3.6. Maternal Pelvis & Fetal Skull

Question 1

What are the 5 functions of the pelvic girdle?

Answer 1

1. Supports and protects pelvic organs and some abdominal ones
2. dynamism in labour
3. Protection and support in pregnancy
4. transmits weight to legs and allows upright posture
5. attaches femurs to axial skeleton

Question 2

There are 4 bones of the pelvic girdle.

What are they?

Answer 2

Coccyx
Sacrum
2 innominate bones

Question 3

What 3 bones fuse to make each innominate bone?

Answer 3

ilium
ischium
pubis

Question 4

What are the 4 pelvic joints?

Answer 4

symphysis pubis
2 x sacroiliac joints
sacrococcygeal joint

Question 5

What is the ‘true pelvis’? and what is it divided into?

Answer 5

The bony canal through which the fetus must pass through during birth.
Brim
Cavity
Outlet

Question 6

What are the 4 diameters of the pelvic brim?

Answer 6

Transverse
Left oblique
Right oblique
Anteroposterior

Question 7

What are the 4 bones of the vault (fetal skull)

Answer 7

• Frontal bone
• Parietal bone
• Occipital bone
• Temporal bone

Question 8

What are the 6 regions of the fetal skull?

Answer 8

• Glabella (brow)
• Sinciput
• Vertex
• Occiput
• Sub-occipital region
• Mentum (chin)

Question 9

What are the 2 fontanelles?

Answer 9

Anterior fontanelle/ bregma (diamond shaped)

Posterior fontanelle/ lambda

Question 10

What are the 4 sutures?

Answer 10

• Coronal suture
• Lamboidal suture
• Sagittal suture
• Frontal suture

Question 11

Name the 2 key transverse diameters of the fetal skull and give their measurements

Answer 11

Biparietal- 9.5cm

Bitemporal- 8.2cm