The fallopian tubes connect the ovaries to the uterus. These two narrow tubes, each about 10 to 12 centimeters long, serve as the passageway that carries eggs from the ovaries into the uterine cavity. They’re also where fertilization happens. A set of ligaments and a sheet of tissue called the mesosalpinx provide additional structural support, holding everything in position within the pelvis.
How the Fallopian Tubes Are Built
Each fallopian tube has four distinct segments, moving from the uterus outward toward the ovary. The first is the uterine portion, a short segment that passes through the wall of the uterus itself. It enters the uterus at a point called the cornu, the upper lateral corner of the uterine body. Next comes the isthmus, the narrowest part of the tube, with an outer diameter of only 5 to 7 millimeters.
Beyond the isthmus, the tube widens into the ampulla, which makes up roughly half the tube’s total length at about 50 millimeters. The ampulla is the most common site of fertilization. Finally, at the far end closest to the ovary sits the infundibulum, which flares open like a funnel and ends in finger-like projections called fimbriae. One specific fimbria, called the fimbria ovarica, physically attaches to the ovary, creating a direct link between the tube and the ovarian surface.
Despite the tube’s outer diameter reaching 8 to 11 millimeters in the ampulla, the inner channel is remarkably small, less than 1 millimeter across in places. That tiny lumen is lined with microscopic hair-like structures called cilia, which play a critical role in moving the egg toward the uterus.
How Eggs Travel From Ovary to Uterus
The fallopian tube doesn’t just sit passively waiting for an egg. During ovulation, the fimbriae actively sweep across the surface of the ovary. Sticky adhesive sites on the cilia lining the fimbriae grab the released egg and pull it into the tube’s opening. This is a remarkably precise process given that the tube and ovary aren’t sealed together; the infundibulum actually opens into the abdominal cavity.
Once inside, the egg moves toward the uterus through two coordinated mechanisms. The tube’s muscular wall contracts in rhythmic waves, similar to how the intestines push food along. At the same time, the cilia lining the inner surface beat in coordinated patterns. These two motions work together to create a traveling wave that steadily transports the egg (or, if fertilization occurs in the ampulla, the early embryo) down through the isthmus and into the uterus. The entire journey typically takes several days.
Ligaments That Hold the Connection in Place
The fallopian tubes don’t float freely. The ovarian ligament is a fibrous cord that runs from the back and side of the uterus (near the cornu, where the tube inserts) to the lower end of the ovary. It keeps the ovary anchored close enough to the tube’s fimbriated end for egg pickup to work reliably.
Supporting the tube itself is the mesosalpinx, a double fold of tissue that drapes beneath the length of the tube like a hammock. The mesosalpinx carries blood vessels, nerves, lymphatic channels, and fat to nourish the tube. Its blood supply comes from an intricate network of connections between branches of two major arteries: one arriving from the uterine side and the other from the ovarian side. These vessels meet and form arches within the mesosalpinx, ensuring the tube, ovary, and surrounding tissue all receive reliable blood flow. The venous drainage mirrors this arterial pattern, running alongside the arteries in what researchers describe as a perivascular complex.
What Happens When the Connection Is Disrupted
Because the fallopian tube is the sole internal passageway between ovary and uterus, anything that damages or blocks it can affect fertility. Infections, endometriosis, and scar tissue from previous surgery can narrow or obstruct the tube’s tiny lumen. When a fertilized egg implants inside the tube instead of reaching the uterus, the result is an ectopic pregnancy. Over 90% of ectopic pregnancies occur within the fallopian tube, and the ampulla is the most commonly affected segment, accounting for roughly 60% of tubal ectopic cases. The isthmus is the next most frequent location.
Tubal sterilization deliberately interrupts this connection for permanent contraception. The procedure typically targets the mid-isthmic segment, the narrowest stretch of tube between the ampulla and the uterus. Surgeons may clip, band, or seal this section with electrical energy, or remove a 2 to 3 centimeter segment entirely. In a complete salpingectomy, the entire tube is removed by cutting it at the cornu, detaching the mesosalpinx beneath it, and separating the fimbria ovarica from the ovary. This approach is increasingly recommended because it may reduce the risk of certain ovarian cancers that appear to originate in the tube’s lining.
Even after complete tube removal, the ovaries remain functional. They continue releasing hormones and ovulating because their blood supply arrives through separate ovarian vessels, not solely through the tube. What changes is that eggs have no path to reach the uterus.