Anatomy of the cervix
The cervix is the part of the inverted pear-shaped uterus that corresponds to the narrow stalk end of the pear. This cylindrical-shaped muscular structure is about 3-5 cm in length and partly lies in the upper vagina, extending superiorly into the retroperitoneal space behind the bladder and in front of the rectum.
It is supported by ligaments (cardinal ligaments laterally and uterosacral ligaments posterolaterally). The cervix opens into the uterine cavity superiorly (via the internal os) and into the vagina inferiorly (via the external os). The os appears round in nulliparous women but can be seen as a transverse slit in those who have gone through labour.
It is mainly composed of involuntary muscle superiorly and fibrous connective tissue inferiorly. The cervix is lined in its upper 2/3 by ciliated, cylindrical epithelium which changes to stratified squamous epithelium at the external os. It receives its blood supply from the ovarian and uterine arteries (originating from the aorta and internal iliac arteries respectively). It has an autonomic (sympathetic and parasympathetic) nerve supply and lymphatic drainage is to the external and internal iliac lymph nodes as well as the obturator node and the sacral nodes.
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Physiology of the cervix
The cervix acts as a canal between the vagina and the body of the uterus. Numerous deep glandular follicles lining the mucus membrane of the endocervix are responsible for the production of mucus. This mucus changes consistency in response to the levels of oestrogen: it is profuse, watery and alkaline when levels are high but, as levels drop post-ovulation, it becomes thick, scant and acidic. During pregnancy, it becomes even thicker and more tenacious, forming a plug rich in leukocytes. Microglandular hyperplasia can occur during pregnancy and immediately postpartum as well as in women taking progesterone treatment.
Examination of the cervix
- Examination of the cervix should be carried out in conjunction with examination of the other associated structures.
- If you are male, have a chaperone. If you are female, offer one (document this).
- Always explain exactly what you are going to do at the outset.
- Prepare everything in advance so that there is no fumbling mid-examination.
- Encourage the patient to empty her bladder before beginning examination.
Preparation: items required
- A comfortable couch.
- A sheet for the patient.
- A flexible light source.
- Non-sterile gloves (double glove if you plan to then do a rectal examination).
- Warm running water.
- Vaginal speculum (place in warm water if metallic) - preferably more than one if different sizes are available.
- Lubricating jelly.
- Any additional instruments you may need, such as cervical smear kit.
- Consent from the patient (verbal is generally fine).
- Position the patient correctly: she should be lying on her back, heels drawn up towards her bottom and knees gently relaxing open.
- Warm the speculum and add lubricating jelly to it.
- Let the patient know that you are going to start.
- Examine the vulva, expose the introitus and insert the closed speculum.
- When the handles of the speculum are almost flush with the perineum, gently open it and position so that the cervix lies between the two arms of the speculum.
- Examine the cervix, making note of the shape of the os, uniformity of colour, any asymmetry, lumps or other abnormalities.
- Carry out a smear as appropriate.
- Gently pull the speculum back just enough to clear the cervix (1-2 cm), then loosen the speculum before fully withdrawing it.
- The elusive cervix:
If the cervix is not immediately visible, don't withdraw immediately:
- Consider angling the blades of the speculum (anteriorly or posteriorly) until it comes into view.
- If it is partially concealed, a swab may be used to bring it fully out (it is essential to be able to see its entire circumference).
- The chaperone may also apply gentle pressure on the suprapubic area.
- If all of those fail, consider whether the size of the speculum is right (if it is too small, it will not reach the fornices).
- Lying the patient on her side is also used with varying success.
Further investigative procedures
- Colposcopy - in certain situations, a speculum examination is not enough (most commonly if abnormal cells are picked up on a routine smear test but also in cases of bleeding after intercourse, persistent severe vaginal discharge, intermenstrual bleeding and in immunocompromised patients) and the cervix is further assessed using a colposcope (a mounted binocular microscope). From the patient's perspective, this involves the same procedure as for a speculum examination, although the procedure is longer and may involve application of acetic acid or iodine. A biopsy may also be taken and laser treatment carried out. Colposcopy can safely be performed during pregnancy but biopsies and treatment will be postponed until after the time of delivery.
- Other procedures - further assessment of the cervix is usually carried out in the context of suspicions of uterine abnormality, in which case, hysteroscopy or laparoscopy may be indicated.
These are relatively uncommon and occur as one of three problems:
- Failure of fusion of the Müllerian ducts during development, resulting in a duplicated or septate cervix (one cervix with two openings).
- Congenital absence or hypoplasia of the cervix - these may be associated with urinary tract or musculoskeletal (notably spinal) abnormalities. Partial agenesis may occur; if there is a primitive uterus containing endometrium, haematometra occurs at puberty, producing cyclic abdominal pain.
- In utero exposure to non-steroidal oestrogens (such as diethylstilbestrol) and other non-steroidal oestrogens. 1 in 1,000-2,000 exposed female fetuses develop clear cell vaginal adenocarcinoma. Other problems include a hypoplastic T-shaped uterus as well as various gross and microscopic colposcopic abnormalities (eg cervical rings, collars and hoods, epithelial changes and a shift in the location of the squamocolumnar junction).
These are the most common benign neoplasms of the cervix (found in 4% of the gynaecological population). These may be endocervical or cervical:
- Endocervical polyps are most usually found in the fourth to sixth decade of life. They are cherry red lesions which may be single or multiple and may appear as a pedunculated lesion on a stalk of varying length.
- Cervical polyps are equally benign and tend to occur as single, smooth grey-white lesions that bleed easily if touched.
Polyps tend to be asymptomatic but may also present as abnormal bleeding (such as during intercourse, heavy menstrual periods, between menstrual periods or after the menopause). Occasionally, they may grow big enough to obstruct the external os and so cause infertility. Malignancy is rare (less than 1 in 200 cases) and the malignancy tends to arise from sources beyond the cervix.
Polyps may be removed. This can simply be done by twisting them off; patients may be referred for this but, if you are confident in carrying out this procedure in your surgery, be mindful of vagally stimulated bradycardia (common, needs treatment with atropine) and haemorrhage which may require cautery for haemostasis. Alternatively, surgical dilatation and curettage, electrosurgical excision or hysteroscopic polypectomy may be performed for more persistent lesions. All patients with suspicious lesions should be referred to a specialist clinic and the lesions sent to histology.
These smooth, firm masses are often solitary and account for about 3-8% of uterine myomata. A fibroid growing down into the cervix from higher up in the uterus is a more common situation. They tend to be small (5-10 mm in diameter). Enlargement causes upward displacement of the uterus and the fibroid may become impacted. Other symptoms also relate to its size and exact location: dysuria, urgency, obstruction and dyspareunia.
Management is guided by the size of the lesion and the age of the patient (whether she wants to retain fertility). It ranges from simple observation, to medical treatment with gonadotrophin-releasing hormone (GnRH) agonists, to surgery. The latter is tricky on account of the relative inaccessibility of these lesions and the proximity to the bladder and ureters.
There are difficult questions arising from incidental findings of asymptomatic fibroids which may become a nuisance in the future. There are no specific management guidelines; this is slightly dictated by the patient's age; they tend to grow in time so a large lesion in a young patient is more likely to become problematic.
Endometriosis in the cervix is relatively common and usually considered to be inoffensive. This may be apparent as blue-red or blue-black lesions 1-3 mm in diameter which may have been implanted during childbirth or surgery. Occasionally, it can cause postcoital bleeding and it may present as a mass. There has been a case report of it presenting as massive vaginal bleeding. Unless there are significant symptoms, the vast majority of patients are managed conservatively.
More unusual tumours:
- Squamous papilloma - 2-5 mm diameter solid tumours situated on the ectocervix, which may arise as a consequence of past inflammation or trauma.
- Microglandular hyperplasia - this is manifest as a polypoid growth measuring 1-2 cm and occurs most often in women who are on oral contraceptive therapy or depot-medroxyprogesterone acetate resulting from the influence of progesterone. This may also be seen in pregnant or postpartum women.
- Papillary adenofibroma - this is an uncommon polypoid structure which may also be found in the endometrium and Fallopian tubes.
- Haemangioma - these are rare and, if they are symptomatic, complaints are of pain and vaginal bleeding. They are similar to those found elsewhere in the body but, as the differential diagnosis is cervical malignancy, treatment is surgical.
- Mesonephric duct remnants - these tend to be incidental findings in the 3 and 9 o'clock positions and are vestiges of the mesonephric (Wolffian) ducts.
- Heterologous tissue - including cartilage, glia and skin - these are most likely the remnants of a previous abortion.
Abnormality of form
- Stenosis - this problem may be congenital or acquired and tends to occur at the level of the internal os. There are a number of causes and associations:
- Diathermy excision of cervical lesions is the most common cause of stenosis (it occurs in 1.3% of cases).
- Other acquired causes include radiotherapy, infection, neoplasia and atrophy following a cone biopsy.
- It may also be associated with endometriosis.
- Ectropion (previously called cervical erosion or abrasion) - this is when the central columnar epithelium extends out through and around the external os.
- This is generally an asymptomatic condition (patients occasionally present with bleeding or infection) which is seen on examination as a red ring around the os.
- It is more commonly seen in teenagers, during pregnancy and in women on the oral contraceptive pill. It may also be seen in newborns. There have also been reports of congenital ectropion following diethylstilbestrol exposure in utero.
- Once a normal cervical smear has been confirmed, it is actively managed only if there are symptoms. Options include thermal cautery with diathermy, cryotherapy and surgery with laser treatment. Microwave therapy is also being considered as a new treatment option.
Other structural problems of the cervix
- Nabothian cysts (epithelial inclusion cysts/mucinous retention cysts):
- These common mucus-filled lesions are almost considered to be a normal part of the adult cervix. They look like multiple translucent or opaque, white or yellow lesions ranging from 2 mm to 10 mm in size.
- They tend to occur following natural tissue regrowth after minor trauma or after childbirth. This new tissue grows over the opening of the nabothian glands, so giving rise to these lesions.They are occasionally a result of chronic cervicitis.
- They are usually asymptomatic and need no treatment. They may very occasionally be problematic if they grow very large, in which case they may be treated with cautery or cryotherapy.
- This can occur following mechanical dilatation of the cervix, particularly where a softening agent (such as a prostaglandin) is not used appropriately. Thus, cervical lacerations can complicate hysteroscopy and abortion.
- It occurs more commonly in the presence of cervical stenosis or atrophy and may also occur during delivery.
- Acute lacerations present with bleeding and need suturing once the extent of the laceration is ascertained.
- Poor repair may lead to subsequent cervical incompetence.
Inflammation of the cervix is very common and thought to be present in almost every sexually active woman. It may be infectious (commonly endocervicitis) or non-infectious (more often ectocervicitis).
- Symptoms - these vary from none to abnormal yellow-green discharge, bleeding (especially postcoital), dysuria.
- Signs - green/yellow/opaque mucopurulent discharge. Endocervical friability (bleeds easily).
- Common culprits - Neisseria gonorrhoeae, Chlamydia trachomatis, human papillomavirus and the herpes simplex virus.
- Treatment - antimicrobial, guided by results from swabs:
See separate article Sexually Transmitted Diseases for further information.
- Symptoms - as with endocervicitis.
- Signs - cervical oedema and erythema, discrete ulceration, cervical petechiae ('strawberry cervix').
- Common culprits - cervical cancer, mechanical trauma (tampons, pessaries, IUCDs), chemical irritants (douching, spermicides), systemic inflammatory disease such as Behçet's disease.
- Treatment - this will depend on the causative factor.
There will also be a significant proportion of cervicitis of unknown aetiology. A cervical smear is mandatory in suspected non-infectious cervicitis.
Problems with the cervix in pregnancy
This is usually diagnosed in the context of a miscarriage occurring after 12-14 weeks or in premature labour. It presents as a painless dilatation of the cervix through which the membranes bulge and eventually spontaneously erupt. Diagnosis is based on a past history of second-trimester miscarriages, and ultrasound scanning may confirm shortening or funnelling of the cervix (although this in itself carries a risk of miscarriage).
Treatment involves prophylactic placement of a cervical stitch (cerclage) with the aim to prevent loss of the pregnancy (an emergency procedure can also be carried out). However, there is controversy over the effectiveness of this procedure which may also be associated with an increased risk of puerperal pyrexia. It is therefore limited to two groups of patients:
- Those with a history of 3 or more spontaneous preterm births or second-trimester losses.
- High-risk patients with a singleton pregnancy who have a short cervix in the second trimester.
Ectopic pregnancy in the cervix
The cervix is the least common site for an ectopic pregnancy. This may be seen as a bluish hue on the cervix and, rarely, a gestational sac and live fetus can be identified on ultrasonography. This is such a rare occurrence that there is no management protocol but, from the case studies available, medical termination appears to be the best option because life-threatening haemorrhage may occur.
Further reading & references
- Lusk MJ, Konecny P; Cervicitis: a review. Curr Opin Infect Dis. 2008 Feb;21(1):49-55.
- Shaw RW, Soutter WP, Stanton SL. Gynaecology (3rd ed.), 2003, Churchill Livingstone; Postgraduate textbook
- Nguyen K-HD; Benign Cervical Lesions, eMedicine, Sep 2010
- Rathe R; Examination of the female pelvis (2000).; Helpful description of complete examination
- Stamatellos I, Stamatopoulos P, Bontis J; The role of hysteroscopy in the current management of the cervical polyps. Arch Gynecol Obstet. 2007 Oct;276(4):299-303. Epub 2007 Jul 25.
- Berzolla CE, Schnatz PF, O'Sullivan DM, et al; Berzolla CE, Schnatz PF, O'Sullivan DM, et al; Dysplasia and malignancy in endocervical polyps. J Womens Health (Larchmt). 2007 Nov;16(9):1317-21.
- Divakar H; Asymptomatic uterine fibroids. Best Pract Res Clin Obstet Gynaecol. 2008 Aug;22(4):643-54. Epub 2008 Mar 28.
- Yokota N, Yoshida H, Sakakibara H, et al; A severe vaginal hemorrhage caused by cervical endometriosis. Am J Obstet Gynecol. 2008 Jul;199(1):e12-3.
- Wingfield M; Not just a cervical ectropion. Three case reports of diethylstilbestrol (DES) exposed women presenting with vaginal discharge and cervical ectropion. J Obstet Gynaecol. 1999 Nov;19(6):649-51.
- Yang K, Li J, Liu Y, et al; Microwave therapy for cervical ectropion. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD006227.
- Nabothian (inclusion) Cysts, Aetna Intelihealth (2002); Articles reviewed by the Harvard Medical School consumer health information board
- National Network of STD/HIV Prevention Training Centers, Cervicitis, January 2003; Collaboration with the US Centers for Disease Control and Prevention
- Drakeley AJ, Roberts D, Alfirevic Z; Cervical stitch (cerclage) for preventing pregnancy loss in women (Review). Cochrane Database of Systematic Reviews 2003, Issue 1. Art. No.: CD003253. DOI: 10.1002/14651858.CD003253.
- Fox NS, Chervenak FA; Cervical cerclage: a review of the evidence. Obstet Gynecol Surv. 2008 Jan;63(1):58-65.
- Debbs RH, DeLa Vega GA, Pearson S, et al; Transabdominal cerclage after comprehensive evaluation of women with previous unsuccessful transvaginal cerclage. Am J Obstet Gynecol. 2007 Sep;197(3):317.e1-4.
- Liddell HS, Lo C; Laparoscopic cervical cerclage: a series in women with a history of second trimester miscarriage. J Minim Invasive Gynecol. 2008 May-Jun;15(3):342-5. Epub 2008 Mar 20.
|Original Author: Dr Olivia Scott||Current Version: Dr Hayley Willacy|
|Last Checked: 20/12/2010||Document ID: 667 Version: 22||© EMIS|
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