Peripheral nerve blocks in the cervical region: from anatomy to ultrasound-guided techniques

Abstract

Cervical plexus nerve blocks have been employed in various head and neck operations. Both adequate anaesthesia and analgesia are attained in clinical practice. Nowadays, ultrasound imaging in regional anaesthesia is driven towards a certain objective that dictates high accuracy and safety during the implementation of peripheral nerve blocks. In the cervical region, ultrasound-guided nerve blocks have routinely been conducted only for the past few years and thus only a small number of publications pervade the current literature. Moreover, the sonoanatomy of the neck, the foundation stone of interventional techniques, is very challenging; multiple muscles and fascial layers compose a complex of compartments in a narrow anatomic region, in which local anaesthetics are injected. Therefore, this review intends to deliver new insights into ultrasound-guided peripheral nerve block techniques in the neck. The sonoanatomy of the cervical region, in addition to the cervical plexus, cervical ganglia, superior and recurrent laryngeal nerve blocks are comprehensively discussed.

Keywords: cervical plexus; interventional ultrasonography; nerve block.

Figure 1.

Anatomy of the cervical plexus.

Figure 2.

(a) Transverse sonogram of C5 transverse process and nerve root. (b) The cervical transverse processes are depicted as hyperechoic curved lines at the sagittal plane, C4, C5, C6 = transverse processes of 4, 5, 6 vertebrae, arrow = nerve roots, *=anterior tubercle of C5 transverse process, **=posterior tubercle of C5 transverse process, insets: transducer position in the posterior and anterior cervical triangle.

Figure 3.

Anatomic area between perivertebral fascia and sternocleidomastoid muscle at the level of C4 transverse process. *=area between perivertebral fascia and sternocleidomastoid muscle, single arrow = nerve roots, inset: transducer position in the posterior cervical triangle. A.SC, anterior scalene muscle; CA, carotid artery; M.SC, middle scalene muscle; STRN, sternocleidomastoidmuscle.

Figure 4.

Anatomic area between perivertebral fascia and sternocleidomastoid muscle at the level of C5 transverse process. *=area between perivertebral fascia and sternocleidomastoid muscle, single arrow = nerve roots, inset: transducer position in the posterior cervical triangle. A.SC, anterior scalene muscle; CA, carotid artery; M.SC, middle scalene muscle; STRN, sternocleidomastoid muscle.

Figure 5.

Transverse oblique view of the submandibular region. The subplatysmal area between the anterior margin of the sternocleidomastoid muscle and the submandibular gland is the target of LA injections (arrow) to block the superficial cervical ansa. Inset: transducer position in the carotid triangle. p, platysma; SBM.G, submandibular gland; STRN, sternocleidomastoid muscle.

Figure 6.

A Sagittal view of the submandibular space. Inset: transducer position in the carotid triangle. M, mandible; MH, mylohyoid muscle; p, platysma; SBM.G, submandibular gland.

Figure 7.

Transverse sonogram of cervical ganglia anatomic area at the level of C7 (A) and C6 (B) vertebrae. Arrow = C7, C6 nerve roots respectively, *=posterior tubercle of the TR.P, **=anterior tubercle of the TR.P, inset: transducer position in the anterior cervical triangle. A, carotid artery; IJV, internal jugular vein; L.C, longus colli muscle; O, oesophagus;TH.G = thyroid gland; TR.P C6, transverse process of C6 vertebra; TR.P C7, transverse process of C7 vertebra.

Figure 8.

Transverse sonogram at the level cricothyroid membrane. Membrane, cricothyroid membrane.