Clinical Cases - Female Reproductive Anatomy

A 24-year-old woman pregnant with her first child had been in the second stage of labor (pushing) for several hours. The crown of the child's head was just visible through the vaginal orifice, but the obstetrician was concerned that the woman was exhausted and was no longer able to push effectively. She decided to perform an episiotomy to enlarge the opening of the birth canal and assist the delivery of the baby.

Questions to consider:

1. What is an episiotomy and when is it performed?

   An episiotomy is an incision made in the perineum to enlarge the distal end of the birth canal. Episiotomies are performed in order to ease delivery, especially in difficult cases like breech and forceps deliveries.
   
   During delivery, as the infant proceeds to move down the vaginal canal, the infant stretches the perineum, levator ani, and pelvic fascia. Specifically, the pubococcygeus muscle is at risk for stretching to the point of tearing. The pubococcygeus muscle supports the urethra, vagina, and vaginal canal and damage to this muscle could lead to urinary stress incontinence post delivery whenever the patient coughs or increases her intraabdominal pressure by bearing down.

2. Episiotomies are generally made as a midline incision. If the incision were to continue tearing, what structures could be damaged?

   If the incision tears further during the delivery, a median incision is more likely than a posterolateral incision to extend posteriorly through the perineal body, the external anal sphincter, the internal anal sphincter, and the rectum.

3. What health risks to mother and child are associated with perineal tears?

   Serious tears (those that involve the anal sphincter and the rectum) may become infected by bowel contents, as may the child as it passes through the birth canal. This may delay or impair adequate healing for the mother or even present significant health risks (i.e. septicemia) for mother or child.

4. What are some potential complications if the perineal body is damaged and not repaired correctly?

   The integrity of the perineal body is critical to the strength of the entire perineum in women. Unrepaired injury can cause dysfunction of the external anal sphincter, internal anal sphincter, and/or sexual dysfunction (e.g. dyspareunia).

A 26-year-old woman pregnant with her second child experienced considerable anxiety when she thought about the pain that she would experience during childbirth. Her obstetrician explained that there were several options that involved the use of local anesthetics which would relieve the pain and said that he usually preferred to use a bilateral pudendal nerve block.

Questions to consider:

1. What is the distribution of the pudendal nerve and its branches?

   The pudendal nerve (from S2, S3, and S4) is the major nerve of the perineum, providing motor and sensory fibers to the perineum. Its branches in the female include: the perineal nerve, which provides branches to the posterior labial region and the muscles of the urogenital triangle; the dorsal nerve of the clitoris, which supplies the prepuce and glans of the clitoris; and the inferior rectal nerves, which supply the perianal region.

2. What other nerves would need to be blocked to provide complete anesthesia to the perineal region?

   Complete anesthesia of the perineal region requires anesthetization of the genital branches of the genitofemoral nerve, the ilioinguinal nerve, and the perineal branch of the posterior femoral cutaneous nerve. This can be accomplished by making an injection along the outer margin of the labia majora.

3. Where is the best place to deliver anesthetic to perform a pudendal nerve block?

   The location to deliver anesthetic to the pudendal nerve is as the nerve wraps around the ischial spine and before it sends out its branches.

4. What landmarks would an obstetrician use to deliver the anesthetic accurately?

   Two different methods may be used for a pudendal nerve block. In the transvaginal procedure, the ischial spine is palpated through the wall of the vagina and the needle is then passed through the vaginal mucous membrane toward the ischial spine, at which point the pudendal nerve is bathed with anesthetic. In the perineal procedure, the ischial tuberosity is palpated through the buttock and the needle is inserted about one inch deep medial to the ischial tuberosity. The anesthetic can then be injected to bathe pudendal nerve.

5. What other methods of anesthesia might be used to provide pain relief during childbirth?

   There are two other methods for delivering anesthetic to reduce the pain of childbirth: spinal anesthesia and epidural anesthesia. In spinal anesthesia, local anesthetics are injected into the subarachnoid space in the lower lumbar region. In epidural anesthesia, local anesthetic is infused into the epidural space through a catheter inserted into the vertebral canal. The methods have the advantage of blocking pelvic pain in general while allowing the mother to remain awake without interfering with uterine contractions.

L.D., a 60-year-old mother of four, visited her family doctor complaining of back pain and the sensation of something "coming down" her vagina, especially when she was standing. In addition, L.D. was troubled by stress incontinence when she coughed, sneezed, or lifted a heavy object, and by the need to micturate about ten times per day and five times each night. Pelvic examination revealed a first degree uterine prolapse (the cervix was still inside the vagina) and prolapse of the bladder base. The physician referred L.D. to a gynecologist, who recommended surgery. A vaginal hysterectomy and an anterior colporrhaphy (a procedure to correct the cystocele and stress incontinence) were performed , and L.D. was subsequently relieved of her symptoms.

Questions to consider:

1. What sphincter controls urinary flow and where is it located?

   Urinary flow is controlled voluntarily by the striated urethrovaginal sphincter muscle. This action is assisted by the pubococcygeus portion (levator prostate in the male) of the levator ani.

2. What is stress incontinence and why might coughing, sneezing, or lifting cause it ?

   Stress incontinence is the involuntary loss of urine caused by an increase in the intra-abdominal pressure when the abdominal muscles contract, as in coughing, sneezing, lifting and the like. Compromised urethral sphincters and/or support are unable to resist this stress, resulting in leakage.

3. How is the uterus ordinarily supported and what causes prolapse?

   The uterus is supported by the pelvic floor, the viscera surrounding it (i.e. the bladder, rectum, etc.), and connective tissue support structures. As the pelvic floor weakens due to aging or injury (like from multiple childbirths), the pelvic organs, including the uterus, will begin to sag if the pelvic diaphragm tone cannot be maintained. Several fascial ligaments, including the round ligament of the uterus and the rectouterine ligaments, and the cardinal ligaments help maintain the orientation of the uterus and cervix, and aid in supporting the pelvic viscera.

4. What is a vaginal hysterectomy?

   A vaginal hysterectomy is a surgical procedure in which the uterus is excised and removed from the body via a vaginal route (rather than abdominal). This procedure is the preferred surgical treatment for prolapse in the United States.

5. The cystocele caused a bulge in the anterior wall of the vagina. What structures could prolapse and cause a bulge in the posterior wall of the vagina?

   Loops of the small intestine in the rectouterine pouch may cause a bulge at the posterior fornix (enterocele) and the rectum may bulge into the lower vagina (rectocele).

You are in the middle of an international rotation in West Africa and consult with a surgeon on a 35-year old female patient who complains of irregular and painful menses, and an unexplained abdominal mass. The patient reports that she has six children. On physical exam you palpate a large (15 cm in diameter) mass in the lower abdomen. The patient denies pain on deep palpation, bowel sounds are present and normal. The surgeon decides to perform an exploratory laparotomy . She advises the patient that she may have to perform a hysterectomy and makes certain that the patient understands the consequences of the surgery. On beginning the surgery, she makes a midline incision up to the umbilicus, retracts the rectus muscles and fascia and notes that the patient has an enlarged uterus which is covered with large fibroid tumors. The surgeon then inspects the ovaries and observes that they are normal in size and morphology. She then proceeds to perform a hysterectomy. The excised uterus weighed in at six kilograms.

Questions and answers:

1. OPTIONAL: What would be the indications for a hysterectomy?
   

   Chronic pelvic pain/discomfort not due to other medical problems such as STD's, sexual abuse, heavy metal exposure, sickle cell disease, and psychiatric or psychosocial disorders. Obvious palpable masses in the abdomen with or without changes in bowel sounds would also suggest the need for an exploratory laparotomy.
   
   Physical exam would also include inspection for hernias, scars or obvious deformities, in addition to assessment of the patient's gait and any restriction of movement while walking. It is also important to auscultate for bowel sounds and palpate the abdomen, flanks, epigastric, back and femoral regions. During palpation special attention should be placed on the character, duration, type of pain and the site at which the pain was elicited. Noting the site of pain may give indication of strictures (urethral, uterine), masses or nodal tenderness. The patient also should be examined for any infectious disease processes, pregnancy, kidney stones, biliary problems or bleeding.
   
   Indications for a hysterectomy would also include treatment for leiomyomas, irregular and painful menses, and chronic pelvic pain. Unsuccessful antibiotic treatment of spontaneous abortion (septic abortion) with a subsequent abscess formation within the uterus would also necessitate a hysterectomy.

2. To excise the uterus what ligaments would the surgeon have to cut?
   

   The round ligament of the uterus, which connects to the uterus anterior and inferior to the uterine tube between the layers of the broad ligament.
   
   The ligament of the ovary (proper ovarian ligament), which lies posterior and inferior to the uterine tube.
   
   The anterior leaf of the broad ligament and the lateral attachments of the broad ligament.
   
   In addition the surgeon would detach the uterus by cutting below the external os of the cervix and suturing the four corners of the vaginal wall.

3. What blood vessels would she be concerned about as she performed the surgery?
   

   The uterine artery is the most significant source of blood to the uterus and therefore requires careful dissection. It is generally a branch of the internal iliac artery which supplies the uterus and uterine tube.
   
   The other major blood supply to the region is the ovarian artery which a direct branch off the aorta.

4. What other vessel or tube would be of great concern?
   

   The ureters pass under the uterine arteries on their way to the bladder - "yellow water" under "red bridge" is the term frequently used to describe their passage.

A 58-year-old woman presents to her physician complaining of rib and back pain following a trip-and-fall accident. She was concerned that she may have broken something. On physical exam, the physician notes some rib tenderness, but also finds a palpable mass in her right breast. The woman says that she does not perform monthly self-exams on her breasts and has not had a breast exam since her last checkup several years ago. A mammogram and rib and spine films were ordered by the physician. The mammogram shows a large mass consistent with cancer in her right breast and the bone films show multiple osseous lesions consistent with metastatic disease.

Questions to consider:

1. Where may breast tissue be found?
   

   Breast tissue may be found anywhere along the mammary or milk line from axilla to groin, but usually in the pectoral region between the clavicle, sternum, costal margin and axilla.

2. Why does the physician order separate breast and bone films?
   

   Both breast and bone films would be ordered since one film will not show both simultaneously due to the differences in density. Since cancer is suspected with the lump in the breast, the film of the bones might show if there are any metastases to them.

3. How can breast cancer spread or metastasize?
   

   Breast cancer can metastasize via the blood or via the lymphatic system.

4. What route did the tumor metastases take to get to the ribs and other bones?
   

   The most likely route for the cancer to reach the bones would be through the intercostal veins, i.e. hematogenous spread.

5. What lymph nodes might show cancer cells in them?
   

   In addition to the bones one would suspect that the axillary lymph nodes, especially the pectoral group might be involved. Parasternal (internal mammary) nodes could be as well.

6. What other organs might be involved?
   

   If the cancerous cells had spread directly via the venous system the next organs in jeopardy would be the lungs, since they are downstream, so to speak, and would be the first capillary bed the cells came to after entering the vascular system. If the tumor cells overwhelmed the axillary lymph nodes, they too ultimately drain into the venous system where lymph enters the venous system at the junction of the internal jugular and subclavian veins.

7. What might be evaluated in determining the prognosis of this patient's disease?
   

   The prognosis would depend upon the extent of the metastases and which organs were involved. This could be assessed by CT scans, nuclear scintigraphy, liver, brain and bone scans, to identify tumors or areas of rapidly dividing cells indicative of cancer metastases.

8. What types of treatment might she expect?
   

   Treatment would be to surgically remove the tumor, breast or some portion of it and perhaps adjacent tissues and axillary lymph nodes. Axillary lymph nodes are not removed to stop the spread, but to stage the cancer. Other treatment would depend upon which if any other organs are involved and might include radiation and/or chemotherapy to kill the tumor cells that have metastasized.

A forty-five-year-old female who recently delivered a healthy infant presents to her primary care physician with complaints of pain when she abducts her right arm. She also reports tenderness around her right axilla and redness around her right nipple. The patient reports she is breast feeding her infant and has also noticed a peculiar drainage from the same breast. The patient also reports that prior to her pregnancy she performed breast self-exams intermittently and noticed no unusual masses or discharges from either breast. On examination, the physician notes that the patient has a reddened area at six o'clock on her right breast. On palpation it is firm, and purulent non-bloody drainage is expressed from the nipple. The physician suspects that it is mastitis and prescribes antibiotics and cessation of breast feeding (while continuing to use a breast pump).

Questions to consider:

1. What groups of lymph nodes filter the lymphatic drainage of the breast and could help prevent or slow down the spread of infectious material?
   

   Pectoral (anterior axillary) nodes
   Central axillary nodes
   Apical/subclavian nodes
   Parasternal (internal thoracic nodes)

2. Which lymph nodes receive most of the lymphatic drainage of the breast? Where will the lymphatics from the nipple drain?
   

   Pectoral and central axillary lymph nodes receive the bulk (75%) of the lymphatic drainage. The anterior intercostal region drains medial toward the parasternal/internal thoracic nodes and the superior portion of the chest wall drains toward the subclavian nodes. More superficial regions of the breast drain along the subcutaneous lymphatics to the contralateral breast and superior abdominal wall. Most of the lymphatics from the nipple, areola, and lobules of the breast will drain to the subareolar plexus. This plexus then meshes with a larger cutaneous circumareolar plexus through which lymphatics may travel to the opposite side of the chest wall.
   
   The major pathway of lymphatic drainage from the mammary gland is along lymphatic channels which parallel:

   1. subcutaneous venous networks to the contralateral breast and to the abdominal wall.
   2. tributaries of the axillary vessels to the axillary nodes.
   3. tributaries of the intercostal vessels to the parasternal nodes and posterior mediastinal nodes.
   4. tributaries of the internal thoracic (mammary) vessels to the parasternal nodes.
   5. tributaries of the thoracoacromial vessels to the apical nodes.

3. What is the origin and insertion of the following muscles and how are they related to the breast?
   

   Pectoralis major:
   
   Origin: Sternal half of the clavicle and the lateral anterior surface of the sternum and manubrium to the seventh rib.
   
   Insertion: Distal fibers from a thick tendon that inserts on the lateral lip of the intertubercular groove of the humerus (aka. crest of the greater tubercle).
   
   Pectoralis minor:
   
   Origin: Third, fourth, and fifth ribs and the aponeurosis of the external intercostal muscles.
   
   Insertion: Coracoid process of the scapula.

4. What nerves provide sensory innervation to the breast? Why has the patient been feeling pain in the nipple and what nerve is involved?
   

   Sensory innervation is provided by lateral and anterior cutaneous branches of intercostal nerves 2 through 6. The pain in the nipple is conveyed by the anterior cutaneous branch of the 4th intercostal nerve which extends midline to the nipple.

5. Why does the patient have pain during abduction? What nerves innervate pectoralis major and minor muscles?
   

   The patient's pain and difficulty in raising her arm might be related to inflammation of the nerves which supply her pectoralis major muscle. These nerves would include both the medial and lateral pectoral nerves, which are branches of the brachial plexus.

6. The following nerves are related to the axillary lymph nodes and to the breast; match the following nerve with the appropriate muscle:

   Long thoracic nerve - Serratus anterior
   Thoracodorsal nerve - Latissimus dorsi
   Medial pectoral nerve - Pectoralis minor and sternocostal portion of major
   Lateral pectoral nerves - Pectoralis major, clavicular head

7. What are the major arteries and veins of the right breast?
   

   Arterial: The arterial blood supply is from several sources. Anterior perforating branches of the internal thoracic artery pierce the second through the fifth intercostal spaces. Branches of the axillary artery include the lateral thoracic artery and thoracoacromial arteries. Finally, there are lateral cutaneous branches from the posterior intercostal arteries.
   
   Venous: Venous drainage occurs from the breast primarily through tributaries to the axillary vein. Additional venous drainage occurs via the internal thoracic, lateral thoracic, and the intercostal veins (third through the fifth).

8. This patient has a subareolar abscess of the breast. Mastitis usually occurs during lactation and breast feeding, and is typically caused by the organism Staphylococcus aureus. Treatment of this patient would include antibiotics, incision and drainage of the abscess and excision of the diseased duct. Due to the patient's age, a careful follow-up should be performed in order to rule out an inflammatory carcinoma. Questions to ask the patient with regard to the nature of nipple discharge would include: Is the discharge uni- or bilateral? Is it milky? Is it blood tinged? Blood tinged discharge from one breast could be suggestive of an underlying malignancy - the most common of which would be an intraductal neoplasm.
   

References:

Clinically Oriented Anatomy (1992): pp 44-48.
Pre-test Self-Assessment and Review (1991) : pp. 87
Gross Anatomy Quizmaster (1996): Quiz 4
Advanced Surgical Recall (1994) pp. 515 -517.
Moore's Clinical Anatomy pp. 72 - 74.
Burkel, et al. pp. 107 - 114.