Exam 4: Regional Anesthesia
What nerve is a sensory only branch of the femoral nerve. A. Saphenous n. B. Tibial n. C. Sural n. D. Superficial peroneal n.
A. Saphenous n. Rational: The saphenous n is a branch of the femoral n. that supplies sensory only properties across the anterior aspect of thigh, knee, medial lower leg, and medial aspect of ankle.
Which nerve provides sensation to the dorsum of the foot and toes? A. Superficial Peroneal Nerve B. Tibial Nerve C. Deep Peroneal Nerve D. Sural Nerve
A. Superficial Peroneal Nerve Rationale: pg 5 on the Blockade of Peripheral Nerves at the Ankle lecture states that the superficial peroneal nerve provides sensation to the dorsum of the foot and toes.
What indicates proper needle placement for the obturator nerve block?
Adductor twitch @ <0.5 mA
Where does the posterior femoral cutaneous nerve and the sciatic nerve diverge away from each other?
As both nerves pass over the quadratus femoris
The posterior femoral cutaneous nerve begins to diverge from the sciatic nerve as both nerves pass over which muscle? A. Piriformis B. Quadratus femoris C. Psoas major D. Inferior gamellus
B (Quadratus femoris) Rationale: "The PFCN accompanies the sciatic nerve through the greater sciatic foramen and btw piriformis and superior gamellus. The PFCN begins to diverge from the sciatic nerve as both nerves pass over the quadratus femoris"
Anatomy of the Lateral Femoral Cutaneous Nerve
Branch of the lumbar plexus L2 & L3 Sensory nerve only
Describe the location of the sciatic nerve
Comes out of the sciatic foramen accompanied by the posterior femoral cutaneous nerve It passes between the superior gemellus & piriformis muscle as it exits the greater sciatic foramen
Which nerve is responsible for dorsiflexion and eversion? A. Tibial B. Posterior Femoral Cutaneous C. Sciatic D. Common Peroneal
D. Common Peroneal
Which of the following nerves will elicit a motor response? A.The saphenous nerve B.The sural nerve C.The posterior femoral cutaneous nerve D.None of the above
D.None of the above
Which of the following muscles borders the popliteal fossa laterally? A.The gracilis and the gastrocnemius muscles B.The psoas muscle and the biceps femoris C.The semimembraneous and the semitendinosus D.The lateral head of the gastrocnemius and the biceps femoris
D.The lateral head of the gastrocnemius and the biceps femoris
Muscles of the posterior leg innervated by the tibial nerve
Gastrocnemius, soleus, tibialis posterior
What muscle extends the great toe and dorsiflexes ankle and what nerve innervates this muscle?
Hallicus longus Peroneal nerve
Muscles of the posterior thigh innervated by the sciatic nerve
Hamstrings-semimembranosus, semitendinosus, biceps femoris
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
Where is the posterior tibial nerve located at the ankle?
Lies to the posterior to medial malleolus,
Which nerve innervates the bone on the medial side of the hip
Obturator
What nerve innervates the gracilis and the obturator externus?
Obturator nerve (L2-L3)
What nerve innervates the adductor brevis?
Obturator nerve (L2-L4)
What nerve innervates the adductor longus?
Obturator nerve (anterior division-L2-L4)
What nerve innervate the knee joint?
Obturator, femoral, and common peroneal nerve
Describe how to perform the classic approach of Labat
Palpate & draw lines between the greater trochanter, posterior superior iliac spine & between greater trochanter & sacral hiatus. At midpoint of line to PSIS a line is drawn perpindicular (this line intersects the line toward the sacral hiatus). 22 ga 100 mm stimulator needle is introduced at this intersection and directed perpindicular to all skin planes.
The superficial peroneal nerve provides sensory to the _____ of _____ & ____.
dorsum of foot & toes
What nerve does the subgluteal approach miss?
Posterior cutaneous nerve of the thigh
What are the 5 major nerves blocked at the ankle?
Posterior tibial, sural, superficial & deep peroneal, saphenous
Indications for a lateral femoral cutaneous nerve blockade
Procedures on the lateral thigh (STSG harvest) Analgesia for tourniquet pain (?)
What muscles are innervated by the femoral nerve (L2-L4)?
Quadriceps femoris-rectus femoris, vastus lateralis, vastus medialis, vastus intermedius
What indicates proper needle placement for the femoral nerve block?
Quadriceps twitch (dancing kneecap) @ < 0.5mA→ aspirate & inject 30-40 cc
What indicates proper needle placement for a psoas compartment block?
Quadriceps twitch at <0.5 mA → aspirate & inject 30-40 cc of local
Muscle of the anterior thigh innervated by the femoral nerve
Quadriceps-rectus femoris, vastus (lateralis, medialis, intermedius); sartorius
Where does the saphenous nerve run in the popliteal fossa?
Superficially along the medial aspect of the knee & leg, just posterior to the saphenous vein
What nerve innervates the tensor fasciae latae?
Superior gluteal nerve (L4-L5)
What nerve innervates the lateral portion of the foot?
Sural
What nerve innervated the 1st web space on the foot?
Deep fibular (peroneal nerve) *marked in yellow
What nerve innervates the tibialis anterior, extensor hallicus, extensor digitorium longus, & fibularis tertius?
Deep fibular nerve (L4, L5)
Describe the popliteal fossa
Diamond shaped Proximal borders: biceps femoris & semitendinosus Distal borders: medial & lateral heads of gastrocnemius muscle
What muscle extends the 2nd thru 5th toes and dorsiflexes the ankle and which nerve innervates this muscle?
Digitorium longus Peroneal nerve
Describe the location of the lumbar plexus
Exit the intervertebral foramina Sandwiched between the quadratous laborum & psoas muscle in a fascial plane.
Muscles of the anterior leg innervated by the peroneal (fibular) nerve
Extensors-digitorum longus, hallicus longus Tibialis anterior Peroneal muscles-longus, brevis, tertius
Which of the following are matched correctly? A. Common peroneal nerve = Dorsiflexion and eversion B. Tibial nerve = plantar flexion and inversion C. Sartorius nerve = anterior thigh twitch D. Obturator = adductor twitch E. Femoral = Quadriceps twitch F. All of the above
F. All of the above
Which of the following are matched correctly? A.Femoral nerve = Sartorius and quadriceps femoris B. Tibial nerve = Gastrocenmius, soleus, tibialis posterior C. Common peroneal = Tibialis anterior D. Obturator = Gracilis muslce E. Obturator + tibial = adductor magnus F. All of the above
F. All of the above
Advantage to the transgluteal approach
Fairly reliably blocks the posterior femoral cutaneous nerve
T/F: A femoral block will provide complete analgesia for a total knee arthroplasty.
False
True/False: You need an elicited motor response at 0.5 mAmps or less for a successful lateral femoral cutaneous block.
False Rationale: The lateral femoral cutaneous is sensory only
Which nerve is most central in the psoas compartment?
Femoral nerve
What nerve innervates the sartorius?
Femoral nerve (L2-3)
What nerve innervates the iliacus?
Femoral nerve (L2-L3)
What nerve innervates the pectineus?
Femoral nerve (L2-L3) & sometimes the obturator nerve
Why does a femoral nerve blockade have the best chance of bidirectional spread, & what nerves would be covered?
Femoral nerve-most central in psoas compartment Lateral-lateral femoral cutaneous nerve Medial-obturator nerve
What is the function of the sartorius muscle?
Flexion of the hip, external rotation of the thigh
What indicates proper needle placement w/ the classic posterior/intertendinous technique for the popliteal fossa block?
Foor dorsiflexion/plantar fexion @ <0.5 mA, aspirate & inject
Indications for the sciatic nerve
Foot & ankle surgery Partial analgesia for BKA, AKA Any sx w/ significant pain in the distribution of the sciatic nerve (TKA)
What indicated proper needle position with the lateral approach the the popliteal fossa block?
Foot twitch (plantar flexion & dorsiflexion ) @ < 0.5 mA
Sural nerve
Formed by the branches from the tibial & common peroneal nerves Pure sensory nerve
What muscle plantar flexes the ankle joint and assists in flexion of the knee joint and what nerve innervates this muscle?
Gastrocnemius Tibial nerve
What muscle adducts thigh, flexes and medially rotates the leg and which nerve innervates this muscle?
Gracilis Obturator nerve
Which of the following muscles is NOT part of the border of the popliteal fossa? A. Semitendinosus muscle B. Gastrocnemius musle C. Biceps femoris muscle D. Gracilis muscle
Gracilis muscle Rationale: The gracilis muscle does NOT make up the border of the popliteal fossa. The borders of the popliteal fossa (which is a diamond shape) are made up of the: SEMIMEMBRANOSUS MUSCLE, SEMITENDINOSUS MUSCLE, GASTROCNEMIUS MUSCLES, and BICEPS FEMORIS MUSCLE
Describe what the femoral nerve looks like on US
Hyperechoic (looks grayish)
4 Sciatic nerve 5 Tibial nerve 6 Common fibular (peroneal) nerve
Identify # 4, 5, 6
1 Tibial nerve (L4, L5, S1, S2, S3) 2 Common fibular (peroneal) nerve
Identify 1, 7
Technique for blocking the deep peroneal nerve
Identify the EHL tendon & dorsalis pedis artery Insert needle just distal to ankle lateral to the EHL tendon Injection is made deep to fascia on lateral side of dorsalis pedis artery
Describe the ankle block
Infiltration block done w/o a nerve stimulator Should be done under sedation d/t multiple sticks Start w/ the posterior tibial nerve, then the deep peroneal nerve, & lastly the superficial peroneal nerve
Landmarks for femoral nerve block
Inguinal ligament, anterior superior iliac spine (ASIS), femoral artery
Technique for blocking the sural nerve
Insert needle just lateral to the achilles tendon at the level of the lateral malleolus Injection is made subcutaneously to the lateral malleolus
What 3 nerves innervates the bones of the knee?
Medial femoral condyle = obturator Lateral femoral condyle = sciatic Majority of femur = femoral
Describe the location of the obturator nerve
Medial side of femoral artery midway between adductor tendon & femoral artery, it's in a tissue plane bounded by the adductor longus, pectineus, & adductor brevis (triangular like muscle plane)
Where is the obturator nerve located?
Medially located in the psoas compartment Exits the psoas compartment medially & travels along the medial side of the psoas Enters the thigh thru obturator canal accompanied by the obturator artery & vein
Sural nerve
Mixed nerve-tibial & common peroneal contributions
Sural nerve
Mixed nerve-tibial & common peroneal nerve
Subgluteal approach to sciatic nerve block
More distal approach, performed between the ischial tuberosity & the greater trochanter inferior to the gluteus muscle
Describe the locations of the lateral femoral cutaneous nerve in the lumbar plexus
Most cephalad
What does an adductor twitch indicate during a psoas compartment block?
Needle tip is too medial
Describe needle orientation for the psoas compartment block.
Needle will penetrate the skin, SQ fat, erector spinae & quadratus lumborum muscles
Describe the sartorius muscle
Not an extensor-flexion of hip, external rotation of thigh Longest muscle in the body
Where is the femoral nerve located?
On the lateral side of the femoral artery NAVL (nerve, artery, vein, lymph)
Posterior femoral cutaneous nerve vs the sciatic nerve
Once passes the quadratus femoris the PFCN is more superficial than the sciatic nerve
Femoral nerve block
Palpate & mark femoral artery just below inguinal ligament Needle insertion is on lateral side of artery 2-3 cm inferior to inguinal ligament Stabilize needle w/ opposite hand (left hand for right femoral block & vice versa)-the back of this hand may be used to retract any panus.
Describe the location of the sciatic nerve
Passes thru greater sciatic notch, passes between the pirformis (superiorly) and superior gamellus (inferiorly), runs midway between the greater trochanter and ischial tuberosity on its course down the posterior thigh
Lateral femoral cutaneous nerve block technique
Patient supine Palpate & mark ASIS Needle is inserted 2cm inferior & 2cm medial to ASIS Needle is passed perpendicular to skin, a "pop" is felt when the fascia is penetrated 20-30 cc of local is fanned medial to lateral above & below fascia
Alternate technique for obturator nerve block
Patient supine thigh slightly abducted Identify adductor longus tendon, femoral artery & inguinal ligament Needle is inserted midway between adductor tendon & femoral artery 2 cm distal to inguinal ligament
Obturator nerve block technique
Patient supine thigh slightly abducted, identify pubic tubercle, insert needle 2 cm lateral & 2 cm caudal Bone is contacted @ 1.5- 4 cm-> redirect laterally nerve is 2-3 cm deeper than pelvic ramus
Injury to what nerve leads to foot drop, and what causes it?
Peroneal (fibular nerve) Pressure on lateral portion of the knee
What muscle dorsiflexes the ankle and aids in eversion of the foot and what nerve innervates this muscle?
Peroneal muscle: tertius Peroneal nerve
What muscles everts the foot and weakly plantar flexes the ankle and which nerve innervates these muscles?
Peroneal muscles : longus & brevis Peroneal nerve
Probe placement for lateral femoral cutaneous block
Placed inferior to the inguinal ligament using the ASIS as an orientation
Which of the following nerve is responsible for sensory over the dorsal portion of the foot? A. Sural nerve B. Superficial peroneal nerve C. Plantar nerve D. Saphenous nerve
B. superficial peroneal nerve
Which of the following are matched correctly? Obturator nerve = adduction Femoral nerve = extension
Both are correct
Describe the location of the sciatic nerve & posterior femoral cutaneous nerve
Both come out of the greater sciatic foramen, come out from behind the piriformis muscle, the 2 nerves diverge away from each other once crosses the quadratous femoris
Anatomy of the tibial and common peroneal nerves
Both nerve run thru the lateral portion of the popliteal fossa superficial & lateral to the popliteal vessels.
Anatomy of the popliteal fossa
Bounded by the medial & lateral heads of the gastrocnemius, tendons of the biceps femoris (laterally) & tendons of the semitendinosus & semimembranosus (medially)
Deep peroneal nerve
Branched from the common peroneal nerve, L4-S2 Passes into the foot just lateral to the dorsalis artery & tendon of the extensor hallicus longus (EHL)
Saphenous nerve
Branches from femoral nerve Follows saphenous vein to the medial malleolus & ramifies to the medial foot
Superficial peroneal nerve
Branches from the common peroneal, L4-S2 Ramifies prior to passing superficially from the anterolateral ankle to the foot
Posterior tibial nerve
Branches from the sciatic nerve, originates from L4-S3
The popliteal fossa block spares the ________ necessitating a separate injection for complete anesthesia. A. Femoral nerve B. Obturator nerve C. Saphenous nerve D. Lateral femoral cutaneous nerve
C Saphenous nerve
Of the following procedures, which one would have inadequate analgesia from a sciatic nerve block? A. Foot and Ankle B. Below the knee amputation C. Femur fracture repair D. Above the knee amputation
C femur fracture repair Rationale: All other choices are indications for sciatic N block, the femur is innervated by the femoral nerve, thus a sciatic block would not be adequate
Describe the location of the sciatic nerve in the popliteal fossa
It is on the medial side of the biceps femoris muscle. It bifurcates at a variable distance above the popliteal fossa.
What can be done is difficulty arises stimulating the common peroneal nerve w/ the inertendinous technique of Staab?
It may be blocked as it crosses underneath the fibula
Were is the common peroneal nerve located at the popliteal fossa?
It passes anteriorly around the head of the fibula then bifurcates into superficial & deep peroneal nerves
Describe the saphenous nerve
It's a sensory only cutaneous branch of the femoral nerve.
Describe the tibial portion of the sciatic nerve and its location
It's larger, medial, and deeper than the common fibular (peroneal) nerve
Describe saphenous nerve injection in the distal leg
Just proximal to the ankle of saphenous vein at the level of the ankle it branches off SQ but it's a tissue plan. Inject along the subcutaneous plane in the distal leg.
Anatomy of the obturator nerve
L2-L4 lumbar nerves
Femoral nerve
Largest branch of the lumbar plexus L2-L4
Lumbar plexus block: 3-in-1 block
Lateral femoral cutaneous (L2, L3) Obturator (L2-L4) Femoral (L2-L4)
Classic posterior/intertendinous technique
Lateral or prone position, mark popliteal skin crease, biceps femoris, & semitendinosis (triangle), equally divide into medial & lateral triangles, need insertion is 5-7 cm proximal to skin crease 1 cm lateral to line dividing the triangles
Intertendinous technique of Staab
Lateral or prone position, needle insertion is 7-10 cm proximal to popliteal crease & 1 cm medial to biceps femoris tendon, inject each nerve (or portion of sciatic) separately
Advantages to the classic approach of Labat
Less likely to miss the posterior cutaneous nerve
Where is the lumbar plexus located?
Lies just on anterior side of transverse processes of the lumbar vertebrae sandwiched between the quadratus lumborum posteriorly & psoas muscle on anterior side
What nerve innervate the long & short head of the biceps femoris?
Long head-tibial division of sciatic nerve (L5-S2) Short head-common fibular (peroneal) division of the sciatic nerve (L5-S2)
The superficial peroneal nerve branches from which nerve? A. Sciatic Nerve B. Sural Nerve C. Common Peroneal Nerve D. Tibial Nerve
C. Common Peroneal Nerve Rationale: pg 5 on the Blockade of Peripheral Nerves at the Ankle lecture states that the superficial peroneal nerve is a branch of the common peroneal nerve.
What is the largest and most centrally located nerve in the psoas compartment? A. Obturator nerve B. Lateral femoral Cutaneous nerve C. Femoral nerve D. Genitofemoral nerve
C. Femoral nerve The femoral nerve is the largest and most centrally located nerve in the psoas compartment
To provide anesthesia for a saphenous nerve blockade, a skin wheal may be placed ..... A. At the level of the tibial plateau B. 5 - 10 cm proximal to the medial malleolus C. None of the above D. Both A and B are true
D Both A and B are true
Which of the following is NOT a landmark used for a sciatic nerve block? A. Greater trochanter B. Posterior superior iliac spine C. Sacral hiatus D. Iliac crest
D Iliac crest Rationale: greater trochanter, PSIS, & sacral hiatus are the three landmarks used in a sciatic block. Lines are drawn between the greater troch & PSIS, also between greater troch & sacral hiatus. Midpoint of the line to PSIS a line is drawn perpendicular & will intersect the line to the sacral hiatus. 90 degrees to the line from greater troch to PSIS
All of the following are indications for a femoral nerve block except: A.surgery on or around the knee B.knee arthroplasty C.below the knee amputation D.all of the above are indications
D- All of the above
Which of the following muscles do not attach to the pes anserinus at the medial aspect of the knee? A. Sartorius B. Semitendinosus C. Gracilis D. Biceps Femoris
D. Biceps Femoris Rationale: Biceps femoris (one of the hamstrings) is on the LATERAL side of the posterior thigh. Citation:
The adductor magnus receives innervation from the: A. Obturator nerve B. Tibial portion of the Sciatic nerve C. None of these D. Both of these
D. Both of these Rationale: The adductor magnus is primarily innervated by the obturator nerve but receives a small branch of the tibial portion of the sciatic nerve
The sciatic nerve supplies sensation to which part of the lower extremity?
Provides sensation below the knee with the exception of skin on medial malleolus and portion of the tibial plateau
Technique for blocking the superficial peroneal nerve
Ramifies subcutaneously at ankle After blockade of the saphenous nerve, direct the needle laterally & inject local superficially around ti the lateral malleolus
Technique for blocking the saphenous nerve
Ramifies subcutaneously at ankle Pull needle back to subcutaneous after deep peroneal injection & fan injection around superficially to medial malleolus
What muscle extends the leg at the knee joint and flexes the thigh at the hip joint and what nerve innervates this muscle??
Rectus femoris Femoral nerve
Advantage to subgluteal approach
Requires less needle depth
Where is the lateral femoral cutaneous nerve located?
Runs along lateral border of the psoas Exits fascia inferior & medial to ASIS
Describe the location of the saphenous nerve
Runs along the sartorius muscle distally & exits at the knee at the level of the pes anserinus & comes out from behind the sartorius & gracilis muscle & crosses posterior to the saphenous vein & continues down the leg
Where is the femoral nerve located?
Runs between Psoas and quadratus lumborum / iliacus muscles in psoas compartment Passes under inguinal ligament just lateral to femoral artery Branches just after inguinal ligament
What nerve is a continuation of the femoral nerve and is a sensory only nerve?
Saphenous
Technique tips for the femoral nerve block
Sarotrius twitch is usually obtained 1st (kneecap doesn't move) this branch of the femoral nerve may lie outside the fascial plane & will not provide analgesia. If motor block is attained, pt won't be able to lift heel off bed.
What is the most important nerve of the sacral plexus?
Sciatic
T/F While performing a sciatic nerve block, you choose to utilize the Classic Approach of Labat knowing that you are less likely to miss the posterior cutaneous nerve?
TRUE Rationale: According to Dr. Staab's lecture on Sciatic Nerve Blockade (pg 8) the classic approach of labat is less likely tomiss the PCN
Injection of 5 cc local anesthetic subcutaneously, to medial malleolus just posterior to posterior tibial artery would anesthetize which nerve? a) Saphenous nerve b) Common peroneal nerve c) Posterior tibial nerve d) Sural nerve
c) Posterior tibial nerve
EHL
Tendon that pulls up the big toe
Describe the relationship between the sciatic nerve and the posterior femoral cutaneous nerve
They are contained in a common fascial plane just underneath the gluteus maximus
What does it mean if bright blood is aspirated while performing the lateral approach to the popliteal fossa block?
This indicated that the needle is too far anteriorly medial, the nerve resides more posteriorly & lateral
What indicates proper needle placement w/ in the intertendinous technique of Staab for the popliteal fossa block?
Tibial (plant flexion-"tippy toes") Common peroneal (dorsiflexion, eversion)
What nerve innervates the semitendinosus & semimembranosus?
Tibial division of the sciatic nerve (L5-S2)
What are the 2 components of the sciatic nerve?
Tibial nerve Common fibular (peroneal) nerve
What nerve innervates the popliteus?
Tibial nerve (L4-S1)
What nerve innervates the flexor digitorum longus, & the tibialis posterior?
Tibial nerve (L5-S1)
What nerve innervates the flexor hallicus longus
Tibial nerve (L5-S2)
What nerve innervates the gastrocnemius, soleus, and plantaris?
Tibial nerve (S1, S2)
What nerve innervates the skin over the calcaneous?
Tibial nerve via the medial calcaneous branch
What nerve innervates the gastrocnemius, soleus, & tibialis posterior and the cutaneous bottom portion of the foot?
Tibial portion of the sciatic nerve ("tippy toes")
What are the major nerves supplying the ankle?
Tibial, common peroneal, & saphenous nerve
What muscle dorsiflexes ankle and inverts foot and which nerve innervates this muscle?
Tibialis anterior Peroneal nerve
What muscle innervates plantarflexes the ankle and inverts the foot and what nerve innervates this muscle?
Tibialis posterior Tibial nerve
3 approaches in which the sciatic nerve can be blocked
Transgluteal approach, subgluteal approach, popliteal
T/F The lumbar plexus branches off the ventral roots of L1 through L4 and a small branch of T12 (in 1/2 of people)
True
T/F: The femoral nerve lies lateral to the femoral artery and femoral vein.
True
T/F: The posterior division of the lumbar plexus includes the lateral femoral cutaneous nerve and the femoral nerve?
True
T/F: The sacral plexus is innervated by L4-S3
True
T/F: The sciatic nerves runs through the middle of the greater trochanter and the ischial tuberosity.
True
T/F: When performing a popliteal fossa block using the intertendinous technique of Stabb the advantage of stimulating and injecting both the tibial (plantar flexion) and common peroneal (dorsiflexion, eversion) nerves individually is to decrease the likelihood of a partial block.
True
T/F: When performing an out of plane U/S guided femoral block, the needle is inserted 90 degrees to plane of the probe.
True
T/F: With a psoas compartment block, bone may be contacted at 4-6cm (iliac crest) and / or 5-7cm (transverse process of L5)?
True
T/F: You are performing a popliteal block using the intertendinous technique of Staab and are having difficulty stimulating the common peroneal nerve at 7-10 cm proximal to the popliteal crease and 1 cm medial to the biceps femoris tendon. Because of your knowledge of lower extremity anatomy you know that this nerve may be blocked as it crosses over the head of the fibula.
True
T/F; The lumbar plexus includes ventral rami if spinal nerves from T12 to L5?
True
True of False: Both the tibial and common peroneal nerve are found latteral and superficial to the popliteal vessels when passing through the popliteal fossa
True
True or False. When using the subgluteal approach to sciatic nerve block a stimulating needle is introduced midway between the greater trochanter and ischial tuberosity?
True
True or False: At the popliteal fossa, the Common Peroneal and Tibeal nerve are LATERAL to the popliteal artery and vein?
True
True or False: The femoral nerve provides motor function to sartorius muscle, extension to the knee and sensory function below the knee.
True
True or False: The sciatic nerve bifurcates, proximal to the poplilteal crease, into the Tibeal (medial) and Common Peroneal (lateral) nerves?
True
True or False: popliteal fossa blockade may be indicated for any surgical procedure on the distal lower extremity
True
True or false: The saphenous nerve, a branch of the femoral nerve, runs superficially along the medial aspect of the knee and leg, just posterior to the saphenous vein.
True
True/False: The correct needle insertion site for a femoral block is on the lateral side of the artery 2-3 cm inferior to inguinal ligament
True
Describe out of plane approach for the femoral block
US probe perpindicular to the femoral crease, needle place at 90˚ angle to the probe.
What nerve innervates the upper lateral portion of the leg?
Upper = lateral sural cutaneous nerve
What muscles extends the leg at the knee joint, and what nerve innervates these muscles?
Vastus lateralis, vastus medialis, vastus intermedius Femoral nerve L2-L4
What nerves innervate the iliopsoas/psoas major?
Ventral rami of lumbar spinal nerves 1-3
Lumbar plexus anatomy
Ventral roots of L1-L4 & a small branch of T12 (in 1/2 of people)
The posterior femoral cutaneous nerve is also a sensory only nerve and supplies sensation to which part of the lower extremity?
Posterior thigh down to the popliteal fossa
Where is the sural nerve located in the ankle?
Posterior to the lateral malleolus
Psoas compartment
Potential space (fascial sheath) between psoas muscles anteriorly & quadratus lumborum (iliacus) posteriorly
All extensors of the lower extremity attach to the _____ ____ & ____-> "_____ ____"
patellar tendon & retinaculum->"dancing kneecap"
What leads to a failed femoral nerve block?
Accidental IM injection
What muscle adducts and flexes the thigh and which nerve innervated this muscle?
Adductor brevis Obturator nerve
What muscle adducts the thigh, and which nerve innervates this muscle?
Adductor longus Obturator nerve
What muscle receives a small branch from the tibial portion of the sciatic nerve?
Adductor magnus
What muscle adducts and flexes the thigh (adductor part) and extends the thigh (hamstring part), and which nerves innervates this muscle
Adductor magnus Adductor part: obturator nerve Hamstring part: tibial nerve
What nerves innervate the adductor magnus?
Adductor portion: obturator nerve (L2-L4) Hamstring portion: tibial nerve (L4)
Indications for an obturator nerve block
Adductor spasm, adjunct to blockade of femoral, lateral femoral cutaneous & sciatic nerves, hip joint pain
What does the obturator nerve supply?
Adductors, skin over medial thigh, part of hip & pelvis, & small contribution to posterior knee joint
Muscles of the medial thigh innervated by the obturator nerve
Adductors-magnus, longus, brevis Gracilis
What does the posterior tibial nerve supply?
All motor function to plantar flexion of ankles ("tippy toes"), soleus, & gastrocnemius
What does the sciatic nerve innervate?
All motos function below the knee & all sensory except for the skin on the medial part of the leg down to the tarsal tunnel around the medial malleous (which is innervated by the saphenous nerve)
Where is the lumbar plexus block performed?
At the level of L4, US probe is placed at L3
At what level is the femoral nerve block performed?
At the level of the inguinal ligament
Plane used for most lower extremity blocks
Axial (cutting body in half)
When performing a Psoas Compartment block, if after stimulating the nerve you see adductor twitch, this indicates that the needle is: A. too lateral B. too medial C. in the right spot D. too caudad
B Too Medial
Using the femoral artery as a landmark, where is the femoral nerve located? A. Medial to the artery B. Lateral to the artery C. Inferior to the artery D. Superior to the artery
B. Lateral to the artery Rationale: The femoral nerve is located on the lateral side of the femoral artery using the mnemonic NAVL to remember its location in the groin Nerve Artery Vein Lymph
Location and function of the psoas muscle
Comes of T12-L5 vertebral bodies Flexion of the hip
Sciatic nerve
Comes off sacral plexus roots from L4-S4 (S5) Major nerve of the sacrococcygeal plexus
Describe the location of the femoral nerve
Comes off the top of the iliac crest around L4, most central in psoas compartment
Elicited motor response from the sciatic nerve with a nerve stimulator
Common peroneal - lateral - dorsiflexion, eversion Tibial - medial - plantar flexion, inversion
If the obturator nerve is being stimulated during a psoas compartment block, how should the needle be redirected?
Slightly lateral
What muscle plantar flexes the ankle and stabilizes the leg over the foot and which nerve innervates this muscle?
Soleus Tibial nerve
Anatomy of the posterior femoral cutaneous nerve
Accompanies the sciatic nerve thru the greater sciatic foramen & between the pirformis and superior gamellus
What is used as a landmark for blocking the sural nerve at the ankle?
Achilles tendon
Surface landmarks for psoas compartment block
1) Iliac crest 2) L4 spinous process
Saphenous nerve block in the popliteal fossa
A skin wheal at the level of the tibial plateau &/or 5-10 cm proximal to the medial malleolus should provide anesthesia
Located the adductor longus tendon
4
Where does the sciatic nerve bifurcate into the tibial and common peroneal nerve
5-10 cm proximal to popliteal crease (variable)
Identify the following hamstring muscles: Semitendinosus Biceps Femoris Semimembranosus Plantaris Piriformis
A - Semitendinosus B - Biceps Femoris C - Semimembranosus
If an up-and-coming contortionist were to shout "Oh My Gracilis!" after painfully stretching this fun-to-say muscle, which of the following muscles were stretched?
A Tensor fascia latae B Gracilis C Sartorius D Vastus medialis muscle
Which of the following muscle does not combine to form the pes anserinus? A. Biceps femoris B.Sartorius muscle C.Semitendinosus D.Gracilis muscle
A. Biceps femoris
Which two muscles of the medial thigh are not SOLELY innervated by the obturator nerver? A. adductor magnus and pectineus B. adductor magnus and gracilis C. adductor magnus and adductor brevis D. gracilis and pectineus
A. adductor magnus and pectineus Rationale: The adductor magnus is innervated by the obturator and tibial nerve, the pectineus is innervated by the femoral nerve and sometimes the obturator nerve
The common peroneal nerve passes _______ around the head of the fibula, then bifurcates into the superficial and deep peroneal nerves A. anteriorly B.posteriorly C.medially D.latterally
A. anteriorly
When performing a femoral nerve block what should you do if you obtain a twitch in the sartorius muscle? A. Advance slightly to obtain a dancing kneecap. B. Pull needle back slightly till the twitching stops. C. Remove needle as you have inserted the needle in the wrong spot. D. Inject. Sartorius causes a dancing kneecap which is the sign you are looking for.
A: Advance slightly to obtain a dancing kneecap.
Describe the in plane approach for a femoral block
Allows for greater control but this approach is difficult for this type of block d/t the depth of the bock.
Indications for a popliteal fossa block
Any surgical procedure on the distal lower extremity Pain from many conditions affecting the distal lower extremity
Indications of an ankle block
Any surgical procedure on the foot except the posterior calcaneus
You are performing a lumbar plexus block and you obtain an adductor twitch. What will be your next action? A.Aspirate and inject 30-40 ml local anesthetic B.Move the needle more laterally C.Advance the needle 3-4cm D.Move the needle more medially.
B. Move the needle more laterally
When using the subgluteal approach to perform a sciatic nerve block which nerve would likely be missed? A. Sciatic nerve B. Posterior cutaneous nerveC. Common Peroneal nerve D. Tibial nerve
B. Posterior cutaneous nerve Rationale: This approach likely misses the posterior cutaneous nerve of the thigh.
What two landmarks should be identified when blocking the deep peroneal nerve? A. The lateral and medial malleolus B. The extensor hallucis longus tendon and dorsalis pedis artery C. The medial malleolus and the posterior tibial artery D. The achilles tendon and the lateral malleolus
B. The extensor hallucis longus tendon and dorsalis pedis artery Rationale: "Deep peroneal nerve- Identify EHL tendon and dorsalis pedis artery."
When setting up for a popliteal fossa block which of the following is NOT part of the triangle of landmarks A. popliteal skin crease B. gastrocnemius C. biceps femoris D. semitendinosus
B. gastrocnemius
The obturator nerve is located A. Laterally in the psoas compartment B. medially in the psoas compartment C. in the subcutaneous lay of the medial epicondyle D. Near the radial nerve
B. medially in the psoas compartment
What muscle flexes and laterally rotates the leg and extends the thigh and which nerve innervates this muscle?
Biceps femoris Sciatic nerve {short head is innervated by the sciatic nerve, common fibular (peroneal) division (L5, S1, S2) Long head is innervated by the sciatic nerve, tibial division (L5, S1, & S2)}
Why is a hematoma a potential complication for a psoas compartment block?
Because it is a potential space, therefore cannot hold pressure, increased risk of retroperitoneal hematoma
Describe the relationship between the tibial nerve and common peroneal nerve in the popliteal fossa
Before bifurcation they are located in a common epineural sheath. A block at or above the bifurcation will anesthetize both portions.
The saphenous nerve is a sensory only nerve and supplies sensation to which part of the lower extremity?
Below the knee
Where is the posterior femoral cutaneous nerve located with the subgluteal approach?
Between the semitendinosus and gluteus maxiumus outside the tissue plane
What is an important landmark for locating the sciatic nerve in the popliteal fossa?
Biceps femoris
Which muscle is stimulated to achieve adequate blockage of the psoas compartment? A. Biceps B. Triceps C. Quadriceps D. Psoas major muscle
C. Quadriceps
Prior to initiating a psoas compartment block, how should the patient be positioned? A. Lithotomy B. Prone C. Sims Position D. Reverse Trendelenburg
C. Sims Position
Which of the following blocks will provide the best chance of blocking the posterior femoral cutaneous nerve? A. A femoral block B. A lumbar plexus block C. The transgluteal approach to a sciatic nerve block D.The subgluteal approach to a sciatic nerve block
C. The transgluteal approach to a sciatic nerve block
The sciatic nerve bifurcates into what 2 nerves at approximately 5-10 cm proximal to the popliteal crease? A.Tibial and Femoral B.Saphenous and obturator C.Tibial and common peroneal D.Common peroneal and axillary
C. Tibial and common peroneal
Complications of a psoas compartment block
Central spread of local->epidural Nerve root injection->subarachnoid or subdural injection Puncture of renal pelvis Puncture of great vessels Hematoma Infection Neuropraxia / Neurolysis
Which techniques for blocking the sciatic nerve spares the saphenous nerve and therefore necessitates a separate injection for complete anesthesia to the distal lower extremitiy?
Classic posterior/intertendinous technique and the lateral approach to the popliteal block.
All of the following muscles are innervated by the femoral nerve EXCEPT A. Rectus femoris B. Vastus lateralis C. Sartorius D. Gracilis
D. Gracilis
When performing an ankle block, 5 nerves are blocked, which of the following nerve is not part of the ankle block? A. Saphenous B. Deep peroneal C. Sural D. Popliteal E. Posterior tibal
D. Popliteal
What nerve does NOT innervate the sole of the foot? A.Sural B.Calcaneal C. Plantar D. Superficial Peroneal
D. Superficial Peroneal Rationale: Diagram- "Innervation of the Plantar surface of the foot involve: Deep peroneal nerve, Plantar nerve, Sural nerve, and Calcaneal nerve."
You are performing a psoas compartment block, if the adductor is stimulated (twitches), the needle tip is? A. in the correct position B. too lateral C. too perpendicular and needs to be advanced D. too medial
D. Too medial Rationale: Correct stimulation is quadriceps twithc, if adductor stimulated, needle tip is too medial.
What is the advantage to the intertendinous technique of Staab?
Decreased likelihood of partial block d/t variability of bifurcation of these nerves
What muscles flex the legs and extend the thighs and what nerve innervates these muscles?
Semimembranosus & semitendinosus Sciatic nerve (tibial division)
Is the lateral femoral cutaneous nerve a mixed nerve, motor, or sensory?
Sensory only
How is the patient positioned in the classic approach of Labat for the sciatic nerve block
Sim's position Independent side (up side) is the side to be blocked, flex independent knee
Describe the soon to be classic approach of Staab for the sciatic nerve block
Sim's position Palpate PSIS & greater trochanter At midpoint between these drop a perpendicular line 3 cm & insert 22 ga 100 mm needle aiming at anterior mid-thigh
Psoas compartment block
Sim's position Palpate iliac crest & spinous process of L4 Insert needle 3cm caudal & 5 cm lateral to L4 Needle should be advanced perpendicular to the plane of the pelvis Bone may be contacted at 4-6 cm (iliac crest) &/or at 5-7 cm (transverse process of L5)→walk needle cephalad off of the bone
Describe subgluteal approach to sciatic nerve block
Sim's postion, palpate & mark greater trochanter & ischial tuberosity 22 ga 100 mm stimulating needle introduced midway between these points aiming at the anterior thigh
The lateral cutaneous femoral nerve supplies sensation to which part of the lower extremity?
Skin on the lateral thigh
What nerve innervates the lower lateral portion of the leg and most of the top of the foot except the lateral aspect and 1st web space?
Superficial fibular (peroneal) nerve
What nerve innervates the fibularis longus and fibularis brevis?
Superficial fibular nerve (L5-S2)
Blockade of the saphenous nerve at the ankle
Superficial skin wheal acros the anterior portion of tibia all the way posterior to the medial malleolus
Describe the lateral approach to the popliteal fossa block
Supine position, hip & knee flexed Mark vastus lateralis & biceps femoris Insert needle 8-10 cm proimal to the popliteal fossa crease Femur is contacted then needle is redirected more posteriorly Nere is contacted approcimately 1-2 cm deeper (medial) than femur, posterior to vessels
Technique for blocking the posterior tibial nerve
Supine w/ leg externally rotated Insert needle 3-4 cm proximal to medial malleolus just posterior to the posterior tibial artery Needle directed anteriorly until tibia is contacted Withdraw needle 2-3 mm & 5+- cc local is injected Angle needle 45-60˚ inferiorly & repeat injection$
Indications of a femoral nerve block
Surgery on or around the knee Surgery involving the extensor mechanism of the knee Knee Arthroplasty Below Knee Amputation (combined w/ sciatic nerve block)
Indications of a lumbar plexus blockade
Surgery w/in the distribution of the femoral, lateral femoral cutaneous, or obturator nerves DOESN'T COVER SCIATIC NERVE (sacral plexus) Amputations - AKA or BKA, hip sx- fracture, arthroplasty, etc., knee sx, femur fracture, tibial plateau fracture Any sx of the knee or extensor mechanism
Disadvantage to the subgluteal approach
The posterior femoral cutaneous nerve diverges away from the sciatic nerve at this level and may not be reliably blocked
What accompanies the posterior tibial nerve at the ankle?
The posterior tibial artery & vein
What does the sciatic nerve {tibial & common fibular (peroneal) innervate?
The hamstring & motor below the knee
What separates the lumbar plexus from the sacral plexus?
The iliacus muscle (#1)
Transgluteal approach to sciatic nerve block
The most proximal block, gluteus muscle is penetrated, performed very close to sciatic foramen.
The femoral and saphenous nerve provides sensation to the skin on which part of the lower extremity?
The anterior medial portion of the the thigh and lower leg.