The hip joint is the largest weight-bearing joint in the human body. It is also referred to as a ball and socket joint and is surrounded by muscles, ligaments, and tendons. The thigh bone or femur and the pelvis join to form the hip joint.
Any injury or disease of the hip will adversely affect the joint's range of motion and ability to bear weight.
The hip joint is made up of the following:
- Bones and joints
- Ligaments of the joint capsule
- Muscles and tendons
- Nerves and blood vessels that supply the bones and muscles of the hip
Bones and Joints
The hip joint is the junction where the hip joins the leg to the trunk of the body. It is comprised of two bones: the thigh bone or femur and the pelvis which is made up of three bones called ilium, ischium, and pubis. The ball of the hip joint is made by the femoral head while the socket is formed by the acetabulum. The Acetabulum is a deep, circular socket formed on the outer edge of the pelvis by the union of three bones: ilium, ischium, and pubis. The lower part of the ilium is attached by the pubis while the ischium is considerably behind the pubis. The stability of the hip is provided by the joint capsule or acetabulum and the muscles and ligaments which surround and support the hip joint.
The head of the femur rotates and glides within the acetabulum. A fibrocartilagenous lining called the labrum is attached to the acetabulum and further increases the depth of the socket.
The femur or thigh bone is one of the longest bones in the human body. The upper part of the thigh bone consists of the femoral head, femoral neck, and greater and lesser trochanters. The head of the femur joins the pelvis (acetabulum) to form the hip joint. Next, to the femoral neck, there are two protrusions known as greater and lesser trochanters which serve as sites of muscle attachment.
Articular cartilage is the thin, tough, flexible, and slippery surface lubricated by synovial fluid that covers the weight-bearing bones of the body. It enables smooth movements of the bones and reduces friction.
Ligaments are fibrous structures that connect bones to other bones. The hip joint is encircled with ligaments to provide stability to the hip by forming a dense and fibrous structure around the joint capsule. The ligaments adjoining the hip joint include:
- Iliofemoral ligament:This is a Y-shaped ligament that connects the pelvis to the femoral head at the front of the joint. It helps in limiting the over-extension of the hip.
- Pubofemoral ligament:This is a triangular shaped ligament that extends between the upper portion of the pubis and the iliofemoral ligament. It attaches the pubis to the femoral head.
- Ischiofemoral ligament: This is a group of strong fibers that arise from the ischium behind the acetabulum and merge with the fibers of the joint capsule.
- Ligamentum teres:This is a small ligament that extends from the tip of the femoral head to the acetabulum. Although it has no role in hip movement, it does have a small artery within that supplies blood to a part of the femoral head.
- Acetabular labrum:The labrum is a fibrous cartilage ring which lines the acetabular socket. It deepens the cavity, increasing the stability and strength of the hip joint.
Muscles and Tendons
A long tendon called the iliotibial band runs along the femur from the hip to the knee and serves as an attachment site for several hip muscles including the following:
- Gluteals:These are the muscles that form the buttocks. There are three muscles (gluteus minimus, gluteus maximus, and gluteus medius) that attach to the back of the pelvis and insert into the greater trochanter of the femur.
- Adductors:These muscles are located in the thigh which helps in adduction, the action of pulling the leg back towards the midline.
- Iliopsoas: This muscle is located in front of the hip joint and provides flexion. It is a deep muscle that originates from the lower back and pelvis and extends up to the inside surface of the upper part of the femur.
- Rectus femoris:This is the largest band of muscles located in front of the thigh. They also are hip flexors.
- Hamstring muscles: These begin at the bottom of the pelvis and run down the back of the thigh. Because they cross the back of the hip joint, they help in extension of the hip by pulling it backward.
Nerves and Arteries
Nerves of the hip transfer signals from the brain to the muscles to aid in hip movement. They also carry the sensory signals such as touch, pain, and temperature back to the brain.
- The main nerves in the hip region include the femoral nerve in the front of the femur and the sciatic nerve at the back. The hip is also supplied by a smaller nerve known as the obturator nerve.
- In addition to these nerves, there are blood vessels that supply blood to the lower limbs. The femoral artery, one of the largest arteries in the body, arises deep in the pelvis and can be felt in front of the upper thigh.
All of the anatomical parts of the hip work together to enable various hip movements. Hip movements include flexion, extension, abduction, adduction, circumduction, and hip rotation.
The inflammation of the joints is referred to as arthritis. Inflammation arises when the smooth lining called cartilage at the ends of bones wears away. In some cases, the inflammation is caused when the lining of the joint becomes inflamed as part of an underlying systemic disease. These conditions are referred to as inflammatory arthritis.
The hip joint is a “ball and socket” joint. The “ball” is the head of the femur or thighbone, and the “socket” is the cup-shaped acetabulum. The joint surface is covered by a smooth articular surface that allows pain-free movement in the joint.
Femoro acetabular impingement (FAI) is a condition where there is too much friction in the hip joint from bony irregularities causing pain and decreased range of hip motion. The femoral head and acetabulum rub against each other creating damage and pain to the hip joint.
The hip joint is a ball and socket joint in which the head of the femur is the ball and the acetabulum forms the socket. The labrum helps to deepen the socket and provide stability to the joint. It also acts as a cushion and enables smooth movement of the joint.Watch Video
Injury or damage to these structures can lead to a condition called hip instability when the joint becomes unstable.
The hip joint is a “ball and socket” joint. The “ball” is the head of the femur or thighbone, and the “socket” is the cup-shaped acetabulum. The joint is surrounded by muscles, ligaments, and tendons that support and hold the bones of the joint in place. Hip dislocation occurs when the head of the femur moves out of the socket. The femoral head can dislocate either backward (posterior dislocation) or forward (anterior dislocation).
Injuries to the hip ligaments are commonly called a hip sprain and can range from minor tears of the ligaments to more serious injuries involving the hip muscles, tendons or bone.
Groin injuries are injuries sustained by athletes during sports activity. Groin injuries comprise about 2 to 5 percent of all sports injuries. The most common kind of groin injury is a groin strain or a pulled groin muscle. Typical groin injuries vary based on athlete’s gender, age, and sports, with most common groin injuries occurring in certain sports such as football with a prevalence rate as high as 12-16%.
The hamstring is a group of three muscles that run along the back of the thigh from the hip to the knee. Hamstring injuries occur when these muscles are strained or pulled. They are common in dancers and athletes of all sorts including runners and those who play football, soccer, basketball, tennis, etc.
Hip pain, one of the common complaints, may not always be felt precisely over the hip joint rather in and around the hip joint. The cause for pain is multifactorial and the exact position of your hip pain suggests the probable cause or underlying condition causing it.
Hip bursitis is a painful condition caused by the inflammation of a bursa in the hip. Bursae are fluid-filled sacs present in the joints between bone and soft tissue to reduce friction and provide cushioning during movement.Watch Video
A gluteus medius tear is the partial or complete rupture of the gluteus medius muscle due to severe muscle strain. Gluteus medius tears often occur at the tendinous attachment to the greater trochanter of the femur bone.Watch Video
Avascular necrosis, also called osteonecrosis, is a condition in which bone death occurs because of inadequate blood supply to it. Lack of blood flow may occur when there is a fracture in the bone or a joint dislocation that may damage nearby blood vessels. Hip joint is most commonly affected; however, the knee and shoulder may also be involved.
Hip arthroscopy, also referred to as keyhole or minimally invasive surgery, is a procedure in which an arthroscope is inserted into your hip joint to check for any damage and repair it simultaneously.
The hip is a ball and socket joint comprising of the femur (thigh bone) and the pelvic bone. The head of the femur (ball) articulates with a cavity (socket) called the acetabulum in the pelvic bone. To facilitate the smooth and frictionless movement of the hip joint, the articulating surfaces of the femur head and acetabulum are covered by spongy articular cartilage.
Labrum is a ring of strong fibrocartilaginous tissue lining around the socket of the hip joint. Labrum serves many functions where it acts as a shock absorber, lubricates the joint, and distributes the pressure equally. It holds the head of the femur in place and prevents the lateral and vertical movement of the femur head within the joint. It also deepens the acetabular cavity and offers stability against femoral head translation.
Hip fractures involve a break that occurs near the hip in the upper part of the femur or thigh bone. The thigh bone has two bony processes on the upper part - the greater and lesser trochanters. The lesser trochanter projects from the base of the femoral neck on the back of the thigh bone. Hip fractures can occur either due to a break in the femoral neck, in the area between the greater and lesser trochanter or below the lesser trochanter.
Stem cells are being used in regenerative medicine to renew and repair diseased or damaged tissues and have shown promising results in the treatment of various orthopedic, cardiovascular, neuromuscular, and autoimmune conditions.
Hip cartilage restoration is a surgical technique to repair damaged articular cartilage in the hip joint by stimulating new growth of cartilage or by transplanting cartilage into areas with defects in order to relieve pain and restore normal function to the hip.
Hip cartilage is a white, tough, flexible tissue covering the ball (femoral head) and socket (acetabulum) of your hip joint. It acts as a cushion or shock-absorber and allows the bones to slide over one another by providing a smooth surface in the joint.
Arthroscopic gluteus medius tendon repair is a minimally invasive surgical procedure employed for the treatment of a gluteus medius tendon tear, when the tear does not respond to conservative treatment.