sing the Sectra table, you will identify the structures of the thorax. Bolded terms are in the objectives for this lab.
The pelvis & perineum
“The pelvis is the area of transition between the trunk and the lower limbs. The bony pelvis serves as the foundation for the pelvic region and provides protection for pelvic organs as well as strong support for the vertebral column on the lower limbs. The pelvic cavity is continuous with the abdominal cavity, with the transition occurring at the plane of the pelvic inlet. The pelvic cavity contains the rectum, the urinary bladder, and the internal genitalia. The perineum is the region of the trunk located between the thighs and separated from the pelvic cavity by the pelvic diaphragm. The perineum contains the the anal canal, the urethra, and the external genitalia (penis and scrotum in the male, vulva in the female).“ – Grant’s Dissector 16th ed.
Review the bones of the pelvis in the VH Dissector:
- Identify bones of the pelvis (individual bones and features are not identifiable on the model): ilium, ischium, pubis, sacrum, coccyx
Q1: What bony features do the sacrotuberous ligament and sacrospinous ligament attach to? (answer)
Pelvic floor
As you identify and dissect muscles, you should review their origin, insertion, innervation, and action(s). As you identify and dissect neurovascular structures, you should review their pathways.
If you are having trouble highlighting narrow structures (arteries, veins, nerves), you can search for them by selecting the Anatomy tab, typing the name of the structure in the search box, and selecting the sun icon next to the listed structure. You can dissect these structures by selecting the eye icon.
As you highlight a structure, note that the structure will also be highlighted in the multiplanar reconstructed (MPR), or cross-sectional images in the leftmost pane. All structures should be identified on the MPR images. Using three fingers, scroll through the MPR images to understand the three-dimensional relationships between different structures as you work though the lab. Structures that are difficult to identify in the MPR images will have additional links to assist you
Use the following view to examine the muscles of the pelvic floor:
- Identify the levator ani muscles. The muscles that make up the levator ani group (puborectalis, pubococcygeus, iliococcygeus) are not selectable on the model, identify them on the diagrams below
- Identify the obturator internus and piriformis
- Use the diagrams below to identify the urogenital hiatus and anal hiatus
Q2: What are the boundaries of the perineum? What are the boundaries of the urogenital triangle? What are the boundaries of the anal triangle? (answer)
Female pelvis
Use the following view to examine the structures of the female pelvis:
- Identify the uterus and the urinary bladder (the outer muscular layer is the detrusor)
- Use the diagams below to identify the parts of the urinary bladder: body, fundus, apex, trigone, and neck
- Dissect the sigmoid colon and identify the rectum
Q3: Look at the sagittal MPR image. Where are the vesicouterine pouch & rectouterine pouch? (answer)
- Use the diagrams below to identify the parts of the uterus: fundus, horns, body, and cervix (including internal os and external os)
- Identify the ovarian ligament, the suspensory ligament of the ovary and the round ligament of the uterus (MPR)
- Identify the parts of the broad ligament: mesosalpinx, mesovarium, mesometrium
- Identify the left and right ovaries and uterine tubes (you may need to dissect the mesosalpinx to see them clearly)
- Use the diagram below to identify the parts of the uterine tube: infundibulum, fimbriae, ampulla, and isthmus
- Identify structures of the rectum and anal canal on the diagrams below: ampulla of the rectum, anal columns, and pectinate line
- Dissect the uterus and rectum and identify the vagina (it will be easier to visualize in the MPR images)
- With the uterus dissected, identify the uterine cavity and the cervical canal
- Use the diagrams below to identify the vaginal fornix
- Rotate the model to view the external genitalia and identify the labia minora and labia majora (MPR)
- Dissect the labia minora and majora and identify the clitoris (“fascia of the clitoris”), the ichiocavernosus muscle, and bulbospongiosus mucle. Dissect these structures
- Identify the corpus cavernosum of the clitoris and the superficial transverse perineal muscle
- Use the diagrams below to understand the erectile tissues of the female genitalia, and the dorsal nerve and artery of the clitoris
Male pelvis
Use the following view to examine the structures of the male pelvis:
- Identify the urinary bladder and ureters
- Identify the seminal gland on the posterior side of the bladder
- Identify the ductus deferens (MPR)
- Dissect the urinary bladder and identify the prostate
- Dissect the prostate to view the ejaculatory duct (MPR)
Q4: Describe the relationship of the ductus deferens in relation to the ureter. (answer)
- Identify the erectile tissues of the male genitalia: the corpus cavernosum (including the crus) and corpus spongiosum (including the glans and the bulb) of the penis (MPR)
- Rotate the model to view the perineum from the inferior side, and identify the ischiocavernosus muscle, the bulbospongiosus muscle, and the superficial transverse perineal muscle (MPR)
- Dissect the corpus cavernosum and identify the dorsal artery of the penis
- Use the diagrams below to identify the coverings of the penis: skin, superficial dartos fascia, deep Bucks fascia
- Use the diagrams below to identify the deep arteries and veins of the penis
Neuorvasculature of the pelvis
Use the following view to examine the neurovasculature of the (female) pelvis:
- Identify the common iliac artery, external iliac artery, and internal iliac artery
- Identify the branches of the internal iliac artery: obturator artery, inferior vesical arteries, uterine artery, vaginal artery, internal pudendal artery, superior gluteal artery, and inferior gluteal artery (not all are visible on both sides on the model)
- Identify the lumbosacral trunk, the sciatic nerve, and the pudendal nerve
- Identify the (sacral) nerves forming the sacral plexus
Q5: What branches of the internal iliac artery would you expect to see in the female pelvis that you don’t see in the male pelvis? (answer)
End of Sectra activity
Answers to activity questions
Below are answers to questions asked during the activity. Clicking the ‘back to lab’ link below each answer will take you back to the question (you may need to scroll up a little to view the question again).
Q1: What bony features do the sacrotuberous ligament and sacrospinous ligament attach to?
- sacrotuberous ligament: connects the ischial tuberosity to the posterior ilium/lateral sacrum/coccyx
- sacrospinous ligament: connects the ischial spine and the lateral sacrum/coccyx
Q2: What are the boundaries of the perineum? What are the boundaries of the urogenital triangle? What are the boundaries of the anal triangle?
- Perineum
- Anterior: pubic symphysis
- Antero-lateral: ischiopubic rami
- Lateral: ischial tuberosities
- Postero-lateral: sacrotuberous ligaments
- Posterior: coccyx
- An imaginary line running between the ischial tuberosities divides the perineum into the urogenital triangle (anterior) and the anal triangle (posterior)
Q3: Look at the sagittal MPR image. Where are the vesicouterine pouch & rectouterine pouch?
- Vesicouterine pouch: a shallow pouch of peritoneum formed between the uterus and the urinary bladder
- Rectouterine pouch: a pouch of peritoneum formed between the uterus and the and rectum
Q4: Describe the relationship of the ductus deferens in relation to the ureter.
- The ductus deferens passes superior to where the ureter enters the urinary bladder, before traveling posteriorly to reach the prostate
Q5: What branches of the internal iliac artery would you expect to see in the female pelvis that you don’t see in the male pelvis?
- Uterine and vaginal arteries are only found in the female pelvis