OS 206: Abdomen & Pelvis - Past Paper PDF

OS 206: ABDOMEN AND PELVIS BONY PELVIS, PELVIC WALL, AND FLOOR UPCM 2029 | Dr. Florida F. Taladtad | LU3 A.Y. 2024-2025 ​ Pelvic articulation OU...

OS 206: ABDOMEN AND PELVIS BONY PELVIS, PELVIC WALL, AND FLOOR UPCM 2029 | Dr. Florida F. Taladtad | LU3 A.Y. 2024-2025 ​ Pelvic articulation OUTLINE ○​ Anteriorly: Joined by the pubic symphysis I.​ Introduction VI.​ Pelvic Floor ○​ Posteriorly: Articulates with the sacrum at the sacroiliac joint II.​ Bony Pelvis A.​ Pelvic Diaphragm A.​ Bones Perineal Body B.​ Ligaments B.​ Perineal or Pelvic C.​ Foramina Floor Injury D.​ Orientation VII.​ Nerves of the Pelvis and III.​ Pelvic Planes Perineum A.​ Superior Pelvic A.​ Lumbar Plexus Aperture or Pelvic B.​ Lumbosacral Trunk Inlet C.​ Sacral Plexus B.​ Inferior Aperture or D.​ Other Nerves Pelvic Outlet VIII.​ Peritoneum C.​ Pelvic Midplane IX.​ Pelvic Fascia D.​ Sexual Dimorphism X.​ Internal Iliac Artery IV.​ Pelvic Joints A.​ Anterior Division A.​ Sacroiliac Joints B.​ Posterior Division B.​ Lumbosacral Joints XI.​ Postpartum C.​ Pubic Symphysis Hemorrhage D.​ Sacrococcygeal Joint A.​ Management V.​ Pelvic Wall B.​ Collateral Circulation A.​ Antero-inferior Pelvic in Pelvis Wall XII.​ Ureter B.​ Lateral Pelvic Wall A.​ Route C.​ Posterosuperior B.​ Areas of Urethral Pelvic Wall Injury XIII.​ Internal Iliac Vein XIV.​ Lymphatic Drainage XV.​ References Figure 2. Hip bones. I.​ INTRODUCTION ​ Pelvis ○​ Inferoposterior part of the trunk, positioned between the abdomen and lower extremities, serving as the transition between them ​ Pelvic Cavity ○​ Bowl-shaped space enclosed by the bony pelvis and perineum, surrounded by the pelvic girdle ○​ Contents: urinary organs, genitals, rectum, and anal canal ​ Perineum ○​ Diamond-shaped area between thighs and buttocks (coccyx to pubis), inferior to the pelvic floor, containing the anus and external genitalia II.​ BONY PELVIS Figure 3. Anterior and lateral view of pelvis(Moore). HIP BONES: ILIUM FUNCTIONS OF THE PELVIC GIRDLE ​ Superior fan-shaped portion of the hip bone ​ Transfer weight when sitting or standing from apical to ​ Serves as attachment for buttocks muscles appendicular skeleton ○​ Gluteus maximus: posterior gluteal line ​ Attachment points for muscles to aid in locomotion and posture ○​ Gluteus medius: anterior gluteal line ​ Support and protection for abdominopelvic structures ○​ Gluteus minimus: inferior gluteal line ○​ Contain and protect pelvic viscera ○​ Support for gravid uterus (pregnant females) ​ Provide attachment for erectile bodies of the external genitalia, muscles, and membranes A.​ BONES Figure 4. Ilium(Osmosis) ​ Iliac Crest ○​ Superior edge of the iliac wing, ending at the anterior superior iliac spine (anteriorly) and the posterior SIS (posteriorly) ○​ Forms the rim of the iliac fossa ○​ Clinical correlates: ​ Intercristal line ​The line joining the superior aspect of the iliac crests posteriorly, located at L4 on spinal imaging Figure 1. Bony pelvis(Netter) ○​ Landmark for neurologists performing a lumbar tap and ​ Composed of two (2) hip bones, sacrum, coccyx anesthesiologists for epidural and spinal anesthesia ○​ Hip bones consist of 3 separate bones: ilium, ischium, and pubis ​ Source of bone grafting from bone marrow ​ Triradiate Cartilage: unites the three pelvic bones at the ​ Arcuate Line acetabulum during infancy and childhood ○​ Found on the internal surface of the ilium ○​ Fuses during puberty ○​ Runs inferiorly to join the pectineal line of the pubis ○​ Matures to form the acetabulum, which articulates with the ○​ Together with the pectineal line, it helps demarcate the pelvic femur inlet ○​ The presence of separate bones indicates the age of an individual is 1000 mL blood loss in cesarean section ​ Types of PPH ○​ Primary PPH: Occurs within the first 24 hours after delivery ○​ Secondary PPH: Occurs after the first day up to 6 weeks postpartum ​ Main Causes (4 Ts) ○​ Tone (Lack of uterine tone) ​ The uterus fails to contract immediately after birth, leading to excessive bleeding ○​ Trauma Figure 64. Collateral circulation in the pelvis(Moore; Dr. Taladtad) ​ Lacerations (vaginal wall, cervix, uterus) or uterine damage ○​ Thrombin ​ Coagulation disorders affecting blood clotting ○​ Tissue (Retained products of conception) ​ The placenta should be fully delivered after birth ​ Issues arise when[2028 Trans]: OS 206 Bony Pelvis, Pelvic Wall, and Floor 14 of 19  XII.​ URETER A.​ ROUTE Figure 65. Route of the ureter(Osmosis) ​ The ureter crosses anterior to the bifurcation of the common iliac artery to the external and internal iliac artery ○​ At the level of L5-S1 (sacroiliac joint) ​ It then goes lower through the pelvic wall and is posteroinferior to the uterine vessels (posterior to the uterine artery) ​ Knowing the route is crucial, because the ureter may accidentally be ligated ○​ The ureter is close to the branches of the internal iliac arteries[2028 Trans] Figure 67. Anterior view of pelvic veins(Moore) ​ Due to this, there is a big risk of ligating, clamping, or dissecting the ureter XIV.​ LYMPHATIC DRAINAGE ​ Lymph from the pelvis and the perineum will travel through Mnemonic: “Water under the bridge” different groups of lymph nodes ​ The uterine vessels are above the ureter ​ Ultimately drains into the thoracic duct ​ Water = ureters ​ Usually follows venous pathways except for structures that drain to ​ Bridge = uterine vessels the external iliac nodes B.​ AREAS OF URETERAL INJURY Table 5. LYMPHATIC DRAINAGE ​ Ligation of ovarian vessels near the pelvic brim (ligation of the DRAINS LYMPH FROM TO infundibulopelvic ligament) Superior parts of ○​ Done when there is an ovarian neoplasm or mass External iliac nodes anterior pelvic viscera Common iliac nodes ○​ The ureter may accidentally be ligated when the ovarian vessels → lateral aortic nodes are being ligated Deep pelvic and deep Internal iliac nodes and lumbar trunks ​ Remember: the ureter is posterior to the ovarian vessels perineal structures (before draining to ​ Ligation of uterine arteries Deep posterior pelvic the thoracic duct) ○​ “Water under the bridge” (refer to mnemonic) Sacral nodes viscera ​ Ligation of the cardinal ligaments ○​ Cardinal ligaments are like the wings of the cervix[2027 Trans] Superficial and deep Perineum External iliac nodes ○​ Removed during hysterectomy inguinal nodes ​ The ureter is within this fascia, so it must be dissected away before cutting[2028 Trans] ​ Excision of the vaginal rim ○​ Ureter is directly lateral[2028 Trans] Figure 67. Lymph nodes of the pelvis(Moore) Clinical Correlates of Lymphatic Drainage ​ Palpate for inguinal nodes (tender) ○​ The perineum drains to the superficial and deep inguinal nodes Figure 66. Areas of ureteral injury(UPCM 2027) ​ Patients present with painful vaginal ulcers (e.g., herpes) ○​ Painful lesions/wounds in the vulva XIII.​ INTERNAL ILIAC VEIN ○​ Painful vesicular ulcers in the vulva drain to the superficial and ​ Veins correspond closely to their counterpart arteries[2026 Trans] deep inguinal nodes ​ Venous drainage from pelvic organs ultimately flows into the ​ One criterion for considering herpes infection (STI)[2027 Trans] internal iliac veins ​ For cancers, check for lymph node involvement in vulvar and ○​ Joins the external iliac vein to form the common iliac vein cervical cancers[2027 Trans] ○​ Lies posteroinferior to the internal iliac artery ○​ Oncologists identify the most likely lymph nodes to be positive ○​ Tributaries are similar to the internal iliac artery for malignancy during surgery[2028 Trans] ○​ Superior gluteal vein → Largest tributary ​ Drainage Sites ○​ Superior rectal and inferior mesenteric veins[2026 Trans] → Hepatic portal system ​ Superior rectal vein anastomoses with the middle rectal vein and inferior rectal vein (tributaries to internal iliac veins) ○​ Lateral sacral veins → Internal vertebral venous plexus ​ Pathway for metastasis of prostatic and ovarian cancers to vertebral and cranial sites ○​ Internal iliac veins → Systemic circulation[2026 Trans] Figure 68. Vulvar cancers or lesions in the vulva(Dr. Taladtad) OS 206 Bony Pelvis, Pelvic Wall, and Floor 15 of 19  XV.​ REFERENCES UPCM 2025. (2022). The Family Living Wage (as of October 2022). https://www.ibon.org/2210-flw/ UPCM 2026. (2022). The Family Living Wage (as of October 2022). https://www.ibon.org/2210-flw/ UPCM 2027. (2022). The Family Living Wage (as of October 2022). https://www.ibon.org/2210-flw/ UPCM 2028. (2022). The Family Living Wage (as of October 2022). https://www.ibon.org/2210-flw/ UPCM 2028. (2022). The Family Living Wage (as of October 2022). https://www.ibon.org/2210-flw/ OS 206 Bony Pelvis, Pelvic Wall, and Floor 16 of 19  APPENDIX Figure 27. Ligaments of the pelvic girdle(Moore). OS 206 Bony Pelvis, Pelvic Wall, and Floor 17 of 19  Figure 28. Iliolumbar ligament(Moore). Table 1. Muscles of the pelvic wall OS 206 Bony Pelvis, Pelvic Wall, and Floor 18 of 19  Table 2. Muscles of the pelvic floor OS 206 Bony Pelvis, Pelvic Wall, and Floor 19 of 19