As with so many terms that are used to describe parts of the human body, there exists both a generic usage and a more precise anatomical or sports science-specific meaning for both the hip and the groin.
The hip is known as the vicinity of the body that extends from the waist across the pelvis to the top of the thigh on each side of the body. The groin is known as the area surrounding the fold in the body created where the top of the thigh meets the abdomen, including the genitals. Both structures are in fact more acutely defined, both by position and by function, within the musculoskeletal structure of the body. The hip is composed of four bones and a series of connective ligaments, with the joint created by a bony extension, the trochanter, which meets with a ball-shaped end situated at the top of the femur (thigh bone), that fits into the pelvis to form a joint referred to as a ball and socket. The hip is secured by an overlay of abductor muscles and tendons that permit the leg to be moved through in a 360° sweep, although the latitude of movement in the hip joint is more pronounced in forward and backward positions than laterally.
The groin is the intersection of the leg abductors and the muscles of the lower abdomen. The movements of the hip necessarily impact upon the groin structures. Many of the stretching and flexibility exercises designed to promote stretch and optimal function in the hip will promote similar health in the groin muscles.
Hip injuries are generally classed as overuse, repetitive strain injuries, and those caused by trauma. As the hip is a large joint that is both the subject of stresses with every step taken, as well as being relatively poorly protected with an insufficient covering of tissues to shield it, hip injuries are a common feature of many sports.
Runners and those involved in running sports commonly sustain hip bursitis, sometimes referred to as trochanteris bursitis. As with many weight-bearing joints in the body, a cushioning sac, known as a bursa, is positioned within the joint to aid in the absorption of shock generated either through movement or by contact against it. When the bursa becomes inflamed through irritation caused by excessive strain, it will cause pain for the athlete. Hip bursitis is treated by conservative measures, namely the application of the RICE (rest/ice/compression/elevation) treatment applied to the site of the pain.
The illiol band is the connective tissue that runs from the outside of the hip to the knee, providing stability to the thigh muscles. An improperly stretched illiol band can cause pain in the hip region. Injuries similar in its cause are strains to the hip flexor and abductor muscles, necessary to the lifting of the leg. Where an imbalance exists between these typically strong tissues and those of the abdomen or the gluteal (buttocks), the athlete can experience a weakness in the muscles.
Fractures of the hip are most common among elderly persons, especially those who suffer from osteoporosis, a disease that causes a weakening of the bone due to decreased bone density. A hip pointer is an injury to the joint caused by a direct blow, such as that in sports such as American football or ice hockey. The pointer, so called as it typically occurs on the most prominent point of the joint, is a bruise of the bone that, in some cases, can be evidence of a fracture.
In many circumstances, the wear and tear upon the hip leads to a condition known as osteoarthritis, where the protective linings of the hip bones in the socket of the joint have become progressively worn away. When treatment of the condition becomes progressively less useful, a hip replacement, known as a hip arthoplasty, may be performed. In this surgical procedure, the entire hip joint is removed and a mechanical hip is implanted. Two-sport athlete Bo Jackson, award-winning American football player and major league baseball player, may be the only athlete to ever return to elite-level competitive sport after receiving an artificial hip.
Groin injuries are almost invariably a result of quick, lateral movements, often in combination with acceleration made from a standing start. Soccer, American football, rugby, and tennis are sports where there exists a significant incidence of groin injury. The least debilitating of the groin injuries is the groin pull, or as it also known, the groin strain. As with any other strain, this injury is cause by an overextension of the muscles of the lower abdomen, causing the muscle to stretch or sustain a micro-tear. A typical groin strain will resolve with rest and gentle stretching over seven to 10 days.
The more serious groin injury is a complete tear of the groin, either as a significant number of fibers or through the complete rupture of the tissue. A tear will sideline an athlete for as long as three months, or longer. Extreme care must be taken with the rehabilitative process; in the specialized form of groin tear known inaccurately as a "sport hernia," which is a tear of the inguinal ligament located directly above