Pelvic cavity

Pelvic cavity

1. Learning objectives

   • pelvis, pelvic cavity and herniation
   • Formation of inguinal canal, femoral canal and pelvic girdle
   • Clinical relevance
     • inguinal and perineal hernias
     • complications of castration
     • partruition

2. Inguinal canal

   • External inguinal ring
     • Split in EAO
   • Internal inguinal ring
     • Caudal edges of IAO
   • BV and nerve passageway
   • Pelvic and abdominal tendon of EAO. Caudal edge of pelvic tendon is the inguinal ligament.
   • testis - inside vaginal process, but outside of body

3. Inguinal ring

   • passage of many structures - VETMEDG
     • Vaginal process/tunic
       • External cremaster muscle
         • muscle within the testis - lowers and raises testis to aid thermoregulation. Also, help testis motiltiy - aiding healthy sperm.
         • Testicular artery, vein and nerve
           • Mesoductus and mesorchium
             • External pudendal vessels
               • Ductus deferens
                 • Genitofemoral nerve
                   • branch of lumbar plexus - cremaster muscle and scrotal skin
                 • fibromuscular continuation of epididymus and excreotry duct for testis
               • vessels supplying pelvic region
         • thermoregulation, sperm motility

4. Open v closed inguinal ring

   • pen = pig, guinea pig
     • some so open, can contract testes into abdomen - require suture?
     • rings overlap - clear passage for abdominal contents
   • closed = dog, cat, ox, horse
     • separated rings - structures travel through space to pass through both rings
     • palpate before castration - if lots of overlap = use sutures or ab. contents can fall out. explain risk to owners!!

5. Femoral canal

   • Base is called VASCULAR LACUNA
   • Vascular lacuna - separated from superficial inguinal ring by inguinal ligament
   • exit from abdomen of FEMORAL ARTERY - branch of external iliac
     • FEMORAL ARTERY - vascular supply to hindlimb, travels in femoral triangle

6. Inguinal canal - testes - between legs

   • Femoral - legs
     • Femoral canal/vascular lacuna
       • femoral artery, vein and femoral nerve
         • blood and nerve supply to hindlimb. NB deep inguinal lymph node lies within FEMORAL CANAL

7. Clinical techniques

   • Castration
   • Inguinal hernia - retained/undescended testicles
   • Cryptorchidism - common
     • One testicle retained in abdomen - to only have one testicle = very rare
       • Must remove - inadequate thermoregulation = cancerous developments
   • taking a pulse - femoral artery

8. Pelvic outlet

   • exit of gastrointestinal, genital and urinary tracts
   • Made up of pelvic girdle (bone), pelvic and urogenital diaphragm
     • pelvic diaphragm separates pelvic and perineal region
     • urogenital diaphragm - pierced by urethra, separates deep perineal sac from upper pelvis
   • STRAINING
     • valsava manouvre
       • forecful expiration against a closed glottis
         • increase in intra-abdominal pressure
         • defecation, parturition

9. Pelvic girdle

   • paired ilium, pubis and ischium
   • sacrotuberous ligament (dog)
     • sacrum to ischial tubers
   • Sacrosciatic ligament (large animal)
     • sacrum to ilium, ischium and ischial tubers
       • broad origin and insertion- looks like big white sheet
       • slacken and dip in pregnant cow - preparation for partruition - ischiorectal fossa
         • If cow struggling to birth - pull diagonally - widest diameter

10. Pelvic diaphragm

    • muscular partition seperating pelvic cavity from perineal region
    • Levator ani (medial)
    • Coccygeus (lateral)
    • Perineal herniation
      • condition occuring in dogs and cats
      • abnormal displacement of abdominal organs around anus region
        • ruptured pelvic diaphragm - ruptured/damaged ligaments
        • Suture ligaments as muscles will be v. weak

11. Urogenital diaphragm

    • muscles associated with external genitalia
      • deep, transverse, perineal muscles, sphincter urethrae and internal and external fascia coverings
    • encloses ventral portion of the pelvic outlet
    • fixes reproductive tract in position to prevent cranial drag from uterus during pregnancy and drag during parturition

12. Anal sacs

    • aka anal glands
    • Stool makes sacs empty and release scent for marking
    • located at 4 and 8 oclock

Images and files in the map