The hip is true diarthroidal ball and-socket style joint, formed from the head of the femur as it articulates with the acetabulum of the pelvis. This joint serves as the main connection between the lower extremity and the trunk, and typically works in a closed kinematic chain.
* Muscles of the Hip:-
The hip joint is one of the most flexible joints in the entire human body. The many muscles of the hip provide movement, strength, and stability to the hip joint and the bones of the hip and thigh. These muscles can be grouped based upon their location and function. The four groups are the anterior group, the posterior group, adductor group, and finally the abductor group.
The anterior muscle group features muscles that flex (bend) the thigh at the hip
(1) Gluteal Group
The gluteal muscles cover the lateral surface of the ilium and include
Tensor fasciae latae
This group includes
The adductors all originate on the pubis and insert on the medial, posterior surface of the femur, with the exception of the gracilis which inserts just below the medial condyle of the tibia.
The iliacus and psoas major comprise the iliopsoas group.
(4)Lateral rotator group
This group consists of
Superior and inferior gemelli
These six originate at or below the acetabulum of the ilium and insert on or near the greater trochanter of the femur.
* Other hip muscles:-
Rectus femoris and the sartorius, can cause some movement in the hip joint but these muscles primarily move the knee, and not generally classified as muscles of the hip.
The hamstring muscles, which originates mostly from the ischial tuberosity and insert on the tibia/fibula, also assist with hip extensio
As noted above, the stability of the hip joint is directly related to its muscles and ligaments. The most notable ligaments in the hip joint are:
Iliofemoral ligament, which connects the pelvis to the femur at the front of the joint. It keeps the hip from hyper-extension
Pubofemoral ligament, which attaches the most forward part of the pelvis known as the pubis to the femur
Ischiofemoral ligament, which attaches to the ischium (the lowest part of the pelvis) and between the two trochanters of the femur.
The labrum is a circular layer of cartilage which surrounds the outer part of the acetabulum effectively making the socket deeper to provide more stability for the joint. Labrum tears are not an uncommon hip injury.
* Motions Available:-
Flexion: forward and upward movement of the femur at the hip occurs in the sagittal plane about an medial-lateral axis.
Extension: upward movement toward the rear of the body of the femur at the hip occuring in the sagittal plane.
Abduction: movement of the femur on the hip in a direction away from the midline of the body in the frontal plane.
Adduction: movement of the femur on the hip in a direction toward the midline of the body in the frontal plane.
Internal Rotation: rotation of the femur toward the midline of the body in the transverse plane.
External Rotation: rotation of the femur away from the midline of the body in the transverse plane.
*Hip joint disorders:-
Hip disorders are often due to developmental conditions, injuries, chronic conditions, or infections.
Degeneration of cartilage in the joint causes osteoarthritis. This makes the cartilage split and become brittle. In some cases, pieces of the cartilage break off in the hip joint. Once the cartilage wears down enough, it fails to cushion the hip bones, causing pain and inflammation.
This condition occurs when a newborn baby has a dislocated hip or a hip that easily dislocates. A shallow hip socket that allows the ball to easily slip in and out is the cause of developmental dysplasia.
This disease affects children between the ages of 3 and 11. Perthes disease is the result of reduced blood supply to bone cells. This causes some of the bone cells in the femur to die and the bone to lose strength.
(4)Irritable Hip Syndrome
Irritable hip syndrome can be common in children after an upper respiratory infection. It causes hip pain that results in limping. In most cases it resolves by itself.
(5)Soft Tissue Pain and Referred Pain
Pain in the hip may be due to an injury or defect affecting the soft tissues outside of the hip. This is known as referred pain.
(6)Slipped Capital Femoral Epiphysis
A slipped capital femoral epiphysis is a separation of the ball of the hip joint from the thigh bone (femur) at the upper growing end (growth plate) of the bone. This is only seen in growing children. Surgically stabilizing the joint with pins is a common effective treatment.
* Hip Strengthening:-
To begin with, the following basic hip strengthening exercises should be performed approximately 10 times, 3 times daily. As your hip strength improves, the exercises can be progressed by gradually increasing the repetitions and strength of contraction provided they do not cause or increase pain.
Begin this exercise lying on your back and Slowly lift your bottom pushing through your feet, until your knee, hip and shoulder are in a straight line. Tighten your bottom muscles (gluteals) as you do this. Hold for 2 seconds and repeat 10 times.
(2)Hip Extension in Lying
Begin this exercise lying on your stomach Keeping your knee straight, slowly lift your leg tightening your bottom muscles (gluteals). Hold for 2 seconds and repeat 10 times.
Begin this exercise lying and rolled towel or ball between your knees Slowly squeeze the ball between your knees tightening your inner thigh muscles (adductors). Hold for 5 seconds and repeat 10 times as hard as possible pain free.