LL Peripheral Nerve Flashcards
Obturator Nerve
From L2-4
MOI:
rare but can occur
due to hip dislocation/during surgery involving the pelvis or abdomen
Sensory loss:
- Numbness@medial thigh
Motor loss:
- Hip adduction impaired
–>abnormalities in gait
Femoral Nerve
From L2-4
MOI:
* Trauma (penetrating pelvic injury)
* Compression (prolonged hip flexion)
* Pelvic, abdominal, or spinal surgery
Sensory loss:
- Numbness@ anteromedial thigh & medial leg/foot
Motor loss:
- Weak hip flexion (psoas still intact)
*Circumduction to step leg through
- Impaired knee extension
* hyperextension/instability
Saphenous Nerve
From L3-4
MOI:
* Trauma to medial aspect of leg or knee
* Leg or ankle fracture
* Entrapment in adductor canal
Sensory loss:
Numbness @ anteromedial leg and ankle
No motor loss
Lateral Femoral Cutaneous Nerve
From L2-3
MOI:
Compression due to:
- Compression under inguinal ligament
- Pregnancy
- Tight clothing
- Obesity
Sensory loss:
Numbness @ anterolateral thigh
No motor loss
Posterior Femoral Cutaneous Nerve
From S1-S3
MOI: Trauma to posterior aspect of thigh
Sensory loss:
Numbness @ posterior thigh and knee
No motor loss
Superior Gluteal Nerve
From L4-S1
MOI:
* Posterior hip dislocation
* Injection to upper medial gluteal region
No sensory loss
Motor loss:
- Impaired hip abduction
+Ve Trendelenburg sign and gait
Inferior Gluteal Nerve
From L5-S2
MOI:
Rare but can occur during hip replacement
No sensory loss
Motor loss:
Impaired hip extension
* Difficulty with climbing stairs, step ups onto curb, arising from chair
* Backward trunk lean or throwing the trunk backward after initial contact
Sciatic Nerve
From L4-S3
MOI:
* Trauma: lumbar IV disc herniation
* Hip surgery
Sensory loss:
Numbness over
- posterolateral leg and foot (via sural N)
- dorsum of the foot and anterolateral leg (via superficial fibular N)
- first webspace (via deep fibular N)
- plantar aspect of foot (via tibial N)
Motor loss:
- Impaired knee flexion
*circumduction gait or increased hip flexion to clear foot during swing
- Impaired ankle dorsiflexion, plantarflexion, inversion and eversion
* AFO required to stabilize ankle
Tibial Nerve
From L4-S3
MOI: Post. knee dislocation
Sensory loss:
before branching->Numbness @
- posterolateral leg and foot (via sural N, which also receives innervation from the common fibular nerve)
- heel (via medial calcaneal N)
- plantar aspect of foot (via medial plantar N and lateral plantar N)
within tarsal tunnel
@heel and plantar aspect of the foot
Motor loss:
Before branching:
- Impaired ankle plantarflexion
- Weak ankle inversion (tibialis anterior can still invert the foot)
- Impaired toe flexion
within tarsal tunnel:
Intrinsic foot weakness
* loss of toe motion, arch support and foot stability
Common Fibular Nerve
From L4-S3
MOI:
- Compression (e.g., tight cast)
- Trauma: fracture of fibular neck (aka bumper fracture)
Sensory loss:
Numbness @
- anterior and lateral leg
- dorsum of the foot including first webspace
Motor loss:
- Impaired ankle dorsiflexion/eversion
- Impaired toe extension
- Weak ankle inversion (tibialis posterior still intact)
*Foot drop–>steppage gait (exaggerated hip and knee flexion to clear foot during swing)
Superficial Fibular Nerve
From L4-S1
MOI:
* Trauma: fibula fractures
* Nerve entrapment
* Compression (e.g., compartment syndrome)
Sensory loss:
Numbness @ anterolateral leg and dorsum of foot (except 1st webspace)
Motor loss:
- Impaired ankle eversion
*ankle instability
- Mild weakness in PF
Deep Fibular Nerve
From L4-L5
MOI:
* Compression (tight laces/ski boots)
* Trauma: anterior ankle trauma
* Nerve palsy (due to inflammatory disorders, diabetes, demyelinating diseases)
Sensory loss:
Numbness @ first webspace
Motor loss:
- Impaired ankle dorsiflexion
* foot drop –> steppage gait
- Impaired toe extension
- Weak ankle inversion (tibialis posterior intact)
