Several groups of muscles attach in the groin area.

• The flexor muscles bend the leg at the hip.
• The adductor muscles allow the legs to move toward each other.
• The abductor muscles allow the legs to move away from each other.
• The rotator muscles allow the toes to be rotated toward or away from each other while the leg is straight.
• The lower abdominal wall muscles and the inguinal canal support pelvic structures.

Acute injury

A forceful blow to the groin can cause damage to muscles, ligaments, blood vessels, or organs in the abdomen or genital area. A sharp object can penetrate and injure the groin or genital area.

You can pull (strain) or tear a groin muscle during exercise, such as running, skating, kicking in soccer, or playing basketball. You can strain a groin muscle during lifting, pushing, or pulling heavy objects. A fall can pull a groin muscle. A sudden pulling or tearing of a groin muscle may cause sudden pain. A snapping sound may be heard with hip or leg movement. Swelling and bruising can occur quickly. Sometimes swelling and bruising do not show up for a few days after the injury.

Inguinal hernias occur when a weak spot develops in the lower abdominal tissue. Often the cause of the hernia is not known, but may be caused by lifting, straining, coughing, obesity, pregnancy, constipation, or aging. A weakness or abnormality in the muscles from birth (congenital) may also increase your chance of having a hernia.

Overuse injury

Some groin injuries come from overuse when repeated minor injuries lead to strains or tears of the muscles. Overuse injuries occur when too much stress is placed on an area. This often happens when you overdo an activity or repeat the same activity day after day. Overuse may cause:

• A hairline crack in a bone (stress fracture).
• Bursitis.
• Osteitis pubis, which is a condition that causes chronic groin pain because of stress on the pubis symphysis. Distance runners and soccer players are most likely to be affected.
• Hip problems.
• Avulsion fractures. This occurs when force causes a muscle to tear away from a bone and break a piece of bone. It most commonly affects teenage athletes who are involved in jumping, kicking, sprinting, or hurdling sports.

Home treatment can relieve the pain, swelling, and bruising that can occur with a pulled groin muscle.

Groin injury in children

In rare cases, a young child may have a hairline fracture of the hip or an avulsion fracture where the hip and upper part of the thighbone are torn apart by force and groin pain is the main symptom. Displacement of the head of the thighbone (slipped capital femoral epiphysis) can occur from an injury. Mild groin or knee pain in a child that does not improve after a few days of home treatment needs to be evaluated by a doctor. If your child's groin pain is severe, immediate evaluation is needed.