Pelvis Flashcards
What are the four functions of the pelvis?
Locomotion, parturition, support of abdominal viscera, protection of pelvic viscera
What is necessary for the pelvis to maintain to permit efficient bipedal locomotion?
Small enough pelvic dimensions
What is necessary for the pelvis to maintain to permit passage of the fetal head during parturition?
Large enough pelvic dimensions
What structures are shaped to support abdominal structures in the pelvic region?
Laterally flaring ilia
In what part of the pelvis does protection of the pelvic viscera take place?
True pelvis
What shape is the overall pelvis?
Basin-shaped
What four bones make up the pelvis?
Left hip bone, right hip bone, sacrum, coccyx
What three bones make up each hip bone?
Ilium, ischium, pubis
In anatomical position, what parts of the pelvis lie in the same vertical plane in the pelvic tilt?
ASIS and upper margin of the pubic symphysis
In anatomical position, what parts of the pelvis lie in the same horizontal plane in the pelvic tilt?
Tip of the coccyx and the upper margin of the pubic symphysis
The pelvic cavity projects in which direction from the abdominal cavity?
Posteriorly
What is the superior aperture of the pelvis?
Pelvic inlet
What are the boundaries of the pelvic inlet?
Sacral promontory, sacral alae, arcuate line, pecten pubis (pectineal line), pubic crest
What is the continuous border formed by the boundaries of the pelvic inlet called?
Pelvic brim/linea terminalis
The area of the pelvis located above the pelvic brim is called what?
Greater (false) pelvis
The area of the pelvis located below the pelvic brim is called what?
Lesser (true) pelvis
What is the function of the greater (false) pelvis?
Supports abdominal viscera, point of attachment for muscles of locomotion
What is the pelvic cavity proper?
Lesser (true) pelvis
What does the true pelvis contain?
Lower part of the GI tract, urinary bladder, lower part of ureter, internal reproductive organs
What is the inferior aperture of the pelvis?
Pelvic outlet
What shape is the pelvic inlet?
Oval or heart-shaped
What shape is the pelvic outlet?
Diamond shaped
What are the boundaries of the pelvic outlet?
Pubic symphysis, ischiopubic rami, ischial tuberosities, sacrotuberous ligament, tip of the coccyx
What makes up the pubic arch?
Pubic symphysis, ischiopubic rami, and ischial tuberosities
What covers the entire pelvic outlet?
Perineum
What characterizes an anthropoid pelvis?
Long A-P diameter and short transverse diameter
What type of pelvis is present in some males and approximately 20% of females?
Anthropoid
What is the rarest pelvis type?
Platypelloid
What characterizes a platypelloid pelvis?
Short A-P diameter and wide transverse diameter
What type of pelvis is rare in males and present in 2% of females?
Platypelloid
What type of pelvis is most associated with birthing difficulties?
Platypelloid
What type of pelvis has a heart-shaped inlet?
Android
What type of pelvis is found in most males and approximately 30% of females?
Android
What type of pelvis can be common among female athletes?
Android
What type of pelvis has an ovoid or round inlet?
Gynecoid
What type of pelvis is present in 50% of females and no males?
Gynecoid
What type of pelvis is ideal for childbirth?
Gynecoid
The pelvis of which gender is generally larger, heavier, and has more pronounced muscle markings?
Male
The male inlet is usually what shape?
Heart-shaped
The female inlet is usually what shape?
Oval
In which gender are the pelvic cavity and outlet larger?
Female
In which gender are the ilia more flaring?
Male
In which gender is the subpubic angle larger?
Female
In which gender is the greater sciatic notch broad and shallow?
Female
In which gender is the greater sciatic notch narrow and deep?
Male
In which gender is the sacrum shorter and wider?
Female
The lumbosacral joint is located between what vertebral osseous features?
L5 and sacrum
Which pelvis joints contain an intervertebral disc?
Lumbosacral joint and sacrococcygeal joint
What is the name of the joint located between the sacrum and ilium?
Sacroiliac joint
What type of joint is the sacroiliac joint?
Synovial
What is significant of the synovial sacroiliac joint?
It is the least mobile synovial joint in the body
What joint is located between the two pubic bodies?
Pubic symphysis
What type of joint is the pubic symphysis?
Fibrocartilaginous joint
What type of disc does the pubic symphysis contain?
Interpubic disc
What joint is located between the sacrum and coccyx?
Sacrococcygeal joint
Which pelvic joint is often fused?
Sacrococcygeal joint
Which pelvic joint may separate by 1 centimeter during pregnancy?
Pubic symphysis
What hormone is responsible for making the joints of the pelvis loose during pregnancy?
Relaxin
What two ligaments are involved in forming the greater and lesser sciatic foramen?
Sacrotuberous and sacrospinous ligaments
Which ligament extends from the sacrum and coccyx to the ischial tuberosity?
Sacrotuberous ligament
Which ligament extends from the sacrum and coccyx to the ischial spine?
Sacrospinous ligament
What are the boundaries of the greater sciatic foramen?
Greater sciatic notch, sacrotuberous & sacrospinous ligaments
Where does the greater sciatic foramen lie in reference to the pelvic floor?
Above it
What does the greater sciatic foramen transmit?
Piriformis muscle, superior and inferior gluteal vessels and nerves, internal pudendal vessels, pudendal nerve, sciatic nerve, posterior cutaneous nerve of thigh, nerve to the obturator internus muscle, nerve to the quadratus femoris muscle
What are the boundaries of the lesser sciatic foramen?
Lesser sciatic notch, sacrotuberous & sacrospinous ligaments
Where does the lesser sciatic foramen lie in reference to the pelvic floor?
Below it
What does the lesser sciatic foramen transmit?
Tendon of the obturator internus muscle, nerve to the obturator internus muscle, internal pudendal vessels, pudendal nerve
What is the only thing that goes through the lesser sciatic foramen and NOT the greater sciatic foramen?
Tendon of the obturator internus muscle
What structures pass through both the greater and lesser sciatic foramen?
Pudendal nerve, internal pudendal vessels, and nerve to obturator internus
What can happen to the sacrum leading to impingement on structures which exit the greater sciatic foramen?
Sacral misalignment
What is especially vulnerable in a sacral misalignment?
Sciatic nerve
What is sciatica?
Pain, numbness, and weakness in the lateral posterior thigh and leg
What are intrapelvic causes of sciatica?
Piriformis syndrome, compression by the fetal head during pregnancy, pelvic tumors
