The Anatomy of the Uterus
At school we were never taught about our female anatomy, reproductive system or menstrual cycle. Today, I’m going to take you on a journey so you can visualise your uterus and understand its true function and anatomy.
You can find your uterus located in the female pelvis between the bladder and rectum. I like the visualisation of a sandwich – it’s just behind the bladder and in front of the rectum. The average dimensions of an adult female uterus is 8cm long, 5cm across and 4cm thick.
It is divided into three main anatomic sections from top to bottom. Firstly, we have the fundus, corpus (body) and cervix (which protrudes into the vagina). The image above shows our 3 sections!
Our uterus is not suspended in space which I believed it was for many years. In fact it’s supported and held by several ligaments. These ligaments include the utero ovarian, round, cardinal and uterosacral ligaments. Endometriosis is commonly found on the uterosacral and round ligaments.
Our uterus is also supported by the pelvic diaphragm also known as our pelvic floor (super important during labour), urogenital diaphragm know called the perineal membrane (layer of dense fascia) and perineal body.
Ladies when you have a pelvic ultrasound, the imaging will show which way your uterus is positioned. The position can be described as anteverted which is normal (tipped forward) or retroverted (tipped or titled uterus towards the back), anteflexed also normal (fundus tilts forward) or retroflexed (tilts posteriorly). For 50% women the uterus lies in anteflexed and anteverted position – which is the most common.
The Mighty Uterus is composed of three distinct tissue layers:
1. Endometrium: the lining of the uterus that modulates thickens and thins over the course of the menstrual cycle. It is known as our menstrual blood. (Soil)
2. Myometrium: is the middle layer of the uterine wall, consists of smooth muscle tissue. Its main function is to induce uterine contractions during menstruation, pregnancy and labour. Side note: Adenomyosis affects the myometrium, it is characterized by the migration of endometrial tissue into this layer. (Terrain
3. The perimetrium is the outer layer of the uterus, it is a serous membrane forming the lining of the abdominal cavity.
The uterus functions by accepting a fertilized egg which passes through the fallopian tube. The egg (zygote) then nestles into the endometrium (our first tissue layer) where it receives nourishment from blood vessels that feed the growing embryo. This is where I encourage my patients to visualise their womb as a garden! As your pregnancy grows, so to does your uterus. It expands to accommodate the pregnancy. During labour the uterus contracts as the cervix dilates!
The uterus receives blood from the uterine and ovarian arteries. This is why Chinese Medicine emphases the importance of a healthy blood flow and supply. Blood supply enters via the myometrium then enters into the endometrium via different arteries.
The nerves from our spinal cord that innervate the uterus are found at T11 and T12 (Thoracic). The parasympathetic supply (relax and rest) is from S2 to s4 (Sacrum).
The uterus will vary in shape and size depending on the life cycle you are in- for example puberty will be smaller and post menopause it will be quiet large- which mine is!! Not to mention our hormones also affect the uterus.
I hope you’ve enjoyed my mini lecture today on the anatomy of our uterus. Please feel free to ask me any questions in the comments below or share this post with a friend who may need this info.
Understanding How the Uterus Changes
The uterus is a dynamic organ rather than a structure that remains exactly the same throughout a woman's life. Its tissues respond to changing hormone levels, particularly during the menstrual cycle, pregnancy and menopause.
During the menstrual cycle, the endometrium responds to hormonal signals by growing and changing in preparation for a possible pregnancy. If pregnancy does not occur, the functional lining is shed during menstruation before the rebuilding process begins again.
The myometrium also has an important role beyond pregnancy. Its muscular tissue allows the uterus to contract, which contributes to menstrual flow and becomes particularly significant during labour. The coordinated activity of the uterine muscle and cervix allows the body to progress through the stages of birth.
The Uterus During Pregnancy
Pregnancy brings some of the most significant changes to the uterus. As the embryo develops, the uterus gradually expands from its usual size to accommodate the growing pregnancy. The uterine wall also changes as blood supply and tissue demands increase.
As pregnancy approaches labour, the myometrium becomes increasingly important. Uterine contractions help move the baby towards and through the birth canal while the cervix gradually changes and dilates.
Understanding these changes can make the uterus feel less mysterious. It is a living, responsive organ that continuously adapts according to what is happening within the body.
Frequently Asked Questions
Where is the uterus located?
The uterus is located within the pelvis, between the bladder and rectum. Its exact position can vary between individuals.
What are the three layers of the uterus?
The three main layers are the endometrium, myometrium and perimetrium. Each has a different structure and role within the uterus.
Does the uterus change during pregnancy?
Yes. The uterus expands significantly during pregnancy to accommodate the developing baby, while its tissues and blood supply also adapt to support pregnancy.
Can the position of the uterus vary?
Yes. The uterus can be tilted or flexed in different directions, including anteverted, retroverted, anteflexed and retroflexed positions. These variations can be seen during pelvic imaging.