Exam 4 Regional
At midpoint of line to PSIS a line is drawn _____. This line will intersect the line toward the sacral hiatus. What is significant about this intersection?
- Perpendicular - Both of these nerves are at a common fascial plane at this point so the posterior cutaneous won't be missed
Landmarks for a pop block (forms a triangle)
- Pop skin crease - Biceps femoris - Semitendinosus
The sciatic nerve travels down the posterior thigh and at a variable distance proximal to the _____ _____. It bifurcates into the _____ _____ nerve and the _____ nerve.
- Popliteal fossa - Common peroneal - Tibial
As the sciatic nerve goes down the _____ thigh it provides innervation to the _____ muscles as well as all motor function below the _____.
- Posterior - Hamstring - Knee
5 nerves blocked at the ankle:
- Posterior tibial - Sural - Superficial peroneal - Deep perineal - Saphenous
The femoral nerve runs between the what muscles in the psoas compartment.
- Psoas - Quadratus lumborum/Iliacus
What are the muscles of the anterior thigh?
- Quadriceps (rectus femoris, vastus lateralis, medialis and intermedius) - Sartorius
Twitch of what muscle is usually obtained first (kneecap doesn't move), this branch of the femoral nerve may lie outside the fascial plane and will not provide reliable analgesia? What should you do to obtain the dancing kneecap in this situation?
- Sartorius - Advance slightly
Classic Approach of Staab: Position? Landmarks? Needle direction?
- Sim's position - PSIS and greater trochanter - At midpoint between these draw a perpendicular line 3 cm and insert 22 ga 100 mm needle aiming at anterior mid-thigh
Utility of the Lateral Femoral Cutaneous Nerve block:
- Skin grafts - Site pain - Completion of a partially successful LP block with residual discomfort
4 Indications for a femoral block:
- Surgery on or around the knee - Surgery involving the extensor mechanism of the knee - Knee Arthroplasty - Below Knee Amputation (combined with sciatic nerve block)
3 major nerves supplying the ankle:
- Tibial - Common perineal - Saphenous
Where do the hamstrings originate from? What are they responsible for?
- Upper lateral ischial tuberosity - Flexes leg and extends the thigh
Landmarks in the lateral approach of a pop block:
- Vastus lateralis - Biceps femoris
If the needle is too medial, you will stimulate the obturator nerve that will be evident by what twitch?
Adductor
Innervation of the lateral portion of the anterior leg:
Common peroneal nerve
A tibial plateau fracture involves a lot of innervation of what nerve?
Femoral
Muscles of the anterior thigh are primarily innervated by what nerve?
Femoral
The saphenous nerve is a branch of what nerve?
Femoral
What nerve in the psoas compartment gives you the best chance of LA spreading bidirectionally (medial and laterally)?
Femoral
What nerve is centrally located and the largest and most important nerve coming off the lumbar plexus
Femoral
What nerve rides down the middle of the psoas muscle coming just under the inguinal ligament and innervates all the extensor mechanisms of the knee?
Femoral
When performing a LP block, we will be seeking any twitch in motor distribution of which nerve?
Femoral
Which nerve is associated with the muscles of the anterior thigh?
Femoral
Which nerve of the LP is the biggest?
Femoral
What is a general term for the semimembrounosis and semitendinosus on the medial side of the posterior thigh?
Hamstrings
Muscles of the posterior thigh:
Hamstrings - Semimembranosus - Semitendinosus - Biceps femoris Adductor Magnus
When performing a psoas compartment block, what do you palpate for?
Iliac crest & spinous process of L4
One of the more common approaches to the pop block is what?
Lateral approach
What nerve provides cutaneous innervation to the lateral part of the thigh.
Lateral femoral cutaneous
Innervation of iliopsoas/psoas major muscle?
Ventral rami of lumbar spinal nerves 1-3
Does the LP block cover the sciatic nerve as well?
No - Sciatic is part of the sacral plexus
Does the sartorius muscle extend the knee?
No - abducts, medially rotates, and flexes the thigh
Innervation of the hip joint receives major contributions from the _____ nerve on the medial side.
Obturator
Muscles of the medial thigh are innervated by what?
Obturator
The knee joint, proximal femur, and the medial femoral condyle all receive innervation from the _____ nerve.
Obturator
What nerve comes down the medial portion of the psoas muscle and exits behind the bony portion of the pelvis? It has it's own canal and it innervates the adductors of the thigh.
Obturator
Which nerve is medial in the psoas compartment?
Obturator
Which nerve is most medial in the LP?
Obturator
Which nerve is the key to a nerve block after hip surgery involving the acetabulum?
Obturator
Muscle of the medial thigh that is innervated by the obturator nerve (L2-L3), laterally rotates the thigh and stabilizes the head of the femur in the acetabulum:
Obturator externus
Movement with tibial stimulation:
Plantar flexion and inversion
The subgluteal approach likely misses what nerve?
Posterior cutaneous nerve of the thigh
Which nerve of the sacral plexus also comes into play for regional anesthesia?
Posterior femoral
The posterior femoral cutaneous begins to diverge away from the sciatic nerve as the sciatic nerve crosses over what structure?
Quadratus femoris
The posterior femoral cutaneous nerve begins to diverge from the sciatic nerve as both nerves pass over what muscle?
Quadratus femoris
If you want to properly anesthetize the sciatic and posterior femoral cutaneous muscles with a single injection, you need to get to them before they diverge over what muscle?
Quadratus femoris- this would be proximally
What muscles will twitch at < 0.5 mA when the stim needle is properly placed in the psoas compartment?
Quadriceps
What nerve is easy to miss in doing a pop block and therefore requires a separate injection for complete anesthesia?
Saphenous
Muscle of the anterior thigh that is innervated by the femoral nerve (L2-L3) and ABducts, medially rotates, and flexes the thigh:
Sartorius
One of the first branches of the femoral nerve goes to what muscle that is not connected to the extensors mechanism of the knee?
Sartorius
What position do you have the pt get into when performing a lateral femoral cutaneous nerve block?
Supine
For which nerve block do you identify the EHL tendon and dorsal is pedis artery?
Deep Peroneal Nerve
Nerve that gets the first web space between the fist and second toe:
Deep peroneal
Which nerve: - Branches from common peroneal - L4-S2 - Passes into foot just lateral to dorsalis pedis artery and tendon of EHL ?
Deep peroneal nerve
When performing a subgluteal approach to sciatic nerve block, what movement are we looking for?
Dorsiflexion - common perineal EMR
Movement with common peroneal stimulation:
Dorsiflexion and eversion
The common peroneal nerve is responsible for what action?
Dorsiflexion of the ankle and eversion of the foot
What technique is most useful if the block is to be used at the primary anesthetic?
Double injection "Staab"
Muscles of the anterior leg:
Extensors - Digitorum longus - Hallucis longus Tibialis anterior Peroneal muscles - Longus - Brevis - Tertius
As the nerve roots of the lumbar plexus leave the vertebral foramina, what are they enclosed in?
Fascial sheath
What blocks are considered the bread and butter of anesthesia cases?
Femoral blocks
What is the largest branch of the lumbar plexus?
Femoral nerve
Action of iliopsoas/psoas major muscle?
Flexes the thigh at the hip and stabilizes the hip
The tibial portion of the sciatic nerve innervates what muscle group?
Flexors (tippy toes)
What movement do we expect to see when checking placement of a pop block?
Foot dorsiflexion/plantar flexion at <0.5 mA
What movement are you looking for in the lateral approach of a pop block?
Foot twitch at <0.5mA
Muscle of the medial thigh that is innervated by the obturator nerve (L2-L3) and is responsible for thigh ADduction and medial rotation:
Gracilis
What is the longest muscle in the body?
Gracilis
Which muscle adducts the thigh, flexes and medially rotates the leg?
Gracilis
As the sacral plexus rearranges into the sciatic nerve, this exits the pelvis via what structure?
Greater sciatic foramen
Where do the sciatic and posterior femoral cutaneous nerves exit the plexus from?
Greater sciatic foramen
What is the anatomical structure in which the sciatic nerve passes through?
Greater sciatic notch
The sciatic nerve runs midway between what two structures on its course down the posterior thigh?
Greater trochanter and ischial tuberosity
In the Staab technique of a pop block, what structure can block the stimulation of the common peroneal nerve?
Head of the fibula
The common peroneal nerve divides into superficial and deep divisions after passing underneath what structure?
Head of the fibula
In the lateral approach of a pop block, the patient is placed supine with the:
Hip and knee flexed
In a LP block, what do we aim for the top of?
Iliac crest- just above L4
Muscle of the anterior thigh that is innervated by the femoral nerve (L2-L3) that flexes the thigh at the hip and stabilizes the hip:
Iliacus
4 minor nerves of the lumbar plexus:
Iliohypogastric Ilioinguinal Genitofemoral Accessory obturator
Muscle of the anterior thigh that is innervated by the ventral rami of the lumbar spinal nerves 1-3 and is responsible for flexion of the thigh at the hip and stabilization of the hip:
Iliopsoas/psoas major
Where are the branches of the lumbar plexus arranged?
In the psoas compartment
The femoral nerve branches just after _____ ligament.
Inguinal
All of the peroneal muscles (longs, brevis, tertius) lie on the _____ side of the femur
Medial
The tibial portion of the sciatic is more _____.
Medial
Are the contributions from T12 minor or major in the lumbar plexus block?
Minor
Blockade of the femoral nerve or the LP is good for any surgery of the knee extensor mechanism not only for anesthesia and analgesia, but what else?
Muscle relaxation blocks the motor function
What muscles are these? Iliopsoas/psoas major Iliacus Tensor fasciae latae Sartorius Rectus femoris Vastus lateralis Vastus medialis Vastus intermedius
Muscles of the anterior thigh
The following muscles are from what group? Pectineus Adductor longus Adductor brevis Adductor magnus Gracilis Obturator externus
Muscles of the medial thigh
Going from lateral to medial, what is the order of the nerve and vessels?
Nerve Artery Vein
The femoral nerve, vein, lymph, and artery from lateral to medial is in what order?
Nerve Artery Vein Lymph
Is the lumbar plexus neatly arranged like the brachial plexus?
No
When performing a femoral block, the back of the hand can be used to hold back what in an obese pt?
Panus
What does the rectus femoris attach to?
Patellar ligament
In the muscles of the anterior thigh, all extensors attach where? "dancing kneecap"
Patellar tendon and the retinaculum
What indicates a motor block in a femoral block?
Patient will be unable to lift heel off of bed
Muscle of the medial thigh that is innervated by the femoral nerve and sometimes obturator nerve that is responsible for thigh ADduction and flexion:
Pectineus
Muscles of the anterior leg innervation:
Peroneal (fibular) nerve
Needle should be advanced _____ to the plane of the pelvis
Perpendicular
After the first branch of the femoral nerve goes to the psoas muscle, the rest of it continues on to innervate what? What does it continue on to become?
- All the extensor mechanisms of the knee - Sensory only branch in the form of the saphenous nerve which provides sensory information to the leg below the knee
6 examples of surgeries in which LP blocks would be indicated?
- Amputations (AKA or BKA) - Hip surgery- fracture, arthroplasty, etc. - Knee surgery - Femur fracture - Tibial plateau fracture - Any surgery of the knee or extensor mechanism
2 Indications for a popliteal block:
- Any surgical procedure on the distal lower extremity - Pain from many conditions affecting the distal lower extremity
7 complications with the psoas block:
- Central spread of LA if epidural - Nerve root injection- SA or SD - Renal pelvis puncture - Great vessel puncture - Hematoma - Infection - Neuropraxia/neurolysis
LP blocks are indicated in surgeries within the distribution of what nerves?
- Femoral - Lateral femoral cutaneous - Obturator nerves
What bone are you going to come in contact with when performing the lateral approach of a pop block? What do you do?
- Femur - Redirect more posteriorly
4 indications for sciatic block:
- Foot and ankle surgery - BKA - AKA - Any surgery with significant pain in the distribution of the sciatic nerve (TKA)
Muscles of the posterior leg:
- Gastrocnemius - Soleus - Tibialis posterior ***these are all flexors of the foot
Nerves of the Lumbar Plexus:
- Iliohypogastric- T12 & L1 - Ilioinguinal- L1 - Genitofemoral- L1 & L2 - Lateral femoral cutaneous- L2 & L3 - Obturator- L2-L4 - Accessory obturator (9% of people)- L3 & L4 - Femoral- L2-L4
3 main nerves of the lumbar plexus include:
- Lateral femoral cutaneous- L2 & L3 - Obturator- L2-L4 - Femoral- L2-L4
Staab's intertendinous technique of a pop block: Position? Stim which nerves? Injection?
- Lateral or prone - Tibial and common peroneal - Inject each nerve individually
Muscles of the medial thigh are primarily innervated by what nerve? What are the 2 exceptions?
- Obturator - Pectinus is femoral and sometimes obturator, and adductor magnus is obturator and tibial
The common peroneal nerve innervates all the muscles on the lateral portion of the legs which includes what compartment? As well as what other muscle?
- Peroneal compartment - Extensors (digitorum and hallucis longus) and the tibialis anterior
Where is the lumbar plexus located? And in 1/2 people?
- Ventral roots of L1-L4 - small branch of T12
Which adductors adduct and flexes the thigh?
Brevis and Magnus
A pop may be felt when what structure is punctured in a psoas compartment block?
Interspinous ligament
What branch of the lumbar plexus is the Lateral Femoral Cutaneous Nerve?
L2 - L3
What levels does the femoral nerve come off of?
L2-L4
The obturator nerve comes off what anterior portions? It runs down what side of the psoas muscle?
L2-L4 Medial (most medial nerve)
When performing a psoas block, you insert needle 3cm caudal & 5 cm lateral to what structure?
L4
The sacral plexus is comprised of what nerve roots?
L4 to the deep sacral area (S4)
The common fibular peroneal portion of the sciatic nerve is more _____.
Lateral
The femoral nerve passes under inguinal ligament just _____ to femoral artery.
Lateral
What nerve comes off the most lateral portion of the major nerves from the lumbar plexus?
Lateral femoral cutaneous
What are the 3 major peripheral nerves of the lumbar plexus?
Lateral femoral cutaneous Femoral Obturator
Positions for pop block:
Lateral or prone
Needle insertion is where in relation to the femoral artery?
Lateral side, 2-3cm inferior to the inguinal ligament
An isolated block of the lateral femoral cutaneous nerve should achieve sensory anesthesia to what portion of the leg?
Lateral thigh
Which adductor adducts thigh only?
Longus
The innervation of the lower extremities is derived exclusively from what?
Lumbar and Sacral Plexus
The lateral femoral cutaneous nerve runs along the lateral border of what muscle?
Psoas
One of the first branches of the femoral nerve goes right through the _____ muscle.
Psoas (genitofemoral nerve?)
Potential space between psoas muscles anteriorly and quadrates lumborum posteriorly where the lumbar plexus lies:
Psoas compartment
The quadratous lumborous muscle on the posterior side and the psoas muscle on the anterior side form what compartment?
Psoas compartment
Dancing kneecap < 0.5mA indicates what?
Quadriceps twitch
What are the muscles of the anterior thigh that extend the knee ?
Quadriceps: - Rectus femoris - Vastus - Lateralis - Medialis - Intermedius
Muscle of the anterior thigh that is innervated by the femoral nerve (L2-L4) and extends the leg at the knee AND flexes the thigh:
Rectus femoris
What is the central and most anterior muscle in the quadriceps?
Rectus femoris
A continuation of the femoral nerve which is the sensory portion is called the _____ nerve - it innervates the skin of the inner portion of the leg from knee down.
Saphenous
What nerve of the posterior leg is sensory only?
Saphenous
In what nerve block do you pull the needle back to subQ after deep perineal injection and fan injection around superficially to the medial malleolus?
Saphenous Nerve
Which nerve: - Branches from femoral nerve - Follows saphenous vein to medial malleolus and ramifies to medial foot?
Saphenous nerve
A twitch of what muscle can imply an inadequate depth when performing a femoral block?
Sartorius
Posterior thigh innervation:
Sciatic
What is the major and most important nerve of the sacral plexus?
Sciatic
What nerve bifurcates 5-10 cm proximal to popliteal crease into tibial nerve (medial, L4-S3) and common peroneal nerve (lateral, L4-S2)?
Sciatic
What nerve is responsible for all motor and sensory function below the knee?
Sciatic
Which nerve bifurcates into the common perineal and the tibial nerves?
Sciatic
Which nerve does the common perineal come off of?
Sciatic
Which nerve has both tibial and common fibular peroneal components?
Sciatic
Typically, an AKA or BKA would also involve what other block besides a LP block?
Sciatic nerve block
The lumbar plexus is comprised of what area?
T12- L5
Psoas compartment location:
T12-L5
Muscle of the anterior thigh that is innervated by the superior gluteal nerve (L4-L5) and ABducts, medially rotates, and flexes the thigh AND stabilizes the trunk on the thigh:
Tensor fasciae latae
Innervation of the posterior leg:
Tibial
Of the common peroneal and tibial, which one is larger, more medial, and slightly deeper?
Tibial
What nerve is the medial portion of the sciatic nerve?
Tibial - will see plantar flexion and inversion of the foot with EMR
The sciatic nerve bifurcates into what 2 nerves approximately 5-10 cm proximal to the popliteal crease?
Tibial and Common Peroneal
Where should the skin wheal be placed in a saphenous block that should provide anesthesia?
Tibial plateau and/or 5-10cm proximal to the medial malleolus
What is the major muscle of the anterior leg?
Tibialis anterior
3 muscles of the anterior thigh that are innervated by the femoral nerve (L2- L4) AND only extend the leg at the knee joint:
Vastus lateralis, medialis, and intermedius
When performing a psoas compartment block, the bone may be contacted at 4-6 cm (iliac creast) and/or at 5-7 cm (transverse process), what do you do?
Walk needle cephalad off the bone
The bifurcation of the sciatic nerve happens 5-10 cm above (cephalad) what structure?
Popliteal fossa
What anatomic location is bounded by the medial and lateral heads of the gastrocnemius, tendons of the biceps femoris (laterally) and tendons of the semitendinosus & semimembranosus (medially)?
Popliteal fossa
What is the region just behind the knee?
Popliteal fossa
Nerve is contacted approximately 1-2 cm deeper (medial) than femur, _____ to vessels.
Posterior
The saphenous nerve runs superficially along the medial aspect of the knee and leg, just _____to the saphenous vein.
Posterior
What nerve accompanies the sciatic nerve through the greater sciatic foramen and between the piriformis and superior gamellus?
Posterior Femoral Cutaneous Nerve
For which nerve block is the pt supine with their leg externally rotated, Needle is inserted 3-4cm proximal to the medial malleolus and posterior to the tibial artery?
Posterior Tibial Nerve
Which nerve: - Branches from the sciatic nerve - L4-S3 - Posterior to medial malleolus - Accompanies posterior tibial artery and vein?
Posterior tibial nerve
Action of sartorius:
Abducts, medially rotates, and flexes the thigh
The sartorius is not a knee extensor but is a muscle of the anterior thigh- what is it responsible for?
Abducts, medially rotates, and flexes the thigh
Which nerve receives a small branch from the tibial portion of the sciatic nerve?
Adductor Magnus
Muscle of the medial thigh that is innervated by the obturator nerve (L2-L4), ADducts AND flexes the thigh:
Adductor brevis
Muscle of the medial thigh that is innervated by the anterior division of the obturator nerve (L2-L4), ADducts thigh:
Adductor longus
Muscle of the medial thigh that is innervated by 2 nerves: the ADductor part is innervated by the obturator nerve and the hamstring part is innervated by the tibial, adducts, flexes, and extends the thigh:
Adductor magnus
The medial thigh consists of what muscles?
Adductors - Magnus (has sciatic nerve innervation also) - Longus - Brevis Gracilis
The obturator innervates what area after it exits the obturator canal?
Adductors of the thigh and a portion of the skin on the medial thigh
The obturator and the femoral nerve innervate the knee joint and get contribution from what nerve?
Common peroneal
Which nerve is associated with foot drop?
Common peroneal
Which nerve passes anteriorly around the head of the fibula then bifurcates into superficial and deep peroneal nerves?
Common peroneal
Sacral plexus location:
L4-S3
Which tendon pops up when you raise your big toe?
EHL
As the needle is passed perpendicular to the skin, what indicates that the fascia has been penetrated?
A pop
Needle is inserted where in relation to the ASIS.
2cm inferior and 2cm medial
How many cc of local is fanned medial to lateral above and below fascia?
20-30mLs
Name the muscles of the anterior thigh:
A- Sartorius B- Rectus femorus C- Vastus lateralis D- Vastus intermedius E- Vastus medialis
Needle insertion is how many cm proximal to the pop fossa crease in a lateral approach of a pop block?
8-10 cm
The lateral femoral cutaneous nerve exits fascia inferior and medial to what structure?
ASIS
What is your landmark to palpate and mark?
ASIS
Where does the sartorius originate?
ASIS and the superior part of the notch below it
Indications for ankle block:
Any surgical procedure on the foot except the posterior calcaneus
Palpate and mark femoral artery just _____ inguinal ligament.
Below
By palpating the tendons of what muscle you can find the tibial nerve?
Biceps Femoris
The femoral nerve is loacted most _____ in the psoas compartment:
Centrally
What are the 5 compartments in the body that a pt can bleed into and die?
Chest Abdomen Retroperitoneal 2 thighs
What is a sign of proper needle placement when doing a femoral nerve block?
Dancing knee cap
What is the benefit of separate injections and a higher approach in the Staab pop block technique?
Decreases the likelihood of missing one of the nerves if they bifurcate higher than expected
Anything cutaneous means what?
Sensory innervation
The posterior femoral cutaneous only provides what function to what area?
Sensory innervation to the majority of the posterior portion of the thigh
What position is used to perform a sciatic nerve block (Labat approach)?
Sim's
What position do we place the pt in for a Psoas Compartment Block?
Sim's position
For which nerve block do you direct the needle laterally to inject LA superficially around to the lateral malleolus after saphenous nerve blockade?
Superficial Peroneal
Which nerve: - Branches from common peroneal - L4-S2 - Sensory to dorsum of foot and toes - Ramifies prior to passing superficially from anterolateral ankle to foot?
Superficial peroneal nerve
Which nerve is a mixed nerve?
Sural (common perineal and tibial)
What nerve block is done by inserting the needle just anterior to the achilles tendon?
Sural Nerve
Which nerve: - Formed by branches from tibial and common peroneal nerves - Posterior to lateral malleolus - Pure sensory nerve?
Sural Nerve
The sciatic nerve passes between what two muscles after it passes through the greater sciatic notch?
The piriformis (superiorly) and superior gamellus (inferiorly)