Ch 5 - EDX: Lower Limb Mononeuropathy Flashcards
Describe the course of the lateral femoral cutaneous nerve
Pass over the iliacus
toward the anterior iliac spine, tunnels under the inguinal ligament to provide sensation for the lateral thigh
What is meralgia parasthetica?
Lateral cutaneous neuropathy
What are etiologies of lateral femoral cutaneous neuropathy?
Protuberant abdomen Pregnancy Tight clothing DM Tumor Infection Rapid weight loss
What is the clinical presentation of lateral femoral cutaneous neuropathy?
Sensory complaints in lateral thigh exacerbated with hip extension or hyperflexion, prolonged sitting/squatting, or
driving
What is the origin of the femoral nerve?
L2, L3, L4 roots into posterior division of lumbar plexus
Describe the course of the femoral nerve.
Runs through psoas, under the inguinal ligament lateral to femoral artery and through femoral triangle
What does the femoral nerve innervate?
Iliacus Pectineus (1/2) Sartorius Quadriceps muscles Saphenous nerve
What are etiologies of femoral neuropathy?
Compressive lesion in the pelvis from trauma, fracture, retroperitoneal hematoma, tumor, inguinal ligament compression, or cardiac catheterization
What is the clinical presentation of femoral neuropathy?
Weakness of KE
Knee instability
Dec sensation over the anterior thigh and medial leg
HF weakness if lesion proximal to inguinal ligament
What is the MCC of femoral neuropathy?
Diabetic amyotrophy
How is the femoral nerve injured in Diabetic Amyotrophy?
ABN of vaso-nevorum d/t DM
Amyotrophy noted after marked weight loss
What is the clinical presentation of Diabetic Amyotrophy?
Asymmetric thigh pain
KE weakness
Femoral innervated muscle atrophy
Loss of patellar reflex
What does the Saphenous nerve innervate?
Sensation to the medial aspect of the leg, the medial malleolus, and medial arch of the foot
What is the largest and longest branch of the femoral nerve?
Saphenous nerve
How can the Saphenous nerve be injured?
Entrapped in the subsartorial (Hunter’s) canal or b/w sartorius and gracilis
Knee arthroscopy
Vascular surgery
What is the clinical presentation of Saphenous neuropathy?
Pure sensory syndrome
Medial knee pain (infrapatellar branch)
ABN sensation along medial leg and foot
What is the origin of the obturator nerve?
L2, L3, L4 roots continue as anterior portion of lumbar plexus
What is the course of the obturator nerve?
Anterior to SI joint through psoas major muscle through obturator foramen
What does the obturator nerve innervate?
Pectineus (1/2) Adductor brevis Adductor longus Adductor magnus Obturator externus Gracilis Cutaneous branch
What are etiologies of obturator neuropathy?
Pelvic fx or hernia w/in obturator foramen
What is the clinical presentation of obturator neuropathy?
Hip adduction/IR weakness
Circumduction gait
Dec sensation along medial thigh
What is the origin of the sciatic nerve?
L4, L5, S1, S2 and S3 roots continue as posterior division of lumbar plexus
Describe the course of the sciatic nerve.
Exits pelvis through greater sciatic foramen b/w lesser trochanter and ischial tuberosity thru posterior leg to popliteal fossa
What does the sciatic nerve splint into at the popliteal fossa?
Tibial (medial) nerve
Peroneal/Fibular (lateral) nerve
What does the peroneal division of sciatic nerve innervate?
Short head of biceps femoris
What does the tibial division of sciatic nerve innervate?
Long head of the biceps femoris
Semitendinosus
Semimembranosus
Adductor magnus (also obturator nerve)
What are etiologies of Sciatic neuropathy?
Hip trauma Injection Hematoma Pelvic fx Penetrating wounds Gravid uterus Piriformis syndrome
Which portion of the Sciatic nerve is largest?
Peroneal division outer 2/3 of nerve
Why is the peroneal division of the Sciatic nerve most vulnerable?
More fixated in the pelvis
Adheres distally to fibular head
Larger fascicles w/ less protective epineural tissue
What is the clinical presentation of sciatic neuropathy?
KF weakness
Hamstring and Achilles reflex ABN
Peroneal and tibial sensory loss
Describe the course of the tibial nerve in the leg.
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)
What does the tibial nerve innervate at the posterior knee?
Plantaris Medial gastrocnemius Lateral gastrocnemius Popliteus Soleus
What does the posterior tibial nerve innervate?
Tibialis posterior (TP) Flexor digitorum longus (FDL) Flexor hallucis longus (FHL)
What does the medial plantar nerve innervate?
Abductor hallucis Flexor digitorum brevis Flexor hallucis brevis Lumbrical Sensory branch
What does the lateral plantar nerve innervate?
Lumbricals Abductor digiti minimi Quadratus plantae Interossei Adductor hallucis Sensory branches
What does the Calcaneal nerve innervate?
Sensory branch
What runs through the tarsal tunnel?
Tibialis posterior
Flexor digitorium longus
Posterior tibial artery/vein/nerve
Flexor hallucis longus
What is the clinical presentation of tarsal tunnel syndrome?
Intrinsic foot weakness
Perimalleolar pain, numbness, and paresthesias may extend to the toes and soles.
Reproduced by ankle inversion
What does the superficial peroneal nerve innervate?
Peronues longus
Peroneus brevis
Medial and lateral cutaneous nerves
What does the deep peroneal nerve innervate?
Tibialis anterior (TA) Extensor digitorum longus (EDL) Extensor hallucis longus (EHL) Peroneus tertius Extensor digitorum brevis (EDB) First dorsal interossei Dorsal distal cutaneous nerve
What is an accessory peroneal nerve?
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
How is accessory peroneal nerve diagnosed on EDX?
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
What can be spared with an accessory peroneal nerve?
EDB can be spared even with a deep peroneal (fibular) nerve injury
What are etiologies of peroneal neuropathy at the fibular head?
Prolonged leg crossing Weight loss Poor positioning during surgery Poor cast application, Prolonged squatting position (strawberry pickers’ palsy) DM
What is the clinical presentation of peroneal neuropathy at the fibular head?
Foot drop and steppage gait
Short head biceps femoris spared
Sensory loss over deep and superficial peroneal nerves
What differentiates a peroneal neuropathy from an L5 radiculopathy?
Peroneal neuropathy: weakness of dorsiflexors and evertors
L5 radiculopathy: Includes ankle invertors
What is anterior tarsal tunnel syndrome?
Injury to deep peroneal nerve under extensor retinaculum
What is the clinical presentation of anterior tarsal tunnel syndrome?
Foot weakness
EDB atrophy
Numbness in 1st and 2nd web space
Pain over dorusm of foot relieved with motion
What are etiologies of superficial peroneal neuropathy?
Trauma
Ankle sprain
Compartment syndrome
Lipoma
What is the clinical presentation of superficial peroneal neuropathy?
Peroneus longus and brevis weakness
Numbness in superficial peroneal nerve distribution
Describe the course of the sural nerve.
Orignates from tibial and peroneal nerves to proxmial posterior calf to lateral malleolus
What does the sural nerve innervate?
Sensation to lateral calf and foot
What are etiologies of sural neuropathy?
Tight sock
Baker’s cyst
Laceration
What is the origin and course of the superior gluteal nerve?
Originate from L4-S1 roots in pelvic region pass through sciatic notch superior to piriformis
What does the superior gluteal nerve innervate?
Gluteus medius
Gluteus minimus
Tensor fascia lata (TFL)
What is the origin and course of the Inferior gluteal nerve?
L5-S2 nerve roots in pelvic region
What does the inferior gluteal nerve innervate?
Gluteus maximus
How are superior/inferior gluteal nerves injured?
Hip joint replacement
Improper IM injection
Pelvic masses
What is the clinical presentation of superior gluteal neuropathy?
Weakness of hip abduction and ER. A Trendelenburg gait demonstrating a pelvic tilt to the strong side
What is the clinical presentation of inferior gluteal neuropathy?
Weakness of hip extension
Sensation is spared
What is mononeuritis multiplex?
Multifocal peripheral neuropathy where damage occurs in two or more different nerve areas
What are etiologies of mononeuritis multiplex?
Axonal injury can be caused by multiple etiologies, including inflammation (vasculitis), vascular compromise (occlusion), compression, and infection
