Hip joint Hip joint Type Synovial Subtype multiaxial

Hip joint

Hip joint • Type – Synovial • Subtype – multiaxial Ball and Socket type • Function – to support the body weight in standing • and transmit the forces during the movements of the trunk upon the femur during walking and running

• The range of movements is possible in all directions • This is due to the presence of long narrow neck which makes an angle with the shaft

Articular surfaces Acetabulum Head of femur

Acetabulum Is a cup shaped cavity It is formed by the fusion of all the three pars of the hip bone The rim presents a notch – acetabular notch in the lower part It is converted in to a foramen by transverse acetabular ligament

Acetabulum It has a articular part - the lunate surface( covered by hyaline cartilage) Non articular part - the acetabular fossa (filled with fat) Acetabular labrum is attached to the rim/margin of the acetabulum It deepens the cup and also forms a tight fit around the head of femur

Head of femur is spherical and is covered by hyaline cartilage except at a rough pit the fovea This gives attachment to the ligament of the head of femur Articular cartilage is thick at the centre and thin towards the periphery

Hip joint Acetabulum of hip is a much deeper cavity than glenoid cavity of scapula and depth of acetabulum is increased by fibrocartilagenous rim- acetabular labrum Due to above adaptation of head of femur is far more intimate and hip joint is more stable and less mobile than shoulder joint

Ligaments of the hip joint • • Fibrous capsule Iliofemoral ligament Pubofemoral ligament Ischiofemoral ligament Actetabular labrum Transverse acetabular ligament Ligament of the head of femur

Fibrous capsule It is very strong and holds the joint tightly Attachments: Medial – attached to the margins of the acetabulum Transverse acetabular ligament Capsule encloses the neck of the femur

Fibrous capsule Lateraly – attached to the femur Attachment to the femur: Anteriorly – attached to the intertrochantric line and root of the greater trochanter. Hence anterior surface of the neck is completely intracapsular

Fibrous capsule Posteriorly – attached to the posterior surface of the neck a short distance medial to the intertrochantric crest. Thus posterior part of the neck is partly extracapsular

Special parts of the capsule Capsule is made up of superficial longitudinal and deep circular fibers (Zona orbicularis) which encircle the neck of femur

Special parts of the capsule Retinacula are longitudinal fibers on the anterior surface of the neck These fibers originate from the capsular attachment to the intertrochanteric line and proceed towards the head in close contact with the neck of femur They support the retinacular arteries running towards the head

Iliofemoral ligament One of the thickest and strongest ligament in the body Shape – inverted Y (triangular) Apex – attached to the anterior inferior iliac spine Lower attachment – to the intertrochanteric line Iliofemoral ligament is more than 0. 5 cm thick. A stress varying between 250 to 700 lb is required to rupture it. Thus it is rarely torn in dislocations of the hip joint

Iliofemoral ligament Lateral part - dense and oblique and is attached to the upper part of the intertrochanteric line Medial part - vertical attached to the lower part of the Medial/ vertical part intertrochanteric Lateral part/oblique Intermediate part is thin

Iliofemoral ligament Function – in erect posture, a vertical line through centre of gravity of body falls slightly behind a line joining the centers of the two hip joints Hence, there is a tendency for the body to fall backward. Iliofemoral ligament resists this tendency It prevents excessive extension of the hip joint

Pubofemoral ligament Triangular ligament Base attached to the iliopubic eminence, superior ramus of the pubis, obturator crest Psoas bursa Laterally it blends with the capsule and the medial band of iliofemoral ligament

Ischiofemoral ligament Located in the posterior part It is attached to the ischium below the lower margin of the acetabulum From its attachment the fibers spiral superolaterally to merge with the fibrous capsule

Acetabular labrum It is a fibrocartilagenous ring attached to the rim of the acetabulum and the transverse acetabular ligament It deepens the cavity of the acetabulum and slightly narrows its mouth

Acetabular labrum Labrum is a tight fit on the head of the femur, and sealing it in the acetabulum Hence exercises an important function of retaining the head within the acetabulum Both surfaces of the labrum are coverd by synovial membrane

Ligament of the head of femur Relatively a weak band of connective tissue surrounded by synovial membrane The narrow end is attached to the pit or fovea on the head of the femur The broad flattened end is attached to the transverse acetabular ligament and adjacent margins of acetabular fossa It transmits small blood vessel to the head of femur

Transverse acetabular ligament Strong band of fibrous tissue that bridges the acetabular notch It converts the notch in to a foramen through which vessels and nerves enter the acetabular fossa and the ligament of the head of femur

Synovial membrane

Synovial membrane • Lines the inner surface of the capsule • It covers the intrcapsular part of the neck of the femur as far as the articular margin of the head • It also covers the acetabular labrum, ligament of the head of femur and fat in the acetabular fossa • Occasionally the synovial membrane may protrude through a opening between iliofemoral and pubofemoral ligaments to become continous with the psoas bursa

Blood supply to the joint • Is supplied from an anastomosis around the neck of femur formed by – • Ascending branches of medial and lateral circumflex femoral arteries • Branches of superior and inferior gluteal arteries • Ascetabular branches of the medial circumflex femoral and obturator arteries

Blood supply Area of the head around the fovea is supplied by the acetabular branch of medial circumflex artery Rest of the head, neck receive blood from the arterial circle around the capsular attachment The main artery is the medial circumflex femoral artery with contributions from the superior and inferior gluteal arteries

Blood supply The retinacular arteries arise from the vascular ring and run along the neck to supply the neck and head of femur. These are the sole supply to the head and neck In rupture of these arteries (fracture of neck) avascular necrosis of the head occurs

Nerve supply • Femoral nerve through nerve to rectus femoris • Obturator nerve (anterior division) • Nerve to quadratus femoris • Superior gluteal nerve

Movements of the hip joint • • • Flexion Extension Abduction Adduction Medial rotation Lateral rotation

Flexion – is very free. It is prevented by thigh coming in to contact with the anterior abdominal wall Muscles – psoas major, iliacus, rectus femoris, pectineus and sartorius Extension – extremely restricted by iliofemoral ligament Muscles – gluteus maximus, semitendinosus, semimembranosus, long head of biceps femoris and ischial part of adductor magnus

Abduction – it is restricted by the pubofemoral ligament Muscles – gluteus medius, minimus and tensor fasciae latae Adduction – crossing one thigh over the other It is limited by the lateral portion of the iliofemoral ligament Muscles – adductor longus, breveis, magnus (pubic fibers) pectineus and gracils

Medial rotation – tightens the ischiofemoral ligament Muscles – tensor fasciae latae, anterior fibers of the gluteus medius and minimus Lateral rotation – limited by the pubofemoral ligament Muscles – piriformis, obturator externus and internus, gemelli, quadratus femoris

Applied aspects • Dislocation of the hip joint – posterior dislocation more common than anterior dislocation (fracture of the acetabulum) • In posterior dislocation – sciatic nerve may be injured

Anterior dislocation Not common. Occurs during forced abduction and lateral rotation of hip

Applied aspects Congenital dislocation – the head of femur slips upwards on to the gluteal surface of ilium because upper margin of the acetabulum is not developed Trendelenberg test is positive

Fracture of the neck It may be intracapsular or extracapsular Intracapsular It may be sub capital near the head, transcervical or basal near the trochanter. The fracture damages the retinacular arteries and causes avascular necrosis of the head Damage maximal in subcapital and least in basal fractures

In intracapsular fracture of the neck the affected limb is shortened and held in characteristic laterally rotated position, toes pointing laterally This is because – the head of femur separates from the shaft (with trochanter) in intracapsular fracture, the shaft rotates independently of the head The gluteus maximus and the short lateral rotators rotate the femur laterally The muscles attaching the hip bone and femur pull the femur upwards making the limb short

Neck shaft angle – angle of inclination

Shenton’s line – is seen in X ray of the pelvis It is continuous curve formed by the upper border of the obturator foramen and lower border of the neck of the femur In fracture dislocation abnormal of the neck or hip the line becomes

Trendelenberg sign: Stability of the hip joint when a person stands on one leg when other leg is off the ground depends on Normal functioning of gluteus medius and minimus Head of femur is in normal position within acetabulum Neck of femur is intact and must have a normal angle with shaft of femur