Trapezius muscle innervation from the spinal accessory nerve and branches of the cervical plexus

The course of spinal accessory nerve in the posterior triangle, the innervation of the sternocleidomastoid and trapezius muscles and the contributions from the cervical plexus were studied in 20 cadaveric dissections. The nerve was most vulnerable to iatrogenic injuries after leaving the sternocleidomastoid. Direct innervation of trapezius by cervical plexus branches was noted in five dissections, whereas connections between the cervical plexus and the spinal accessory nerve were observed in 19 dissections. These were usually under the sternocleidomastoid (proximal to the level of division of the nerve in nerve transfer procedures). Although the contribution from the cervical plexus to trapezius innervation is considered minimal, trapezius function can be protected in neurotization procedures by transecting the spinal accessory nerve distal to its branches to the upper position of trapezius.

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Anatomical variations of the spinal accessory nerve and its relevance to level IIb lymph nodes

Otolaryngology ◽

10.1016/j.otohns.2009.07.005 ◽

2009 ◽

Vol 141 (5) ◽

pp. 639-644 ◽

Cited By ~ 19

Author(s):

Sang Hyuk Lee ◽

Jong Kyu Lee ◽

Sung Min Jin ◽

Jin Hwan Kim ◽

Il Seok Park ◽

...

Keyword(s):

Lymph Nodes ◽

Case Series ◽

Anatomical Variations ◽

Ventral Side ◽

Spinal Accessory Nerve ◽

Accessory Nerve ◽

Cervical Plexus ◽

Spinal Accessory ◽

Adjacent Structures ◽

Inferior Border

Objective: This study was conducted to identify anatomical variations of the spinal accessory nerve (SAN) in the upper neck, the landmark of the anterior and inferior border of level IIb, and to evaluate the nerve's effect on the border and the number of lymph nodes (LNs) in level IIb. Study Design and Setting: Case series with planned data collection. Subjects and Methods: A total of 181 neck dissections (NDs) were prospectively enrolled in this study. The relation between the SAN and adjacent structures (internal jugular vein [IJV], sternocleidomastoid muscle [SCM], cervical plexus) and the number of LNs in level IIb was investigated. Results: The SAN crossed the IJV ventrally in 72 cases (39.8%) and dorsally in 104 cases (57.4%), and passed through the IJV in five cases (2.8%). The SAN ran along the inner surface of the SCM and sent branches to the SCM without penetration of the muscle in 83 cases (45.9%), whereas in 98 cases (54.1%) the nerve sent branches to the SCM by penetration. Cervical plexus contribution to the SAN was seen from C2 in 96 cases (53.1%), C2 and C3 in 69 cases (38.1%), and C3 in 16 cases (8.8%). The mean number of LNs of level IIa and level IIb was 6.5 and 8.2 in cases in which the SAN crossed the IJV ventrally, and 6.8 and 5.4 in dorsally crossing cases. LNs included in the neck level IIb in ventrally crossing SAN cases were significantly larger than the dorsally crossing cases ( P < 0.05). Conclusions: Our results may help to minimize the incidence of injuring the SAN in the upper neck during ND. Neck level IIb would contain more LNs if the course of the nerve leans toward the ventral side.

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A practical suggestion on functional neck dissection with preservation of spinal accessory nerve and cervical plexus

JOURNAL OF JAPAN SOCIETY FOR HEAD AND NECK SURGERY ◽

10.5106/jjshns.5.185 ◽

1995 ◽

Vol 5 (2) ◽

pp. 185-192

Author(s):

Wataru Nishijima

Keyword(s):

Neck Dissection ◽

Spinal Accessory Nerve ◽

Accessory Nerve ◽

Cervical Plexus ◽

Spinal Accessory ◽

Practical Suggestion ◽

Functional Neck Dissection

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Lateral pectoral nerve transfer for spinal accessory nerve injury

Journal of Neurosurgery Spine ◽

10.3171/2016.5.spine151458 ◽

2017 ◽

Vol 26 (1) ◽

pp. 112-115 ◽

Cited By ~ 9

Author(s):

Andrés A. Maldonado ◽

Robert J. Spinner

Keyword(s):

Nerve Injury ◽

Motor Function ◽

Standard Treatment ◽

Trapezius Muscle ◽

Nerve Transfer ◽

Spinal Accessory Nerve ◽

Accessory Nerve ◽

Supraclavicular Approach ◽

Spinal Accessory ◽

Pectoral Nerve

Spinal accessory nerve (SAN) injury results in loss of motor function of the trapezius muscle and leads to severe shoulder problems. Primary end-to-end or graft repair is usually the standard treatment. The authors present 2 patients who presented late (8 and 10 months) after their SAN injuries, in whom a lateral pectoral nerve transfer to the SAN was performed successfully using a supraclavicular approach.

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Contralateral spinal accessory nerve for ipsilateral neurotization of branches of the brachial plexus: a cadaveric feasibility study

Journal of Neurosurgery ◽

10.3171/2011.2.jns1122 ◽

2011 ◽

Vol 114 (6) ◽

pp. 1538-1540 ◽

Cited By ~ 6

Author(s):

R. Shane Tubbs ◽

Martin M. Mortazavi ◽

Mohammadali M. Shoja ◽

Marios Loukas ◽

Aaron A. Cohen-Gadol

Keyword(s):

Brachial Plexus ◽

Spinous Process ◽

Trapezius Muscle ◽

Nerve Transfer ◽

Average Diameter ◽

Spinal Accessory Nerve ◽

Accessory Nerve ◽

Nerve Injuries ◽

Potential Donor ◽

Spinal Accessory

Object Additional nerve transfer options are important to the peripheral nerve surgeon to maximize patient outcomes following nerve injuries. Potential regional donors may also be injured or involved in the primary disease. Therefore, potential contralateral donor nerves would be desirable. To the authors' knowledge, use of the contralateral spinal accessory nerve (SAN) has not been explored for ipsilateral neurotization procedures. In the current study, therefore, the authors aimed to evaluate the SAN as a potential donor nerve for contralateral nerve injuries by using a novel technique. Methods In 10 cadavers, the SAN was harvested using a posterior approach, and tunneled subcutaneously to the contralateral side for neurotization to various branches of the brachial plexus. Measurements were made of the SAN available for transfer and of its diameter. Results The authors found an SAN length of approximately 20 cm (from transition of upper and middle fibers of the trapezius muscle to approximately 2–4 cm superior to the insertion of the trapezius muscle onto the spinous process of T-12) available for nerve transposition. The average diameter was 2.5 mm. Conclusions Based on these findings, the contralateral SAN may be considered for ipsilateral neurotization to the suprascapular and axillary nerves.

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