Summary Medicine; the pelvis - pelvic floor and perineum Review

The Pelvis, Pelvic Floor and Perineum
Bony Pelvis

- Is female
- Juvenile pelvis will
have black structures
indicating growth plates –
cartilage
- Sacroiliac joint on
either side posteriorly
attach each hemipelvis to
the sacrum
- Pubic symphysis
anteriorly attaches the
two hemipelvis
- Running around the
outside is the arcuate line
- Number of
important nerves that come through the obturator foramen
- Ischial spine are spines of bone that sit internally in towards the pelvis
o Above and below are openings through which nerves and vessels travel through
- ASIS = anterior superior iliac spine of the iliac bone

Bony Pelvis – Position

- Greater pelvis (or false pelvis)
o Space enclosed by the pelvic girdle above and in front of the pelvic brim
o Bounded on either side by the ilium and incomplete ant.
- Lesser pelvis (or true pelvis)
o Space enclosed by the pelvic girdle inf. to pelvic brim: between the pelvic inlet and
the pelvic floor
- Pubic tubercles and the anterior superior
spines should be in a vertical spine –
pelvis is further forward than assumed
- When pelvis is correctly positioned there
is a horizontal line that exists from the
sacral prominence to the pubis symphysis
o = PELVIC INLET/BRIM
- Above pelvis inlet/brim = GREATER PELVIS
- Below pelvic inlet/brim = LESSER PELVIS
- Pelvic organs are contained within the
lesser pelvis
- In pregnancy, the uterus slowly migrates
towards the abdominal cavity becoming a
temporary abdominal organ

, Bony Pelvis – Male vs Female

- Pelvic outlet in male is oval shaped, in females it is circular




Female Pelvis

- need to make sure that the new born is able to
fit through the axis of the birth canal
- Can measure this by inserting the fingers in the
vagina to the point where you can feel the
pubic symphysis
- Image C – the shape of the inlet that a female
can have
o Typically see gynecoid