Lower extremity blocks (new) Flashcards
Match each nerve with its corresponding nerve roots:
femoral
lateral femoral cutaneous
posterior femoral cutaneous
sciatic
L2-L4
L2-L3
S1-S3
L4-S3
Femoral: L2-L4
Lateral Femoral cutaneous: L2-L3
Posterior femoral cutaneous: S1-S3
Sciatic: L4-S3
What plexuses innervate the lower extremities?
Lumbar plexus: L1-L4 (T12 contribution in ~50% of the population
sacral plexus: L4-S4
The lumbar plexus gives rise to 6 nerves:
iliohypogastric nerve
ilioinguinal nerve
genitofemoral nerve
lateral femoral cutaneous nerve
obturator nerve
femoral nerve (largest branch)
What is the pneumonic to remember the nerves of the lumbar plexus?
I Invariably Get Lazy on Fridays
The sacral plexus gives rise to the following 5 major nerves:
superior gluteal nerve
inferior gluteal nerve
posterior cutaneous nerve
pudendal nerve
sciatic nerve
What is the pneumonic to remember the sacral plexus?
SIPPS
The foot and ankle are innervated by the following 5 nerves:
saphenous nerve
sural nerve
superficial peroneal nerve
deep peroneal nerve
posterior tibial nerve
The obturator nerve originates from
L2-L4
The lateral femoral cutaneous nerve originates from
L2-L3
The femoral nerve originates from
L2-L4
The iliohypogastric nerve originates from
L1
The ilioinguinal nerve originates from
L1
The genitofemoral nerve originates from
L1-L2
The pudendal nerve originates from
S2-S4
The lumbar plexus forms within the ____________ and passes in front of the
psoas muscle and; quadratus lumborum muscle
The lateral femoral cutaneous nerve forms at the
midpoint of the psoas muscle
The femoral nerve forms near the
middle and lower third of the psoas muscle
The femoral nerve divides into
anterior and posterior branches- posterior: saphenous nerve which courses through the adductor canal
The obturator nerve forms near the
medial border of the psoas muscle at the level of the sacroiliac joint
This nerve is often injury in patients undergoing extensive pelvic surgery:
obturator nerve
The sacral plexus forms
anterior to the psoas major
The sacral plexus arises from
L4-S3
The largest nerve in the body is the
sciatic nerve
The sciatic nerve arises from
L4-S3
The sciatic nerve divides into
the tibial nerve & common peroneal nerve
The tibial nerve gives rises to
the terminal branch: posterior tibial nerve
The common peroneal nerve gives rise to
3 terminal branches: deep peroneal nerve, superficial peroneal nerve, and sural nerve
The coccygeal plexus encompasses
S4-Co
The primary nerves of the coccygeal plexus include
pudendal
inferior anal
perineal
The lumbar plexus provides sensory and motor innervation to the
lower abdominal wall
anteriomedial thigh
knee
The sacral plexus provides sensory and motor innervation to the
gluteal region
posterior thigh
lower leg
& foot
What nerve would assess hip flexion?
femoral nerve
What nerve would assess hip extension?
sciatic nerve
What nerve assesses knee flexion?
sciatic nerve
What nerve assess knee extension?
femoral nerve
What nerve is responsible for plantar flexion?
tibial nerve
What nerve is responsible for dorsiflexion?
peroneal nerve
What nerve is responsible for eversion?
superficial peroneal nerve
What nerve is responsible for inversion?
deep peroneal nerve
Peripheral nerves are either
pure sensory or combined sensory-motor
Sensory only nerves include
lateral femoral cutaneous
saphenous
sural
The sensory region of the pudendal nerve is the
perineum
anal canal + external sphincter
The sensory region of the posterior tibial nerve is the
plantar surface of the foot
The sensory region of the superficial peroneal nerve is the
dorsal surface of the foot
The sensory region of the deep peroneal nerve is the
web space between big toe and 2nd toe
The sensory region of the sural nerve is the
lateral aspect of the foot
Describe how to assess motor function of the femoral nerve
Hip–> flexion + rotation (lateral)
knee–> extension + flexion (minor contribution from sartorius)
Describe how to assess motor function of the obturator nerve.
Hip–> ADDuction + flexion+ extension
Describe how to assess motor function of the pudendal nerve.
Anal sphincter tone
Describe how to assess motor function of the sciatic nerve.
Hip–> extension
knee–> flexion
Describe how to assess motor function of the tibial nerve.
Toe–> ABduction+ extension+ flexion
ankle–> plantar flexion
Describe how to assess motor function of the superficial peroneal nerve.
Ankle–> eversion
Describe how to assess motor function of the deep peroneal nerve.
ankle–> inversion + dorsiflexion
