In the inguinal region the femoral nerve (FN) runs lateral to the femoral vessels and on top of the iliopsoas muscle
The femoral nerve runs below the iliacus fascia
To reach the nerve with your needle you have to penetrate two fascia: fascia lata and the iliacus fascia
The femoral nerve runs below the iliacus fascia and on top of the iliacus muscle
The lumbar part of the lumbosacral plexus emerges from five spinal nerves: T12, L1, L2, L3 and L4
It gives origin to three important nerves in lower limb innervation: The femoral, the obturator and the lateral femoral cutaneous nerves
The most important lumbar plexus nerve concerning basic peripheral nerve blockade is the femoral nerve
It originates from the L2, L3, and L4 spinal nerves of the lumbar plexus
The branches of the femoral nerve innervate the anterior side of:
– the hip joint
– the femoral bone
– the knee joint including the patella
– the medial tibial epicondyle
A femoral branch to the hip joint arises from the nerve to rectus femoris
Branches to the knee joint arise from each of the nerves supplying the vastus muscles with a fourth branch from the saphenous nerve
Before inserting the needle through the skin, the hose and the needle should be filled with saline or local anaesthetic
Just after insertion of the needle 1/2 ml of fluid should be flushed through the hose and needle to make sure that no air is contained in the “system”
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Colour Doppler can be used to visualise the proxy marker – the axillary artery – and blood vessels that you do not want to perforate with the needle
It is also possible to use colour Doppler to visualise the injection of local anaesthetic
In that case it is an advantage to lower the PRF (Pulse Repetition Frequency) in order to enhance the visibility of the injectate
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The medial cord is located between the axillary artery and vein around the two o’clock position of the artery
The local anaesthetic does not always spread around the artery to the two o’clock position from a seven o’clock point of injection
In that case the needle tip should be repositioned in front of the axillary artery to the interspace between the axillary artery and vein and local anaesthetic should be injected periarterially
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Repositioning of the needle tip is oftentimes necessary in order to cover all three cords around the axillary artery from two o’clock to ten o’clock
Care should be taken not to pierce the axillary vein
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In the video: Notice that local anaesthetic is injected on the wrong side of the clavipectoral fascia which has to be penetrated by the needle before local anaesthetic spreads appropriately around the medial cord
In the infraclavicular block the local anaesthetic should be injected periarterially in the seven o’clock position (seeing the axillary artery as a clock face)
However, it is often necessary to reposition the needle tip in order to inject local anaesthetic periarterially from the two o’clock position around the artery to the ten o’clock position
Click on the VIDEO CLIP button to view the video
Select a linear high-frequency probe. Adjust gain, focus and depth 3-4 cm
Turn the orientation mark on the probe cranially. Place the probe below the clavicle, medial to the coracoid process in the parasagittal plane
Locate the black, pulsatile axillary artery (AA) and align it to the centre of the monitor. Seeing AA as a clock face the lateral cord is located at nine o’clock, the posterior cord at six o’clock and the medial cord at two o’clock. Often the cords are not sonographically visible
Insert the needle below the clavicle and advance it in-plane aiming periarterially at seven o’clock. Empty the needle of air by injecting 1/2 mL local anaesthetic subcutaneously
Avoid piercing any vessels or nerves
The endpoint of injection is periarterially from two o’clock to ten o’clock. Reposition the needle tip as necessary to reach the endpoint
(B) Look for the axillary artery (A); lateral cord (L); medial cord (M); posterior cord (P). Anterior (ant), posterior (post)
