Learning About the Hip

            “To keep the body in good health is a duty...”~Buddha

         The hip joints are responsible for bearing the weight of our bodies.  When a person is standing, the weight of the upper body is divided in half where the spine meets the pelvis and distributed evenly between the two hip joints.  Since each of these joints must bear one half of the body weight, we would expect them to be extremely stable, strong joints.  Surprisingly, the hip joint is one of the most flexible joints in the body, second only in flexibility to the shoulder joint.

            This joint is a ball and socket joint formed where the ball-shaped head of the thigh bone, or femur, fits into an indentation, or shallow socket, in the pelvis called the acetabulum.  This type of joint allows for movement in almost any direction.  The hip is capable of flexing, extending, abducting (moving away from the center of the body), adducting (moving toward the center of the body), or a combination of all these movements called circumduction, which allows for hip rotation.

            The joint is lined with a pearly blue hyaline cartilage.  This type of cartilage is strong but flexible and elastic and is found in most of the body’s joints.  It allows for a free gliding motion between the femur and the acetabulum and also acts as a shock absorber, during activities like jumping, running, or walking.

            The joint is also lined with synovial membranes.  These membranes secrete synovial fluid, which lubricates the body’s joints, reducing friction and keeping the bones sliding freely against each other.

From teachmeanatomy.info
            The femur is held in place by a capsule made up of the iliofemoral ligament, the pubofemoral ligament, and the ischiofemoral ligament.  The iliofemoral ligament, which is also called the Y-ligament because of its shape, runs from the outer rim of the acetabulum to the base of the femoral neck and to the lesser trochanter (the small protrusion on the inside of the femur).  The pubofemoral ligament runs across the front of the joint, and the ischiofemoral ligament runs across the back of the joint, and these both help prevent hyperextension of the hip joint.  The ligamentum teres is a ligament that attaches the femur to the acetabulum.

            The hip joint is surrounded by a multitude of muscles that provide strength and stability to this flexible joint.  Each of these muscles perform at least two actions.  Generally, the muscles that run along the front of the thigh, often referred to as the quadriceps, are responsible for flexing the hip, and the muscles that run along the back of the thigh, often called the hamstrings, are responsible for extending the hip

, and most of the muscles responsible for outwardly rotating the leg begin at the back of the hip joint and run down the outside of the leg.

            My next blog post will focus on conditions and injuries of the hip that are common in dance.

Acute Knee Injuries

         "There are three steps you have to complete to become a professional dancer: learn to dance, learn to perform, and learn how to cope with injuries." -D. Gere

       Acute injuries are those that occur as a result of a specific action or trauma.  They manifest themselves immediately and will usually heal in a set amount of time compared to chronic injuries which develop over time and can take a relatively long time to heal.

          The knee joint is cushioned by C-shaped discs of cartilage called menisci.  These discs lay between the femur, or thigh bone, and the tibia, or larger shin bone.  When a dancer lands a jump poorly or twists, or torques, the knee, one or both of these discs can tear.  A minor tear will cause delayed pain, but a more severe tear will cause immediate pain accompanied by swelling.  As with all injuries, ice, rest, elevation, and anti-inflammatories will help when the injury first occurs.  A physical therapist can usually help the dancer through rehabilitation exercises although severe tears may require surgery.

          Another common acute injury among dancers and athletes is a torn ligament. 

           The medial collateral ligament, or MCL, runs along the inside of the knee and limits sideways movement of the femur.  This ligament can be torn as a result of trauma from twisting, jumping, or turning.  The dancer will experience immediate pain on the inside of the knee.  The area will be painful to touch, and the knee's range of motion will be severely limited.  Ice, rest, elevation, and anti-inflammatories will help limit the swelling and ease the pain. Minor tears can be worked through with a physical therapist but more serious tears may require a doctor.

           The anterior cruciate ligament, or ACL, crosses at the center of the knee behing the patella, or knee cap, and connects the femur to the tibia.  This ligament helps resist hyperextension and limits forward motion of the tibia while keeping the femur from sliding backwards.  When this ligament is torn, an audible "pop" can often be heard.  This ligament will tear when the knee is twisted in an unnatural way.  ACL tears often need surgery and require intensive rehabilitation through strengthening exercises.  The healing time for this type of injury is usually 3-4 months.

          Since the knee is the site of many chronic and acute injuries in dance, it is important that dancers know as much about this joint as possible, immediately care for injuries that happen at this site, and seek medical attention whenever they experience knee pain.

Chronic Conditions of the Knee

         "There are three steps you have to complete to become a professional dancer: learn to dance, learn to perform, and learn how to cope with injuries." -D. Gere

      The knee is the largest joint in the body and is constantly supporting the body’s weight.  Dancers depend upon their knees to support their bodies while turning, jumping, and performing extensions.  Since the knee joint is found between sets of muscles that dancers use repeatedly, and dancers often have muscular imbalances in the leg that cause misalignments, it is not surprising that knee injuries account for 14-20% of complaints among dancers.

            This week’s post will discuss some chronic dance injuries that affect dancers.  These injuries develop over time and increase in severity until the cause is determined and eliminated.

            A condition that occurs in children and adolescents who are involved in activities like dance that involve quick turns or jumping is Osgood Schlatter’s Disease.  One in five adolescent athletes is diagnosed with this condition, and it occurs when quick movement demands are placed upon the body during the growth spurt.  During the growth spurt, bones grow quicker than muscles placing a strain on the body.  When this strain is exacerbated by activities that stress the body, this condition develops.  It manifests itself as a painful lump on the leg right below the kneecap.  Dancers may experience swelling, tenderness around the knee, tightness in the quadriceps and/or hamstrings, and/or pain with exercise.  It can involve inflammation of bone, cartilage, the patellar tendon, or any combination of the three.  It should be treated using the PRICE method (protection, rest, ice, compression, elevation) and anti-inflammatories.  It usually resolves itself in 12-24 months when the growth spurt is completed.  A physical therapist can help the dancer find ways to navigate through classes and rehearsals.  In extreme cases, a dancer may be forced to take a break from dance until the pain begins to subside.

            Patellar femoral syndrome occurs due to a misalignment in the leg.  Muscular imbalances or forcing the body into unnatural positions that are unhealthy for the body, like forcing turnout from the knee, can cause the 
patella, or kneecap, out of position.  Instead of sliding back and forth in the groove on the femur, or thighbone, the kneecap is “derailed”.

          As the back of the kneecap rubs against the femur, the cartilage under the kneecap wears away causing chondromalacia.  It is characterized by pain around the kneecap during jumps, during pliés, and after sitting for a long period of time.  The dancer may also experience some swelling around the knee and/or hear a “crunching” sound when moving it.  Rest and ice may help, and a physical therapist should be consulted to determine the underlying cause.  The dancer’s technique can be examined to determine what alignment issues may be present, and the dancer can be evaluated for muscular imbalances that may be the cause.  A physical therapist who works with dancers will be able to help correct technical problems and/or provide strengthening and stretching exercises to fix any imbalances that are present.

           Another knee problem that can be caused by alignment issues and/or muscular imbalances is patellar tendonitis.  In this condition, the patellar tendon, which connects the quadriceps to the kneecap, becomes inflamed.  When the tendon is pulled on excessively due to tight quadriceps muscles, it becomes swollen and painful.  Rest, ice, and anti-inflammatories will help alleviate swelling and pain, and a physical therapist can provide exercises to eliminate the tightness in the quadriceps.

            Prepatellar bursitis is a condition found mostly in modern and jazz dancers because of the knee work involved in these techniques.  Bursae are tiny fluid-filled sacs found in the joints of the body that act as cushioning.  When repeated friction occurs in a joint, the bursae become inflamed and painful.  When executing knee work, the constant friction between the knee and the floor becomes a source of irritation.  Rest, ice, anti-inflammatories, compression, and physical therapy can alleviate the swelling.  In more severe cases, cortisone shots or surgery may be necessary.

            My next post will cover acute knee injuries that are the direct result of trauma and tend to be more serious in nature.