Pelvis

Question 1

What are the bones of the pelvis?

Answer 1

Two hip bones called the os coxae

A sacrum and a coccyx

Question 2

Discuss the features of the Os Coxae

Answer 2

The hip bone, the os coxae, has three parts to it. At birth, the three bones which are joined by cartilaginous joints at the acetabula fossa – is where the head of the femur articulates with the hip. This is the hip joint. The ilium lies superiorly, the ischium, posteroinferiorly and the pubis, anteroinferiorly. They’re all joined by cartilaginous joints and are fused in the adult. It’s actually one large bone in the adult.

Question 3

Ilium

Answer 3

The iliac crest is a flattened crest at the top of the ilium. It lies at the level of L4 and where the aorta bifurcates.

The iliac crest is a useful landmark to know because it marks the point of L4 and you know that the level of L4 is well below the end of the spinal cord. It’s a useful landmark for lumbar punctures.

Question 4

Describe the divisions of the pelvic cavity.

Answer 4

The pelvis is divided by the pelvic inlet (pelvic brim):

• Greater pelvis or false pelvis - above brim
• Lesser or true pelvis - below brim

Question 5

Diagram of the Bony Pelvis

Answer 5

Question 6

Ligaments of the Pelvis

Answer 6

Ligaments of the posterior hip bone and and sacrum. Both the interosseus sacroiliac ligament and the posterior sacroiliac ligaments support the sacroiliac joint.

The posterior sacroiliac ligament blends with the fibers of the sacrotuberous ligament which attaches from the sacrum to the ischial tuberosity.

Question 7

Image of Pelvic Ligaments

Answer 7

Question 8

Image of Pelvic Ligaments (Female)

Answer 8

Question 9

Pelvic Inlet (Superior aperature of the pelvis)

Answer 9

Boundaries

Posteriorly

• Sacral promontory

Each side

• ­ Ant. margin of ala of sacrum
• ­ Arcuate line of ilium
• ­ Pecten pubis (pectineal line of pubis)

­ Pubic crest

Anteriorly

• Upper margin of pubic symphysis

Question 10

Pelvic Outlet

Answer 10

Also called inferior aperture of pelvis

Anteriorly

Pubic symphysis

On each side

Ischiopubic rami
Ischial tuberosity
Sacrotuberous ligament

Posteriorly

Coccyx

Question 11

Pelvic Inlet and Outlet

Answer 11

Question 12

What is the sub-pubic angle?

Answer 12

Angle between ischiopubic rami and lower margin of pubic symphysis

Width of subpubic angle is determined by distance between right & left ischial tuberosity

Measured with gloved fingers in vagina during a pelvic examination

Approximately width of fist
Adequate Intertuberous diameter > 10 cm

Question 13

Describe the Pelvic Cavity.

Answer 13

• Space between inlet and outlet
• ̈ Pelvic cavity is continuous above with abdominal cavity, limited below by pelvic diaphragm
• ̈ Cavity is more roomy (larger) in females than in males

Question 14

Describe the contents of the pelvis.

Answer 14

Sigmoid colon and rectum – posteriorly 


Urinary bladder - anteriorly 


Genital septum - in between bladder and rectum Transverse septa made up of connective tissue 


In male genital septa contains prostate, 


In female it contains

Question 15

Image of the anatomy of the hip

Answer 15

Question 16

Sacroiliac joint

Answer 16

Sacroiliac joint is a plane synovial joint

Articular surfaces

Auricular surface of sacrum and auricular surface of ilium

Ligaments

Fibrous capsule, interosseous sacroiliac lig, anterior and posterior sacroiliac ligament

Transmits weight of body to the hip joint

Question 17

Pubic Symphasis

Answer 17

Pubic symphysis

Secondary cartilaginous joint between bodies of pubic bones

Two surfaces covered by hyaline cartilage and separated by a fibrocartilagenous disc

Question 18

Sacrococcygeal joint

Answer 18

Sacrococcygeal joint
Secondary cartilaginous joint between sacrum and coccyx

Bones united by intervertebral disc

Question 19

Measurement of the dimensions of the pelvis

Answer 19

Question 20

Pelvic differences in males vs. females

Answer 20

Important differences

¡ Inlet is heart shaped in male and oval in female 


¡ Greater sciatic notch are wider in female narrower in males 


¡ In males inlet is much larger than outlet (funnel shaped) while in females 
inlet outlet are having less difference ( cavity cylinder) 


¡ Subpubic angle is wider in females (>90 degree); narrower in males 


¡ Body of S1 vertebra is wider than each ala of sacrum in males. In female 
both are equal 


¡ Ischiopubic rami is markedly everted in male, slightly everted in female 


¡ Preauricular sulcus is deeper in female 


Question 21

Muscles of the Pelvic Floor

Answer 21

Question 22

Muscles of the Pelvic Floor 2

Answer 22