Lecture 21: Gluteal region + Posterior thigh

Question 1

What are the boundaries of the gluteal region

Answer 1

Posterior to the pelvis, the gluteal region is bound superiorly by the iliac crests and inferiorly by the gluteal sulcus created by the gluteus maximus muscles

Question 2

What is on the same plane as the pubic symphysis

Answer 2

The ASIS

Question 3

Compare the attachments of the sacrospinous ligament and Sacrotuberous ligament in the pelvis.
Ligaments hold the pelvis together and provide passageway to other areas

Answer 3

The Sacrospinous ligament attaches from the sacrum horizontally to the ischial spine Whereas the Sacrotuberous ligament attaches from the upper sacrum behind the sacrospinous ligament vertically down to the ischial tuberosity.

Question 4

What are the two spaces created by the ligaments in the pelvis and what is the purpose of these spaces

Answer 4

The Greater sciatic foramen is created by the upper boundary of sacrospinous and the Lesser sciatic foramen is created by the lateral border of sacrotuberous ligament
The Greater sciatic foramen allows passage to arteries and nerves from the pelvis to the gluteal region and/or lower limb
The lesser sciatic foramen allows passage for structures entering or leaving the perineum- eg pundendal nerve

Question 5

What is the origin, insertion of Gluteus maximus

Answer 5

O: Upper posterior portion of illium, posterior sacrum-> coccyx + sacrotuberous lig

I: Iliotibial band and gluteal tuberosity of the femur

Question 6

What is the nerve supply and action of the Gluteus maximus

Answer 6

N: inferior gluteal nerve
Action: extends and laterally rotates the thigh/hip

Question 7

What is the origin, insertion of Gluteus medius and gluteus minimus

Answer 7

O Glut Medius: Ilium between the posterior and middle gluteal lines
O Glut Minimus: ilium between middle and inferior gluteal lines

Insertion for both is: Greater trochanter (lateral side)

Question 8

What is the nerve supply and action of Gluteus medius and gluteus minimus. What other muscle shares these actions and nerve supply

Answer 8

N: Superior gluteal nerve

Action for all is to abduct the thigh and internally rotate the thigh.
Other muscle is Tensor fascia lata which doesn’t internally rotate but also stabilises the pelvis when walking like Glut med.

Question 9

What is the origin and insertion of Piriformis

Answer 9

O: Anterior sacrum + sacrotuberous ligament
-> goes through the greater sciatic foramen
I: greater trochanter (medial side)

Question 10

What is the origin and insertion of Obturator internus

Answer 10

O: Obturator foramen and membrane
I: greater trochanter (medial side)

Question 11

What is the origin and insertion of Superior and inferior Gemelli

Answer 11

Origin (s) : ischial spine, Origin (i): ischial tuberosity

Insertion of both: greater trochanter (medial side

Question 12

What is the origin and insertion of Quadratus femoris

Answer 12

O: ischial tuberosity
I: Intertrochanteric crest of the femur (Quadrate tubercle)

Question 13

What muscles externally rotate the thigh

Answer 13

Piriformis, Obturator internus, Superior/inferior gemelli, Quadratus femoris

Question 14

What is the nerve supply to the muscles that rotate the thigh

Answer 14

Piriformis: sacral plexus,
Obturator internus and Superior gemelli: Nerve to OI
Inferior gemelli and Quadratus femoris: Nerve to QF

All nerves are from the sacral plexus

Question 15

What are the hamstring muscles - what compartment is this part of

Answer 15

Biceps femoris, Semimembranosus and Semitendinosus. This is the posterior comp of thigh muscles

Question 16

What is the origin and insertion of Biceps femoris

Answer 16

O: Long head: ischial tuberosity, O short head: linea aspera
I: head of fibula

Question 17

What is the origin and insertion of Semitendinosus

Answer 17

O: Ischial tuberosity
I: Pes anserinus (sup. part of medial tibia)

Question 18

What is the origin and insertion of Semimembranosus

Answer 18

O: Ischial tuberosity
I: Medial condyle of the tibia

Question 19

What is the action of biceps femoris compared to the action of semimembranosus + semitendinosus

Answer 19

All of them extend the hip and flex the knee.
However Biceps femoris externally rotates the leg at knee whereas Semi tendinosus/ membranosus internally rotates the leg.

Question 20

What is the nerve supply to the hamstring muscles

Answer 20

All supplied by the tibial branch of the Sciatic nerve, except for the short head of biceps femoris which is supplied by Peroneal nerve

Question 21

What is the ‘half’ muscle included with the hamstring muscles. (O, I action and nerve)

Answer 21

The hamstring part of abductor magnus
O: ischial tuberosity and I: linea aspera, medial supracondylar ridge and adductor tubercle
This part is n: Sciatic nerve (tibial) and extends the thigh

Question 22

Describe the arterial supply to the gluteal region/ passageways through the greater and sciatic foramen

Answer 22

• Superior and inferior Gluteal arteries come from internal illiac arteries and leave the pelvis through the Greater Sciatic foramen, with Sup passing superior to Piriformis and Inf passing inferior. (this is the path of their corresponding veins+ nerves).
• Another artery also leaves the GSF called Internal pudendal artery but it hooks around the ischial spine to re enter the pelvis through the Lesser sciatic foramen.
• Around the head of the femur, the sup+ inf gluteal arteries anastomose with the med+ late circumflex arteries that came from profunda femoris (external illiac artery)

Question 23

Describe the path of the nerves in the gluteal region

Answer 23

-The sup and inf gluteal nerves follow the path of the arteries with sup between glut med+ minimus.
The sciatic nerve is v big as it is continuation of sacral plexus and it has its own artery from the inf gluteal artery. It exits under gluteas maximus, inferior to Piriformis and divides into Tibial and Peroneal components more distally in the thigh.

-Along its medial side is also the Posterior cutaneous nerve of the thigh

Question 24

What is Trendenlenburg gait - clinical features, cause

Answer 24

This is when a person stands on one leg and the pelvis tilts down toward the lifted leg. This is because the Gluteal medius muscle or its superior gluteal nerve supply is injured on the side of the leg on the floor so its not able to abduct and pull the pelvis on lifted leg side level.
As a result the person must lean over to the flat leg side to pull up the pelvis and clear the leg in the swing through phase of gait cycle.

Question 25

Where is the safe place to do intra-muscular injections in the gluteal region

Answer 25

Have to avoid the sciatic nerve so safest side is the upper lateral quadrant of the buttock

Question 26

What are the two bursitis in the gluteal region caused by

Answer 26

Ischial bursitis: From prolonged periods of friction (in cyclists)
Trochanteric bursitis: from Glut maximus fibres rubbing over the greater trochanter (in stair climbing)

Question 27

What is the extreme of hamstring injuries and what can cause it

Answer 27

Through kicking or running sports injuries can be tears in the muscle or even avulsion of the ischial tuberosity completely : pull off bone

Question 28

What is Piriformis syndrome caused by and symptoms

Answer 28

The sciatic nerve being compressed by the piriformis muscle causing pain, tingling and numbness in the buttocks and along the path of the sciatic nerve descending down the lower thigh and leg

Question 29

What are the myotomes for flexion of the hip vs extension of the hip

Answer 29

Flex: L2/(3)
Ext: L4/L5

Question 30

What are the myotomes for adduction of the hip vs abduction of the hip

Answer 30

Add: L4
Abd: L5/S1