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Finally, a simple block for hip procedures.  I was pointed towards this block by an Australian ER physician who was looking for help with hip fracture patients.  I am very thankful to him for pulling my head out of the sand.  While I was busy trying to find the safest way to address the lumbar plexus directly through a paravertebral approach, he directed my attention to this clever use of an anatomical compartment to act as the conduit between the syringe and the nerves of the lumbar plexus.

The Fascia Iliaca Compartment Block (FICB) is a simple block for post-operative pain relief for procedures and injuries involving the hip, anterior thigh, and knee.  This block is useful, pre and post-operatively, for fractures of the hip and proximal femur, as well as total hip arthroplasties.

The Neuraxiom version of the FICB uses ultrasound to locate the superficial fascial layer of the iliopsoas muscle at the anterior edge of the ilium and the introduce a needle just beneath that fascia.  Local anesthetic solution is then injected, creating a local anesthetic filled space below the fascia.  As this local-filled space increases in size during injection, the fluid travels cephalad beneath the fascia and contacts the nerves of the lumbar plexus which are located there.  These nerves are the lateral femoral cutaneous nerve, the femoral nerve and the obturator nerves.

The effect of the FICB is the same as the 3 in 1 block described by Alon Winnie, but the FICB provides a much more reliable method of reaching the lumbar plexus targets.

The Neuraxiom version of the FICB block is performed with the ultrasound, but other, previous versions of this block use only surface landmarks and the feel of the needle as it passes the fascia lata and the iliacus fascia (2 pops), to position the needle.  We use ultrasound to assure that the needle tip is not only in the correct plane, but to allow the operator to safely advance the needle further into the fluid filled space after the initial bolus of local anesthetic solution is concluded.  Ultrasound also allow the operator to directly observe the spread of the local solution cephalad, towards the superior ilium during injection.

Since this is a compartment block we use a fairly large amount of volume to assure adequate spread of the solution in the compartment, 40 to 50 mls being commonly used.

When we are performing the FICB for post-operative pain relief for patients haing total hip replacement surgery, we use a more dilute local anesthetic solution to minimize motor block while preserving pain control so as not to interfere with early ambulation protocols.  For these total hip patients, we use a 50 ml of a mixture of ropivacaine 0.21% and mepivacaine 0.8%.  For patients who will not be weight-bearing immediately following surgery, such as fractured femoral neck or proximal femur, we can use 50 ml of a stronger solution such as 0.25% - 0.375% bupivacaine or ropivacaine with the addition of mepivacaine or lidocaine for faster onset.

Anatomy of the Fascia Iliaca Block

The Iliacus muscle is a large, flat, triangular muscle that lines and fills the ilium.  It originates from all along the upper portions of the ilium and iliac crest, sacrum and iliolumbar ligaments.  The iliacus muscle joins with the lateral side of the psoas major muscle.  Together they are referred to as the iliopsoas.  The iliopsoas exits the pelvis from beneath the inguinal ligament, wraps around the proximal neck, and inserts into the lesser trochanter, acting as a powerful hip flexor.

The fascial covering of the iliopsoas is thin superiorly, becoming significantly thicker as it reaches the level of the inguinal ligament.  This thickness provides a great deal of resistance and a large “pop” as a needle tip is passed through the fascia. 

The lumbar plexus is made up of the nerve roots from the T12 through L5 vertebrae.  The largest branch of the lumbar plexus is the Femoral nerve is, arising from the L2, L3, & L4 roots.  The femoral nerve descends through the fibers of the psoas major and exits at the lower portion of the psoas' lateral border, passing downward between the psoas and iliacus muscle, deep to the iliacus fascia.  The femoral nerve exits the pelvis into the upper thigh, lateral to the common femoral artery and vein.

The Lateral Femoral Cutaneous nerve is a purely sensory nerve arising from the L2 & L3 nerve roots that provides sensation from the iliac crest down the lateral portion of the thigh to the area of the lateral femoral condyle.  The lateral femoral cutaneous nerve emerges from the lumbar plexus and travels downward lateral to the psoas muscle and crosses the iliacus muscle deep to the iliacus fascia.

The anterior and posterior Obturator nerves innervate a portion of the distal, medial thigh.  They arise from the L2, L3, & L4 nerve roots and cross the iliacus muscle, deep to the fascia, to the medial thigh.  The obturator nerves are sometimes involved in the FICB but probably plays little role in post-operative pain relief for most surgeries of the hip and proximal femur.


Key Points of the Fascia Iliaca Block

Make sure you are looking at iliacus fascia. While this seems easy, the sartorius muscle crosses the iliopsoas just after it passes over the edge of the ilium and passes under the inguinal ligament.  The simplest way to find the correct fascial layer is to clearly identify the ilium (bone) on ultrasound.  The muscle lying in contact with the bone and directly overlying it, is the iliacus muscle and so the fascial layer covering it is the iliacus fascia.

Watch for the local solution to move superiorly as you inject. We introduce the needle at the rim of the ilium and since the nerves we are after arise from the lumbar plexus, they are coming from the superomedial edge of the ilium.  So, the local solution needs to travel superiorly to encounter them at the earliest opportunity.  Make sure you know which side of the ultrasound picture is superior and which is inferior.  To ensure that the solution travels superiorly, after inserting the needle through the iliacus fascia and injecting a small amount of solution, advance the needle tip superiorly, under ultrasound, into the space created by the injected local solution.  The needle tip must remain beneath the fascia and above most of the iliacus muscle as it is advanced.  You should see the injected local solution expanding or “running off” towards the superior edge of the iliacus muscle on the ultrasound image.  It is alright if your local solution is injected within the body of the iliacus muscle, just try to keep it in the superficial (anterior) portion if possible.

If you are having trouble getting the injected solution to move superiorly toward the lumbar plexus consider placing manual pressure below the injection site to discourage retrograde flow.

This is a compartment block, volume is the key. The goal is not to place the local solution next to nerve, instead, we place the local anesthetic into an anatomical compartment containing nerves, and let the distribution of the local solution within the compartment take the local to the nerves.  The most efficient way to take advantage of this is to make sure you are using adequate volume for the block. 

We routinely use a total of 50 ml of local anesthetic mixture injected incrementally, 10 – 15 ml after needle placement, advance the needle into the space created by the volume, then inject the remainder of the local anesthetic mix. 

Some centers advocate injecting a bolus of normal saline after the initial needle placement, to initiate hydro-dissection of the sub-fascial plane, followed by the local anesthetic solution. While this technique seems reasonable, since the saline and the local will eventually occupy the same space, it makes more sense to simply start and end with the solution of the final concentration.


Performing the Fascia Iliaca Block

You will need an ultrasound machine with an linear array ultrasound probe usually in the mid to high frequency range (e.g.-8-10 MHz).  Occasionally you will have a patient which requires a probe with a lower frequency to visualize the edge of the ilium.  In this case the abdominal-type probe in the 2 – 4 mHz range with a curved face will work.

Besides the skin prep solution, sterile gel, and a skin wheal, you will need a 3.5” - 4” needle for the block.  The needle can be a short bevel block needle or a Tuohy needle.  We routinely use a 20G 3.5” Tuohy needle and hold the needle bevel up for the passage through of the fascial layers.  Because of the angle at which the needle is usually held to the skin, it is a good idea to attach an IV extension tubing between the  needle and the syringe with the local solution to allow for more freedom of movement.

You will also need a syringe with your choice of local anesthetic solution.  You should use about 50 ml of solution for the block to make sure that you get a good spread through the compartment.  If you are performing the block for hip or femoral fracture, you will probably want to use a stronger local anesthetic solution such as ropivacaine 0.5%, possibly with lidocaine or mepivacaine mixed into it, for faster onset.  If you are performing the block for post-operative pain control following total hip replacement, you may want to use a lighter concentration, like ropivacaine 0.2% with some lidocaine or mepivacaine for less motor block. 

The patient is placed in supine position with you (the blocker) standing along-side the operative hip and thigh within comfortable reach of the area to be surveyed (the area between the femoral artery and the anterior superior iliac spine).  The ultrasound video screen should be opposite blocker's position for easy viewing.

Your non-dominant hand should hold the ultrasound probe while your dominant hand holds the needle.

If the patient has a pannus, this should be retracted by assistant or held up using adhesive tape.  Many times you can enlist the patient's help in holding up their own pannus to assist you.



Apply gel and place the ultrasound probe in a perpendicular orientation over the inguinal ligament, between the anterior superior iliac spine (ASIS), and the femoral artery.  It is helpful to palpate and place the probe over the ASIS first then move the probe medially along the line of the inguinal ligament.

It is important to know the orientation of the ultrasound probe, and the resulting ultrasound survey picture, for which side is superior and which is inferior.

Moving or aiming the probe medially will allow you to identify the relative location of the common femoral artery.

Palpate for the anterior superior iliac spine (ASIS) and then move the probe over it and visualize it on ultrasound.  Now move the probe medial 2 – 3 cms and inferior a little bit to see the edge of the ilium.  Look for the muscle covering the ilium and descending into the pelvis with it.  This muscle is the iliacus muscle.  The bright band covering the iliacus is the iliacus fascia. (or fascia iliacus). 

Move the probe superiorly over the edge of the ilium so that the echo-reflective curve of the ilium is on the inferior side of the ultrasound survey picture and you can clearly see the fascia and iliacus muscle. 

Stabilize the hand holding the ultrasound probe to minimize movement.  Perform a skin wheal at the inferior edge of the ultrasound probe and insert the block needle at the site of the skin wheal for an In-Plane approach.

Advance the needle In-Plane so that you can see its passage in the subcutaneous tissue moving superiorly.  Angle the needle to try to cross the iliacus fascia about midway across the bony edge of the ilium.  You should feel a pop and see the needle tip puncture the iliacus fascia.

Ideally then needle tip should be kept just beneath the iliacus fascia but this is not always possible but try to keep the needle tip from moving to deeply into the iliacus muscle after it has punctured the iliacus fascia.  The block will still work if the local solution is injected into the superficial layers of the iliacus but having the local spread superiorly, subfascially will provide the fastest onset and most solid block.

Once the needle tip is sub-fascial, aspirate then inject a few mls of the local solution to see how it spreads.  Ideally the solution with lift the fascia off of the superficial layer of the iliacus muscle and spread in a superior direction.  If the needle tip is within the iliacus muscle, you will note the muscle fibres spreading apart and solution moving in the superior direction.  After injecting 5 – 10 mls, advance the needle another centimeter or 2 while watching on ultrasound.  Advancing the needle will help the solution to move superiorly during subsequent injection. 


After the needle is advanced into the space made by the initial injection, inject the remainder of the local solution slowly.  Watch carefully during injection to make sure that the solution is moving in the superior or cephalad direction.  Adjust the needle position, if necessary, to correct placement of the solution.

  • Note that the proximal sartorius muscle crosses the iliopsoas and appears on the survey as a separate muscle end with differently oriented bundles, overlapping the iliopsoas diagonally from the inferior side.  You really don't want to inject the local solution into the sartorius muscle, it won't help.
  • It's necessary to be sure you are looking at the fascia of the iliacus muscle and not the sartorius muscle.  Once you have positively identified the iliacus fascia, stabilize your hand holding the probe to prevent it from moving and proceed with the skin wheal and introduction of the block needle.
  • * Note that whenever an ultrasound survey picture includes a hollow (dark) circle, it is a good idea to verify whether the circle is a vascular structure.  To do this turn on the Color Flow or Power Doppler function of your ultrasound machine and move the active square over the structure of concern.  Angle the probe slightly to bring out any Doppler evidence of flow.  Once you are sure of the nature of the structure, you can make better decisions about whether to change your target site or to take measures to avoid the vessel, if necessary.


  • Aspirate occasionally during injection of the local. 
  • When performing the fascia iliaca block you will generally not see the local solution accumulating at the site of injection.  More commonly the local solution will spread along the planes almost as soon as it is injected.  When you stop injecting you will usually note the space holding the fluid in the tissue will shrink slightly as the local solution spreads out in an attempt to equalize the pressure at the site of injection with the surrounding intramuscular pressure.
  • If you feel excessive resistance to injection, either withdraw the needle slightly or advance it, depending on what you are seeing in the survey window.
  • If you feel there excessive inferior runoff of the local solution, in other words, some or too much of the local appears to be spreading out in the direction opposite the lumbar plexus, you may want to use one you hands or the hand of an assistant to place manual pressure inferior to the injection site to encourage antegrade flow towards the lumbar plexus.
  • Placing pressure over the injection site for 10 seconds or so, after completing the injection will probably speed up the onset of the block by spreading the local solution with external pressure.  This maneuver is also a common way of trying to enhance the block's effects, expecially during the first few times you perform the fascia iliaca block.
  • CATHETER INSERTIONS – If you are inserting a catheter into the fascia iliaca compartment, do so after you have injected all of the solutions.  This will make sure there is ample space for the catheter to move into as it is inserted. 

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