Lumbosacral Plexus Flashcards
What is the origin of the femoral nerve?
L2 through L4 posterior divisions
What is the origin of the obturator nerve?
L2 through L4 anterior divisions
What is the origin of the tibial nerve?
L4 through S3 anterior divisions
What is the origin of the common fibular nerve?
L4 through S2 posterior divisions
What muscles are innervated by the femoral nerve?
Anterior compartment of thigh (quadriceps femoris, sartorious, pectineus
What muscles are innervated by the obturator nerve?
Medial compartment of thigh (gracilis, adductor longus, adductor brevis, anterior portion of adductor magnus)
What muscles are innervated by the tibial nerve?
Posterior compartment of thigh (semimembranosus, semitendinosus, long head of biceps femoris, posterior portion of adductor magnus).
Posterior compartment of leg (gastrocnemius, soleus, flexor digitorus longus, flexor hallucis longus, tibialis posterior)
Plantar muscles of the foot
What muscle is innervated by the common fibular nerve?
Short head of the biceps femoris
What muscles are innervated by the superficial fibular nerve?
Lateral compartment of the leg (fibularis longus, fibularis brevis)
What muscles are innervated by the deep fibular nerve?
Anterior compartment of the leg (tibialis anterior, extensor hallucis, extensor digitorum, fibularis tertius)
What is the primary action of the femoral nerve?
To extend the knee.
What are the primary actions of the obturator nerve?
To adduct the thigh; to medially rotate the thigh.
What are the primary actions of the tibial nerve?
To flex the knee, to extend the thigh.
To plantar flex the foot (S1-S2), to flex digits, to invert the foot.
What is the primary action of the common fibular nerve?
To flex the knee.
What is the primary action of the superficial fibular nerve?
To evert the foot.
What are the primary actions of the deep fibular nerve?
To dorsiflex the foot (L4-L5), to extend digits, to invert the foot.
What lower limb nerve is the most commonly damaged?
The common fibular nerve (crosses the lateral aspect of the knee at the neck of the fibula)
How do patients with damage to the common fibular nerve present?
With loss of dorsiflexion at the ankle (foot drop), loss of eversion, and sensory loss on the lateral side of the leg and dorsum of the foot.
How does a complete sciatic nerve lesion present?
With sensory and motor deficits in the posterior compartment of the thigh and all functions below the knee. In an incomplete lesion, weakened extension of the thigh, loss of knee flexion.
What nerve is damaged in a patient with a ‘trendelenburg gait’?
Superior Gluteal nerve.
Damage to what nerve is classically associated with weakened plantar flexion and inversion?
Tibial nerve.
Damage to what nerve is classically associated with weakened dorsiflexion (foot drop) and inversion?
Deep fibular nerve.
Damage to what artery causes avascular necrosis of the head of the femur?
Medial circumflex femoral artery (branch of the profunda femoris artery)
