Ultrasound Guided Peripheral Nerve Blocks

1. Ultrasound
guided nerve
blocks
Jo McDonnell

2. Femoral nerve block


The femoral nerve
block provides
anesthesia for the
entire anterior thigh,
the knee, and the
femur.
In addition, skin
anesthesia is conferred
over the medial
aspect of the distal
lower extremity via the
terminal branches of
the femoral nerve.

3. Anatomy



The lumbar plexus gives rise to the femoral
nerve (L2 – L4).
The femoral nerve enters the thigh passing
under the inguinal ligament, located lateral
to the femoral artery surrounded by the fascia
iliaca which separates it from the femoral
artery and vein.
Distal to the inguinal ligament, the femoral
nerve splits into the anterior branch, providing
skin sensation, and the posterior branches,
supplying the quadriceps muscle, medial
knee and skin sensation to the medial calf.

4. Femoral nerve block

6. Why use a probe?

Ultrasound application allows



monitor the spread of local anesthetic and needle
placement and make appropriate adjustments,
should the initial spread be deemed inadequate.
because of the proximity to the femoral artery,
ultrasound may reduce the risk of arterial puncture
that often occurs with this block with the use of nonultrasound techniques.
Palpating the femoral pulse as a landmark for the
block is not required with ultrasound guidance, a
process that can be challenging in obese patients.

7. 
A high frequency (6 – 18 MHz) linear array

A curvilinear probe can be used if more depth is
warranted.

The probe is placed in the inguinal crease, in
transverse.

The probe is slid until the femoral vessels are seen.
The nerve lies about 1-2 cm lateral to the artery,
positioned below fascia iliaca and lata and
above the ilieopsoas muscle

The nerve itself can have a triangular or oval
shape and is often not clearly visualized. Because
of this, the triangle created by the femoral artery
medially, fascial planes anteriorly and the iliopsoas
muscle posteriorly is used as the target for the
block. The nerve becomes visualized after
injection.

12. Goal
 The
goal is to place the needle tip
immediately adjacent to the lateral
aspect of the femoral nerve, into the
wedge-shaped tissue space lateral to the
femoral artery.
 Proper deposition of local anesthetic is
confirmed by observation of the femoral
nerve being lifted off of the surface of the
iliopsoas or of the spread of the local
anesthetic above in the wedged-shaped
space lateral to the artery.

13. Median nerve block

14. Median nerve block


toward the wrist deep to
the flexor digitorum
superficialis in the center
of the forearm.
superficial position until it
is located beneath the
flexor retinaculum in the
carpal tunnel with the
tendons of flexor
digitorum profundus,
flexor digitorum
superficialis, and flexor
pollicis longus

15. Median nerve-at the wrist

16. MN- at the wrist

17. MN-at the elbow



In the antecubital fossa, the
median nerve lies medial to
the brachial artery.
With the arm extended, a
high-frequency (8-18 MHz)
probe is placed tranversely
over the brachial artery
pulse.
Medial to the artery, the
median nerve is exhibits its
classic honeycomb
appearance

18. Ankle block
 There
are five nerves that provide sensory
innervation to the foot at or below the
level of the ankle. These are four distal
branches of the sciatic nerve (posterior
tibial, sural, deep and superficial peroneal
nerves) and one branch from the femoral
nerve (saphenous nerve).

19. 
Ankle block
5 nerves

2 deep



Deep peroneal
Posterior tibial
3 superficial



Sup. Peroneal
Sural
Saphenous

20. Ankle nerve distribution

21. Ankle nerve distribution

22. Posterior tibial nerve



Groove behind the
medial malleolus
and achilles tendon
Locate posterior
tibial artery
Nerve posterior to
artery

26. Superifical nerves


Blockade of all three superficial nerves is
accomplished using a circumferential injection of
local anesthetic subcutaneously
Level joint line to 5cm above joint

27. Complications
 Haematoma
 Failed
block
 Intravascular injection
 infection

28. Contraindications
 Infection
over injection site
 coagulopathy

29. Images obtained from www.nysora.com