LL1 - Muscles of the thigh region

Question 1

list the muscles of the anterior compartment of the thigh (7)

Answer 1

pectineus
iliopsoas
sartorius
rectus femoris
vastus lateralis
vastus intermedius
vastus medialis

Question 2

list the muscles of the medial compartment of the thigh (5)

Answer 2

adductor magnus
adductor longus
adductor brevis
gracilis
obturator externus

Question 3

list the muscles of the posterior compartment of the thigh (3)

Answer 3

semitendinous
semimembranous
biceps femoris

Question 4

What nerve primarily innervates the anterior compartment of the thigh?

Answer 4

femoral nerve

Question 5

What four muscles make up the quadriceps femoris group?

Answer 5

rectus femoris
vastus lateralis
vastus intermedius
vastus medialis

Question 6

What is the common insertion of the quadriceps femoris group?

Answer 6

on the patella via the quadriceps tendon - continues as the patellar ligament to the tibial tuberosity

Question 7

pectineus - origin? insertion? action? innervation?

Answer 7

origin: pectinate line (superior pubic ramus)

insertion: posterior proximal femur

action: hip adduction, flexion & medial rotation

innervation: femoral nerve

Question 8

what are the variations in pectineus nerve innervation?

Answer 8

80& of people - femoral nerve
20% of people - nerve to obturator internus

Question 9

sartorius - origin? insertion? action? innervation?

Answer 9

origin: ASIS

insertion: pec anserinus (tibia)

action: hip flexion, abduction & lateral rotation; knee flexion (‘crossing legs’ muscle)

innervation: femoral nerve

Question 10

which muscle of the anterior thigh compartment originates from the ASIS?

Answer 10

sartorius

Question 11

which muscle is commonly known as the ‘crossing legs’ muscle?

Answer 11

sartorius (knee flexion; hip flexion, abduction & lateral rotation)

Question 12

iliopsoas - origin? insertion? action? innervation?

Answer 12

origin:
- iliacus = iliac fossa
- psoas major = L1-5 IVDs & transverse processes; T12-L5 vertebral bodies

insertion: lesser trochanter

action: hip flexion

innervation: femoral nerve

Question 13

rectus femoris - origin? insertion? action? innervation?

Answer 13

origin: AIIS & superior acetabulum

insertion: patella (quadriceps tendon)

action: hip flexion, knee extension

innervation: femoral nerve

Question 14

vastus medialis - origin? insertion? action? innervation?

Answer 14

origin: medial lip of linea aspera

insertion: patella (quadriceps tendon)

action: knee extension

innervation: femoral nerve

Question 15

vastus intermedius - origin? insertion? action? innervation?

Answer 15

origin: anterolateral femur

insertion: patella (quadriceps tendon)

action: knee extension

innervation: femoral nerve

Question 16

vastus lateralis - origin? insertion? action? innervation?

Answer 16

origin: greater trochanter & linea aspera (lateral lip)

insertion: patella (quadriceps tendon)

action: knee extension

innervation: femoral nerve

Question 17

common action of the quadriceps muscles?

Answer 17

knee extension (only rectus femoris is involved in hip flexion)

Question 18

action of sartorius?

Answer 18

knee flexion
hip flexion, abduction & lateral rotation

Question 19

action of iliopsoas muscle?

Answer 19

hip flexion

Question 20

action of pectineus?

Answer 20

hip adduction, flexion & medial rotation

Question 21

What is the primary action of the vastus muscles?

Answer 21

knee extension

Question 22

Which anterior thigh muscle helps cross the legs by flexing, abducting, and laterally rotating the hip, and flexing the knee?

Answer 22

sartorius

Question 23

Which of the following muscles contributes to both hip flexion and knee extension?
A. Vastus medialis
B. Sartorius
C. Rectus femoris
D. Pectineus

Answer 23

C. Rectus femoris

Question 24

A patient cannot flex their hip but has normal knee extension. Which muscle is most likely affected?
A. Vastus intermedius
B. Rectus femoris
C. Iliopsoas
D. Vastus lateralis

Answer 24

C. Iliopsoas - primary hip flexor; vasti muscles (A, D) don’t flex the hip, and rectus femoris would also impair knee extension if affected

Question 25

Which of the following muscles is innervated by both the femoral nerve and, in some people, the obturator nerve? A. Iliopsoas B. Pectineus C. Sartorius D. Vastus medialis

Answer 25

B. Pectineus

Question 26

All of the following muscles insert into the quadriceps femoris tendon EXCEPT: A. Vastus lateralis B. Vastus medialis C. Rectus femoris D. Sartorius

Answer 26

D. Sartorius- inserts onto the medial tibia at the pes anserinus

Question 27

Which anterior compartment muscle contributes to lateral rotation of the hip? A. Vastus intermedius B. Pectineus C. Sartorius D. Iliacus

Answer 27

C. Sartorius

Question 28

gracilis - origin? insertion? action? innervation?

Answer 28

origin: pubic bone (body; inferior pubic ramus) insertion: pec anserinus (tibia) action: hip adduction, knee flexion innervation: obturator nerve

Question 29

obturator externus - origin? insertion? action? innervation?

Answer 29

origin: obturator membrane insertion: trochanteric fossa action: lateral rotation of hip innervation: obturator nerve

Question 30

adductor magnus (hamstring & adductor parts) - origin? insertion?

Answer 30

origin: - adductor part = ischiopubic ramus - hamstring part = ischial tuberosity insertion: - adductor part = linea aspera (femur) & medial supracondylar line - hamstring part = adductor tubercle (femur)

Question 31

adductor magnus (hamstring & adductor parts) - action?

Answer 31

hip adduction weak knee flexion hip extension (only hamstring part)

Question 32

adductor magnus (hamstring & adductor parts) - innervations?

Answer 32

adductor part = obturator nerve hamstring part = tibial part of sciatic nerve

Question 33

adductor longus - origin? insertion? action? innervation?

Answer 33

origin: pubis (body) insertion: linea aspera action: hip adduction & weak knee flexion innervation: obturator nerve

Question 34

adductor brevis - origin? insertion? action? innervation?

Answer 34

origin: pubis (body; inferior pubic ramus) insertion: linea aspera action: hip adduction & weak knee flexion innervation: obturator nerve

Question 35

What muscle of the medial compartment inserts into the pes anserinus?

Answer 35

gracilis

Question 36

Which muscle in the medial compartment has dual innervation and includes a "hamstring" portion? describe this dual innervation

Answer 36

adductor magnus - adductor part = obturator nerve - hamstring part = tibial part of sciatic nerve

Question 37

the adductor longus & brevis muscles have the same action - what is it?

Answer 37

weak knee flexion hip adduction

Question 38

What is the function of the adductor hiatus?

Answer 38

within adductor magnus; passageway for **femoral vein & artery** to transition into the popliteal fossa

Question 39

Which medial thigh muscle is involved in hip lateral rotation?

Answer 39

obturator externus

Question 40

general innervation to posterior compartment thigh muscles? what muscle the exception?

Answer 40

general innervation = tibial part of sciatic nerve exception = biceps femoris (short head - fibular part of sciatic nerve)

Question 41

semitendinosus - origin? insertion? action? innervation?

Answer 41

origin: ischial tuberosity insertion: pec anserinus action: hip extension, knee flexion innervation: tibial part of sciatic nerve

Question 42

semimembranosus - origin? insertion? action? innervation?

Answer 42

origin: ischial tuberosity insertion: fibular head action: hip extension, knee flexion innervation: tibial part of sciatic nerve

Question 43

biceps femoris (long & short heads) - origin? insertion? action? innervation?

Answer 43

origin: - long head = ischial tuberosity - short head = linea aspera (lateral lip) insertion: head of fibula action: hip extension, knee flexion innervation: - long head = tibial part of sciatic nerve - short head = fibular part of sciatic nerve

Question 44

A 25-year-old footballer presents with groin pain after overstretching his leg during a kick. On examination, pain is reproduced on resisted hip adduction. Which muscle is most likely injured? A) Adductor brevis B) Pectineus C) Gracilis D) Semimembranosus E) Sartorius

Answer 44

C) Gracilis - most superficial adductor, commonly strained in groin injuries

Question 45

Which of the following muscles both flexes the knee and adducts the hip, and is innervated by the obturator nerve? A) Semitendinosus B) Sartorius C) Gracilis D) Biceps femoris (short head) E) Adductor longus

Answer 45

C) Gracilis - crosses both hip and knee joints and inserts on the pes anserinus

Question 46

Which structure passes through the adductor hiatus? A) Obturator nerve B) Femoral artery and vein C) Great saphenous vein D) Sciatic nerve E) Popliteal artery and vein

Answer 46

B) Femoral artery and vein - become the popliteal vessels after passing through the hiatus

Question 47

Which of the following is a true statement regarding the adductor magnus muscle? A) It flexes the knee via its hamstring part B) Its adductor part is innervated by the tibial part of the sciatic nerve C) It inserts on both the linea aspera and adductor tubercle D) It laterally rotates the hip E) It’s innervated entirely by the obturator nerve

Answer 47

**C) It inserts on both the linea aspera and adductor tubercle** (adductor part = linea aspera; hamstring part = adductor tubercle)

Question 48

A patient has difficulty extending the hip and flexing the knee. You suspect an issue with the tibial part of the sciatic nerve. Which muscle is least likely to be affected? A) Semitendinosus B) Semimembranosus C) Biceps femoris (short head) D) Biceps femoris (long head) E) Adductor magnus (hamstring part)

Answer 48

**C) Biceps femoris (short head)** - innervated by the common fibular part

Question 49

common actions of the posterior thigh muscle compartment?

Answer 49

hip extension knee flexion

Question 50

common action of the three muscles that insert on the pec anserinus?

Answer 50

sartorius, gracilis, semitendinosus - knee flexion

Question 51

A patient presents with difficulty adducting their thigh. On exam, you note intact lateral rotation. Which nerve is most likely affected? A) Femoral nerve B) Obturator nerve C) Sciatic nerve D) Tibial nerve E) Common fibular nerve

Answer 51

**B) Obturator nerve** - innervates most hip adductors (medial compartment)

Question 52

Which muscle is innervated by the same nerve as the muscle immediately inferior to it in the deep gluteal region? A) Obturator externus B) Piriformis C) Gemellus superior D) Quadratus femoris E) Gluteus minimus

Answer 52

**C) Gemellus superior** - innervated by nerve to obturator internus, like the muscle just inferior (obturator internus)

Question 53

Which muscle inserts onto the trochanteric fossa and assists in lateral rotation of the hip? A) Gluteus minimus B) Sartorius C) Obturator externus D) Adductor brevis E) Biceps femoris

Answer 53

C) Obturator externus

Question 54

Which of the following correctly matches a muscle to its innervation and action? A) Semimembranosus – femoral nerve – knee extension B) Adductor longus – obturator nerve – hip adduction C) Sartorius – obturator nerve – hip adduction D) Vastus lateralis – tibial nerve – knee flexion E) Biceps femoris (short head) – tibial nerve – hip extension

Answer 54

B) Adductor longus – obturator nerve – hip adduction