissue

  • Corpus cavernosa 

  • Corpus spongiosum

• Deep artery of penis

• Spongy (penile) urethra

18.) Using a scalpel or scissors, make a transverse incision through the body of the penis. Locate the three masses of erectile tissue and associated vasculature within.

Note: The body of the penis largely consist of three masses of erectile tissues: paired, dorsal corpus cavernosa (supplied by the deep arteries of the penis), and a ventral corpus spongiosum (which surrounds the spongy urethra).

Photo 26. Transverse section of penis

• • Incision through pelvic viscera. 

Note: Make midline incisions through the rectum, body of the uterus (if present), and urinary bladder.

Note: Clean any fecal matter to prevent spreading. 

Photo 28. Soft tissue incisions through pelvic viscera

• • Vertical incision along soft tissue superficial to the distal lumbar vertebral column, sacrum, and pelvic floor.

Note: Starting at the transverse cut (around L4) of the vertebral column, make a midline  incision inferiorly over the internal surface of the sacrum and through the posterior pelvic floor until you reach the rectum

Note: This incision will sagittally section neurovasculature, including the distal portion of the abdominal aorta (just proximal to the bifurcation into the common iliac aa.) and the superior hypogastric plexus

Photo 29. Planned soft tissue incisions 

• • Anteroposterior incision of perineum and pelvic floor. 

Note: Make a midline incision at the level of the pubic symphysis and continue as posteriorly as possible while the donor is supine. 

Note: Incisions through the genitalia (clitoris and vagina, or length of penis and scrotum), urogenital openings, perineal body, and anus should be as midline as possible.

Note: Abducting (e.g. moving away from midline) the lower limbs is helpful to gain access to deeper tissue.

Photo 30. Soft tissue incisions of perineum 

Photo 31. Soft tissue incisions of perineum & pelvic floor, female

Photo 32. Soft tissue incisions of perineum, male

Photo 33. Soft tissue incisions of perineum, male

Note: These incisions should completely traverse the perineum and pelvic floor, creating an opening into the pelvic cavity. 

23.) Bisect the pelvis by using a hand saw to separate the attachments at the pubic symphysis and lumbar spine.

Note: One person should saw while other teammates stabilize the donor at the hips and thighs. 

24.) Saw incisions: 

• • At the level of the transverse soft tissue incision of the posterolateral abdominal wall, use a hand saw to cut half way (to the midline) through the vertebral column.

Photo 34. Saw line for posterolateral abdominal wall

• • Saw through the pubic symphysis, using the previous soft tissue scalpel incision as a guide.

Photo 35. Saw line for pubic symphysis

25.) Using a hand saw, section the sacrum and distal lumbar spine.

Note: Start at the coccyx and saw superiorly at the midline to meet the transverse saw incision that was previously made in the lumbar vertebrae (around L4).

Note: Abducting the lower limbs will be helpful for palpating the coccyx prior to sawing; continue to increase abduction of the thighs as the sawing progresses superiorly, to assist with separation. 

Note: Be cautious to not disrupt the pelvic viscera while sawing the distal sacrum and coccyx. 

26.) Abduct the lower limb that is being removed with purposeful force to aid in breaking any remaining bony attachments. Cut any remaining soft tissue attachments with a scalpel.  

27.) Clean the rectum of any remaining fecal matter.

Photo 34. Bisected pelvis