Gluteal region of hip joint

Question 1

Gluteus maximus:
* Origin
* Insertion
* Nerve supply
* Action

Answer 1

• Origin - iliac crest, gluteal surface of ilium, sacrum, coccyx, sacrotuberous ligament, thoracolumbar fascia.
• Insertion - iliotibial tract and gluteal tuberosity of femur.
• Nerve supply - inferior gluteal nerve (L5, S1, 2)
• Action - hip extension, ER, abduction.

Question 2

Gluteus medius:
* Origin
* Insertion
* Nerve supply
* Action

Answer 2

• Origin - gluteal surface of the ilium.
• Insertion - lateral surface of the greater trochanter.
• Nerve supply - superior gluteal nerve (L4, 5, S1).
• Action - hip abduction. Anterior fibres - IR.

Question 3

Gluteus minimus:
* Origin
* Insertion
* Nerve supply
* Action

Answer 3

• Origin - gluteal surface of the ilium, between the anterior and inferior gluteal lines.
• Insertion - anterolateral surface of greater trochanter.
• Nerve supply - superior gluteal nerve (L4, 5, S1).
• Action - hip abduction. Anterior fibres - IR.

Question 4

Piriformis:
* Origin
* Insertion
* Nerve supply
* Action

Answer 4

• Origin - anterior aspect of sacrum (S2-4), periphery of greater sciatic notch, sacrotuberous ligament.
• Insertion - superomedial aspect of greater trochanter.
• Nerve supply - anterior rami of S1 and S2.
• Action - Hip ER, abduction.

Question 5

Obturator internus:
* Origin
* Insertion
* Nerve supply
* Action

Answer 5

• Origin - inferior margin of the superior pubic ramus and from the pelvic surface of the obturator membrane.
• Insertion - Its tendon exits the pelvis through the lesser sciatic foramen to insert onto the greater trochanter of the femur.
• Nerve supply - obturator internus nerve (L5, S1, 2)
• Action - hip ER, abduction.

Question 6

Superior gemellus:
* Origin
* Insertion
* Nerve supply
* Action

Answer 6

• Origin - arises from the spine of the ischium.
• Insertion - Blended insertion with the upper part of the tendon of obturator internus on greater trochanter.
• Nerve supply - Nerve to obturator internus (L5, S1, 2).
• Action - hip ER, abduction.

Question 7

Inferior gemellus:
* Origin
* Insertion
* Nerve supply
* Action

Answer 7

• Origin - ischial tuberosity at the margin of the lesser sciatic notch.
• Insertion - together with the superior gemellus and obturator internus, inserts on greater trochanter of femur.
• Nerve supply - nerve to quadratus femoris (L4, 5, S1)
• Action - hip ER, extension, abduction.

Question 8

Quadratus femoris:
* Origin
* Insertion
* Nerve supply
* Action

Answer 8

• Origin - ischial tuberosity.
• Insertion - quadrate tubercle of the femur.
• Nerve supply - nerve to quadratus femoris (L4, 5, S1)
• Action - hip ER, abduction.

Question 9

What type of joint is the hip joint?

Answer 9

The hip joint is a multiaxial synovial joint of the ball-and-socket variety, between the acetabulum of the innominate (hip) bone and the head of the femur.

Question 10

Outline hip mobility and stability.

Answer 10

In general it can be said that in all joints stability and range of movement are in inverse proportion to each other; the hip joint provides a remarkable example of a high degree of both.

• Stability - largely the result of the adaptation of the acetabulum and femoral head to each other. The snug fit of the femoral head into the acetabulum, deepened by the labrum, makes the hip a very stable joint, further reinforced by the ligaments on the outside of the capsule, especially the iliofemoral. The short muscles of the gluteal region are important muscular stabilisers. The joint is least stable when flexed and adducted.
• Mobility - its great range of mobility results from the femur having a long neck that is much narrower than the head.

Question 11

Describe the structure of the acetabulum and labrum.

Answer 11

• The cup-shaped acetabulum is formed by fusion of the three components of the hip bone: ilium, ischium, and pubis.
• The articular surface, covered with hyaline cartilage, does not occupy the whole of the acetabular fossa, but is a C-shaped concavity that is broadest above, where the body weight is transmitted in the erect posture.
• Its peripheral edge is deepened by a rim of fibrocartilage - the acetabular labrum - which encloses the femoral head beyond its equator, thus increasing the stability of the joint.
• The labrum is triangular in section, with its base attached to the acetabular rim. It is continued across the acetabular notch at the inferior margin of the acetabulum as the transverse ligament.
• The central non-articular part of the acetabulum is occupied by a pad of fat (the Haversian pad).

Question 12

Describe the structure of the femoral head.

Answer 12

• The spherical head of the femur is covered with hyaline cartilage.
• The non-articulating summit of the head is excavated into a pit (fovea) for attachment of the ligament of the head of the femur (ligamentum teres), whose other end is attached to the transverse ligament and the margins of the acetabular notch.

Question 13

Describe the capsule of the hip joint.

Answer 13

• The capsule of the joint is attached circumferentially around the labrum and transverse ligament, hence it passes laterally, like a sleeve, to be attached to the neck of the femur.
• In front it is attached to the intertrochanteric line, but at the back it extends for only half this distance, being attached halfway along the femoral neck.
• The capsule is loose but extremely strong.
• From these attachments, the fibres of the capsule are reflected back along the neck of the femur to the articular margin of the femoral head.
• This reflected part constitutes the retinacular fibres, which bind down the nutrient arteries that pass, chiefly from the trochanteric anastomosis, along the neck of the femur to supply the major part of the head.
• The fibrous capsule is strengthened by three ligaments, which arise one from each constituent bone of the hip bone.

Question 14

Outline the 3 ligaments of the hip joint.

Answer 14

• The iliofemoral ligament is the strongest of the three, and has a triangular shape. The apex is attached to the lower half of the anterior inferior iliac spine and the base is attached to the intertrochanteric line. The margins are thick and the ligament has the appearance of an inverted V. The ligament limits extension at the hip joint.
• The pubofemoral ligament is attached to the superior ramus and obturator crest of the pubic bone. It passes distally deep to the iliofemoral ligament, and blends with the capsule.
• The ischiofemoral ligament is the weakest of the three. It arises from the posteroinferior margin of the acetabulum, and its fibres, passing laterally to the capsule, spiral upwards and blend with circular fibres of the capsule, the zona orbicularis.

Question 15

Describe the synovial membrane of the hip joint.

Answer 15

• As in all synovial joints, the synovial membrane is attached to the articular margins.
• From its attachment around the labrum and transverse ligament it lines all the capsule and is reflected back along the neck of the femur, where it invests the retinacular fibres up to the articular margin of the head of the femur.
• The Haversian fat pad and the ligament of the head are likewise invested in a sleeve of synovial membrane that is attached to the articular margins of the concavity of the acetabulum and of the fovea on the femoral head.

Question 16

Outline the blood supply of the hip.

Answer 16

• The capsule and synovial membrane are supplied from nearby vessels.
• The head and intracapsular part of the neck receive their blood from the trochanteric anastomosis, mainly through branches of the medial circumflex femoral artery.

Question 17

Outline the nerve supply of the hip.

Answer 17

• Femoral nerve via the nerve to rectus femoris.
• Obturator nerve directly from its anterior division.
• Nerve to quadratus femoris.
• Articular twigs from the sciatic nerve.

The femoral, obturator and sciatic nerves also supply the knee joint and pain arising in the hip joint may be referred to the knee.

Question 18

What movements are possible at the hip?

Answer 18

• As in any ball and socket joint, movement is possible in all directions.
• Flexion, extension, adduction and abduction are free; a combination of all four produces circumduction.
• In addition, medial and lateral rotation of the femur occur.

Question 19

Outline flexion of the hip.

Answer 19

• In flexion of the hip the head of the femur rotates about a transverse axis that passes through both acetabula and the thigh is flexed upon the trunk.
• The muscles responsible for flexion are psoas major and iliacus, assisted by rectus femoris, sartorius and pectineus.
• Flexion is limited by the thigh touching the abdomen, or by tension of the hamstrings if the knee is extended.
• The normal range is about 120˚, with the knee flexed.

Question 20

Outline extension of the hip.

Answer 20

• Extension of the thigh, the reverse of the above movement, is performed by gluteus maximus at the extremes of the movement and by the hamstrings in the intermediate stage.
• The movement is limited by tension in the iliofemoral ligament, and amounts to about 20˚.

Question 21

Outline adduction of the hip.

Answer 21

• In adduction and abduction of the thigh the femoral head rotates in the acetabulum about an anteroposterior axis.
• Adduction of about 30˚is produced by contraction of the pectineus, adductors longus, brevis and magnus and the gracilis.
• It is limited by contact with the other leg or, if the latter is abducted out of the way, by the tension of gluteus medius and minimus.

Question 22

Outline abduction of the hip.

Answer 22

• Abduction is produced by contraction of gluteus medius and minimus, assisted by tensor fasciae latae and sartorius.
• It is limited by tension in the adductors and in the pubofemoral ligament, and amounts to about 60˚.
• Contraction of the abductors is essential in normal one-legged stance and in walking and running.
• In the sitting position, piriformis and the gemelli and obturator muscles act as abductors, e.g. helping to move the leading leg when getting out of a car.

Question 23

Outline rotation of the hip.

Answer 23

• In rotation the femoral head rotates in the acetabulum about a vertical axis that passes through the centre of the femoral head. On account of the angulation of the neck of the femur, this axis does not coincide with the axis of the femoral shaft.
• Consequently the femoral neck and greater trochanter move forwards during medial rotation, and backwards during lateral rotation.
• Medial rotation is produced by the anterior fibres of gluteus medius and minimus assisted by tensor fasciae latae. It is restricted by tension in the lateral rotators and the ischiofemoral ligament.
• Piriformis, obturator internus and the gemelli, quadratus femoris and obturator externus are lateral rotators, assisted by gluteus maximus and sartorius.
• Lateral rotation is restricted by tension in the medial rotators and the iliofemoral ligament.
• Rotation in either direction amounts to about 40˚.