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)

Greater sciati foramen Lesser sciatic foramen Ischial tuberosity UGT Obturatorforamen Perinea' body

Lateral view of the pelvic triangles.

 

Transverse view.

 


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

Leave a Reply

Your email address will not be published. Required fields are marked *