Anatomy of Female pelvic
Uterus: divided into 2 core parts (356)
- Body:
- Tapers as it approaches the vagina into the cervix
- Has a subdivision: domed superior end of the uterus between the entry of the uterine tubes, projects superiorly = called the fundus.
- Cervix: also subdivided
- Supravaginal part: the portion lying external to the vagina: supravaginal part
- Vaginal part: the portion projecting into vaginal canal- Pierces anterior wall of the vagina.
- As vaginal part projects into the vagina, it creates a recess that surrounds the tip of the cervix (upper end of the vagina). This is the Fornix.
- Is very important anatomical point for using a diaphragm.
- Outer brim of diaphragm fits into the fornix.
- Has very thick wall:
- Wall has a serosa covering the body exterior.
- The thickest part is muscular, called the myometrium. .
- Body and cervix are lined by endometrium. This is the portion that undergoes cyclic changes responding to female hormonal cycle.
- Thickness will vary, part of it will be shed during menses.
- The endometrium that is sloughed as menstrual fluid is the endometrial lining of the body, the endometrium of the cervical canal is not shed, it persists.
- Where uterus body and cervix meet, the body narrows
- The canal that connects the canal of cervix and body = internal os.
- This is the lumen at the junction of the two parts of the uterus.
- At the tip of the vaginal part of the cervix is the opening of the cervical canal to the vagina = external os.
- External os:
- Nulliparous cervix: external os at tip of cervix is round (not delivered a baby yet). This is an open foramen into the uterus from the vagina.
- Stellate: appearance of the external os after the first vaginal delivery. It is the delivery itself that changes the apperance- thus an abortion will not do it. Still has a lumen, but it has been distended to be a stelate shape.
- Thus, clinically easy to discern whether woman has had a vaginal delivery.
- (354) Supravaginal part of the cervix:
- This is the fixed (anchored) point for the entire uterus. Most of the body of the uterus is quite mobile. The body must be able to move freely since bladder is dynamic and in close proximity.
- 354 is cross section of anchor point. Deep fascia comes into sides to anchor = endopelvic fascia.
Endopelvic fascia:
- A fascial plane that lines the entire pelvic cavity, is thickened in some regions to form ligaments (now referring to a thickening of fascia – distinct from skeletal ligaments or embryonic remnants).
- This endopelvic fascia is continuous with the transversalis fascia. Remember, peritoneum is not fascia, it is a membrane. (more on relative position transversalis / peritoneum)
- Fascia given names pending on where it is coming from
- A thick band comes from the sacrum posteriorly- attaches to the supravaginal cervix = sacrocervical ligament (sacrouterine ligament).
- Less developed band coming from the pubis anteriorly = pubocervical ligament (puboutero)
- Most important is coming in directly from lateral pelvic wall = transverse cervical ligament (cardinal ligament). This is the thickest part of the tissues fixing (stabilizing) the uterus.
Vagina: (347)
- A musculofascia sheath. The anterior and posterior walls of the vagina are in contact, thus canal is only a potential canal except at upper endà here the cervix is projecting in to push the two walls apart.
- 3 functions:
- Acts as the lower portion of the birth canal, is capable of great distension.
- Is the female organ of copulation
- Acts as a duct for menstrual fluid
- It is in a superior – posterior plane as it goes from opening to cervix.
- The orifice is in the superficial perineal pouch.
- Majority is within the pelvic cavity.
- When the cervix projects into vaginal canal, creates the fornix. Subdivided:
- Anterior fairly shallow
- Posterior deepest part
- The one most important clinically, close relationship with peritoneal cavity.
- Only have thickness of vaginal wall and peritoneum separating vaginal canal from peritoneal cavity.
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- Most important relationship: between cervix and vaginal canal.
- They are in a 90 degree association when uterus is in normal position.
- This is also when bladder is empty. 90 degree is the target, it is not absolute.
(358) Relationship of cervix and vaginal canal:
- Anteversion orientation:
- Angle between vaginal canal and cervical canal is 90 degrees.
- This is the anteversion orientation of the uterus.
- Is the normal uterus. Thus the normal uterus is antiverted.
- This angle is at the external os at tip of cervix.
- Anteflexion angle:
- Another important angle is the angle at the juction of the body (internal os specifically) with the body of the cervix.
- Angle is between cervical canal and the uterine cavity.
- This angulation at the internal os should be about 170 degrees.
- Thus, normal uterus is anteverted and anteflexed.
- Retroversion:
- If the 90 degree angle at external os increases, the uterus begins to tip posteriorly so that 90 angle goes up to 130+
- The uterus comes into more alignment with vaginal canal
- This is an increase in the 90 angle between C canal and V canal. Range over 110 is a clinical issue.
- Age may be an issue. These angles are only important if the woman is in reproductive years. Normal position is better for implantation.
- Chance for abnormal implantation increases with retroversion (may occur at internal os for example).
- Retroflexion:
- If the 170 degree angle increases, a straightening occurs, called retroflexion.
- When the urinary bladder is very full and distended, retroversion and retroflexion occurs until voiding is complete.
- This is because uterus rests on the urinary bladder, this is natural.
- The key is that when bladder is empty, the uterus should come back and rest where it should.
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- Another issue: if you align the uterus with the vaginal canal, it will cause the uterus to drop into the vaginal canal: called prolapse. Prolapse of the uterus may result in the cervix protruding into the vestibule.
- Retroversion is more critical than retroflexion.
- May have retroversion / retroflexion independently or together.
- There are some very severe degrees of retroflexion while still have anteverted uterus.
- Uterus may tip back and be up against the uterus.
More Pathology:
- Rectocele: a distension anteriorly of the rectum that impinges on posterior wall of the vagina.
- If the pelvic floor is damaged, the weight of the organs causes them to sag deeper into the pelvis.
- The rectum may distend anteriorly and impinge on posterior vaginal wall.
- Retrocession: the uterus has sagged posteriorly against the rectum and is impending on it. puts pressure on the rectum.
- Cystocele: the urinary bladder has lost its support and is sagging against the anterior wall of the vagina.
- Urethrocele: the urethra is impinging on the vaginal canal.
- During pelvix exam, many pathologies can be determined using the vagina as the portal. Presenting symptom may be pain during intercourse.
Bimanual palpation: method for accessing the health / size of organs.
- Can palpate uterus easily. Cannot easily palpate the ovaries.
- Use one hand on abdominal wall, one gloved hand (2 fingers) in the vagina.
