The femoral artery is the largest artery in the leg, serving as the main vessel that supplies oxygenated blood to the entire lower limb. It is situated high in the upper thigh, passing through an area known as the femoral triangle near the groin. The common femoral artery, where it begins, has a substantial diameter, typically measuring between 7 and 8 millimeters across in an adult. Because it carries a massive volume of blood directly from the aorta’s network, an injury to this vessel constitutes an extreme medical emergency with a high risk of rapid, life-threatening blood loss.
The Mechanics of Arterial Blood Flow
Bleeding from an artery is significantly more severe than bleeding from a vein because of the underlying physics of the circulatory system. Arteries are engineered to carry blood under high pressure, as they receive blood directly pumped from the heart. This high systemic pressure means that when the femoral artery is breached, blood is expelled forcefully, often in a distinct spurting or pulsating rhythm that matches the heartbeat.
The resting volume flow rate in the common femoral artery of a healthy person is substantial, averaging around 350 to 400 milliliters per minute. A complete tear could result in a dangerous amount of blood loss very quickly. The intense pressure and volume of the flow actively work against the body’s natural defense mechanisms, making it extremely difficult for a blood clot to form and seal the wound.
The blood expelled from the femoral artery is bright red, indicating its high oxygen content as it is fresh from the heart. This visual characteristic, combined with the pulsating flow, immediately distinguishes arterial bleeding from the darker, steadier flow of venous bleeding. The physical dynamics of high-pressure, pulsatile flow are the reason why a femoral artery injury rapidly escalates into a catastrophic hemorrhage.
Estimated Timeframe and Key Modifying Variables
The time it takes to lose a life-threatening amount of blood from a femoral artery injury can be alarmingly short, often measured in minutes. In cases of a severe or complete severance of the vessel, a person can potentially bleed out and die in less than five minutes. This rapid timeline is based on the average adult having a total blood volume of about 5 liters, and the potential for losing over a liter of blood per minute from a major artery.
The specific timeframe is highly variable and depends significantly on the exact nature of the wound. A clean, penetrating injury that fully severs the artery will result in the most rapid blood loss, acting like a wide-open hose. A partial tear or a puncture may bleed less violently, potentially allowing a slightly longer window for intervention, although the risk remains immense.
The location of the injury along the artery also modifies the rate of blood loss. An injury closer to the torso, where the artery is larger and the blood pressure is highest, will bleed more profusely than one further down the leg. Patients taking anticoagulant medications will have a significantly impaired ability to clot, drastically accelerating the rate of hemorrhage. Immediate external compression is the most important variable a bystander can control, as firm pressure can reduce the rate of blood loss and buy valuable time for emergency services to arrive.
Recognizing Massive Hemorrhage
Recognizing a massive hemorrhage from the femoral artery requires observing both the characteristics of the bleeding and the systemic effects on the injured person. The most telling sign is a bright red stream that is spurting or pulsing out of the wound, synchronized with the person’s heartbeats. This forceful ejection of blood often leads to the rapid formation of a large pool of blood around the victim.
As the person loses a significant volume of blood, signs of hemorrhagic shock will set in quickly. Initial symptoms often include a noticeably rapid heart rate, which is the body’s attempt to compensate for the sudden drop in blood volume. The injured person may also begin to feel dizzy, lightheaded, or confused due to low blood pressure and reduced blood flow to the brain. Pale, cool, and clammy skin is a common sign as the body redirects blood flow away from the extremities to protect the internal organs.
Emergency Steps for Controlling Bleeding
Immediate action is necessary when faced with a massive hemorrhage from the femoral artery. The first step is to call for emergency medical services immediately, as professional help is required to permanently stop the bleeding. While waiting for help, the most effective life-saving measure a bystander can perform is to apply direct, continuous pressure to the wound.
Use a clean cloth, gauze, or any readily available material to pack the wound opening. Then press down with both hands as hard as possible directly over the bleeding site. This pressure must compress the artery against the underlying bone, a technique that is necessary to slow the flow.
If the bleeding does not stop with direct pressure, a commercial tourniquet should be applied high on the limb, two to three inches above the wound, but not directly over a joint. The tourniquet must be tightened until the bright red, spurting bleeding stops completely, and the time of application should be noted for medical personnel.
Do not remove any material used to pack the wound or apply pressure, even if it becomes soaked with blood. Instead, simply add more material on top and maintain the pressure. Continuous, unwavering pressure is the single most effective action to stabilize the person until trained medical responders can take over.