Internal Pelvic Anatomy

Basic pelvic structure is established by the pelvic bones. Three bones form the pelvis, two hip bones and the sacrum. The areas where the hip bones join the sacrum are called the sacro-iliac joints. When unstable, such as during pregnancy, movement of these joints can cause discomfort. Similarly uncomfortable is instability of the symphysis pubis.

The muscles of the pelvic floor provide support for the bottom of the pelvis. The pelvic floor muscles have openings to allow passage of the urethra, the vagina, and the rectum.

When performing abdominal surgery, the pelvis is viewed from above.

We start by making an incision into the abdomen.

Once inside the abdomen, we can inspect various structures. In this case, we’re examining the left ovary. The infundibulopelvic ligament runs from the ovary to the pelvic sidewall.

The uterus is being felt here with two hands.

The round ligament shown here extends anteriorly and laterally.

This model depicts the major pelvic structures, and includes the uterus, fallopian tubes, ovaries, bladder, ureters, uterosacral ligaments and rectum.

The uterus is a firm, muscular organ located centrally in the pelvis. In this hysterectomy case, we begin by placing clamps at the corners of the uterus. This will make it easier for us to visualize the pelvic structures.

The ovaries lie lateral to the uterus. They are suspended between the uterus and the pelvic sidewall. They are much more mobile than generally appreciated.

The fallopian tube extends laterally from the uterus to the general area of the ovary. Like the ovary, the fallopian tube is quite mobile.

The uterosacral ligaments are part of the main supporting structures of the uterus. They are also a common site for endometriosis implantation.

The round ligaments start at the uterus, pass through the inguinal canal, and terminate in the upper portion of the labia majora.

The bladder is positioned right next to the uterus. The open space between them is called the anterior culdesac. This model portrays the relationship between the bladder and the uterus as fixed. However, the bladder expands and contracts with urine, and the uterus is relatively mobile. Here, a catheter tip can be demonstrated within the bladder.

The ureters pass along the pelvic sidewalls coming within about a centimeter of the cervix before passing into the bladder. The ureter crosses the external iliac vessels and passes just underneath or just next to the infundibulopelvic ligament.