Supraclavicular Nerve
Original Editor - Sumayyah Musa
Top Contributors - Mohamed A Hassanin
Description
The supraclavicular nerves are three cutaneous nerves originate as a common trunk from the cervical plexus under the skin behind the posterior border of the sternocleidomastoid muscle.[1] Then, superior to the clavicle, between sternocleidomastoid and trapezius, the nerve pierces the platysma muscle and deep fascia to branch into three rami which spread and terminate over the clavicle[2] [3].
Root
The supraclavicular trunk is formed from c3-c4 roots of cervical plexus.[3]
Branches
Medial (Suprasternal), Intermediate (Supraclavicular) and lateral (supra-acromial) branches[1][4].
The lateral branch divides into two or three rami that end laterally or posteriorly or at the level of the anterior border of the acromion process while the intermediate branch divides into two or three secondary rami. Its most internal ramus crosses the middle third of the clavicle and its most external ramus crosses the second lateral quarter of the bone.[1]
The medial branch appeared to cross at the clavicle’s medial third. The lateral branch showed a trend to cross at the lateral third of the clavicle. When present, the intermediate branch displayed wide variability. [2]
Anatomical variations
Jelev and Surchev reported some anatomical variations of intermediate and lateral branches[3]:
- Intermediate branch passes through trans-clavicular canal.
- Fibrous band attaches the intermediate supraclavicular nerve to the clavicle.
- Passing of the lateral supraclavicular nerve through the superior fibers of the trapezius.
- Lateral and intermediate supraclavicular nerves are covered by a variant muscular or tendinous structures formed by the trapezius in relation to the clavicle.
Function
Supraclavicular nerves are cutaneous nerves.
Motor
No motor function mentioned for these nerves until now.
Sensory
The Supraclavicular nerves innervate the skin over the clavicle, anteromedial shoulder and proximal chest.[1]
Clinical relevance
Vulnerable to injury in cases of:
- Supraclavicular nerve entrapment syndrome: entrapment of a supraclavicular nerve branch within a canal through the clavicle.[3]
- Clavicular or acromial fracture. [2]
- Compression by safety belt during car accidents.[1]
- Surgical incisions over shoulder, clavicle or posterior triangle of the neck e.g. cervical tumor biopsy or torticollis surgery.[5]
- Violent muscular contraction or after repetitive stresses.[1]
- Inter-scalene or supraclavicular brachial plexus block.[1]
Assessment
- Tinel sign could be found along the border of the trapezius muscle (lateral branch)[1].
- Sensory Nerve Conduction studies which may be:
- Orthodromic procedure where the stimulating electrode (cathode) is placed just below the clavicle to stimulate at distances of 2.5 cm, 7 cm, and 10.5 cm lateral to the sternoclavicular joint, recording surface electrode is placed over the posterior border of the sternocleidomastoid muscle 6–7 cm from the sternoclavicular joint and reference electrode is situated 2.5 cm cranially in relation to recording electrode. Stimulus duration was 0.1 ms. The intensity did not exceed 20 mA. The amplifier gain was 10 lV/div, low frequency filter 20 Hz and high frequency filter 10 kHz. Ten to 20 responses were averaged.[5]
- Antidromic procedure where stimulating electrode is located 7 cm proximal to the active recording electrode, on a horizontal line joining the sternocleidomastoid muscle posterior edge and the superior trapezius muscle anterior edge. Recorded with a pair of electrodes, 3 cm apart, over the middle of the clavicle .The stimulating electrode is adjusted to produce the largest Sensory Nerve Action Potential (SNAP) amplitude without motor artifact. The stimulus duration is 0.2 ms and the intensity varies from 4 to 6 mA. The filter settings are 20 and 1600 Hz, respectively; the time scale is 1 ms/division, and the sensitivity is 20 μV/division. [6]
Treatment
- In cases of violent muscular contraction: local anesthetic and corticoid injection is recommended. [1]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Havet E, Duparc F, Tobenas-Dujardin AC, Muller JM, Fréger P. Morphometric study of the shoulder and subclavicular innervation by the intermediate and lateral branches of supraclavicular nerves. Surgical and Radiologic Anatomy. 2007 Sep 13;29(8):605–10.
- ↑ 2.0 2.1 2.2 Nathe T, Tseng S, Yoo B. The Anatomy of the Supraclavicular Nerve During Surgical Approach to the Clavicular Shaft. Clinical Orthopaedics & Related Research. 2011 Mar;469(3):890–4.
- ↑ 3.0 3.1 3.2 3.3 Jelev L, Surchev L. Study of variant anatomical structures (bony canals, fibrous bands, and muscles) in relation to potential supraclavicular nerve entrapment. Clinical Anatomy. 2006 Jul 12;20(3):278–85.
- ↑ Hovelacque AÉÉ. Anatomie des nerfs craniens et rachidiens et du système grand sympathique chez l’homme. Paris, France: Gaston Doin et cie; 1927.
- ↑ 5.0 5.1 Martinez‐Aparicio C, Jääskeläinen SK, Muyor JM, Falck B. Nerve conduction study of the three supraclavicular nerve branches. Muscle & Nerve. 2018 Mar 24;58(2):300–3.
- ↑ Seror P. The supraclavicular nerve. Muscle & Nerve. 2022 Apr 2;65(6):698–701.