Female Pelvis and Fetal Skull Flashcards
What are the 4 bones that form the pelvis?
Sacrum, Coccyx and 2 coxal bones
What 3 things make up the pelvic space?
Pelvic brim, pelvic cavity and pelvic outlet
What makes up the true pelvis?
Pelvic cavity and pelvic outlet
What is the pelvic cavity?
From the brim to the outlet, following the curve of carus
What is the pelvic outlet?
The lower border of the symphysis, pubic arch, ischial spines and tuberosites, lower coccyx and sacrotuberous and sacrospinous ligaments
What are the three pelvic ligaments?
Anteroposterior, Oblique and transverse
What are the 4 types of pelvis?
Anthropoid, android, gynaecoid and platypelloid (flat)
Which pelvis is the most common?
Gynaecoid
What is the occiput?
The region lying between the foramen magnum and the posterior fontanelle
What is the vertex?
The area bound by posterior fontanelle, the two parietal eminences and anterior fontanelle
What is the Sinciput or brow?
It extends from the anterior fontanelle and coronal structure to orbital ridges
What is ossification?
The formation and hardening of fetal skull incomplete at birth
What are suture lines?
Small gaps left between the bones
What is a fontanelle?
Where two or more sutures meet
What are the 5 stages of the birth mechanism?
engagement
descent and flexion
internal rotation
extension
external rotation
What is the pelvic floor made of?
Muscle fibres and soft tissues suspended within the outlet of the pelvis forming a dome like sheet of tissue
What is the Levator ani muscle (LAM)?
The pelvic floor
What do the muscles of the Levator ani muscle do?
- Maintain constant tone, except during voiding and defecation
- Have the ability to contract quickly at times of acute stress like coughing and sneezing to maintain continence
- Distend to allow the passage of the infant during childbirth and contract following to resume normal the function
What are the superficial pelvic floor muscles?
Ishiocavernosus
Bulbocavernosus muscle
Superficial transverse perineal muscle
Anal sphincter
How are the pelvic joints held together?
By very strong ligaments that are designed not to allow movement
What gradually loosens the pelvic ligaments allowing slight pelvic movements?
The hormone relaxin
What is nutation?
opening the outlet
What is counter- nutation?
opening the inlet
