Cervix

CERVIX ANATOMY AND FIGO STAGING

CERVIX ANATOMY

Dr. Nisarga Bhama, PG IInd Yr MD Radiation Oncology

Contents:

Introduction
Embryology
Anatomy and Histology
Relations with surrounding structures
Blood supply
Nerve supply
Lymphatic supply
CT images
Staging of cervical cancer

Introduction:

•The word cervix derived from Latin word ‘’CERVIX’’ which means

‘’NECK’’.

•Cervix is the lower portion of uterus which connects vagina with the main body of the uterus.

•The cervical canal communicates above with uterine cavity at the internal os and below with the vagina at the external os.

EMBRYOLOGY:

Embryology:

•Derived from Mullerian duct. •Appears around 6 weeks of gestation. •Fused part of Mullerian duct forms uterus. Canalisation of uterus completes around 18 weeks of gestations.

Embryonic formation of female reproductive system

Anatomy:

•A pear shaped muscular organ. •Measuring about 7.5×4.0×2.5 cm in longitudinal,transverse and anteroposterior diameters. •It is divided into upper expanded part- Body. •Lower cylindrical part- Cervix.

    Body: Above the internal os.

    Cornu: The area of insertion of fallopian tubes.

   Fundus: Above the insertion of tubes.

Cervix Anatomy

Isthmus:

•An area 4-5mm in length. •It lies between anatomical intenal os above

 and histological internal os below. •Lined by lower columnar epithelium

 and contains few glands.

Isthumus of Cervix

ENDOCERVIX is the inner part of cervix lining the canal leading into the uterus.

ECTOCERVIX is the outer part of the cervix.

•Cervix is elongated lower part of uterus.

•Length is about 2.5-3cms.

•Divided by vaginal attachment into

    – Supravaginal portion above

    -Vaginal portion(portio-vaginalis)below

•Cervical mucosa has two ridges from which

  transverse ridges radiates to form

   arbor vitae uteri.

Cervix Anatomy
Cervix Anatomy

Histology

Endocervix: Lined by simple columnar epithelium.

    •Ectocervix: Lined by stratified squamous epithelium.  

•Muscle layer: Outer longitudinal and inner circular muscle fibres.

  Transformation zone: 1-3mm

Cervix Histology

Normal position and angulations:

•The uterus is kept in an anteverted and anterflexed position with the external os lying at the level of ishchial spines,by the support of cervical ligaments, endopelvic fascia and pelvic floor muscles.

Position and Angulation of Cervix

Relations of body of Uterus :

•Anteriorly:

          -The bladder and vesicouterine pouch

•Posteriorly:

            -The pouch of Douglas

•Laterally:

             -The broad ligaments on each sides

Relations of body of Uterus

Relations of the cervix:

•Supravaginal part of cervix:

        Anteriorly – Bladder.

        Posteriorly – Recto uterine pouch.

        Laterally – Ureter and uterine artery.

•Vaginal part of cervix:

         The part projects into the anterior wall of vagina.

Vaginal fornices

SUPPORTS OF UTERUS:

PRIMARY SUPPORT     

Muscular / Active Support :

  1. Pelvic diaphargm
  2. Perineal body pouch
  3. Distal Uretrhral Sphincter Mechanism

Fibromuscular / Mechanical Support :

1.Pubo cervical ligament

2.Uterosacral ligament

 3.Uterine axis

 4.Transvers cervical ligament   

  5.Round ligament 

 SECONDARY SUPPORTS  

1.Broad ligament

2.Vesico uterine  pouch

3.Rectovaginal/recto uterine

De Lancey-3 level systems of supports:

•Level 1: The cardinal uterosacral ligament complex.

•Level 2: The pubo-cervical and recto-vaginal fascia.

•Level 3: Levator ani muscle supports the lower 1/3rd of vagina.

De Lancey-3 level systems of supports

Ligaments supporting uterus:

•Anteriorly – Pubocervical ligaments.

•Posteriorly – Uterosacral ligament’s.

•Laterally-Transvers cervical /Cardinal/Mackenrodt’s ligaments.

•Inferiorly- Levator Ani muscle.

Ligaments supporting uterus

Uterosacral ligament are paired supports for the lower uterus extending from uterus to sacrum,running along rectouterine peritoneal fields.

Cardinal ligaments are thickened connective tissue arising at the upper lateral margin of the cevix and inserting into the fascia covering  of the pelvic diaphragm.

Parametrium is the fibrous tissue that seperates the supravaginal part of cervix from bladder,it lies infront of cervix and extends laterally between the layers of broad ligaments.

Blood supply(Arterial supply):

Uterine artery: Arising from anterior division of internal iliac artery. 2 cm lateral to cervix at the level of internal os it crosses above the ureter.

 •Ascending branch supplies body of the uterus.

•Descending branch suppliesthe cervix.

Blood supply to female reproductive tract

Venous drainage:

•Veins form plexus (Pampiniform plexus) along the lateral border of the uterus.

    It drains through uterine, ovarian and vaginal veins into the internal iliac veins.

Venous dainage of cervix

Nerve supply:

•Innervations:

    -Parasympathetic form S2,3,4

    -Sympathetic from:

             T5 and T6(motor)

              T10,T11,T12 and L1(sensory)

 Both reach uterus through branches of   Inferior hypogastric plexus.

Innervation of Uterus and Cervix

Lymphatic drainage:

Fundus: To the paraaortic lymph nodes via ovarian vessels.

•Cornu: To the superficial inguinal lymph nodes via lymphatics of round ligaments. •Body:To the internal and external iliac lymph nodes via uterine vessels.

Isthmus and Cervix:

    Primary group: Obturator, paracervical,parametrial,internal and external iliac lymph nodes.

     Secondary group: Common iliac,para-aortic and lateral sacral lymph nodes.

Cervix lymphatic drainage
Cervix lymphatic drainage

POINT- A  and  POINT- B:

•Point A: 2cm lateral to cervix and 3cm above externa os (corresponds to paracervical lymph nodes and ureter)

•Point B: 3cm lateral to point A and 2cm above external os (corresponds to obturator lymph nodes)

Point A and Point B

CT IMAGES OF FEMALE PELVIS:

CT Cervix
CT Cervix
CT Cervix

MRI IMAGES OF FEMALE PELVIS:

MRI Cervix
MRI Cervix
MRI Cervix
MRI Cervix

FIGO staging of cervical carcinoma:

•Stage I: Carcinoma strictly confined to cervix(extended to uterine corpus should be disregarded

     Stage I A: Invasive carcinoma diagnosed only by microscopy,with maximum depth of invasion <5mm

     Stage I A1: Measured stromal invasion <3mm in depth

     Stage I A2: Measured stromal invasion ≥ 3mm and <5mm

•Stage I B: Invasive carcinoma with measured deepest invasion >5mm(greater than Stage 1A),lesion limited to the cervix uteri.

          StageI B1: Invasive carcinoma ≥ 5mm in depth of stromal invasion and <2cm in greatest dimension.

          StageIB2: Invasive carcinoma ≥2cm and <4cm in greatest dimension.

          StageIB3: Invasive carcinoma ≥4cm in greatest dimention.

•Stage II: Tumor invades beyond cervix but not extended onto the  pelvic wall or lower third of the vagina.

      Stage II A: Involvement limited into the upper 2/3rd of vagina without parametrial involvement

     Stage IIA1: Invasive carcinoma <4cm in greatest dimension.

     Stage II A2: Invasive carcinoma ≥4cm in grestest dimension.

Stage II B: With parametrial involvement but not up to the pelvic wall.

•Stage III: The carcinoma involves the lower third of vagina and/or extends to the pelvic wall and/or causes hydronephrosis or non functioning kidney and/or involves pelvic and /or para aortic lymph nodes.

   Stage III A: Tumor involves lower third of vagina with no extension to the pelvic wall.

   Stage III B: tumor extends to pelvic wall and/o hydronephrosis or non functioning kidney(unless known to be due to other cause)

•Stage III C:  Involvement of pelvic and/or para aortic lymph nodes, irrespective of tumor size and extent.

     Stage III C1: Pelvic lymphnode metastasis only.

     Stage III C2: Para aortic lymphnode metastasis.

•Stage IV: Carcinoma extended beyond the true pelvis or has involved(biopsy proven) the mucosa of the bladder or rectum.

       Stage IV A: Spread to adjacent pelvic organs.

       Stage IV B: Spread to distant organs.

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