MSK 7b: buttock and gluteal region

Question 1

Ligaments of the gluteal region

Answer 1

Bind the hip bones, sacrum and coccyx:

• POSTERIOR SACRO-ILIAC: continuous inferiorly with the sacrotuberous
• SACROTUBEROUS: across sciatic notch and into foramen
• SACROSPINOUS: further divides into greater and lesser sciatic foramina. Greater for structures entering/leaving pelvis e.g. sciatic nerve; lesser for structures entering/leaving perineum e.g. pudendal nerve

Question 2

Superficial and deep gluteal muscles

Answer 2

Superficial: gluteus maximus, gluteus medius, gluteus minimus, tensor fasciae latae
Deep: piriformis, superior and inferior gemelli, obturator internus, quadratus femoris

Question 3

Proximal attachment of all the superficial gluteal muscles

Answer 3

External surface and margins of the ala of ilium

Slightly different for each, not time to learn

Question 4

Gluteus maximus

Answer 4

Most superficila, large, covers all except the superior 1/3 of gluteus medius

I: iliotibial tract, gluteal tuberosity (of linea aspera)
N: inferior gluteal nerve (L5, S1, S2)
A: hip extension, lateral rotation (Assists in rising from sitting)

Question 5

Gluteus medius

Answer 5

Fan-shaped

I: lateral side of greater trochanter
N: superior gluteal nerve (L5, S1)
A: abduction and medial rotation of hip (keeps pelvis level, advance unsupported during swing phase of gait cycle)

Question 6

Gluteus minimus

Answer 6

Fan-shaped

I: anterior surface of greater trochanter
N: superior gluteal nerve (L5, S1)
A: abduction and medial rotation of hip (keeps pelvis level, advance unsupported during swing phase of gait cycle)

Question 7

Tensor fasciae latae

Answer 7

Fusiform

I: iliotibial tract
N: superior gluteal nerve (L5, S1)
A: abduction and medial rotation of hip (keeps pelvis level, advance unsupported during swing phase of gait cycle)

Question 8

General action of the deep gluteal muscles?

Answer 8

Stabilise the femoral head in the acetabulum

Question 9

Piriformis

Answer 9

Pear-shaped

O: anterior sacral surface and sacrotuberous ligament
I: superior border of greater trochanter
N: branches of anterior rami of S1-2
A: lateral rotation, hip extension and abduction when hip flexed

Question 10

Obturator internus

Answer 10

O: pelvic surface of obturator membrane
I: medial surface of greater trochanter
N: nerve to obturator internus (L5, S1)
A: laterally rotate extended thigh and abduct flexed thigh

Question 11

Which muscles form the triceps coxae?

Answer 11

Obturator internus, superior and inferior gemelli and quadratus femoris

Question 12

Superior and inferior gemelli

Answer 12

O: ischial spine (S), ischial tuberosity (I)
I: medial surface of greater trochanter
N: nerve to obturator internus (S), nerve to quadratus femoris (I)
A: lat rotation of extended thigh and abduction of flexed thigh

Question 13

Quadratus femoris

Answer 13

Short, flat quadrangular muscle

O: lateral border of ischial tuberosity
I: quadrate tubercle on intertrochanteric crest
N: nerve to QF (L5, S1)
A: lateral rotation

Question 14

Iliotibial tract/band

Answer 14

Ligament running down lateral side of thigh: from iliac tubercle to lateral condyle of tibia
Fibrous reinforcement of the tensor fasciae latae
Point of insertion for gluteus maximus
Stabilises knee in extension and partial flexion

Question 15

Iliotibial band syndrome

Answer 15

Common overuse injury in runners: pain and inflammation on lateral side of knee
RICE and anti-inflammatory medicines, physiotherapy

Question 16

Piriformis syndrome

Answer 16

Piriformis spasms and causes buttock pain and instability due to compression of sciatic nerve
Can be from sports or trauma; women more prone to it

Question 17

Intragluteal injection area

Answer 17

Penetrate skin, fascia and muscle
Some restrict area o f buttocks to most prominent part but this dangerous as sciatic nerve lies deep to this area

Safe:

• in supero-lateral quadrant of buttocks, or superior to a line extending from the PSIS to the superior border of the greater trochanter
• anterolateral part of thigh where needle enters tensor fasciae latae as it extends distally from the iliac crest and ASIS: index finger placed on ASIS, fingers spread posteriorly along iliac crest until tubercle of crest is felt by middle finger: IM injection in triangular area between fingers as superior to sciatic nerve

Consequences of improper technique: nerve injury, haematoma, abscess