Pelvis / Bones

What are the four functions of the pelvis?

Locomotion

Parturition

Support of abdominal viscera

Protection of pelvic viscera

What bones form the pelvis?

L/R hip bone

Sacrum

Coccyx

What is the other name for the hip bones?

Os coxa

What bones form the hip bones?

Ilium

Ischium

Pubis

The pelvis is tilted so the ASIS and upper margin of pubic symphysis lie in what plane?

Vertical plane

The pelvis is tilted so that the tip of the coccyx and upper margin of pubic symphysis lie in what plane?

Horizontal plane

T/F: The pelvic inlet is the superior aperture of the pelvis.

True

What are the boundaries of the pelvic inlet?

Sacral promontory

Sacral alae

Arcuate line

Pecten pubis

Pubic crest

What is another term for the pecten pubis?

Pectineal line

The pelvic inlet boundaries from what structure?

Pelvic brim

What is another name for pelvic brim?

Linea terminalis

What is another name for the lesser/true pelvis?

Pelvic cavity proper

What are the boundaries of the pelvic outlet?

Pubic symphysis

Ischiopubic rami

Ischial tuberosities

Sacrotuberous ligament

Tip of coccyx

What forms the pubic arch?

Pubic symphysis

Ischiopubic rami

Ischial tuberosities

How does the pelvic cavity project from the abdominal cavity?

Posteriorly

What pelvic type is characterized by a long A-P diameter and short transverse diameter? This is found in some males and 20% of females.

Anthropoid pelvis

What pelvic type is characterized by a short A-P diameter and a wide transverse diameter? This is rare in males and present in 2% of females.

Platypelloid pelvis

What pelvic type usually involves a difficult birth and frequent C-sections?

Platypelloid pelvis

What pelvic type has a heart-shaped inlet and is present in most males and 30% of females?

Android pelvis

What pelvic type has an ovoid or round inlet, and is present in 50% of females and no males?

Gynecoid pelvis

What pelvic type is idea for childbirth?

Gynecoid pelvis

What is the function of the greater/false pelvis?

Support abdominal viscera

Attachment point for muscles of locomotion

What structures make up the pubic arch?

Pubic symphysis

Ischiopubic rami

Ischial tuberosities

Which pelvis is larger, heavier, and has more pronounced muscle markings?

Male

What pelvic inlet is heart-shaped?

Male

What pelvic cavity and outlet are larger?

Female

What sex has more flaring ilia?

Male

Which sex has a larger subpubic angle?

Female

What sex has a broad and shallow sciatic notch?

Female

What sex has a narrow and deep sciatic notch?

Male

Which sex has a shorter and wider sacrum?

Female

Where is the lumbosacral joint found?

Between L5 and sacrum

T/F: The lumbosacral joint contains an IVD.

True

T/F: The sacroiliac joint is a synovial joint.

True

What kind of joint is the pubic symphysis?

Fibrocartilaginous joint

T/F: There is an interpubic disc in the pubic symphysis.

True

What is found in the sacrococcygeal joint?

IVD (can be fused sometimes)

What hormone can cause the joints of the pelvis to become loose during pregnancy?

Relaxin

What is uniquely transmitted in the greater sciatic foramen?

Piriformis muscle

Superior and inferior gluteal vessels/nerves

Sciatic nerve

Posterior cutaneous nerve of the thigh

Nerve to quadratus femoris

What is uniquely transmitted in the lesser sciatic foramen?

Tendon of obturator internus muscle

What structures pass through both the greater and lesser sciatic foramina?

Pudendal nerve

Internal pudendal vessels

Nerve to obturator internus muscle

What are some intrapelvic causes of sciatica?

Piriformis syndrome

Compression by fetal head during pregnancy

Pelvic tumors

What can misalignment of the sacrum cause?

Sciatica - pain, numbness, and weakness in lateral/posterior thigh and leg

What bounds the lateral wall of the pelvis?

Obturator internus and obturator fascia

What covers the posterior wall of the pelvis?

Piriformis and coccygeus

What forms the floor of the pelvis?

Peritoneum and pelvic diaphragm

What is the lowest point in the male peritoneum?

Rectovesical pouch

What is the lowest point in the female peritoneum?

Rectouterine pouch

Where can blood or ascites accumulate in the peritoneum?

Rectovesical or rectouterine pouch

Where is an abdominal ectopic pregnancy located?

Rectouterine pouch

What muscle is the major constituent of the pelvic diaphragm?

Levator ani

What is the function of the coccygeus muscle?

Support pelvic viscera, draw coccyx forward

What is the most posterior part of levator ani?

Iliococcygeus

What is the main part of the levator ani?

Pubococcygeus

What forms a sling around the urethra beneath the male prostate?

Puboprostaticus

What forms a sling around the urethra and vagina in female?

Pubovaginalis

What parts of the pubococcygeus function in bladder emptying and micturition?

Puboprostaticus and pubovaginalis

Fibers from each side of the puborectalis behind the anorectal junction form what?

Puborectal sling

What is the function of the puborectalis?

Maintain angle at anorectal junction

Relax during defecation

Direct fetal head during parturition

What is the name of the curved thickening of the obturator fascia which gives origin to parts of the pubococcygeus and iliococcygeus?

Tendinous arch of levator ani

What can misalignment of the sacrum affect? (S3 and S4)

Integrity of the pelvic floor (prevent prolapse)

Fecal incontinence

Urinary incontinence