The uterus

Parts

Body

• Expanded superior 2/3rd
• Fundus- rounded superior part
• Cornu- part of the body where the uterine tubes insert

Isthmus

• A narrow cone
• Transition between the body and the cervix
• Most obvious in  nulliparous women

Cervix

• Cylindrical inferior 1/3rd of the uterus
• Supravaginal part
• Infra vaginal part
• Internal/ external os

Anteflexed: Uterus is bent anteriorly over the bladder between the cervix and  the body

Anteverted: The entire uterus is bend anteriorly with respect to the vagina

Sometime especially in older women, the uterus may be bent posterioly (retroversion)

Note: When the urinary bladder fills, the uterus is straightened into line with the vagina.

Peritoneal relations

• Peritonioum covers , posterior, superior and anterior surfaces of the uterus, except vaginal part of cervix
  
  
• Peritoneum is reflected anteriorly onto the bladder and posteriorly onto the rectum
  
  
• A double layered peritoneal sheet - the broadligament- extend from the sides of the uterus to the lateral walls, and the floor of the pelvis.

Anteriorly

• Separated from urinary bladder by the vesico uterine pouch
• This pouch is normally empty when the uterus is in the normal position. 
• When the uterus is retroverted the pouch contains a loop of intestine.

Posteriorly

• A layer of peritoneum  and the peritoneal cavity separate the posterior part from sigmoid colon.
• The recto uterine pouch separates the uterus from the rectum.

Superiorly

• The coils of small intestine

Laterally:

• The broad ligaments and their contents

• The principal supports of the uterus are the pelvic floor  and the pelvic viscera surrounding the uterus and its continuity with the vagina
  
  
• The broad ligaments hold the uterus in its relatively normal position.
  
  
• The body of the uterus is freely mobile. The cervix is not very mobile because it is held in position by several ligaments (Thickenings of the endopelvic fascia).
  
  (+) Transverse cervical (Cardinal) ligaments
  (+) Utero sacral ligaments (recto uterine),
  (+) Pubocervical

• Uterine arteries from the internal iliac
• Ovarian arteries from the aorta
• These two anastomose
• The uterine veins form a uterine venous plexus on each side of the cervix. Their tributaries drain into the internal iliac veins.
• This plexus is connected with the superior rectal veins forming a porto systemic anastomsis

Lymphatics

• Aortic (lumbar) nodes.
• Superficial inguinal nodes.
• Body- para uterine lymph nodes thence to the external iliac nodes
• cervix – internal iliac and sacral lymph nodes.

Innervation

• Autonomic from the inferior hypogastric plexus largely from the uterovaginal plexus in the broad ligament.
• Most of the efferent fibres ascend through the hypogastric plexus and the spinal cord via T10- L1 spinal nerves