Each spinal nerve can be tracked from the branches of the brachial plexus in the transition zone behind the subclavian artery on top of the first rib to the sulcus of the spinal nerve of each transverse process
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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
The brachial plexus is sandwiched between the anterior and the middle scalene muscles in the interscalene groove
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
– 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 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
Basic UGRA (Ultrasound Guided Regional Anaesthesia) consists of easily learned and safe peripheral nerve blocks allowing effective perioperative analgesia for the majority of surgical procedures involving the upper and lower limbs and the anterolateral abdominal wall
The basic nerve blocks are exclusively performed as single shot injections using the in-plane needle approach to the target nerve
The learning objectives of the basic ultrasound guided regional anaesthesia program are:
– Understanding the basic anatomy and sonoanatomy of the basic nerve blocks
– Understanding how to perform each of the basic nerve blocks
– Knowledge about the pitfalls
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
