Sat27November0556PM 37

A patient has a lumbar epidural for foot surgery. Following the procedure the patient has residual weakness of hip flexion but normal knee flexion/extension.

Which nerve roots are most likely to be implicated?

(Please select 1 option)

L2/3/4

L3/4

L1/2/3 Correct

L5/S1

L4/5

Explanation

The most important muscles that produce flexion at the hip are:

Iliacus, and

Psoas major.

Collectively they are termed the iliopsoas muscle. The origin of the iliacus muscle is the ilium and the origin of the psoas major muscle is the lumbar vertebrae and sacrum. They insert into the lesser trochanter of the femur and extend distally. The action of these muscles is to produce flexion and external rotation of the hip. The nerve supply is by branches of the lumbar plexus (L1, 2, 3) femoral nerve (L2, 3, 4) and short direct muscular branches (T12, L1, L2, L3 and L4).

The following muscles are two-joint muscles, also acting at the knee and have less influence on hip flexion:

Sartorius

Rectus femoris

Tensor fasciae latae, and

Pectineus

Sartorius and rectus femoris are involved in extension of the knee. The nerve supply is also by branches of the femoral nerve.

The following list of myotomes are associated with key movement patters of the lower limb:

L1/L2 - Hip flexion

L2/L3/L4 - Hip adduction, quadriceps (knee extension)

L4/L5 - Hip abduction

L5 - Great toe dorsiflexion.

The fact that knee extension is unaffected implies that L2, L3 and L4 are still intact.

Answer Statistics

1

17%

2

8%

3

66%

4

7%

5

3%

Times answered: 246