Bones Flashcards
What bones form the pelvis?
- left hip bone
- right hip bone
- sacrum
- coccyx
What is the shape of the pelvis?
basin-shaped
What is each hip bone formed by?
three fused bones:
- ilium
- ischium
- pubis
In anatomical position, how is the pelvis tilted?
- the anterior superior iliac spine and upper margin of the pubic symphysis lie in the same vertical plane
- the tip of the coccyx and the upper margin of the pubic symphysis lie in the same horizontal plane
How does the pelvic cavity project from the abdominal cavity?
posteriorly
What is the pelvic inlet?
- the superior aperture of the pelvis
- heart, oval, or round-shaped
What are the boundaries of the pelvic inlet?
- sacral promontory
- sacral alae
- arcuate line (on ilium)
- pecten pubis (pectineal line)
- pubic crest
What is the pelvic brim?
- also called the linea terminalis
- continuous border formed by the boundaries of the pelvic inlet
- divides the pelvis into the greater (false) pelvis above and the lesser (true) pelvis below
What is the greater pelvis?
- the expanded upper portion of the pelvis
- part of the posterior abdominal wall
What are the functions of the greater pelvis?
- supports abdominal viscera
2. provides muscle attachment for muscles of locomotion
What is the lesser pelvis?
- the pelvic cavity proper
- lies between the pelvic inlet above and the pelvic outlet below
What does the lesser pelvis contain?
- lower part of the GI tract
- urinary bladder
- lower part of ureter
- internal reproductive organs
What is the pelvic outlet?
- the inferior aperture of the pelvis
- diamond shaped
What are the boundaries of the pelvic outlet?
- pubic symphysis (anterior tip)
- ischiopubic rami (lateral/anterior))
- ischial tuberosities (lateral points)
- sacrotuberous ligament (posterior wall)
- tip of the coccyx (posterior tip)
What occupies the pelvic outlet?
structures of the perineum
What is the pubic arch?
formed by pubic symphysis, ischiopubic rami, and ischial tuberosities
What is an anthropoid pelvis?
- characterized by a long A-P diameter and short transverse diameter
- present in some males and approximately 20% of females
What is a platypelloid pelvis?
- characterized by a short A-P diameter and wide transverse diameter
- rare in males, present in 2% of females
- flattened pelvis
- most associated with birth difficulties
What is an android pelvis?
- has a heart-shaped inlet
- present in most males and approximately 30% of females
What does the term “android” mean?
male-like
What is a gynecoid pelvis?
- has an ovoid or round inlet
- present in 50% of females and no males
- this is the ideal pelvis for childbirth
- very spatious: wide A-P and transverse diameters
What does the term “gynecoid” mean?
female-like
What are the differences between the male and female pelvi?
- male pelvis is generally larger, heavier, and has more pronounced muslce markings than the female pelvis
- male inlet is usually heart-shaped; female inlet is usually oval
- pelvic cavity and pelvic outlet are larger in female
- ilia are more flaring in male
- subpubic angle larger in female
- greater sciatic notch of female is broad and shallow; that of the male is narrow and deep
- female sacrum is shorter and wider than the male sacrum
