Ch 5 - EDX: Lower Limb Mononeuropathy

Question 1

Describe the course of the lateral femoral cutaneous nerve

Answer 1

Pass over the iliacus

toward the anterior iliac spine, tunnels under the inguinal ligament to provide sensation for the lateral thigh

Question 2

What is meralgia parasthetica?

Answer 2

Lateral cutaneous neuropathy

Question 3

What are etiologies of lateral femoral cutaneous neuropathy?

Answer 3

Protuberant abdomen
Pregnancy
Tight clothing
DM
Tumor
Infection
Rapid weight loss

Question 4

What is the clinical presentation of lateral femoral cutaneous neuropathy?

Answer 4

Sensory complaints in lateral thigh exacerbated with hip extension or hyperflexion, prolonged sitting/squatting, or
driving

Question 5

What is the origin of the femoral nerve?

Answer 5

L2, L3, L4 roots into posterior division of lumbar plexus

Question 6

Describe the course of the femoral nerve.

Answer 6

Runs through psoas, under the inguinal ligament lateral to femoral artery and through femoral triangle

Question 7

What does the femoral nerve innervate?

Answer 7

Iliacus
Pectineus (1/2)
Sartorius
Quadriceps muscles
Saphenous nerve

Question 8

What are etiologies of femoral neuropathy?

Answer 8

Compressive lesion in the pelvis from trauma, fracture, retroperitoneal hematoma, tumor, inguinal ligament compression, or cardiac catheterization

Question 9

What is the clinical presentation of femoral neuropathy?

Answer 9

Weakness of KE
Knee instability
Dec sensation over the anterior thigh and medial leg
HF weakness if lesion proximal to inguinal ligament

Question 10

What is the MCC of femoral neuropathy?

Answer 10

Diabetic amyotrophy

Question 11

How is the femoral nerve injured in Diabetic Amyotrophy?

Answer 11

ABN of vaso-nevorum d/t DM

Amyotrophy noted after marked weight loss

Question 12

What is the clinical presentation of Diabetic Amyotrophy?

Answer 12

Asymmetric thigh pain
KE weakness
Femoral innervated muscle atrophy
Loss of patellar reflex

Question 13

What does the Saphenous nerve innervate?

Answer 13

Sensation to the medial aspect of the leg, the medial malleolus, and medial arch of the foot

Question 14

What is the largest and longest branch of the femoral nerve?

Answer 14

Saphenous nerve

Question 15

How can the Saphenous nerve be injured?

Answer 15

Entrapped in the subsartorial (Hunter’s) canal or b/w sartorius and gracilis
Knee arthroscopy
Vascular surgery

Question 16

What is the clinical presentation of Saphenous neuropathy?

Answer 16

Pure sensory syndrome
Medial knee pain (infrapatellar branch)
ABN sensation along medial leg and foot

Question 17

What is the origin of the obturator nerve?

Answer 17

L2, L3, L4 roots continue as anterior portion of lumbar plexus

Question 18

What is the course of the obturator nerve?

Answer 18

Anterior to SI joint through psoas major muscle through obturator foramen

Question 19

What does the obturator nerve innervate?

Answer 19

Pectineus (1/2)
Adductor brevis
Adductor longus
Adductor magnus
Obturator externus
Gracilis
Cutaneous branch

Question 20

What are etiologies of obturator neuropathy?

Answer 20

Pelvic fx or hernia w/in obturator foramen

Question 21

What is the clinical presentation of obturator neuropathy?

Answer 21

Hip adduction/IR weakness
Circumduction gait
Dec sensation along medial thigh

Question 22

What is the origin of the sciatic nerve?

Answer 22

L4, L5, S1, S2 and S3 roots continue as posterior division of lumbar plexus

Question 23

Describe the course of the sciatic nerve.

Answer 23

Exits pelvis through greater sciatic foramen b/w lesser trochanter and ischial tuberosity thru posterior leg to popliteal fossa

Question 24

What does the sciatic nerve splint into at the popliteal fossa?

Answer 24

Tibial (medial) nerve

Peroneal/Fibular (lateral) nerve

Question 25

What does the peroneal division of sciatic nerve innervate?

Answer 25

Short head of biceps femoris

Question 26

What does the tibial division of sciatic nerve innervate?

Answer 26

Long head of the biceps femoris Semitendinosus Semimembranosus Adductor magnus (also obturator nerve)

Question 27

What are etiologies of Sciatic neuropathy?

Answer 27

``` Hip trauma Injection Hematoma Pelvic fx Penetrating wounds Gravid uterus Piriformis syndrome ```

Question 28

Which portion of the Sciatic nerve is largest?

Answer 28

Peroneal division outer 2/3 of nerve

Question 29

Why is the peroneal division of the Sciatic nerve most vulnerable?

Answer 29

More fixated in the pelvis Adheres distally to fibular head Larger fascicles w/ less protective epineural tissue

Question 30

What is the clinical presentation of sciatic neuropathy?

Answer 30

KF weakness Hamstring and Achilles reflex ABN Peroneal and tibial sensory loss

Question 31

Describe the course of the tibial nerve in the leg.

Answer 31

Distal 1/3 of thigh runs posterior to knee to soleus and continues on as posterior tibial nerve to run under flexor retinaculum and divides into 3 branches (medial and lateral plantar nerves, calcaneal nerve)

Question 32

What does the tibial nerve innervate at the posterior knee?

Answer 32

``` Plantaris Medial gastrocnemius Lateral gastrocnemius Popliteus Soleus ```

Question 33

What does the posterior tibial nerve innervate?

Answer 33

``` Tibialis posterior (TP) Flexor digitorum longus (FDL) Flexor hallucis longus (FHL) ```

Question 34

What does the medial plantar nerve innervate?

Answer 34

``` Abductor hallucis Flexor digitorum brevis Flexor hallucis brevis Lumbrical Sensory branch ```

Question 35

What does the lateral plantar nerve innervate?

Answer 35

``` Lumbricals Abductor digiti minimi Quadratus plantae Interossei Adductor hallucis Sensory branches ```

Question 36

What does the Calcaneal nerve innervate?

Answer 36

Sensory branch

Question 37

What runs through the tarsal tunnel?

Answer 37

Tibialis posterior Flexor digitorium longus Posterior tibial artery/vein/nerve Flexor hallucis longus

Question 38

What is the clinical presentation of tarsal tunnel syndrome?

Answer 38

Intrinsic foot weakness Perimalleolar pain, numbness, and paresthesias may extend to the toes and soles. Reproduced by ankle inversion

Question 39

What does the superficial peroneal nerve innervate?

Answer 39

Peronues longus Peroneus brevis Medial and lateral cutaneous nerves

Question 40

What does the deep peroneal nerve innervate?

Answer 40

``` Tibialis anterior (TA) Extensor digitorum longus (EDL) Extensor hallucis longus (EHL) Peroneus tertius Extensor digitorum brevis (EDB) First dorsal interossei Dorsal distal cutaneous nerve ```

Question 41

What is an accessory peroneal nerve?

Answer 41

An anomalous nerve branch from the superficial peroneal (fibular) nerve that travels posterior to the lateral malleolus to innervate some or all of the EDB. 1/3 of the population

Question 42

How is accessory peroneal nerve diagnosed on EDX?

Answer 42

Lower peroneal (fibular) CMAP (recording at EDB) with stim at the ankle compared to stim at the knee. Confirmed by stim behind the lateral malleolus, which will also elicit a CMAP from the EDB

Question 43

What can be spared with an accessory peroneal nerve?

Answer 43

EDB can be spared even with a deep peroneal (fibular) nerve injury

Question 44

What are etiologies of peroneal neuropathy at the fibular head?

Answer 44

``` Prolonged leg crossing Weight loss Poor positioning during surgery Poor cast application, Prolonged squatting position (strawberry pickers’ palsy) DM ```

Question 45

What is the clinical presentation of peroneal neuropathy at the fibular head?

Answer 45

Foot drop and steppage gait Short head biceps femoris spared Sensory loss over deep and superficial peroneal nerves

Question 46

What differentiates a peroneal neuropathy from an L5 radiculopathy?

Answer 46

Peroneal neuropathy: weakness of dorsiflexors and evertors | L5 radiculopathy: Includes ankle invertors

Question 47

What is anterior tarsal tunnel syndrome?

Answer 47

Injury to deep peroneal nerve under extensor retinaculum

Question 48

What is the clinical presentation of anterior tarsal tunnel syndrome?

Answer 48

Foot weakness EDB atrophy Numbness in 1st and 2nd web space Pain over dorusm of foot relieved with motion

Question 49

What are etiologies of superficial peroneal neuropathy?

Answer 49

Trauma Ankle sprain Compartment syndrome Lipoma

Question 50

What is the clinical presentation of superficial peroneal neuropathy?

Answer 50

Peroneus longus and brevis weakness | Numbness in superficial peroneal nerve distribution

Question 51

Describe the course of the sural nerve.

Answer 51

Orignates from tibial and peroneal nerves to proxmial posterior calf to lateral malleolus

Question 52

What does the sural nerve innervate?

Answer 52

Sensation to lateral calf and foot

Question 53

What are etiologies of sural neuropathy?

Answer 53

Tight sock Baker's cyst Laceration

Question 54

What is the origin and course of the superior gluteal nerve?

Answer 54

Originate from L4-S1 roots in pelvic region pass through sciatic notch superior to piriformis

Question 55

What does the superior gluteal nerve innervate?

Answer 55

Gluteus medius Gluteus minimus Tensor fascia lata (TFL)

Question 56

What is the origin and course of the Inferior gluteal nerve?

Answer 56

L5-S2 nerve roots in pelvic region

Question 57

What does the inferior gluteal nerve innervate?

Answer 57

Gluteus maximus

Question 58

How are superior/inferior gluteal nerves injured?

Answer 58

Hip joint replacement Improper IM injection Pelvic masses

Question 59

What is the clinical presentation of superior gluteal neuropathy?

Answer 59

Weakness of hip abduction and ER. A Trendelenburg gait demonstrating a pelvic tilt to the strong side

Question 60

What is the clinical presentation of inferior gluteal neuropathy?

Answer 60

Weakness of hip extension | Sensation is spared

Question 61

What is mononeuritis multiplex?

Answer 61

Multifocal peripheral neuropathy where damage occurs in two or more different nerve areas

Question 62

What are etiologies of mononeuritis multiplex?

Answer 62

``` Axonal injury can be caused by multiple etiologies, including inflammation (vasculitis), vascular compromise (occlusion), compression, and infection ```