The indications of the interscalene block are:

– Anaesthesia for shoulder surgery & shoulder
procedures

– Analgesia after shoulder surgery & shoulder
procedures

The ultrasound guided interscalene brachial plexus block is a basic level block

The brachial plexus is sandwiched between the anterior and the middle scalene muscles in the interscalene groove

The shoulder muscles are innervated by

1) the axillary nerve (C5-C6; deltoid and teres minor)
2) the suprascapular nerve (C5-C6; supraspinatus and infraspinatus)
3) the subscapular nerve (C5-C6; subscapularis and teres major)
4) the medial and lateral pectoral nerves (C5-T1; major and minor pectorals)
5) the musculocutaneous nerve (C5-C7; coracobrachialis and long and short heads of biceps brachii)
6) the thoracodorsal nerve (C6-C8; latissimus dorsi)
7) the radial nerve (C5-T1; long and lateral heads of the triceps brachii)

The muscles innervated by the axillary and suprascapular nerves are the most clinically important for shoulder surgery

1)-3) and the major part of 4)-7) are anaesthetised by an interscalene brachial plexus block

The cutaneous innervation of the shoulder is:

1) the axillary nerve (C5-C6; superior lateral brachial cutaneous nerve)

2) the supraclavicular nerve (C4; from the cervical plexus)

3) intercostal nerves (T2-T4; anterior cutaneous branches)

4) radial nerve (C5-T1; inferior lateral brachial cutaneous branches)

The interscalene brachial plexus block typically covers only C5-C6

– Select a high-frequency linear probe
– Adjust gain, focus, and depth 2-3 cm
– Turn the orientation mark on the probe postero-lateral on the right side and antero-lateral on
the left side of the patient
– Place the probe behind the clavicle on top of the first rib oriented practically in the
parasagittal plane
– Locate the black, pulsatile subclavian artery (SA) on top of the first rib between the anterior
and the middle scalene muscles
– Locate the branches of the brachial plexus (BP) posterior to the SA
– Track the BP branches proximally until the profiles of the C5 and C6 spinal nerve roots line
up like a string of black pearls in the interscalene groove. C5 appears as one profile, C6 as
two
– Capture the best possible cross sectional image by tilting the probe and fine-tuning gain,
focus, and depth

The brachial plexus (BP) innervates the upper limb

The BP originates from five spinal nerve roots: C5 to T1

The shoulder is innervated by the suprascapular nerve and the axillary nerve. They both originate from the spinal nerve roots C5 and C6

Anaesthesia of the shoulder requires blockade of the BP proximal to the level of the trunks, because the suprascapular nerve branches off the superior trunk

The shoulder and the shoulder joint is innervated by the axillary nerve and the suprascapular nerve

Minor contributions from the long thoracic nerve and capsular filaments from the infraspinatus nerve are not clinically significant

It is important to advance the needle tangential to the target nerves and NOT penetrate the nerves

Click on the VIDEO CLIP button to view the video

When local anaesthetic is injected it generates a contrast effect that enhances visualisation of the target nerves, because of the black background of the fluid

Click on the VIDEO CLIP button to view the video

To localise the brachial plexus you should start by localising the pulsating subclavian artery where it runs across the first rib

The branches of the brachial plexus are located just lateral to the artery

Track the branches of the brachial plexus proximally until they line up as a string of black pearls in the interscalene groove

Click on the VIDEO CLIP button to view the video