Nerves of the lower limb Flashcards
What forms the lumbar plexus?
-Anterior divisions of lumbar spinal nerves L1 to L4 (small contribution from T12)
What are the major branches of the lumbar plexus?
- Iliohypogastric nerve
- Ilioinguinal nerve
- Genitofemoral nerve
- Lateral cutaneous nerve of the thigh
- Femoral nerve
- Obturator nerve
What is the sensory function of iliohypogasrtic nerve?
-Posteriolateral skin of gluteal region
What is the nerve root of ilioinguinal nerve?
-L1
What is the sensory function of the ilioinguinal nerve to lower limb?
-Innervates upper medial thigh
What is the sensory function of genitofemoral nerve in the lower limb?
-Femoral branch innervates skin on the upper thigh
What is the sensory function of lateral cutaneous nerve of the thigh?
-Innervates anterior and lateral thigh down to the knee
What nerve roots serve obturator nerve?
-L2, L3 and L4
What is the motor function of obturator nerve?
-Gracillis, Adductors, Pectineus and obrurator externus
What is the sensory function of obturator nerve?
-Innervates skin over medial thigh
What are the nerve roots of the femoral nerve?
-L2, L3 and L4
What are the motor functions of femoral nerve?
-Quadratus femoris, sartorius, iliopoas, pectineus
What is the sensory function of the femoral nerve?
- Anterior thigh (anterior cutaneous branch)
- Medial leg and foot (Saphenous branch)
What is a pneumonic for remembering the branches of lumbar plexus?
-I, I Get Leftovers On Fridays
What spinal nerves makes the sacral plexus?
-Anterior divisions of spinal nerve L4-S4
What are the 5 main peripheral nerves of the sacral plexus?
- Superior gluteal
- Inferior gluteal
- Sciatic
- Posterior femoral
- Pudendal
What are the motor functions of the superior gluteal nerve?
-Gluteus medius, gluteus minimus and tensor facsia latae
What are the sensory function of the superior and inferior gluteal nerve?
-None
What is a pneumonic for remembering the branches of the sacral plexus?
-Some Irish Sailor Pesters Polly
What is the motor function of inferior gluteal nerve?
-Gluteus maximus
What are the nerve roots of the sciatic nerve?
-L4, L5, S1,S2, S3
What are the motor functions of the sciatic nerve?
- Tibial portion -> hamstrings apart from short head of biceps -> posterior compartment of leg-> sole of foot
- Common fibular portion -> Short head of biceps femoris -> anterior compartment (deep nerve) and lateral (superficial nerve) compartments of leg
What is the sensory function of the branches of the common fibular nerve?
- Sural -> Lower posterolateral
- Lateral sural -> upper lateral
- Superficial -> lower anterolateral and dorsum of foot except skin between 1st and 2nd toes
- Deep -> innervates skin between first and second toe
What is the sensory function of the posterior femoral cutaneous nerve?
-Innervates skin of posterior thigh and leg
What are the smaller nerve branches of the sacral plexus?
- Nerve to piriformis
- Nerve to Obturator internus
- Nerve to Quadratus femoris
What happens to the sciatic nerve?
-Bifurcates into tibial and common fibular nerve at the popliteal fossa
What are the branches of the common fibular nerve (coommon peroneal nerve)?
- Superficial fibular (peroneal) nerve
- Deep fibular (peroneal) nerve
- Lateral sural nerve
- Sural nerve (with contribution from tibial)
What is the consequence of damage to the common fibula (peroneal) nerve?
-Loss of dorsiflexion, eversion and extension of digits (Loss of anteriolateral compartment)
How does damage to common fibular nerve commonly occur?
-Fracture (pedestrian hit by car bumper) or tight plaster cast
What causes foot drop?
-Damage to deep fibular nerve or common fibular nerve causing paralysis of muscles in anterior compartment of leg resulting in unopposed plantar flexion
What are the sensory functions of the tibial nerve?
- Posterioleteral side of leg (sural)
- Lateral side and sole of foot
What is tarsal tunnel syndrome?
- Tibial nerve is compressed within the tarsal tunnel due to:
- osteoarthritis
- Rheumatoid arthritis
- Post-trauma ankle deformities
List the major nerves of the lower limb
- Lumbar and Sacral plexus
- Femoral nerve
- Obturator nerve
- Sciatic nerve
- Common fibular nerve->Superficial and deep fibular nerves
- Tibial nerve