5 Suprascapular Nerve Block

10.1055/b-0035-124647

5 Suprascapular Nerve Block

5.1 Anatomy

The upper trunk is formed by the roots of C5/C6. The suprascapular nerve branches from the brachial plexus in the region of the upper trunk (Fig. 5.1 and Fig. 5.2). It continues along the lateral border of the brachial plexus in the supraclavicular fossa as far as the scapular notch. After passing through the notch, which is bordered by the sometimes calcified superior transverse scapular ligament, it reaches the supraspinous fossa (Fig. 5.3).

**Fig. 5.1** Course of the suprascapular nerve. 1 Upper trunk 2 Suprascapular nerve 3 Transverse ligament 4 Suprascapular artery 5 Spine of scapula 6 Acromion

**Fig. 5.2** Suprascapular nerve, origin from upper trunk. 1 Sternocleidomastoid 2 Superficial cervical artery 3 Scalenus anterior muscle with phrenic nerve 4 Subclavian artery 5 Suprascapular artery 6 Suprascapular nerve 7 Dorsal scapular artery 8 Upper trunk

**Fig. 5.3** Scapula, seen from behind. 1 Suprascapular artery and vein 2 Suprascapular nerve 3 Acromion 4 Infraspinatus 5 Spine of the scapula 6 Transverse ligament

The supraspinous fossa is shaped like a tub. On the floor of this “tub,” the nerve runs laterally and then passes along the posterior branch of the neck of the scapula to reach the infraspinous fossa and shoulder. It divides into a motor branch to the supraspinatus and infraspinatus muscles and gives off a sensory branch to the shoulder (Fig. 5.4, Fig. 5.5, Fig. 5.6).

**Fig. 5.4** Scapula, seen obliquely from behind. Note “tub” shape between the scapula and the spine of the scapula (supraspinous fossa). 1 Acromion 2 Spine of the scapula 3 Scapula

**Fig. 5.5** Suprascapular nerve block, Meier approach (view from behind). 1 Acromion 2 Suprascapular nerve 3 Spine of the scapula 4 Infraspinatus 5 Trapezius

**Fig. 5.6** Suprascapular nerve block, Meier approach (view from behind). 1 Suprascapular nerve 2 Suprascapular artery 3 Superior transverse scapular ligament 4 Acromion 5 Supraspinatus 6 Spine of the scapula 7 Trapezius

5.2 Meier Approach

Meier et al (2002) were able to show from anatomical studies that dye, when injected on the floor of the supraspinous fossa, drains out through the notch and thus definitely reaches the suprascapular nerve (Fig. 5.7). Dangoisse et al (1994) and Feigl et al (2007) also arrived at similar results.

**Fig. 5.7** Right shoulder region, seen from above after injection of dye into the supraspinous fossa. Note the passage of the dye through the scapular notch with staining of the suprascapular nerve. Dissection in prone position. 1 Dye in the supraspinous fossa 2 Transverse ligament with scapular notch 3 Suprascapular nerve before its passage through the scapular notch, bathed in dye

5.2.1 Procedure

The patient is in sitting position with the head bent slightly forward. A line is drawn from the medial end of the spine of the scapula to the lateral posterior border of the acromion. Half way along this line, the injection site is established 2 cm medial and 2 cm cranial from this point (Fig. 5.8 and Fig. 5.9).

**Fig. 5.8** Site of injection and needle direction for suprascapular block, Meier approach. 1 Middle of spine of the scapula 2 Injection site (2 cm cranial and 2 cm medial to the middle of the spine of the scapula)

**Fig. 5.9** Scapula, seen from behind. Note “tub” shape. 1 Acromion 2 Scapular notch

A 6-cm needle is advanced in a lateral direction on the floor of the supraspinous fossa at an angle of 75° to the skin surface. The needle should be directed roughly toward the head of the humerus (Fig. 5.10). For a continuous technique, the catheter is advanced 2 to 3 cm ahead (Fig. 5.11 and Fig. 5.12).

**Fig. 5.10** Suprascapular nerve block, Meier approach: needle direction.

**Fig. 5.11** Supraspinous fossa, seen from above: position of indwelling catheter. 1 Scapular notch 2 Acromion 3 Spine of the scapula

**Fig. 5.12** Suprascapular nerve catheter for postoperative pain therapy. Alternative when an interscalene plexus catheter is not possible.

Material

Needle: 6 cm

Continuous technique: pencil-point needle (catheter-through-needle technique)

Tips and Tricks

The block can be performed with or without a nerve stimulator. The presence of a motor response at 0.5 mA and 0.1 ms shows that the needle is in the correct position. If no nerve stimulator is used, bone contact is found and the needle is then withdrawn somewhat.
A catheter can be advanced without difficulty using a pencil-point needle with lateral opening that should be facing laterally.
The block technique takes advantage of the fact that the blade of the scapula forms a “tub” with the spine of the scapula that can be filled with local anesthetic. Local anesthetic thus reaches the suprascapular nerve through the scapular notch. There is practically no danger of causing pneumothorax (Büttner and Meier 2006).
An ultrasound-guided block is possible and easy to perform (Chan and Peng 2011).