Physical structures; uterus and pelvis. Flashcards
Name all the bones of the pelvis and pelvic floor?
-2 innominate bones, 1 sacrum, 1 coccyx
What are the three bones fused together for the innominate bones?
-Pubis, ischium and ileum
Name the structures of the ileum
-Iliac crest, iliac fossa, anterior superior iliac spine, posterior iliac spine, sacroiliac joint, forms 2/5 of the acetabulum, greater sciatic notch, lesser sciatic notch.
Name the structures of the ischium
-Forms 2/5 of acetabulum, forms lower boundary of obturator foramen, ischial spines, ischial tuberosity.
Name structures of the pubic
-Superior ramus, inferior ramus, sub-pubic angle is 90 degrees, pubic symphysis.
Name structures of the sacrum
-5 vertebrae fused together, superior surface is smooth and articulates with the 5th lumbar vertebra joined by the lumbo-sacral joint. Hollow of the sacrum. Sacral promontory is the first sacral vertebra which overhangs the sacral hollow. There are four pairs of foramina which allow nerve to exit the sacral canal, forming the sacral plexus.
Name structures of the coccyx?
-Small triangular bone of 4 fused coccygeal vertebrae, joined to the sacrum via scare-coccygeal joint, it is possible to dislocate this joint. It supports the rectum, external anal sphincter is attached to the coccyx. Joint allows the coccyx to move backwards, making more room for the passage of the fetal head in labour.
Name the pelvic joints?
-Sacroiliac joints, 1 sacrococcygeal joint, 1 symphysis pubic joint.
What are the pelvic ligaments?
-Sacroiliac ligaments (A+P), sacrospinous ligament (side of sacrum to ischial spines). Sacrococcygeal ligaments. Inter-pubic ligaments. Sacro tuberous ligament.
What are the planes/regions of the true pelvis?
-Pelvic brim/inlet, pelvic cavity, pelvic outlet.
What are the characteristics of the pelvic brim?
-AP diameter is 11cm, extends from the sacral promontory to the upper inner border of the symphysis pubis. Transverse diameter is 13m. Oblique diameter is 12cm.
What are the characteristics of the pelvic cavity?
-Lies between the brim and the outlet. Circular are equal diameters. AP Is 12cm, oblique is 12 and transverse is 12.
Characteristics of the pelvic outlet?
-Diamond shape, longer back to front, AP Is 13cm, transverse is 11, oblique is 12
In order of deep to superficial what are the layers of the pelvic floor?
- Pelvic peritoneum
- Visceral layer of pelvic fascia thickened to form pelvic ligaments which support the uterus
- Deep pelvic floor muscles
- Superficial pelvic floor muscles
- Subcutaneous fat
- Skin
What are the deep pelvic floor muscles?
- Pubococcygeus
- Iliococcygeus
- Ischiococcygeus
What is the pubococcygeus?
-It arises from the posterior surface of the pubic bone. Fibres pass backwards to be inserted into the side of the coccyx. They pass below the bladder and either side of the urethra, the lower 1/3 of the vagina and the anal canal. Bands of fibres blend with musculature of the urethra, vagina and anus. This provides support for these organs and enables compression/occulsion of the vagina urethra and anus. It maintains the ano-rectal angle.
What is the iliococcygeus?
-Arises from the white line of pelvic fascia, which extends from the lower part of the symphysis pubis to the ischial spines crossing the obturator foramen. Muscle fibres pass downwards and inwards. They insert into the sides of the coccyx and lower sacrum.
What is the ischiococcygeus?
-Situated in front pf the macro-spinous ligament. It arises from the ischial spine and inserts into the side of occur and lower part of the sacrum. It helps to stabilise the sacroiliac-iliac and sacroiliac-coccygeal joints.
What are the superficial muscle layers?
-perineal membrane, transverse perineal muscles/2, bulbospongiosus x2, bulbocavernosisx2, ischiocavernosus x2, external anal sphincter and external urethral meatus.
What is the perineal membrane?
-triangular sheet of muscle and facia stretched across the pubic arch. It is perforated by the urethra and vagina.
What are the transverse perineal muscles?
-Crosses pelvic floor between ischial tuberosities via the perineal body, helps fix the position of the perineal body.
What is the position of the bulbospongiosus?
-From the perineal body to the clitoris around the vagina and urethra. It causes the erection of the clitoris.
What is the ischiocavernosus?
-Either side of the pubic arch, links with the pubic sphincter
What is the external urethral meatus?
-From one pubic bone to the other, passing in front of and behind the urethra, can occlude the urethra.
