Test 4 - Pelvic Girdle Biol 313 Dr. Howell

What is the most inferior part of the abdominopelvic cavity?

Pelvis

What is the transition between body trunk and lower limbs?

The pelvis

What are the two parts or the pelvis?

The greater and lesser

Which part is true and which is false?

Greater is false, lesser is true

Does the pelvis have surface anatomy?

No

What is the pelvis bound by?

The abdomen, lower back (dorsum), hips, thighs gluteal and peritoneum (inferior)

What is the perineum?

Surface area between the thighs and buttock (muscles deep to pelvic floor and external to genitalia)

What is the orientation of organs in the pelvic cavity (inferior abdoninopelvic cavity) in relation to the peritoneum?

All are sub peritoneal

What defines the superior limit of the pelvic cavity?

Pelvic inlet

What defines the inferior pelvic cavity?

Pelvic floor

Does the perineum have a cavity?

No

What does the pelvic girdle connect?

Connects the vertebral column to two femurs (basin shaped ring of bones)

What is the pubic symphysis?

More of a floor (less than a wall)

What are the three main functions of the pelvis?

Bear weight of upper body when standing/sitting, transfer weight from axial skeleton to lower limbs, attachment site for larger muscles for posterior locomotion.

How does the size of the pelvic girdle compare to the pectoral girdle?

Pelvic is slightly more massive

What are three more functions of the pelvis?

Contain and support the pelvic viscera (urinary and reproductive organs), support for pregnant (gravid) uterus, support for erectile tissues organs for intercourses

What three bones fuse to form the coxae? When do they form?

Ischium, ilium, pubis, form during puberty

What three bones make up the pelvic girdle in adults?

Two coxae and sacrum

What are the two joints of the pelvic girdle?

Pubic symphysis (anteriorly), and sacroiliac joint (posteriorly)

What defines the pelvic inlet?

pelvic brim: sacral promontory, arcuate line (ilium), pectin rap line (pubis), pubic crest

What defines the inferior pelvic outlet anteriorly?

Pubic symphysis

What defines the inferior pelvic outlet laterally?

Ischial tuberosities

What defines the inferior pelvic outlet posteriorly?

Coccyx

What is the only hip bone to articulate with the sacrum? (Also the largest)

Ilium

What is the prominent ridge of the ilium?

Iliac crest

What does the iliac crest mark?

Superior edge of the ilium

What does the iliac crest terminate in?

ASIS (Anterior superior iliac spine) PSIS ( posterior superior iliac spine) and also inferiors (AIIS, PIIS)

What line defines the pelvic inlet?

Arcuate line

What separates the widening part of the ilium (ala) from the narrow body?

Arcuate line

What structure provides passage for soft tissue structure?

Lesser and great sciatic notches

What might pass through the sciatic notch?

Sciatic nerve, piriformis muscle, obturator internus muscle

What comprises the ischium?

Body and narrow ramus

What does the body of the ischium help form?

Acetabulum

What is the ischial spine?

Sharp pointy projection from the ischium

What is the attachment site for the sacrospinous ligament?

Ischial spine

What is the sitz bone?

Tuberosities of the ischium

What is the ischial tuberosity?

large postero-inferior protuberance of the ischium

What converts the greater sciatic notch into the greater sciatic foramen?

Sacrospinous ligament

What forms the lesser sciatic notch?

Depression under the ischial spine

What is a foramen?

Opening, hole or passage

Where do the left and right pubic bones articulate?

Anteriorly at the pubic symphysis

What is created around this articulation site?

Pubic crest

What do pubic bones consist of?

Body and ramus

What does the body of the pubis make up?

Pubic symphysis

What forms the pubic crest?

Rami

What is the function of the pubic symphysis?

Allows twisting action while walking

What is the pectin pubis? And what does it form?

Oblique ridge on pubic ramus, part of the pelvic brim

What is the pubic arch angle for men? Women?

Less than 70, anything above 80

When standing what do the pubix bones form?

Weight bearing floor (not a wall)

What three bones fuse in adulthood that are not in preadolescent? What do these attribute to?

Pubis, ilium and ischium, the acetabulum

What is the socket of the hip joint? What type of joint?

Acetabulum, ball and socket

How much of the joint is each of these?

1/3

What is the obturator foramen formed by?

Pubis and ischium

What is the obturator foramen larger closed by?

The orbturator membrane

What is the small gab that allows passage of the obturator nerve, artery and vein?

Obturator canal

How many lines does the ilium posses?

Three gluteal lines

Where does the gluteal minimums orginate?

Between the interior and anterior gluteal lines

Where does the gluteus medius originate?

Between the iliac crest and posterior gluteal lines

What is the shape of the sacrum? What compromises it?

Triangle, five fused vertebra

What does the sacrum articulate with superiority?

L5 vertebra

What does the sacrum articulate with laterally?

The ilium

What does the sacrum articulate with inferiorly?

Coccyx (tailbone)

What is the structure of the sacrum?

Wide base with two broad wings (ala), and sacral promontory (defines pelvic brim), and a narrow apex

What are the broad wings called?

Ala

What is the shape of the sacral apex?

Narrow

Is the base of the sacrum inferior or superior?

Superior

What does sacral promontory define?

Pelvic brim

How many pairs of sacral foramina are there?

4

What is the coccyx?

Fusion of 4-5 vertebrae

What skeletal feature is often used in forensic medicine?

General differences between male and female pelvis

What is forensic medicine?

Application of medical and anatomical knowledge for law enforcement

Are there overlap in pelvis feature? What is one overlap that can cause problems?

Yes, problems during birth of hips are too narrow

Male vs Female pelvis - General structure

Thick and heavy. Thin and light

Male vs Female pelvis - Greater pelvis (pelvis major)

Deep, shallow

Male vs Female pelvis - lesser pelvis (pelvis minor)

Narrow and deep tapering, wide and shallow cylindrical

Male vs Female pelvis - pelvic inlet (superior pelvic aperture)

Heart shaped and narrow, oval rounded and wide

Male vs Female pelvis - pelvic outlet (inferior pelvic aperture)

Comparatively small, comparatively large

Male vs Female pelvis - pubic arch and su pubic angle

Narrow less than 70 degrees, wide greater than 80 degrees

Male vs Female pelvis - obturator foramen

Round, oval

Male vs Female pelvis - Acetabulum

Large, small

Male vs Female pelvis - greater sciatic notch

Narrow - 79 inverted V, wider about 90 degrees

Male vs Female pelvis - carrying angle

Due to wider pelvis women have larger carrying angle at the elbow 10-15 degrees then men 5 degrees

What must be of appropriate dimensions to pass an infants head?

Lesser pelvis

What are the two lines used marking the narrowest path? Where is each line? How far apart do they need to be?

Obstetric conjugate (sacrum to pubic symphysis), inter spinous line (ischial spine to ischial spine) both greater than 10

Which distance is not fixed?

Interspinous

Why is interspinous variable?

The pubic symphysis can pop (via relaxin)

What does the hormone relaxin do? How does this affect the coccyx and sacrum?

Loosens pubic symphysis and sacroiliac joints, allow them to move posteriorly

Does relaxin affect interspinous disease? (By affecting pelvic ligaments)

Yes

How much does the interspinous distance increase during pregnancy?

10-15%

Does relaxin affect other joints? And what does it increase risk for?

Yes, dislocation

Is the obstetric conjugate variable?

No it's fixed

How long should the diagonal conjugate be?

13cm

How long would the obstetric conjugate be if the diagonal was 13 cm? Why?

11.5 cm, hand can't palpitate at the correct angle

What is palpitated for, for diagonal conjugate?

Sacral promontory

What is the most inferior part of the abdominopelvic cavity?

Funnel shaped pelvic cavity

Where does the inferior pelvic cavity extend from?

Begins at pelvic inlet and extends posteroinferiorly to the pelvic floor

What composes the pelvic floor?

Bowl shaped pelvic diaphragm

How far does the pelvic diaphragm extend?

Below the pelvic outlet

What are the bony land Mark of the pelvis anteriorly, laterally, and posteriorly?

Pubic symphysis, ischial rami, coccyx

What muscles make up the pelvic floor?

Lavator ani and coccygeus.