Unit 8 - Lower Extremity Blocks Flashcards
(170 cards)
1
Q
A
A = lateral femoral cutaneous
B = obturator
C = saphenous
D = superficial peroneal
2
Q
nerves anesthetized by a 3-in-1 femoral n. block
A
femoral n.
lateral femoral cutaneous n.
obturator n. (commonly missed)
3
Q
which nerve innervates this osteotome
A
superficial peroneal n.
4
Q
which nerve is anesthetized by injecting LA into the plane of the line between the Achilles tendon and lateral malleolus
A
sural n.
5
Q
LA is injected around which nerves for a popliteal block
A
common peroneal n.
tibial n.
6
Q
assessing which movement is the best way to assess femoral n. block
A
knee extension
7
Q
the sural n. is formed by collateral branches of what 2 nerves
A
tibial n
common peroneal n
8
Q
largest peripheral nerve in the body
A
sciatic nerve
9
Q
6 terminal branches of the lumbar plexus
A
Iliohypogastric
Ilioinguinal
Genitofemoral
Lateral femoral cutaneous
Obturator
Femoral
I
Invariably
Get
Lazy
On
Fridays
10
Q
2 plexuses that innervate lower extremities
A
sacral plexus
lumbar plexus
11
Q
where does the lumbar plexus originate
A
from anterior rami of L1-L4 (+T12 contribution in ~50% of the population)
12
Q
what does the lumbar plexus primarily innervate
A
front of leg
13
Q
origin of sacral plexus
A
originates from anterior rami of L4-S4
14
Q
primary innervation of sacral plexus
A
back of leg
15
Q
where does the lumbar plexus form
A
within psoas muscle and passes in front of quadratus lumborum
16
Q
which nerve roots give rise to lateral femoral cutaneous n.
A
L2-L3 (posterior divisions)
17
Q
which nerve roots give rise to femoral n.
A
L2-L4 (posterior divisions)
18
Q
which nerve roots give rise to obturator n.
A
L2-L4 (anterior divisions)
19
Q
where does lateral femoral cutaneous n form
A
midpoint of psoas muscle
20
Q
where does femoral n form
A
near middle and lower third of psoas
21
Q
branch of femoral n. that gives rise to saphenous n
A
posterior branch
22
Q
where does obturator n form
A
medial border of psoas at level of SI joint
23
Q
nerve often injured in pts undergoing extensive pelvic surgery
A
obturator
24
Q
where does sacral plexus form
A
anterior to psoas major
25
5 major branches of sacral plexus
Superior gluteal
Inferior gluteal
Posterior cutaneous
Pudendal
Sciatic
| SIPPS
26
trunks that comprise sciatic n
tibial
common peroneal/fibular
27
where does sciatic n divide into tibial & common peroneal nerves
proximal popliteal fossa
28
where does tibial n arise from
anterior branches of L4-S3
29
where does common peroneal n arise from
posterior branches of L4-S3
30
3 terminal branches of common peroneal n.
Deep peroneal n.
Superficial peroneal n.
Sural n.
31
terminal nerves at ankle that originate from sciatic n.
Superficial peroneal
Deep peroneal
Sural
Posterior tibial
32
primary nerves of coccygeal plexus
pudendal
inferior anal
perineal
33
sensory innervation of L2 dermatome
upper medial thigh
34
sensory innervation of L3 dermatome
lower medial thigh
35
sensory innervation of L4 dermatome
lateral thigh + anterior knee
36
sensory innervation of L5 dermatome
lateral lower leg + top of foot
37
sensory innervation of S1 dermatome
posterior leg (more lateral)
38
sensory innervation of S2 dermatome
posterior leg (more medial)
39
peripheral nerves from lumbar plexus that are sensory only
lateral femoral cutaneous, saphenous, sural
40
sensory & motor innervation of femoral n.
sensory = anterior thigh, medial leg
motor = hip flexion/lateral rotation, knee extension + flexion
41
sensory & motor innervation of obturator nerve
sensory = hip joint, medial thigh
motor = hip ADDuction, flexion, & extension
42
sensory innervation of lateral femoral cutaneous n
lateral thigh to knee
| no motor
43
sensory & motor innervation of pudendal n
sensory = perineum, anal canal, external sphincter
motor = anal sphincter tone
44
sensory innervation of posterior femoral cutaneous n
posterior hip to midcalf
45
sensory & motor innervation of superficial peroneal n
sensory = dorsal surface of foot
motor = ankle eversion
46
sensory innervation of deep peroneal n.
web space between big toe and 2nd toe
47
motor innervation of tibial n
Toe: ABduction + ADDuction + extension + flexion
Ankle: plantar flexion
48
motor innervatin of sciatic n
hip extension
knee flexion
49
peripheral nerve responsible for sensory innervation of dorsal surface of foot
superficial peroneal n
50
peripheral nerve responsible for hip flexion and knee extension
femoral n
51
peripheral n responsible for hip extension and knee flexion
sciatic n
52
peripheral n responsible for plantar flexion
tibial n
53
peripheral nerve responsible for dorsiflexion
peroneal n
54
peripheral nerve responsible for ankle eversion
superficial peroneal n
55
peripheral nerve responsible for ankle inversion
deep peroneal n
56
nerves that innervate the hip joint
femoral
obturator
sciatic
57
nerve that innervates the biceps femoris, semitendinosus, and semimembranosus
sciatic n
58
spinal nerve roots posterior femoral cutaneous n arises from
S1-S3
59
spinal nerve roots lateral femoral cutaneous n arises from
L2-L3
60
provides sensory and motor innervation to lower abd wall, anteromedial thigh, and knee
lumbar plexus
61
provides sensory and motor innervation to gluteal region, posterior thigh, lower leg, and foot
sacral plexus
62
A = lateral femoral cutaneous n
B = femoral n
C = posterior femoral cutaneous n
D = obturator n
E = saphenous n
F = common peroneal n
G = superficial peroneal n
H = deep peroneal n
I = sural n
J = medial calcaneal n
K = lateral plantar n
L = medial plantar n
63
how to assess motor function of femoral n
hip: flexion & rotation
knee: extension & flexion
64
how to assess function of obturator n
hip adduction, flexion, & extension
65
how to assess function of pudendal n
anal sphincter tone
66
how to assess function of sciatic n
hip extension
knee flexion
67
how to assess function of tibial n
toe abduction, flexion, & extension
ankle plantar flexion
68
how to assess function of superficial peroneal n
ankle eversion
69
how to assess function of deep peroneal n
ankle dorsiflesion + inversion
70
objective of PENG block
inject LA deep into psoas tendon at level of iliopubic prominence
71
PENG block indications
hip fracture, hip arthroplasty
72
why are high conncentrations of LA not required for PENG block
73
LA volume for PENG block
30-40 mL
74
what is the iliopublic eminence
junction of ilium and pubis
75
what does PENG block target
articulating branches from lumbar plexus that supply only sensory innervation to hip capsule
| *Femoral nerve is spared
76
why are high concentrations of LA not required for PENG block
analgesic block (not anesthetic)
77
PENG block complications
**few**
direct injection in psoas = quad weakness
ureter injury
78
3 nerves targeted by fascia iliaca block
femoral, obturator, lateral cutaneous
79
advantages of fascia iliaca block over lumbar plexus block
faster and more consistent blockade of femoral & lateral cutaneous nerves
80
increases risk of ureter injury with PENG block
Inserting needle above level of inguinal ligament & advancing too
81
fascia iliaca block indications
* Surgical procedures of femur, quadriceps, knee
* Acute pain management for hip fractures
82
lower extremity block only performed with US
PENG
83
objective of fascia iliaca block
deposit LA below fascia iliaca that travels towards lumbar plexus
84
transducer used for fascia iliaca block
high-frequency linear array transducer in a sagittal orientation
85
total LA volume for fascia iliaca block
40 mL
86
landmarks for fascia iliaca block
ASIS
pubic tubercle
sartorius
internal oblique
| sartorius & IO form "bowtie"
87
when is LOR felt with fascia iliaca block (landmark technique)
as needle passes through fascia lata
2nd loss of resistance as it pierces fascia iliaca
88
what happens if you if needle inserted too superficially and medial to femoral nerve for fascia ilacia block
stimulation of sartorius mucle (inner thigh twitching)
## Footnote
If it happens, withdraw needle and advance slightly laterally until you obtain a ‘patellar snap’
89
what happens if you if needle inserted too superficially and medial to femoral nerve for fascia ilacia block
stimulation of sartorius mucle (inner thigh twitching)
## Footnote
If it happens, withdraw needle and advance slightly laterally until you obtain a ‘patellar snap’
90
fascia iliaca block complications
failed/incomplete block if LA injected above fascia
LAST
quad weakness
91
where do L2-L4 roots merge to form femoral n
in psoas major
92
borders of femoral triangle
* Sartorius muscle
* Adductor longus muscle
* Inguinal Ligament
| "SAIL"
93
borders of femoral triangle
* Sartorius muscle
* Adductor longus muscle
* Inguinal Ligament
| "SAIL"
94
anatomic structures inside the femoral triangle
femoral vein
femoral artery
femoral nerve
95
where does femoral n divide into anterior and posterior branches
once under the inguinal ligament
96
best assessment of femoral n block
assess knee extension
97
what does the anterior branch of femoral n innervate
ventral surface of the thigh and sartorius muscle
98
what does the posterior branch of femoral n innervate
quadriceps muscle, knee joint, and its medial ligament
99
combination of what 2 blocks provides almost complete surgical coverage to lower extremity
femoral + sciatic blocks
100
can femoral n block be used for surgical anesthesia?
nope, not alone
| combine with sciatic block
101
can femoral n block be used for surgical anesthesia?
nope, not alone
| combine with sciatic block
102
femoral n block indications
* Surgical anesthesia & analgesia for procedures involving hip, femur, quadriceps, and knee
* acute pain management for hip fractures
103
position for femoral n block
supine position with slight external extremity rotation
104
transducer used for femoral n block
high-frequency linear array transducer (10-12 MHz) in transverse orientation
105
major anatomical landmarks for US-guided femoral n block
femoral artery
femoral vein
femoral n
106
LA volume for femoral n block
20-30 mL
107
regardless of technique, needle must penetrate ____ to ensure efficacious block
fascia lata & fascia iliaca
108
indicates proper needle placement for nerve stim. guided femoral n block
quadriceps contraction
109
3-in-1 block approach to femoral n is designed to block what 3 nerves
femoral n
lateral femoral cutaneous n
obturator n (often missed)
110
why is femoral block assoc with falls
quadriceps weaness
111
boundaries of femoral triangle
1. Base of triangle = inguinal ligament
2. Medial side of triangle = Medial aspect of sartorius
3. Lateral side of triangle = medial aspect of adductor longus
112
nerves in adductor canal
* saphenous n. (terminal branch of femoral n.)
* the nerve that innervates the vastus medialis (branch of posterior femoral n.)
113
lateral wall of adductor canal
vastus medialis
114
where does the femoral artery become popliteal artery
popliteal fossa
115
indications for adductor canal block
ACL repair, MCL repair, patella fracture, vein stripping & harvesting, supplementation to sciatic nerve block for foot/ankle surgery
116
transducer used for adductor canal block
high-frequency linear array transducer (10 - 12 MHz) in transverse orientation
| May need a lower frequency for patients with increased body habitus
117
transducer used for adductor canal block
high-frequency linear array transducer (10 - 12 MHz) in transverse orientation
| May need a lower frequency for patients with increased body habitus
118
how does saphenous n appear on US in adductor canal approach
hyperechoic - anterolateral to artery
119
LA volume for adductor canal lbock
15-20 mL
120
increases likelihood of quadriceps weakness with adductor canal block
proximal injections and local anesthetic volumes that exceed 20 mL
121
where is the popliteal fossa formed
between muscles in posterior compartment of the lower extremity
122
key anatomic landmarks for popliteal block
* Popliteal artery & vein
* Biceps femoris, semitendinosus, semimembranosus muscles
* Bifurcation of sciatic n. into common tibial n. and common peroneal n.
123
where does the sciatic n become superficial and divide into tibial & common peroneal n
approx 7-10 cm proximal to popliteal fossa
124
how to identify the approximate location of the sciatic nerve
by finding the 'triangle' in the posterior knee created by the popliteal crease (the base) and the convergence of the biceps femoris and semitendinosus muscles (the apex)
125
target of popliteal block
sciatic nerve branches in proximal popliteal fossa
126
indications of popliteal n block
* Provides pain control for below-the-knee surgical procedures (ankle surgery, Achilles repair, foot surgeries)
* Helps manage acute pain
* Combined with saphenous n. block, provides complete coverage of lower extremity and knee
127
how does tibial n appear on US for popliteal block
hyperechoic structure dorsal and lateral to anechoic artery and vein in popliteal fossa
128
what positions can patient be in for an US-guided popliteal block
prone, lateral, or supine
129
total LA volume for popliteal block
25 mL
130
optimal location for LA placement for popliteal block
point where sciatic n. divides into TN & CPN
## Footnote
Some use PNS with US
131
main drawback of popliteal block
foot drop
numbness of sole
| may contribute to patient falls
132
main drawback of popliteal block
foot drop
numbness of sole
| may contribute to patient falls
133
5 nerves blocked for a total ankle block
1. saphenous
2. sural
3. superficial peroneal
4. deep peroneal
5. posterior tibial
134
nerves of ankle block that are sensory only in the ankle and foot
saphenous
sural
superficial peroneal
135
mnemonic for nerves and actions at ankle/foot
TIPPED
Tibial: Inversion, Plantarflexion
Peroneal: Eversion, Dorsiflexion
136
landmarks for ankle block -posterior tibial n
posterior tibial artery
achilles tendon
medial malleolus
137
landmarks for ankle block - sural n
lesser saphenous vein
Achilles tendon
lateral malleolus
138
landmarks for ankle block - deep peroneal n
medial malleolus
tendons of anterior tibial & long mucles of great toe
139
landmarks for ankle block - superficial peroneal n
lateral malleolus
140
landmarks for ankle block - saphenous n
greater saphenous vein, medial malleolus
141
nerves of ankle block in close proximity to arteries
posterior tibial n. (posterior tibial a.)
deep peroneal n. (anterior tibial a.)
142
sensory and motor functions of deep peroneal n.
* Sensory innervation = Lateral side of the great toe (hallux),medial side of the 2nd digit
* Motor innervation = eversion + dorsiflexion
143
sensory and motor innervation of posterior tibial n.
* Sensory innervation = Sole of the foot
* Motor innervation = Inversion + plantar flexion
144
transducer used for ankle blocks
* high-frequency (10-12 MHzO) linear array
* Use a small footprint transducer, such as a "hockey stick," to reduce the incidence of air artifact due to the limited surface area of the ankle.
145
equipment needed for ankle block with landmark technique
10 mL syringe with 1.5" 25g needle
nerve stimulation not necessary
146
nerves of ankle block that can be blocked without removing the needle (one skin puncture)
deep peroneal, superficial peroneal, and saphenous nerves
147
LA volume of ankle block
3-5 mL per nerve
148
where must LA reach to anesthetize sural n
superior border of lateral malleolus (landmark technique)
149
goal of LA distribution in US-guided sural n block
circumferential spread around lesser saphenous vein
150
complication of nerve blocks
vascular injury (except superficial peroneal n)
nerve compression/ischemia
| avoid excessive LA volumes, vasoconstrictors
150
complication of nerve blocks
vascular injury (except superficial peroneal n)
nerve compression/ischemia
| avoid excessive LA volumes, vasoconstrictors
151
where is the lumbar plexus contained
within a sheath inside psoas compartment
152
location of lumbar plexus within the psoas compartment
* Lateral to the vertebral column
* Anterior to the quadratus lumborum muscle
* Posterior to the psoas muscle
153
3 major nerves targeted by psoas compartment (lumbar plexus) block
1. lateral femoral cutaneous n
2. femoral n
3. obturator n
154
patient position for lumbar plexus block
lateral decubitus - block side up
155
landmarks for lumbar plexus block
intercristal line/L4-L5 interspace
PSIS
156
point of needle entry for lumbar plexus block
3 cm caudad from L4 and 5 cm lateral from the midline.
157
mean skin to lumbar plexus depth
8 cm
158
total LA volume for lumbar plexus block
20-30 mL
159
complications of lumbar plexus block
* sympathectomy of ipsilateral extremity
* retroperitoneal hematoma
* renal capsular injection
160
what increases risk of bilateral extremity spread in lumbar plexus block
LA volumes > 20 mL
161
contraindication to lumbar plexus block
coagulopathies
162
nerve roots that contribute to sciatic nerve
L4-L5 and S1-S3
163
where does the sciatic nerve divides into tibial and common peroneal nerves
As it passes between the major trochanter and the tuberosity of the ischium into the lower third of the thigh
164
uses of sciatic n block by itself
useful for procedures on the back of the thigh, lower leg, ankle, and foot
165
sciatic n. block approach often combined with femoral n block to provide complete coverage for TKA
posterior landmark approach (Labat approach)
166
landmarks for sciatic n block
greater trochanter
PSIS
sacral hiatus
167
what motor response is desired when using nerve stimulation for a sciatic n block
dorsiflesion or plantarflexion
| For surgical anesthesia, plantar flexion (foot inversion) is preferred
168
what motor response is desired when using nerve stimulation for a sciatic n block
dorsiflexion or plantarflexion
| For surgical anesthesia, plantar flexion (foot inversion) is preferred
169
at the level of the ankle, which nerve is not immediately adjacent to a vascular structure
superficial peroneal n.
