Musculoskeletal: Anatomy - Gluteal and posterior thigh regions

Question 1

Describe the gluteal ligaments

Answer 1

Posterior sacroiliac ligament (continuous inferiorly with sacrotuberous ligament)
Posterior sacrococcygeal ligaments
Sacrotuberous ligament
Sacrospinous ligament

Question 2

How are the greater and lesser sciatic foramina formed and what is the significance of each?

Answer 2

Sacrotuberous ligament extends across sciatic notch, converting it into a foramen that is subdivided by the sacrospinous ligament and ischial spine into the greater and lesser sciatic foramen
Greater sciatic: structures travelling to and from pelvis
Lesser sciatic: structures travelling to and from perineum

Question 3

Which muscle fills most of the greater sciatic foramen?

Answer 3

Piriformis

Question 4

Four muscles of the superficial layer of the gluteal region

Answer 4

Gluteus maximus
Gluteus medius
Gluteus minimus
Tensor fascia latae

Question 5

Five muscles of the deep layer of the gluteal region

Answer 5

Obturator internus
Piriformis
Superior gemellus
Inferior gemellus
Quadratus femoris

Question 6

Describe the proximal attachment and actions of the superficial gluteal muscles generally

Answer 6

Proximal attachments to posterolateral (external) surface and margins of ala of ilium
Mainly extend, abduct and medially rotate the hip

Question 7

Describe the distal attachment and actions of the deep gluteal muscles generally

Answer 7

Distal attachments to intertrochanteric crest
Lateral rotators and stabilise femoral head in acetabulum

Question 8

Six lateral rotators of the thigh

Answer 8

Obturator externus (anterior compartment)
Obturator internus
Piriformis
Superior gemellus
Inferior gemellus
Quadratus femoris

Question 9

Which three muscles form the triceps coxae?

Answer 9

Superior and inferior gemelli, and obturator internus

Question 10

Proximal and distal attachments, innervation, and main actions of gluteus maximus

Answer 10

Proximal: ilium posterior to posterior gluteal line, dorsal sacrum and coccyx, sacrotuberous ligament
Distal: gluteal tuberosity, iliotibial tract
Innervation: inferior gluteal n. (L5, S1-2)
Actions: hip extension, assists in lateral rotation

Question 11

Proximal and distal attachments, innervation, and main actions of gluteus medius

Answer 11

Proximal: ilium between anterior and posterior gluteal lines
Distal: lateral greater trochanter
Innervation: superior gluteal n. (L5, S1)
Actions: hip abduction and medial rotation

Question 12

Proximal and distal attachments, innervation, and main actions of gluteus minimus

Answer 12

Proximal: ilium between anterior and inferior gluteal lines
Distal: anterior greater trochanter
Innervation: superior gluteal n. (L5, S1)
Actions: hip abduction and medial rotation

Question 13

Proximal and distal attachments, innervation, and main actions of obturator internus

Answer 13

Proximal: pelvic surface of obturator membrane and surrounding bones
Distal: medial greater trochanter (trochanteric fossa)
Innervation: nerve to obturator internus (L5, S1)
Actions: abduction of flexed thigh and lateral rotation of extended thigh, steadies femoral head in acetabulum

Question 14

Proximal and distal attachments, innervation, and main actions of superior gemellus

Answer 14

Proximal: ischial spine
Distal: medial greater trochanter (trochanteric fossa)
Innervation: nerve to obturator internus (L5, S1)
Actions: abduction of flexed thigh and lateral rotation of extended thigh, steadies femoral head in acetabulum

Question 15

Proximal and distal attachments, innervation, and main actions of inferior gemellus

Answer 15

Proximal: ischial tuberosity
Distal: medial greater trochanter (trochanteric fossa)
Innervation: nerve to quadratus femoris (L5, S1)
Actions: abduction of flexed thigh and lateral rotation of extended thigh, steadies femoral head in acetabulum

Question 16

Proximal and distal attachments, innervation, and main actions of piriformis

Answer 16

Proximal: anterior sacrum and sacrotuberous ligament
Distal: superior greater trochanter
Innervation: anterior rami S1-2
Actions: abduction of flexed thigh and lateral rotation of extended thigh, steadies femoral head in acetabulum

Question 17

Proximal and distal attachments, innervation, and main actions of quadratus femoris

Answer 17

Proximal: lateral ischial tuberosity
Distal: quadratus tubercle on intertrochanteric crest
Innervation: nerve to quadratus femoris (L5, S1)
Actions: lateral rotation of thigh, steadies femoral head in acetabulum

Question 18

Proximal and distal attachments, innervation, and main actions of tensor fascia latae

Answer 18

Proximal: ASIS, anterior iliac crest
Distal: iliotibial tract to lateral tibial cond0yle
Innervation: superior gluteal n. (L5, S1)
Actions: hip abduction and medial rotation

Question 19

Three bursae associated with gluteus maximus

Answer 19

Trochanteric bursa: separates from greater trochanter (largest, present at birth)
Ischial bursa: separates from ischial tuberosity
Gluteofemoral bursa: separates iliotibial tract from vastus lateralis

Question 20

Describe the role of piriformis as a landmark in the gluteal region

Answer 20

Superior gluteal vessels and nerves emerge superior to it
Inferior gluteal vessels and nerves emerge inferior to it

Question 21

Four posterior thigh muscles. Which of these are the hamstring muscles?

Answer 21

Semitendinosus*
Semimembranosus*
Biceps femoris: long head*
Biceps femoris: short head

• Hamstring muscles

Question 22

What are the common features of the hamstring muscles?

Answer 22

Proximal attachment to ischial tuberosity
Distal attachment to bones of leg
Innervation by tibial division of sciatic nerve

Question 23

Proximal and distal attachments, innervation, and main actions of semitendinosus

Answer 23

Proximal: ischial tuberosity
Distal: superomedial tibia via pes anserinus
Innervation: tibial division of sciatic n. (L5, S1-2)
Action: hip extension, knee flexion (and medial rotation of leg when knee is flexed)

Question 24

Proximal and distal attachments, innervation, and main actions of semimembranosus

Answer 24

Proximal: ischial tuberosity
Distal: posterior part of medial tibial condyle, reflected attachment forms oblique popliteal ligament (to lateral femoral condyle)
Innervation: tibial division of sciatic n. (L5, S1-2)
Action: hip extension, knee flexion (and medial rotation of leg when knee is flexed)

Question 25

Proximal and distal attachments, innervation, and main actions of biceps femoris

Answer 25

Proximal: long head to ischial tuberosity, short head to linea aspera and lateral supracondylar line of femur
Distal: lateral head of fibula (tendon split by lateral collateral ligament)
Innervation: long head by tibial division of sciatic n. (L5, S1-2), short head by common fibular division of sciatic n. (L5, S1-2)
Action: hip extension, knee flexion (and lateral rotation of leg when knee is flexed)

Question 26

The tendon of which muscle is reflected to form the oblique popliteal ligament?

Answer 26

Semimembranosus

Question 27

Three superficial gluteal nerves

Answer 27

Superior clunial
Middle clunial
Inferior clunial

Question 28

Seven deep gluteal nerves

Answer 28

Sciatic nerve
Posterior cutaneous nerve of thigh
Superior gluteal
Inferior gluteal
Nerve to quadratus femoris
Pudendal
Nerve to obturator internus

Question 29

Origin, course and distribution of superior clunial nerve

Answer 29

Origin: lateral cutaneous branches of posterior rami L1-3
Course: inferolateral across iliac crest
Distribution: skin of superior buttocks to tubercle of iliac crest

Question 30

Origin, course and distribution of middle clunial nerve

Answer 30

Origin: lateral cutaneous branches of posterior rami S1-3
Course: exits posterior sacral foramina laterally
Distribution: skin over sacrum and adjacent buttocks

Question 31

Origin, course and distribution of inferior clunial nerve

Answer 31

Origin: posterior cutaneous nerve of thigh
Course: ascends superiorly from inferior border of gluteus maximus
Distribution: inferior half of buttocks to greater trochanter

Question 32

Origin, course and distribution of sciatic nerve

Answer 32

Origin: sacral plexus (L4-S3)
Course: enters gluteal region via greater sciatic foramen inferior to piriformis and deep to gluteus maximus, descends in posterior thigh deep to biceps femoris, bifurcates into tibial and common fibular nerves at apex of popliteal fossa
Distribution: all muscles of posterior thigh compartment (tibial division to all except short head of biceps femoris which is supplied by common fibular)

Question 33

Origin, course and distribution of superior gluteal nerve

Answer 33

Origin: sacral plexus (L4-S1)
Course: enters gluteal region via greater sciatic foramen superior to piriformis, courses laterally between gluteus medius and minimus to tensor fascia latae
Distribution: gluteus medius, gluteus minimus, tensor fascia latae

Question 34

Origin, course and distribution of inferior gluteal nerve

Answer 34

Origin: sacral plexus (L5-S2)
Course: enters gluteal region via greater sciatic foramen inferior to piriformis and deep to gluteus maximum
Distribution: gluteus maximus

Question 35

Origin, course and distribution of nerve to obturator internus

Answer 35

Origin: sacral plexus (L5-S2)
Course: exits pelvis via greater sciatic foramen inferior to piriformis, descends posterior to sacrospinous ligament, enters perineum through lesser sciatic foramen
Distribution: superior gemellus and obturator internus

Question 36

Origin, course and distribution of nerve to quadratus femoris

Answer 36

Origin: sacral plexus (L4-S1)
Course: enters gluteal region via greater sciatic foramen inferior to piriformis, deep (anterior) to sciatic nerve
Distribution: hip joint, inferior gemellus, and quadratus femoris

Question 37

Origin, course and distribution of posterior cutaneous nerve of thigh

Answer 37

Origin: sacral plexus (S1-3)
Course: enters gluteal region via greater sciatic foramen inferior to piriformis and deep to gluteus maximus, descends in posterior thigh deep to fascia lata
Distribution: skin of inferior half of buttocks (via inferior clunial nerves), skin over posterior thigh and popliteal fossa, skin of lateral perineum and upper medial thigh (via perineal branch)

Question 38

Origin, course and distribution of pudendal nerve

Answer 38

Origin: sacral plexus (S2-4)
Course: exits pelvis via greater sciatic foramen inferior to piriformis, descends posterior to sacrospinous ligament, enters perineum through lesser sciatic foramen
Distribution: principal nerve to perineum

Question 39

Four arteries of gluteal and posterior thigh region

Answer 39

Superior gluteal
Inferior gluteal
Internal pudendal
Perforating

Question 40

Course and distribution of superior gluteal artery

Answer 40

Course: enters gluteal region through greater sciatic foramen superior to piriformis, divides into superficial and deep branches, anastamoses with inferior gluteal and medial circumflex femoral arteries
Distribution: superficial branch to gluteus maximus, deep branch to gluteus medius and minimus, and tensor fascia latae

Question 41

Course and distribution of inferior gluteal artery

Answer 41

Course: enters gluteal region through greater sciatic foramen inferior to piriformis, descends medial to sciatic nerve, anastamoses with superior gluteal artery and as part of cruciate anastamosis
Distribution: supplies gluteus maximus, obturator internus, quadratus femoris, and superior part of hamstrings

Question 42

Course and distribution of perforating arteries

Answer 42

Course: enters posterior compartment by perforating aponeurotic attachment of adductor magnus and medial intermuscular septum, provides muscular branches to hamstrings then continues to anterior compartment of thigh by piercing lateral intermuscular septum
Distribution: majority of hamstrings, vastus lateralis

Question 43

Course and distribution of internal pudendal artery

Answer 43

Course: enters gluteal region via greater sciatic foramen, descends posterior to ischial spine, enters perineum through lesser sciatic foramen
Distribution: external genitalia and perineal muscles

Question 44

Contents of the greater sciatic foramen (supra- and infra-piriform)

Answer 44

Suprapiriform foramen:
Superior gluteal artery and vein
Superior gluteal nerve

Infrapiriform foramen:
NIP SNIP
Nerve to obturator internus
Inferior gluteal artery, vein and nerve
Pudendal nerve

Sciatic nerve
Nerve to quadratus femoris
Internal pudendal artery and vein
Posterior cutaneous nerve of thigh

Question 45

Contents of the lesser sciatic foramen

Answer 45

PINTO:
Pudendal nerve
Internal pudendal artery and vein
Nerve to obturator internus
Tendon Of obturator internus

Question 46

Arteries involved in cruciate anastamosis of thigh

Answer 46

1. First perforating artery of profunda femoris
2. Medial circumflex femoral artery
3. Lateral circumflex femoral artery
4. Inferior gluteal artery

Question 47

From which major artery do the arteries of the gluteal and posterior thigh regions originate?

Answer 47

Internal iliac

Question 48

From which four arteries does the posterior compartment of the thigh receive its blood supply?

Answer 48

1. Inferior gluteal
2. Medial circumflex femoral
3. Perforating
4. Popliteal