Root

Peroneal Deep

Peroneal

Common

 

Sciatic

 

LS plexus

 

L5 Root

Weak

 

 

 

 

 

 

DF

L4

X

X

X

X

X

Eversion*

L5/S1

 

X

X

X

X

Inversion

L4/L5 *

 

 

X

X

X

KF

S1

 

 

X

X

X

Glutei*

L4-S1

 

 

 

X

X

 

 

 

 

 

 

 

Sensory:

 

 

 

 

 

 

Web space

 

X

X

X

X

X

Dorsum foot

 

 

X

X

X

X

Lat. Calf

 

 

X

X

X

X

Lat Knee

 

 

 

X

X

X

Sole

 

 

 

X

X

X

Post. thigh

 

 

 

 

X

X

Other

 

 

 

 

 

 

Tinelís sign

 

X

X

 

 

 

Back Pain

 

 

 

 

 

X

Hip/thigh pain

 

 

 

X

X

 

SLR +

 

 

 

 

 

X

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Foot Drop:

 

 

Differentiating LS plexus from L5 is difficult to do clinically.

 

Sciatic nerve L4-S1

Sciatic: common peroneal and tibial nerve just proximal to the fibular head

The short head of the biceps femoris is the only muscle innervated by the peroneal division of the sciatic nerve that arises proximal to the fibular head. All the other hamstrings (semimembranosus, semitendinosus, BF long head) are from the tibial branch.

 

Common peroneal: deep and superficial branches and lateral cutaneous n. of knee.

Deep peroneal nerve: (proximal to distal branches): TA, EDL, EHL, peroneus tertius; EDB and dorsal digital cutaneous nerve

Superficial peroneal: peroneus longus, peroneus brevis and medial and intermedial dorsal cutaneous branch

 

 

Tibial nerve: gastrocs, soleus; Tib posterior; FDL; medial and lateral plantar nerve

 

Famous Question:

 

Differentiate a L5 Root from (common) peroneal nerve palsy?

  1. weakness of hip abductors,: L5
  2. Weakness of inversion: L5
  3. weakness of EHL (L5-S1) out of proportion to TA: L5
  4. lateral knee sensory: L5
  5. sensory loss over sole (plantar); lateral foot (sural); or medial calf (saphenous)
  6. posterior thigh sensory loss: L5
  7. weakness of hip extension or IR
  8. any asymmetry of ankle jerk (L5)

 

Thanks to Dr. Verity J. John for this page.