Pelvis

Summary

• Viscerae and potential spaces
• Bones
• Ligaments
• Muscles
  • Pelvic Floor
• The perineum
• Nerve supply

---

Pelvic Viscerae 

• The pelvis contains many structures
  • Urological:
    • Bladder
    • Ureters
    • Urethra
  • GI:
    • Sigmoid colon
    • Rectum
    • Anus
  • Males:
    • Prostate
    • Ductus deferens
    • Seminal vesicles
  • Females:
    • Uterus + uterine tubes
    • Ovaries
    • Vagina + cervix

• Potential spaces
  1. Rectovesical space (males)
     • Between bladder and rectum
  2. Rectouterine space  (females)
     • Difficult to access

       

---

Bones

• There are two hip bones (left and right)
  • There are three sections to each hip bone:
    1. Ilium
    2. Ischium
       • Body
       • Spine
       • Tuberosity
    3. Pubis

---

Ligaments

• Sacroiliac ligaments
  1. Anterior
  2. Posterior

• Sacrotuberous ligament
  • Attach to ischial tuberosity

• Sacrospinous ligament
  • Attach to the Ischial spine

• The sacrotuberous and sacrospinous ligaments form the two sciatic foramina
  • Greater sciatic foramen
  • Lesser sciatic foramen

---

Muscles

• There are two main areas to consider muscles:

• Pelvic floor muscles:
  • Coccygeus
  • Levator Ani – form a concave, circular bowl at the inferior aspect of the pelvis
    • Iliococcygeus
    • Pubococcygeus
    • Puborectalis

• Other muscles – attach to greater trochanter of femur
  • Obturator internus
    • Covered by fascia and the Tendinous arch
  • Piriformis
    • Posterior
    • Across greater sciatic foramen

---

Perineum

• Space between ischial tuberosities, coccyx, and pubic symphysis
  • Divided into 2 areas
    1. Urogenital triangle 
       • This lies anterior
       • Bounded by the pubis and the two ischial tuberosities
       • Covered by perineum
    2. Anal triangle
       • This lies posterior
       • Bounded by the coccyx and two ischial tuberosities
       • Not covered in perineum
         • Contains the ischioanal fossa.

Both triangles are supplied by the Pudendal nerve (S2-S4)

 

 

---

Nerve Supply

• Somatic nerves
  • Pudendal (S2-4)
  • Nerve to levator ani (S3-S4))

• Sympathetic nerves
  • Distal sympathetic trunk (Sacral Splanchnic nerves)
    • Lumbosacral nerves input into this
  • Hypogastric nerve

• Parasympathetic nerves
  • Pelvic splanchnic nerves

• Autonomic fibres all feed into the Inferior hypogastric plexus
  • Then distributed out from there