Apex- Lower extremity blocks Flashcards
Which nerves arise from the lumbar plexus? (3)
- Obturator
- Posterior femoral cutaneous
- Sciatic
- Lateral femoral cutaneous
- Pudendal
- Femoral
Femoral
Obturator
Lateral Femoral Cutaneous
The lumbar plexus arises from the (anterior/posterior/ventral/dorsal) rami of ____________.
anterior/ventral rami of L1-L4
What 6 nerves arise from the lumbar plexus? (mneumonic)
I Inevitably Get Lazy On Fridays
Iliohypogastric
Ilioinguinal
Genitofemoral
Lateral femoral cutaneous
Obturator
Femoral
What is another name for the common peroneal nerve?
The common fibular nerve
What supplies sensory innervation to:
- Anterior thigh:
- Lateral thigh:
- Posterior thigh:
- Anterior thigh ► Femoral (L2-L4) [Lumbar plexus]
- Lateral thigh:► Lateral Fem. Cutaneous (L2-L3) [Lumbar plexus]
- Posterior thigh ► Posterior Fem Cutaneous (S1-S3) [Sacral plexus]
Motor innervation of the lateral cutaneous nerve
none
just sensory to the lateral thigh
L2-3
Lumbar plexus
Motor innervation of the femoral nerve
Sartorius (Anterior Branch)
Quadriceps (Posterior Branch)
(Sesnory = anterior thigh)
(L2-L4)
[Lumbar Plexus]
Sensory and motor innervation of the obturator nerve
Sensory = Distal inner thigh & Part of hip
Motor = Hip Adductors
(L2-L4)
[Lumbar Plexus]
What is the largest nerve in the body
Sciatic
(L4-S3)
[Sacral Plexus]
What supplies sensory and motor innervation to the posterior thigh?
Sensory = Posterior fem. cutaenous (S1-S3)
Motor = Sciatic
What nerve supplies the vast majority of sensory and motor innervation of the lower leg & foot
Siatiac
L4-S3
Sacral plexus
Roots of:
- Iliohypogastic
- Ilioinguinal
- genitofemoral
- Lateral Femoral cutaneous
- Obturator
- Femoral
- Iliohypogastic ► L1
- Ilioinguinal ► L1
- Genitofemoral ► L1 + L2
- Lateral Femoral cutaneous ► L2 + L3
- Obturator ► L2 + L3 + L4
- Femoral ► L2 + L3 + L4
(I ineveitably get lit on fridays)
Posterior Femoral Cutaneous vs Sciatic Roots
Sciatic - L4-S3
Post fem- S1-S3
match cutaneous innervations with:
Sural
Obturator
Superficial peroneal
Posterior Femoral cutaneous
A = Posterior Femoral cutaneous
B = Obturator
C = Superior peroneal
D = Sural
What does the saphenous nerve branch off of?
The femoral nerve
-sensory to the medial lower leg
what nerve is the common peronal nerve a branch of?
The sciatic ( > superifical and deep peroneal)
What nerve is the tibial nerve a branch of?
sciatic ( > Sural and posterior tib)
label
What nerve pervices sensory innervation to the medial lower leg
Saphenous (branch of femoral)
What nerve supplies sensory innervation to the lateral foot
Sural (branch of sciatic > tibial)
Which nerves supplies sensory innervation to the back of the heel?
Tibial nerve (branch of sciatic)
fill this sucker in
The Psoas compartment block anesthetizes all of the following nerves EXCEPT the:
A. Obturator
B. Lateral Femoral Cutaneous
C. Sciatic
D. Saphenous
C. Sciatic
*Lumbar plexus = Obturator, Lat Femoral, & Femoral
- Saphenous is a division of the femoral so rule that out and your left with sciatic which is from the sacral plexus
The lumbar plexus is contained within a sheath inside the _____ compartment. At this poin the plexus is:
- Lateral to the ►
- Anterior to the ►
- Posterior to the ►
Psoas compartment
- Lateral to the ►Vertebral column (LoVe)
- Anterior to the ► QUAd muscle (AQUA)
- Posterior to the ► Psoas muscle (PP)
A psoas compatment block targets what 3 major nerves of the lumbar plexus?
When is this block useful?
Lateral fem cutaneous, Femoral, Obutrator
LFO!!!
-useful when neuraxial anesthesia is contraindicated and/or anesthesia to one lower extremity is preferred
Another name for a Lumbar Plexus Block
Psoas Compartment block
Where is the intercristal line is where
L4-5 interspace
- What the heck are we looking at
- Where would you mark the hot spot
It’s a psoas compartment block
AKA lumbar plexus block
*3cm caudad from L4 and 5cm lateral from midline
T/F- blockade of the lumbar plexus creates a sympathectomy of the ipsilateral extremity
True
Which lower extremity block has the highest complications rates and what are they?
Psoas compartment block/Lumbar plexus block
-retroperitonal hematoma and renal capsular injection
(coagulation = contraindication)
What is the contraindication to a lumbar plexus block?
coagulopathy
(high risk of retroperitonal hematoma and renal capsular injection)
with a psoas compartment block, volumes greater than ____mls increase risk of bilateral spread and contralateral imb involvement
>20mls
Match with:
Femoral vein, Femoral Artery, Femoral Nerve, Fascia lata
A + Femoral vein
B + Femoral artery
C + Fascia lata
D + Femoral nerve
VAN (from medial to lateral): Vein > Artery > Nerve
Pick 2 statements that BEST describe the proper technique for performing a fascia iliaca compartment block:
- Two pops should be felt before injecting the local anesthetic
- Ultrasound is required
- Local anesthetic is deposited anterior to the iliopsoas muscle
- Local anesthetic should be deposited b/t the fascia iliaca and fascia lata
-Two pops should be felt before injecting the local anesthetic
-Ultrasound is required
-Local anesthetic is deposited anterior to the iliopsoas muscle
-Local anesthetic should be deposited b/t the fascia iliaca and fascia lata
T/F: A femoral nerve block provides almost complete surgical coverage to the lower extremity
False
-it provides coverage to the thigh, knee, and medial lower leg
*when combined with sciatic nerve block, it provides almost complete surgical coverage to the lower extremity
The femoral nerve arises from the (anterior/posterior) divisions of ___ - ____.
Posterior L2-L4
label
Gray = medial: adductor longus
Black = Superior: inguinal ligament
Brown = Lateral: Sartorius
Remember the borders of the femoral nerve as SAIL:
S= Sartoris muscle (Lateral
A= Adductor longus muscle (Medial)
IL= inguinal ligament
The femoral nerve runs:
Deep to the ►
Anterior to the ►
Inferior to the ►
Deep to the ► inguinal ligament
Anterior to the ► iliopsoas msucle
Inferior to the ► fascia lata and fascia iliaca
Mneumonic to remember the femoral nerve borders
SAIL:
S= Sartoris muscle (Lateral
A= Adductor longus muscle (Medial)
IL= inguinal ligament
During a femoral nerve block, what should you do if you observe inner thigh twitches and what does that indicate?
your stimulating the sartorius muscle
needle is too superficial and/or medial to the femoral nerve
-withdraw and advance in a slighlty lateral direction away from the femoral artery until proper stimulation is achieved (quad contraction “Patellar snap”)
Where should the transducer be placed to identify the major anatomical landmarks for a femoral nerve block?
inguinal crease
Label
The (anterior/posterior) division of the femoral nerve innervates the quadriceps muscle which is generally found on the (medial/lateral) aspect of the femoral triangle.
posterior- lateral
What kind of block can be thought of as a femoral nerve block lower in the thigh
Adductor Cannal Block
(The femoral nerve is beneath the sartorius muscle at this location).
Why is the adductor canal block used instead of just a regular femoral nerve block up higher
bc motor nerves branch off higher in the femoral nerve, above the level of the adductor canal - so you can provide analgesia without affecting quad function
What is a different approach to the femoral nerve block where the needle insertion point is more lateral and distant from the femoral neurovascular bundle?
Fascia Iliaca Block
T/F - nerve stimulation or ultrasound is not required when performing a fascia iliaca block
True
Where is the local anesthetic depostied when doing a fascia iliaca block?
inferior to the fascia iliaca but superior to the iliopsoas muscle
Which peripheral nerve block can be combined with a sciatic nerve block to enhance the tolerance of a lower leg tourniquet?
- Sural
- Common peroneal
- Saphenous
- Posterior tibial
-Saphenous
(Aa continuation of the posterior branch of the femoral nerve)
The combination of what 2 blocks provides complete anesthesia to the lower leg, ankle, and foot.
Sciatic (or popliteal) + Saphenous
Increasing tolerance of an upper leg tourniquet requires what kind of nerve block?
Sciatic + psoas compartment block
or 3-in-1 block (femoral, obturator, lateral, femoral cutaneous)
T/F- the saphenous nerve provides no motor innervation
true
What nerve provides sensory innervation from the medial knee to the medial malleous
Saphenous
What is the saphenous nerve a terminal branch of?
the posterior division of the femoral nerve
Which block involves locating the hunters canal and what is that
Saphenous nerve
-point where the sartorius, adductor longus, and vastus medialis meet distal to this? idk
The sciatic nerve provides motor innervation to the: (select 2):
- semitendinous
- biceps femoris
- quadriceps
- sartorius
- semitendinosus
- biceps femoris
(and the semimembranous muscles)
T/F- the sciatic nerve is two nerves
True
The siatic nerve is 2 nerves contained within a sheath
(Tibial and peroneal nerves
What two nerves make up the sciatic nerve
the tibial and peroneal
label
leg anatomy answers
What two blocks can be done for a patient having surgery on the leg/knee who may not tolerate sympathectomy from a neuraxial block?
Sciatic nerve block and lumbar plexus block
or
Sciatic nerve block & Femoral nerve block (knees)
What block has a landmark approach known as the classic or Lambat approach?
Sciatic
For a sciatic block, the patient is placed in what position with the operative leg in the (dependent/nondepdendent) position and slightly (flexed/exteneded)
Sims position
-operative > nondependent position
slightly flexed
What should you do if while advancing through the gluteal muscles for a sciatic nerve block, a motor response is encountered
continue advancing the needle until plantar or dorsiflexion is elicited
For surgical anesthesia with a sciatic nerve block, what is preferred…. plantar flexion or dorsiflexion and which nerve component correleates
-which is foot inversion vs foot eversion?
Plantar FLEXION preferred
- Foot Inversion
- Tibial nerve component
Dorsiflexion
- Foot eversion
- Common peroneal nerve
During a sciatic nerve block, how should you redirect your needle if you contact bone?
what about aspirate blood? (& where would it come from?)
Bone ► redirect medially
Blood ►redirect laterally (Superior gluteal artery)
What nerve does the popliteal nerve block target?
The sciatic nerve (in the proximal popliteal fossa)
At the proximal popliteal fossa, how is the sciatic nerve positioned to the popliteal artery and vein?
- borded medially by:
- borded laterally by:
posterior and lateral to the popliteal artery and vein
-borded medially by:
- The semitendinosus and semimembransoues muscles
-borded laterally by:
- The biceps formis muscle
What forms the apex and base of the triangle when doing a popliteal block
Base = popliteal crease at the knee
Apex = convergence of the biceps formis and semitendinousus muscles
Label
Optimal position when placing a popliteal nerve block
Prone
For a popliteal block, a line is drawn along hte popliteal crease from what to what?
at midpoint, a 2nd line is drawn perpindicular and cephalad _____ cm to the apex of the triange.
-the needle insertion point is ___cm (medial/lateral) to the apex
Medial border of the biceps femoris > lateral border of the semitendinousus muscle
- 7-10cm to apex
- 1cm laterally
When doing a popliteal block, when do you stop advancing the needle?
once plantar or dorsiflexion is obtained
(plantar flexion = better [tibial])
label
Common peroneal nerve and Tibial nerve
Popliteal vein > Popliteal artery
If using ultrasound for a popliteal block, which patient position would make the U/S image be inverted?
supine - it should be reversed to the proper orientation
When doing a popliteal block, what is the desired location for local anesthetic placement?
Where the sciatic nerve begins to bifurcate
T/F- once the sciatic nerve is identified, the needle should be aimed directly at the nerve
False - slighlty to one side
(Remember the goal is not to directly inject the nerve but to bathe it)
Match:
- Dorsum of the foot ►
- Lateral aspect of the foot ►
- Web space between 1st and 2nd toe ►
- Heel ►
With: Superficial peroneal nerve, Deep peroneal nerve , sural nerve, tibial nerve
- Dorsum of the foot ►Superficial peroneal
- Lateral aspect of the foot ► Sural
- Web space between 1st and 2nd toe ►Deep peroneal (deep in that web)
- Heel ► Tibial nerve
What 5 nerves does an ankle block anesthetize? Which ones are purely sensory vs sensory + motor
- Superficial Peroneal
- Sural
- Saphenous
- Tibial (inversion + plantar flexion)
- Deep peroneal (eversion + dorsiflexion)
*The S’s are purely sensory
label
What is the medial calcaneal nerve and what does it innervate?
It’s a subdivision of the tibial nerve and it innervates the heel
Label
Injecting a ring of local anesthetic from the midpoint of the distal tibia toward the inferior border of the medial malleolus will most likely anesthetize the:
A. Sural nerve
B. Tibial nerve
C. Superficial peroneal nerve
D. Saphenous nerve
D. Saphenous nerve
T/F- an ankle block can be used for surgies involving the foot and the ankle
false- foot BELOW the ankle
