Muscles of the Thigh

Question 1

Rectus Femoris

Answer 1

Origin: anterior inferior iliac spine and ilium superior to acetabulum

Insertion: base of patella and to tibial tuberosity via patellar ligament

Innervation: femoral nerve

Action: extends leg at knee joint and flexes thigh at hip joint

Blood Supply: profunda femoris and lateral circumflex femoral arteries

Region: anterior thigh
(quadriceps)

Question 2

Sartorius

Answer 2

Origin: anterior superior iliac spine and superior part of notch below it

Insertion: superior part of medial surface of tibia

Innervation: femoral nerve

Action: abducts, laterally rotates, and flexes thigh; flexes knee joint

Blood Supply: femoral artery

Region: anterior thigh

Question 3

Vastus Intermedius

Answer 3

Origin: anterior and lateral surfaces of body of femur

Insertion: base of patella and to tibial tuberosity via patellar ligament

Innervation: femoral nerve

Action: extends leg at knee joint

Blood Supply: lateral circumflex femoral and profundal femoris arteries

Region: anterior thigh
(quadriceps)

Question 4

Vastus Lateralis

Answer 4

Origin: greater trochanter, lateral lip of linea aspera of femur

Insertion: base of patella and to tibial tuberosity via patellar ligament

Innervation: femoral nerve

Action: extends leg at knee joint

Blood Supply: lateral circumflex femoral and profundal femoris arteries

Region: anterior thigh
(quadriceps)

Question 5

Vastus Medialis

Answer 5

Origin: intertrochanteric line, medial lip of linea aspera of femur

Insertion: base of patella and to tibial tuberosity via patellar ligament

Innervation: femoral nerve

Action: extends leg at knee joint

Blood Supply: femoral and profundal femoris arteries

Region: anterior thigh
(quadriceps)

Question 6

Iliacus

Answer 6

Origin: superior 2/3 of iliac fossa, iliac crest, ala of sacrum, anterior sacro-iliac ligaments

Insertion: lesser trochanter of femur and shaft inferior to it, to psoas major tendon

Innervation: femoral nerve

Action: flexes thigh at hips and stabilizes hip joint, acts with psoas major

Blood Supply: iliac branches of iliolumbar artery

Region: anterior thigh (iliopsoas)

Question 7

Psoas Major

Answer 7

Origin: transverse processes of lumbar vertebrae, sides of bodies of T12-L5 vertebrae, intervening intervertebral discs

Insertion: lesser trochanter of femur

Innervation: ventral rami of first lumbar nerve

Action: acting superiorly with iliacus, flexes hip; acting inferiorly, flexes vertebral column laterally; used to balance trunk in sitting position; acting inferiorly with iliacus, flexes trunk

Blood Supply: lumbar branches of iliolumbar artery

Region: anterior thigh (iliopsoas)

Question 8

Articularis Genus

Answer 8

Origin: distal femur on anterior surface

Insertion: suprapatellar bursa

Innervation: femoral nerve

Action: pulls suprapatellar bursa superiorly with extension of knee

Blood Supply: femoral artery

Region: anterior thigh

Question 9

Gracilis

Answer 9

Origin: body and inferior ramus of pubis

Insertion: superior part of medial surface of tibia

Innervation: obturator nerve

Action: adducts thigh, flexes and medially rotates leg

Blood Supply: profundal femoris artery, medial circumflex femoral artery

Region: medial thigh

Question 10

Obturator Externus

Answer 10

Origin: margins of obturator foramen, obturator membrane

Insertion: trochanteric fossa of femur

Innervation: obturator nerve

Action: laterally rotates thigh, stabilizes head of femur in acetabulum

Blood Supply: medial circumflex femoral artery, obturator artery

Region: medial thigh

Question 11

Pectineus

Answer 11

Origin: superior ramus of pubis

Insertion: pectineal line of femur

Innervation: femoral nerve and sometimes obturator nerve

Action: adducts and flexes thigh at hip

Blood Supply: medial circumflex femoral artery, obturator artery

Region: medial thigh

Question 12

Adductor Brevis

Answer 12

Origin: body and inferior pubic ramus

Insertion: pectineal line and proximal part of linea aspera of femur

Innervation: obturator nerve

Action: adducts thigh at hip, weak hip flexor

Blood Supply: profunda femoris, medial circumflex femoral, and obturator arteries

Region: medial thigh

Question 13

Adductor Longus

Answer 13

Origin: body of pubis inferior to pubic crest

Insertion: middle third of linea aspera of femur

Innervation: obturator nerve (anterior division)

Action: adducts thigh at hip

Blood Supply: profunda femoris and medial circumflex femoral arteries

Region: medial thigh

Question 14

Adductor Magnus

Answer 14

Origin: inferior pubic ramus, ramus of ischium

Insertion: gluteal tuberosity, linea aspera, medial supracondylar line; hamstring part: adductor tubercle of femur

Innervation: adductor part: obturator nerve; hamstring part: sciatic nerve (tibial division)

Action: adductor part: adducts and flexes thigh; hamstring part: extends thigh

Blood Supply: femoral, profunda femoris, and obturator arteries

Region: medial thigh

Question 15

Semimembranosus

Answer 15

Origin: ischial tuberosity

Insertion: posterior part of medial condyle of tibia

Innervation: sciatic nerve (tibial division)

Action: flexes leg, extends thigh

Blood Supply: perforating branch of profundal femoris and medial circumflex femoral arteries

Region: posterior thigh

Question 16

Semitendinosus

Answer 16

Origin: ischial tuberosity

Insertion: superior part of medial surface of tibia

Innervation: sciatic nerve (tibial division)

Action: flexes leg, extends thigh

Blood Supply: perforating branch of profundal femoris and medial circumflex femoral arteries

Region: posterior thigh

Question 17

Biceps Femoris

Answer 17

Origin: long head: ischial tuberosity; short head: linea aspera and lateral supracondylar line of femur

Insertion: lateral side of head of fibula

Innervation: long head: sciatic nerve (tibial nerve) (L5-S2); short head: sciatic nerve (common fibular division)

Action: flexes and laterally rotates leg, extends thigh at hip

Blood Supply: perforating branches of profunda femoris, inferior gluteal, and medial circumflex femoral arteries

Region: posterior thigh