1、NERVE INJURIES OF THE LOWER EXTREMITY,STACY RUDNICKI, MD ASSOCIATE PROFESSOR OF NEUROLOGY,Dermatomes of the Leg,Root Innervation of the Leg,Hip Flexion L 1, 2, 3 Knee Extension L 2, 3, 4 Foot Dorsiflexion L 4,5 Foot Plantar Flexion S1, 2 Knee Flexion L5, S1, S2 Hip Extension L5, S1, S2,Clinical Prin
2、ciples,Detecting subtle weakness Get up from squat Quadriceps/Gluteus maximus Stand on tip toes Gastrocnemius/Soleus Stand on heels Tibialis Anterior,Reflexes,Knee Jerks - evaluates Quadriceps muscle Femoral Nerve Primarily L4 nerve root (also L2, L3) Ankle Jerk - evaluates Gastrocnemius muscle Tibi
3、al Nerve Primarily the S1 nerve root (also S2),CASE 1,History,20 yo college student involved in an MVA She suffers multiple pelvic fractures She complains of weakness and numbness of the right leg She is aware that her right foot is “dropped” relative to the left, and that she must lift her foot up
4、higher to clear her toes,Exam,She has weakness of: Foot dorsiflexion Foot eversion Toe extension Strength is normal in: Foot plantar flexion Foot inversion Toe flexion There is just a hint of weakness in knee flexion,SENSORY LOSS,Localization,Finding Muscle Nerve Root Involved Ft Dorsiflex TIB ANT F
5、IB L4,5 Grt toe ext EHL FIB L5 Toe ext EDL, EDB FIB L4,5 Foot eversion FIB L, B FIB L4,5 Knee flex Mult TIB/Fib L5S1S2 Spared Foot plant flex GASTROC, TIB S1,2SOLEUS Toe flex FDL/FDB TIB L5,S1 Foot inv POST TIB TIB L4,5,Localization,Finding Muscle Nerve Root Involved Ft Dorsiflex TIB ANT FIB L4,5 Gr
6、t toe ext EHL FIB L5 Toe ext EDL, EDB FIB L4,5 Foot eversion FIB L, B FIB L4,5 Knee flex Mult TIB/Fib L5S1S2 Spared Foot plant flex GASTROC, TIB S1,2SOLEUS Toe flex FDL/FDB TIB L5,S1 Foot inv POST TIB TIB L4,5,Common Fibular (Peroneal) Nerve,Common Fib Short head BF Deep FibSuperficial Fib Fib Longu
7、s Tib AntFib Brevis EHLFib TertiusEDB,Differentiating b/w L5 radiculopathy and Fibular Neuropathy,Motor exam Foot inversion - Posterior tibial muscle Spared - Fibular neuropathy Involved - L5 Sensory exam,Sensory loss in deep fibular, common fibular, and L5 disease,Final Diagnosis,Sciatic neuropathy
8、 with selective involvement of the fibular (peroneal) nerve fibers at the level of the pelvisPearl: The fibular component of the sciatic nerve is more susceptible to traumatic injury than the tibial component - “false localization”,CASE 2,History,The patient is a 45 yo man who complains of burning p
9、ain in his right lateral thigh He is otherwise healthy, though over the last 2 years, he has gained 30 pounds because he cant find time to exercise,Exam,He has normal strength in all muscles of his leg Reflexes are normal,SENSORY LOSS,Localization,Finding Muscle Nerve RootSens loss - - Lat fem L2cut
10、,Final diagnosis,Lateral femoral cutaneous neuropathy (AKA: Meralgia Parasthetica)Pearls: This nerve does not come from the femoral nerve but rather the L-S plexus There is no motor component It is trapped as it crosses the pelvic brim, and wt loss or gain can precipitate sxs,CASE 3,History,A 27 yo
11、man is shot at multiple sites in the thigh, popliteal fossa, and foot He complains of burning pain in the foot and weakness of the foot,Exam,He has weakness of: Foot plantar flexion Foot inversion Toe flexion Strength is normal in: Knee flexion Foot dorsiflexion Foot eversion His foot has a “cocked
12、up” appearance and is everted compared to the other foot,SENSORY LOSS,Exam,Finding Muscle PN Root Involved Ft plant flex GASTROC TIB S1, S2 Toe flex FDL, FDB TIB L5, S1, S2 Foot inv POST TIB TIB L4, L5 Sens loss - MP+LP (tib) S1 Spared Ft dorsiflex TIB ANT FIB (per) L4,5 Foot ever FIB L, B, T FIB (P
13、er) L5S1 Knee flex HS SHBF SCIATIC L5, S1, S2(Tib and Fib),Exam,Finding Muscle PN Root Involved Ft plant flex GASTROC TIB S1, S2 Toe flex FDL, FDB TIB L5, S1, S2 Foot inv POST TIB TIB L4, L5 Sens loss - MP+LP (tib) S1 Spared Ft dorsiflex TIB ANT FIB (per) L4,5 Foot ever FIB L, B, T FIB (Per) L5S1 Kn
14、ee flex HS SHBF SCIATIC L5, S1, S2(Tib and Fib),Sciatic Nerve in Thigh/ Tibial Nerve in Leg,Sciatic NerveSemitendonous Biceps Long HdSemi Membranous Biceps Short HDAdd Magnus Tibial Nerve Common Fib NvGastroc, Med PopliteusSoleus Gastroc, latTibialis Post FDL FHL Med Plantar Lateral PlantarAH, FDB,
15、FHB ADM, FDM, AH, Int,Final Diagnosis,Tibial neuropathy at the popliteal fossaPearl: The appearance of the foot at rest may help distinguish b/w a fibular and a tibial neuropathy - unopposed action of spared muscles,CASE 4,History,An 81 yo man with diabetes mellitus complains of onset of deep aching
16、 pain in his right thigh that evolved over a few weeks He is having trouble walking because his knee “gives out” He complains of numbness on the top of his leg,Exam,He has weakness of: Hip flexion Knee extension He has normal strength of: Hip adduction Hip abduction Foot dorsiflexion/plantar flexion
17、 His knee jerk is absent, his ankle jerk is preserved,SENSORY LOSS,Localization,Finding Muscle PN Root Hip flex IP/Rec Fem Fem L1,2,3 Knee Ext Quads Fem L2,3,4 Sens Loss - Fem L2-4 Hip Add ADD L, B, M Obt L2,3,4Add M Sciatic L5, S1 Hip Abd Gl Med/Min Sup Glut L5, S1, S2 Foot DF Tib ant Fib (Per) L4,
18、5 Foot PF Gastroc/sol Tibial S1,S2,Localization,Finding Muscle PN Root Hip flex IP/Rec Fem Fem L1,2,3 Knee Ext Quads Fem L2,3,4 Sens Loss - Fem L2-4 Hip Add ADD L, B, M Obt L2,3,4Add M Sciatic L5, S1 Hip Abd Gl Med/Min Sup Glut L5, S1, S2 Foot DF Tib ant Fib (Per) L4,5 Foot PF Gastroc/sol Tibial S1,
19、S2,Femoral nerve,IliopsoasSartorius PectiniusRectus FemorisVastus LatVastus interVastus Med,Distinguishing b/w a femoral neuropathy and L2 or L3 radiculopathy,Motor exam Thigh adduction (obturator nerve) Spared with a femoral neuropathy Involved with L2,3 disease Sensory exam Loss extends below the
20、knee (medial foreleg) with femoral neuropathy Saphenous nerve,Final Diagnosis,Femoral Neuropathy Related to Diabetes MellitusPearl: The femoral nerve is also liable to injury during procedures involving the femoral artery or vein,CASE 5,History,A 27 yo body builder complains of a 4 week history of l
21、ow back and leg pain Pain travels down the back of the leg and into the sole of the He is unaware of weakness and he continues to lift weights,Exam,His routine strength exam is normal He can stand on his heels with ease He can stand on his tiptoes on the right but not on the left His left ankle jerk
22、 is absent, right is normal Sensory exam Decreased sensation of the sole of the foot, lateral distal leg, and lateral dorsum of the foot,Localization,Finding Muscle PN Root Stand toes GASTROC/SOL TIB S1,2 Abs AJ GASTROC/SOL TIB S1,2 Sens - MP, LP, SU S1Stand Heels TIB ANT FIB L4,5 Foot Inv POST TIB
23、TIB L4,5,Localization,Finding Muscle PN Root Stand toes GASTROC/SOL TIB S1,2 Abs AJ GASTROC/SOL TIB S1,2 Sens - MP, LP, SU S1Stand Heels TIB ANT FIB L4,5 Foot Inv POST TIB TIB L4,5,Differentiating b/w radicular disease and focal tibial neuropathy,Back pain that radiates into the leg highly suggestiv
24、e of radicular process Tibial nerve also innervates the foot inverters yet these are spared Spontaneous (ie not associated with penentrating trauma) tibial neuropathies would be very unusual,Final diagnosis,S1 radiculopathy related to a herniated disc Pearl: The term sciatica is a misnomer - it is r
25、eally a root based process, not one of the sciatic nerve Particularly in large muscles, weakness may be subtle and hence easily missed,Final Comments,Overall, nerves in the leg are less liable to chronic compression/entrapment compared to those in the arms Most common entrapment in the leg is a fibular (peroneal) palsy at the fibular head May get the common, superficial, or fibular (peroneal) nerve Traumatic nerve injuries related to penetrating injury / bony trauma (hip / pelvic fxs) are seen,
