Muscles - Anterior Thigh

Question 1

Give an overview of the anterior thigh compartment, including:

location
structure
function
muscles

Answer 1

Location:
These muscles are located in the anterior compartment of the thigh, which is bordered by the lateral and medial intermuscular septa, and the fascia lata. These muscles span between the pelvis, femur and tibia, and via the psoas major to the lumbar vertebrae.

Structure:
The muscles of the anterior compartment are primarily long muscles with a single origin and single insertion. The four muscles of the quadratus femoris group make up the bulk of the musculature in the anterior compartment, and have a common insertion into the tibial tuberosity via the patella tendon and quadriceps tendon. The pectineus is the shortest muscle in the group, spanning between the pelvis and femur, and the iliopsoas is a combination of the iliacus and psoas major muscles.

Function:
Collectively these muscles have 2 major functions:

hip flexion
knee extension

in addition the pectineus is a hip adductor and internal rotator of the thigh, iliopsoas is a flexor and side bender of the trunk, and sartorius provides weak hip abduction, knee flexion and external rotation of the thigh.

Muscles:
There are 7 muscles in the anterior thigh compartment:

Iliopsoas
Rectus femoris
vastus medialis
vastus intermedialis
vastus lateralis
pectineus
sartorius

Question 2

Give an overview of the muscles of the anterior compartment:

Answer 2

Rectus femoris:
PA: AIIS and ilium superior to acetabulum
DA: Tibial tuberosity via quadriceps tendon and patella tendon
NS: Femoral
A: Hip flexion and knee extension

Vastus lateralis:
PA: greater trochanter of femur, lateral lip of linea aspera
DA: tibial tuberosity via quadriceps tendon and patella tendon, and lateral retinaculum of knee joint
NS: femoral
A: knee extension

Vastus intermedius:
PA: femoral shaft (anterior and lateral surfaces)
DA: tibial tuberosity via quadriceps tendon and patellar tendon
NS: femoral
A: knee extension

Vastus medialis:
PA: intertrochanteric line of the femur, medial lip of linea aspera
DA: tibial tuberosity via quadriceps tendon and patellar tendon, medial retinaculum of knee joint
NS: femoral
A: knee extension

Pectineus:
PA: pectineal line of superior pubic ramus
DA: pectineal line of femur
NS: femoral
A: adducts, flexes, and internally rotates thigh

Sartorius:
PA: ASIS and superior part of notch inferior to it
DA: superior medial tibia (pes anserine)
NS: femoral
A: flexion, abduction and external roation of the hip, and slight flexion of the knee

Iliopsoas:
PA: psoas major - sides of T12 - L5, TPs and IVDs of L1-5; iliacus: iliac fossa on internal surface of ilium
DA: lesser trochanter of femur
NS: femoral, anterior rami nerves L1-3
A: hip flexion, trunk flexion, sidebending of trunk

Question 3

Which nerve innervates the anterior compartment of the thigh?

Answer 3

Femoral

Question 4

Give an overview of the quadratus femoris muscles:

Answer 4

Rectus femoris:
PA: AIIS and ilium superior to acetabulum
DA: Tibial tuberosity via quadriceps tendon and patella tendon
NS: Femoral
A: Hip flexion and knee extension

Vastus lateralis:
PA: greater trochanter of femur, lateral lip of linea aspera
DA: tibial tuberosity via quadriceps tendon and patella tendon, and lateral retinaculum of knee joint
NS: femoral
A: knee extension

Vastus intermedius:
PA: femoral shaft (anterior and lateral surfaces)
DA: tibial tuberosity via quadriceps tendon and patellar tendon
NS: femoral
A: knee extension

Vastus medialis:
PA: intertrochanteric line of the femur, medial lip of linea aspera
DA: tibial tuberosity via quadriceps tendon and patellar tendon, medial retinaculum of knee joint
NS: femoral
A: knee extension

Question 5

Give an overview of the iliopsoas muscles:

Answer 5

Iliopsoas:
PA: psoas major - sides of T12 - L5, TPs and IVDs of L1-5; iliacus: iliac fossa on internal surface of ilium
DA: lesser trochanter of femur
NS: femoral, anterior rami nerves L1-3
A: hip flexion, trunk flexion, sidebending of trunk

Question 6

Give an overview of the sartorius muscle:

Answer 6

Sartorius:
PA: ASIS and superior part of notch inferior to it
DA: superior medial tibia (pes anserine)
NS: femoral
A: flexion, abduction and external roation of the hip, and slight flexion of the knee

Question 7

Give an overview of the pectineus muscle:

Answer 7

Pectineus:
PA: pectineal line of superior pubic ramus
DA: pectineal line of femur
NS: femoral
A: adducts, flexes, and internally rotates thigh