Cardinal ligament

The cardinal ligament, also known as the transverse cervical ligament, is a key structure that provides support to the uterus within the pelvic cavity. It extends from the cervix and the lateral part of the uterus to the lateral walls of the pelvis, anchoring the uterus in place. The cardinal ligament is positioned on either side of the uterus, running alongside the base of the broad ligament, and contains important blood vessels, including the uterine artery and vein, that supply the uterus. It plays a significant role in supporting the pelvic organs and maintaining the uterus’s position within the pelvic cavity.

Structure and Anatomy

The cardinal ligament, also known as the transverse cervical ligament, is a major supporting structure of the uterus within the pelvic cavity. Below is a detailed description of its anatomy, including its location, structure, and relationship to surrounding organs.

Location and Position

The cardinal ligament is located in the pelvic cavity, extending from the lateral sides of the cervix and the upper part of the vagina to the lateral pelvic wall. It plays a key role in anchoring the uterus and maintaining its position.

• Cervical Attachment: The cardinal ligament originates from the lateral part of the cervix and the upper portion of the vagina. It attaches firmly to these structures, providing substantial support to the lower part of the uterus.
• Pelvic Wall Attachment: The ligament extends laterally from the cervix and upper vagina to the lateral pelvic walls. It connects to the ischial spines, which are bony projections located on the sides of the pelvis. This attachment helps keep the uterus in a central position within the pelvic cavity.
• Position Relative to Other Ligaments: The cardinal ligament runs perpendicular to the uterosacral ligament, which attaches the uterus to the sacrum. Together, these ligaments form a crucial part of the support system that holds the uterus in place.

Structure and Composition

The cardinal ligament is composed of dense connective tissue that provides strong structural support to the uterus and surrounding pelvic organs. It contains fibrous tissue as well as smooth muscle fibers.

• Connective Tissue: The ligament is primarily made up of collagen fibers, which give it its strength and ability to support the uterus under the forces exerted by gravity and intra-abdominal pressure. The connective tissue is relatively dense, ensuring that the ligament can hold the uterus and cervix securely.
• Smooth Muscle Fibers: In addition to fibrous tissue, the cardinal ligament contains some smooth muscle fibers. These fibers provide elasticity and allow for slight movement and flexibility of the uterus during activities such as walking, sitting, or during childbirth.

Relationship to the Broad Ligament

The cardinal ligament is closely associated with the broad ligament, another key supportive structure of the female reproductive system.

• Base of the Broad Ligament: The cardinal ligament forms the lower part (or base) of the broad ligament, a double-layered fold of peritoneum that supports the uterus, fallopian tubes, and ovaries. While the broad ligament helps support the overall structure of the reproductive organs, the cardinal ligament provides the primary structural support for the cervix and lower uterus.
• Tension and Stability: The broad ligament primarily helps in the spatial arrangement of the uterus and ovaries, but the cardinal ligament is responsible for maintaining the cervix’s position and preventing excessive downward movement of the uterus. The combination of these ligaments helps maintain pelvic organ stability.

Blood Supply

The cardinal ligament plays an important role in carrying blood vessels that supply the uterus and surrounding structures.

• Uterine Artery and Vein: The uterine artery and uterine vein, which supply blood to the uterus, run within the cardinal ligament. These vessels are critical for delivering oxygenated blood to the uterus and for removing deoxygenated blood. The close proximity of these vessels to the cervix and uterus makes the cardinal ligament important in surgical procedures, such as hysterectomies, where care must be taken to avoid damaging these vessels.
• Vascular Network: The cardinal ligament forms part of the larger vascular network in the pelvis, connecting the uterine artery and vein to the internal iliac artery and vein. This vascular network ensures that the uterus and cervix receive sufficient blood flow for their functional demands, particularly during pregnancy.

Nerve Supply

The cardinal ligament contains nerve fibers that provide autonomic innervation to the uterus and cervix.

• Autonomic Nervous System: Nerve fibers within the cardinal ligament originate from the inferior hypogastric plexus, which is part of the autonomic nervous system. These nerves regulate uterine contractions, blood vessel dilation, and other involuntary processes in the pelvic region.
• Sympathetic and Parasympathetic Fibers: Both sympathetic and parasympathetic fibers run through the cardinal ligament. Sympathetic nerves are involved in the contraction of the smooth muscle fibers within the ligament and surrounding pelvic structures, while parasympathetic fibers are involved in relaxation and regulating blood flow to the uterus.

Lymphatic Drainage

The cardinal ligament contains lymphatic vessels that are crucial for draining lymphatic fluid from the uterus and cervix.

• Lymphatic Pathways: The lymph from the uterus and cervix drains through the lymphatic vessels within the cardinal ligament and flows toward the internal iliac lymph nodes and sacral lymph nodes. This drainage system helps filter waste products and pathogens, contributing to the immune defense of the pelvic region.
• Significance in Cancer Spread: The lymphatic vessels in the cardinal ligament are important in the spread of certain gynecological cancers, such as cervical cancer. Understanding the lymphatic pathways helps surgeons plan treatment for cancers and prevent the spread of malignant cells.

Relationship to Ureters

The ureters, which carry urine from the kidneys to the bladder, pass close to the cardinal ligament, making this anatomical relationship clinically important.

• Proximity to Ureters: The ureters travel through the pelvic cavity and pass directly under the cardinal ligament on their way to the bladder. This proximity to the uterus and cervix means that any surgical procedure involving the uterus, such as a hysterectomy, must carefully account for the location of the ureters to avoid accidental injury.
• Surgical Considerations: Because of the close relationship between the cardinal ligament and the ureters, surgeons must exercise caution during pelvic surgeries, particularly when ligating the uterine artery, which runs near the ureters. Damage to the ureters can result in significant complications, including urine leakage or obstruction.

Histological Features

Histologically, the cardinal ligament is composed of fibrous tissue, smooth muscle fibers, and vascular structures, contributing to its role as a structural and functional support for the uterus.

• Fibrous Tissue: The dense collagen fibers in the cardinal ligament provide structural integrity and are responsible for maintaining the tension needed to support the uterus and cervix in the pelvic cavity.
• Vascular Components: The blood vessels within the cardinal ligament are surrounded by connective tissue that ensures they remain stable and secure while transporting blood to and from the uterus. This vascular structure is a key feature of the ligament, distinguishing it from other ligaments that provide structural support without significant vascular involvement.
• Smooth Muscle: The presence of smooth muscle fibers allows the ligament to maintain some elasticity and flexibility, ensuring that the uterus and cervix can move slightly in response to changes in intra-abdominal pressure or uterine contractions.

Embryological Development

The cardinal ligament develops from the paramesonephric ducts (Müllerian ducts) during embryonic development. These ducts also give rise to other structures in the female reproductive system, such as the uterus, fallopian tubes, and upper part of the vagina.

Müllerian Duct Derivatives: As the paramesonephric ducts develop into the major structures of the female reproductive system, the cardinal ligament forms alongside them to provide the necessary support. This developmental process ensures that the uterus remains securely anchored within the pelvic cavity throughout a woman’s life.

Function

The cardinal ligament, also known as the transverse cervical ligament, plays several essential roles in supporting the female reproductive system and maintaining the stability of the pelvic organs. Below is a detailed explanation of its functions.

Support and Stabilization of the Uterus

The primary function of the cardinal ligament is to provide structural support to the uterus, ensuring that it stays in its proper position within the pelvic cavity.

• Anchoring the Uterus: The cardinal ligament extends from the lateral sides of the cervix and upper vagina to the lateral pelvic walls, anchoring the uterus in place. This support prevents the uterus from moving excessively within the pelvis, particularly during changes in body position or physical activity.
• Maintaining Uterine Position: Along with other pelvic ligaments, such as the uterosacral ligaments, the cardinal ligament helps maintain the uterus in its natural anteverted and anteflexed position, where the uterus tilts forward over the bladder. This positioning is crucial for the proper function of the uterus and the surrounding pelvic organs.

Prevention of Uterine Prolapse

The cardinal ligament plays a key role in preventing uterine prolapse, a condition where the uterus descends into or through the vaginal canal due to weakened support structures.

• Supporting Uterine Weight: By providing strong lateral support to the uterus, the cardinal ligament helps bear the weight of the uterus and prevents it from descending into the vaginal canal. This is especially important in maintaining the uterus in position during pregnancy, when its size and weight increase significantly.
• Counteracting Intra-abdominal Pressure: The cardinal ligament helps counteract the effects of intra-abdominal pressure that can result from activities such as coughing, sneezing, or lifting heavy objects. By securing the uterus to the pelvic wall, the ligament prevents downward displacement of the uterus, which could otherwise lead to prolapse.

Support of the Cervix and Upper Vagina

The cardinal ligament provides crucial support not only to the uterus but also to the cervix and the upper portion of the vagina.

• Cervical Stability: The ligament firmly attaches to the cervix and helps maintain its position within the pelvic cavity. This stability is vital for the proper function of the cervix during menstruation, sexual intercourse, and childbirth.
• Vaginal Support: The cardinal ligament also helps support the upper part of the vagina. This is particularly important in preventing conditions such as vaginal vault prolapse, which can occur after a hysterectomy when the uterus is removed. The ligament acts as a stabilizing structure to maintain the integrity of the vaginal walls.

Providing a Pathway for Blood Vessels

The cardinal ligament plays a significant role in providing a pathway for the uterine artery and vein, which supply blood to the uterus and surrounding structures.

• Transporting Blood to the Uterus: The uterine artery, which passes through the cardinal ligament, supplies oxygenated blood to the uterus, ensuring that the uterine tissue receives the nutrients and oxygen it needs to function properly, especially during the menstrual cycle and pregnancy.
• Venous Drainage from the Uterus: The uterine vein, which also runs through the cardinal ligament, carries deoxygenated blood away from the uterus, draining into the internal iliac vein. The cardinal ligament thus ensures proper circulation within the uterus by providing a stable route for blood flow.
• Preserving Vascular Integrity: During surgical procedures such as hysterectomy, the cardinal ligament’s role in housing the uterine vessels requires careful attention to avoid damaging these critical structures. Surgeons rely on the cardinal ligament as a guide to safely ligate the uterine artery and vein.

Maintaining Pelvic Organ Alignment

The cardinal ligament helps maintain the alignment and stability of the pelvic organs, including the bladder, rectum, uterus, and vagina.

• Preventing Bladder and Rectal Prolapse: By stabilizing the uterus and cervix, the cardinal ligament indirectly supports the bladder and rectum, which are located near the uterus. This support helps prevent prolapse of these organs, which can occur when the pelvic floor weakens or when the supporting ligaments fail to hold the organs in place.
• Coordinating with Other Ligaments: The cardinal ligament works together with the uterosacral ligament, pubocervical fascia, and other pelvic ligaments to form a network of support that maintains the correct anatomical positions of the pelvic organs. This coordination ensures that the organs remain properly aligned, allowing the reproductive, urinary, and digestive systems to function efficiently.

Providing Nerve Pathways

The cardinal ligament contains nerve fibers that provide autonomic innervation to the uterus and cervix.

• Autonomic Nervous System Regulation: Nerves running through the cardinal ligament, derived from the inferior hypogastric plexus, help regulate uterine contractions, blood vessel dilation, and other involuntary processes within the uterus and cervix. These autonomic nerves are involved in the functioning of the uterus during the menstrual cycle, sexual arousal, and childbirth.
• Nerve Sensitivity and Pain Transmission: Although the ligament itself is not highly innervated with sensory nerves, the nerve fibers passing through it can contribute to pelvic pain in certain conditions, such as endometriosis. In this condition, endometrial-like tissue may grow on or around the cardinal ligament, leading to pain during menstruation or sexual intercourse.

Supporting Lymphatic Drainage

The cardinal ligament contains lymphatic vessels that are essential for draining lymph from the uterus and cervix, playing a role in the body’s immune system and fluid balance.

• Lymphatic Drainage Pathways: Lymphatic vessels within the cardinal ligament drain lymph from the uterus, cervix, and upper vagina into the internal iliac lymph nodes and sacral lymph nodes. This drainage helps remove waste products, excess fluid, and potentially harmful substances, supporting the immune defense of the pelvic region.
• Importance in Cancer Spread: The lymphatic pathways within the cardinal ligament are significant in the spread of certain gynecological cancers, particularly cervical cancer. Understanding these lymphatic routes is important for surgeons when performing procedures to remove cancerous tissue or when planning radiation therapy for pelvic cancers.

Facilitating Surgical Access and Procedures

The cardinal ligament plays an important role in various gynecological surgeries, particularly those involving the uterus and cervix.

• Guiding Surgical Procedures: During procedures such as hysterectomy or pelvic organ prolapse repair, surgeons often rely on the cardinal ligament to provide a stable anchor for sutures and to ligate the uterine arteries. The ligament is a key reference point for surgical access to the uterus and surrounding structures.
• Repairing Pelvic Support: In surgeries aimed at treating uterine or vaginal prolapse, the cardinal ligament may be used as an anchor for suturing the vaginal walls or supporting structures back into place. Its strength and location make it an ideal structure for reestablishing pelvic floor stability after surgical repair.

Clinical Significance

The cardinal ligament is clinically significant due to its role in providing structural support to the uterus, cervix, and upper vagina. It is essential in preventing uterine prolapse, a condition where the uterus descends into the vaginal canal due to weakened support. The cardinal ligament’s role in stabilizing the cervix and upper vagina also helps maintain pelvic organ alignment and prevent vaginal prolapse, especially after a hysterectomy.

Because the uterine artery and uterine vein run through the cardinal ligament, it is an important anatomical structure during gynecological surgeries such as hysterectomies and prolapse repairs. Surgeons must carefully navigate this area to avoid damaging these vessels or the nearby ureters, which can lead to significant complications. Additionally, the ligament’s lymphatic vessels are important in the spread and treatment of cervical cancer, making it a key structure in oncological procedures.