Hip Joint: The hip joint is a ball and socket variety of synovial joint, formed by an articulation between the acetabulum of the pelvic bone and the head of the femur.The hip joint is very stable joint unlike the shoulder joint, which is highly mobile, but not so stable.
Ligaments of the Hip joints
The ligaments of the hip joint exploit to increase stability. They divided into two groups – intracapsular and extracapsular:
Intracapsular ligament of the Hip Joints
The single intracapsular ligament is the ligament of head of the femur. It is a comparatively small structure, which goes from the acetabular fossa to the fovea of the femur.
Extracapsular ligament of the Hip Joints
There are three principal extracapsular ligaments, connected with the outer surface of the hip joint capsule:
Iliofemoral ligament – connecting the anterior inferior iliac spine and the intertrochanteric line of the femur.
It produces a ‘Y’ shaped image and limits hyperextension of the hip joint.
Ischiofemoral – spans within the body of the ischium and the greater trochanter of the femur.
It becomes a spiral orientation and prevents extreme extension.
Pubofemoral – spans within the superior pubic rami and the intertrochanteric line of the femur.
It produces a triangular shape and prevents undue abduction and extension of the hip joint.
Neurovascular Supply of the Hip joint
The arterial supply of the hip joint is medial and lateral circumflex femoral arteries – branches of the profunda femoris artery. They anastomose at the bottom of the femoral neck to form a ring, from which tinier arteries arise to supply the hip joint itself.
The medial circumflex femoral artery is responsible for the majority of the arterial supply. Damage to the medial circumflex femoral artery can result in avascular necrosis of the femoral head.
The head of the femur supplied by the superior/inferior gluteal arteries provides some additional supply.
The hip joint is innervated by the obturator nerve, femoral nerve, superior gluteal nerve, and nerve to quadratus femoris.
Hip Joints Movements
- Medial Rotation
- Lateral Rotation
In abduction-lower limb away from the midline in the coronal plane.
Muscles involvement in abduction: Gluteus medius, gluteus minimus and the deep gluteals (piriformis, Gemelli etc.)
In adduction-lower limb towards midline in the coronal plane.
Muscles involvement in abduction: adductors longus, brevis and magnus, pectineus and gracillis
Flexion-lower limb forwards in the sagittal plane.
Muscles involvement in flexion: iliopsoas, rectus femoris, Sartorius
In extension-lower limb backwards in the sagittal plane.
Muscles involvement in extension: gluteus maximus, semimembranosus, semitendinosus and biceps femoris
In medial Rotation-rotation towards the midline, so that the big toe is pointing medially.
Muscles involvement in medial rotation: gluteus medius and minimus, semitendinosus, and semimembranosus
In lateral Rotation -rotation away from the midline, so that the big toe is pointing laterally.
Muscles involvement in lateral rotation:– biceps femoris, gluteus maximus, and the deep gluteals (piriformis, Gemelli etc.)