Korean J Radiol.  2017 Feb;18(1):180-193. 10.3348/kjr.2017.18.1.180.

High-resolution Imaging of Neural Anatomy and Pathology of the Neck

• Lee JH
• Cheng KL
• Choi YJ
• Baek JH

• KMID: 2468132
• DOI: http://doi.org/10.3348/kjr.2017.18.1.180

Abstract

The neck has intricately connected neural structures, including cervical and brachial plexi, the sympathetic system, lower cranial nerves, and their branches. Except for brachial plexus, there has been little research regarding the normal imaging appearance or corresponding pathologies of neural structures in the neck. The development in imaging techniques with better spatial resolution and signal-to-noise ratio has made it possible to see many tiny nerves to predict complications related to image-guided procedures and to better assess treatment response, especially in the management of oncology patients. The purposes of this review is to present imaging-based anatomy of major nerves in the neck and explain their relevant clinical significance according to representative pathologies of regarded nerves in the neck.

Keyword

Magnetic resonance imaging; Neck; Vagus nerve; Cervical plexus; Brachial plexus; Sympathetic ganglion; Spinal accessory nerve; Anatomy; Pathology; Cervical vertebrae

MeSH Terms

Brachial Plexus/anatomy & histology/diagnostic imaging/pathology
Cervical Plexus/anatomy & histology/diagnostic imaging/pathology
Humans
Magnetic Resonance Imaging
Neck/*anatomy & histology/diagnostic imaging/pathology
Signal-To-Noise Ratio
Vagus Nerve/anatomy & histology/diagnostic imaging/pathology

Figure

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  Fig. 1 Diagram of cervical sympathetic trunk (A) and brachial plexus (B). AS = ansa subclavia, AScM = anterior scalene muscle, C1–C8 = 1st to 8th cervical nerves, ICSG = inferior cervical sympathetic ganglion, ITA = inferior thyroid artery, LC = lateral cord, LCM = longus capitis muscle, LT = lower trunk, MC = middle cord, MCSG = middle cervical sympathetic ganglion, MPScM = middle and posterior scalene muscles, MT = middle trunk, PC = posterior cord, PhN = phrenic nerve, SCA = subclavian artery, SCSG = superior cervical sympathetic ganglion, UT = upper trunk, VA = vertebral artery, XII = hypoglossal nerve

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  Fig. 2 Normal MRI appearance of cervical sympathetic ganglia (CSGs). A-C. Coronal fat-suppressed (FS) T2-weighted image (T2WI) (A), axial contrast-enhanced fat-suppressed T1-weighted image (B), and axial T2WI (C) demonstrating typical locations and signal characteristics of superior (triple arrows on A), middle (single arrow on B), and inferior (double arrows on A and C) CSGs. Coronal FS T2WI (A) clearly shows that connecting nerve branches with superior CSG (dotted triple arrows) and inferior CSG (dotted double arrows). Note that middle CSG is located posterior to common carotid artery (empty arrow on B), anterior to vertebral artery (VA, short arrow on B), and lateral to longus colli muscle (arrowhead on B). Inferior CSG on either side is present as stellate ganglion lateral to longus colli muscle (arrowhead on C) and posteromedial to origin of VA (short arrows on C). Asterisk = subclavian artery, C2 = 2nd vertebra, C7 = 7th vertebra, dotted arrow = T1 nerve root, T1 = 1st thoracic vertebra

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  Fig. 3 60-year-old male with squamous cell carcinoma of right pyriform sinus (T3N1M0) after definitive concurrent chemoradiation therapy. Pretreatment (A, B) and post treatment (C, D) axial T2-weighted images (T2WIs) and contrast-enhanced fat-suppressed T1-weighted images (CE FS T1WIs) demonstrate homogeneously enhanced superior cervical sympathetic ganglia (CSG, thin arrows on A-D) on either side lateral to longus capitis muscle (arrowheads on A) and posterior to internal carotid artery (empty arrows on A). Note that there is typical intraganglionic hypointensity at center of superior CSGs both on T2WI and CE FS T1WI. Superior CSGs become enlarged in anterior to posterior dimensions along with diffuse radiation-induced change in retropharyngeal space, pharyngeal wall, and bilateral cervical level II.

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  Fig. 4 Schwannomas arising from cervical sympathetic ganglia (CSGs). Axial contrast-enhanced fat-suppressed T1-weighted images (A, B) and axial T2-weighted image (C) showing shwannomas arising from superior (thick arrow on A), middle (thick arrow on B), and inferior (thick arrow on C) CSGs. Masses arising from superior and middle CSGs typically displace internal carotid artery (empty arrow on A) or common carotid artery (empty arrow on B) to lateral side with internal jugular vein (arrowhead on A). Triple and double arrows on A and C showing normal superior and inferior CSGs, respectively.

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  Fig. 5 58-year-old female with left breast cancer. Coronal fat-suppressed T2-weighted images (FS T2WIs) (A) and contrast-enhanced (CE) FS T1-weighted image (T1WI) (B) showing infiltrative and enhanced tumor involving entire trunks of left brachial plexus (arrows). Coronal FS T2WI (C) depicts hyperintense change without enhancement of roots (empty arrows), part of lower trunk (dotted arrow), and medial cord (thin arrow) originating from secondary compressive plexopathy, different from infiltrative tumor (thick arrows on A and B). There is no enhancement at corresponding segments of left brachial plexus on coronal CE FS T1WI (D).

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  Fig. 6 66-year-old female with diffuse and large B-cell lymphoma involving brachial plexus. Coronal fat-suppressed (FS) T2-weighted image (T2WI) (A), axial T2WI (B), and contrast-enhanced (CE) FS T1-weighted image (C) demonstrating ill-defined infiltrating mass (arrows on A-C) involving left C5 and C6 nerve roots and upper trunk that displaces left middle trunk (double arrows on A) inferiorly. Note denervation changes with T2 hyperintensity and homogeneous enhancement of subscapularis (asterisk on B and C), supraspinatus (empty arrows on B and C), and pectoralis major (dotted arrow on C) muscles.

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  Fig. 7 56-year-old male with left shoulder weakness after radiation therapy for metastatic lymph nodes in left supraclavicular area due to right lung cancer. Coronal fat-suppressed (FS) T2-weighted images (T2WIs) (A, B) and axial T2WI (C) showing marked T2 hyperintensity of left C6 (long arrow on A), C7 (short arrows on A and B), and C8 (long arrow on B and C) nerve roots caused by radiation-induced brachial plexopathy. There are atrophy, T2 hyperintense change, enhancement of left paravertebral (thick arrow on C and D), middle and posterior scalene (asterisk on C and D), and levator scapulae (dotted arrow on C and D) muscles secondary to plexopathy. Note that C8 nerve roots (long arrow on D) are also diffusely enhanced by contrast agent on axial contrast-enhanced FS T1-weighted image (D). Short arrows on C denote normal right C6 and C7 nerve roots in interscalene triangle.

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  Fig. 8 55-year-old female with breast cancer and history of lymph node metastasis in left supraclavicular area. A-D. Axial T2-weighted images for evaluation of recent left Horner's syndrome and brachial plexopathy depicting infiltrating tumor invading longus colli, anterior, middle, and posterior scalene muscles, intervening brachial plexus (short arrows on A and B), and inferior cervical sympathetic ganglion (CSG, short arrows on C and D) on left side. Note normal middle CSG (long arrow on A) and inferior CSG (long arrow on D) on right side. Dotted arrows on B and D denote C8 and T1 nerve roots, respectively.

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  Fig. 9 Diagram of cervical plexus and its branches. A = greater auricular nerve, B = lesser occipital nerve, C = transverse cervical nerve, C2–C5 = 2nd to 5th cervical nerves, D = supraclavicular nerve, DI = intermediate branch, DL = lateral branch, DM = medial branch, E = phrenic nerve, EJV = external jugular vein, F = ansa cervicalis, G = trapezius muscle, H = platysma, I = cervical branch of facial nerve, J = parotid gland, K = SCM muscle, XI = spinal accessory nerve, XII = hypoglossal nerve

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  Fig. 10 Imaging appearance of normagreater auricular nerve and its pathology. A-E. Axial T2-weighted images depicting greater auricular nerve (long arrows) branching off from cervical plexus (dotted arrow on A and B), running posterolaterally in posterior cervical triangle, and wrapping around edge of sternocleidomastoid muscle (SCM, asterisk) to proceed to parotid gland. Note external jugular vein (EJV, arrowheads) running just anterior to greater auricular nerve on surface of SCM. F. Axial CT image showing typical case of schwannoma (arrow) arising from greater auricular nerve on outer surface of SCM (asterisk) posterior to EJV (arrowhead).

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  Fig. 11 24-year-old female with venolymphatic malformation in left posterior cervical triangle treated with radiofrequency ablation. Pre-treatment axial CT images (A-C) showing that part of non-enhancing lobulating mass (arrowheads on A-C) is incorporating greater auricular nerve (arrow on A). Patient had decreased sensation of left auricle and mastoid area following her treatment. Post-treatment axial contrast-enhanced CT images (D-F) showing decreased size with post-treatment enhancement of lesion at edge and posterior surface of sternocleidomastoid muscle (arrowheads on E and F). Note greater auricular nerve (arrow on D) at same location on A.

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  Fig. 12 56-year-old female with metastatic lymph node in left level IV after total thyroidectomy and left lateral neck dissection. A. Axial CT image showing enhancing lymph node with cystic change in left level IV (thick arrows) posterior to internal jugular vein (IJV, arrowhead) and anteromedial to left anterior scalene muscle (asterisk). B. Transverse ultrasonography image before radiofrequency ablation of lymph node clearly showing that phrenic nerve (thin arrow) is in close contact with metastatic lymph node (thick arrows) anteromedial to left scalene muscle (asterisk). Arrowhead denotes IJV. C. Axial T2-weighted image in another patient demonstrating relationship of phrenic nerve (thin arrow), IJV (arrowhead), anterior scalene muscle (asterisk), and vagus nerve (dotted arrow).

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  Fig. 13 66-year-old male after total thyroidectomy and right modified radical neck dissection for thyroid carcinoma. A. Postoperative axial CT image showing small ill-defined hypoattenuating mass in right level III (arrow). B. Ultrasonography image clearly showing C4 spinal nerve (short arrows) continuous from neural foramen to heterogeneous hypoechoic mass (long arrow), thus confirming traumatic neuroma.

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  Fig. 14 Distribution of vagus (A) and spinal accessory (B) nerves in neck. A = pharyngeal branch, B = superior laryngeal nerve, BE = external branch, BI = internal branch, C = left recurrent laryngeal nerve, D = superior, middle, and inferior cardiac nerves, E = right recurrent laryngeal nerve, F = trapezius muscle, G = sternocleidomastoid muscle, H = lymph node (level V), IX = glossopharyngeal nerve, SCA = right subclavian artery, SLA = superior laryngeal artery, STA = superior thyroid artery, X = vagus nerve, Xs = superior ganglion, Xi = inferior ganglion, XI = spinal accessory nerve

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  Fig. 15 A, B. Axial three-dimensional contrast-enhanced (CE) T1-weighted turbo field echo (T1-TFE) images (acquisition, 0.6 mm; reconstruction, 1.2 mm) showing relationship of glossopharyngeal (thin arrow on A) and spinal accessory (dotted arrow on A) nerves and superior vagal ganglion (thick arrow on A) at jugular foramen. After exiting jugular foramen, vagus nerve becomes prominent, forming inferior vagal ganglion (thick arrow on B). C. On CE fat-suppressed (FS) T1-weighted image (turbo spin echo; image acquisition, 3-mm slice thickness with no gap) in different patient, inferior vagal ganglion (thick arrow) is homogeneously enhanced by contrast agent similar to top of superior sympathetic ganglion (arrowhead) located medial to ICA. D. Axial CE FS T1-TFE image of patient with metastasis to skull base showing large enhancing mass invading right occipitotemporal bone, including jugular foramen (short arrows) but not containing discernible lower cranial nerves. Note normal, superior vagal ganglion (long arrow), and glossopharyngeal nerve (thin arrow) on left side.

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  Fig. 16 Axial CT (A-C) and axial contrast-enhanced fat-suppressed T1-weighted (D) images in four different patients with vagal schwannomas (long arrows) demonstrating anatomical variations of vagus nerve within carotid sheath displacing internal jugular vein (short arrows) and internal carotid artery (thin arrow on A) or common carotid artery (thin arrows on B-D) in different directions. Note vocal-cord atrophy (asterisk) caused by vagus nerve palsy on ipsilateral side in B.

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  Fig. 17 A 54-year-old male with recent voice change. A. Reconstructed coronal CT image showing subtle fatty atrophy of right vocal cord (arrow) with secondary dilatation of ipsilateral laryngeal ventricle from vocal cord palsy. B. Axial CT image at level of thyroid demonstrating irregular cystic mass insinuating into right tracheoesophageal groove (arrow). Lesion was confirmed as ruptured parathyroid cyst with intracystic bleeding.

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  Fig. 18 55-year-old male with voice change after interbody fusion of C6/7 using anterior approach. A-C. There is metallic fusion device at C6/7 level (A). Laryngeal ventricle is dilated (asterisk on B) due to atrophy of thyroarytenoid muscle on right side. Note aberrant right subclavian artery (arrow on C) running posterior to esophagus at thoracic inlet, implying presence of right non-recurrent laryngeal nerve.

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  Fig. 19 32-year-old female who underwent radical neck dissection for advanced tongue cancer. There is neither internal jugular vein nor sternocleidomastoid muscle on left side caused by previous surgery. Note denervation atrophy of left trapezius muscle (arrows) and secondary hypertrophy of rhomboid muscle (arrowheads).

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  Fig. 20 47-year-old male with multiple cranial nerve palsy after explosion. A-D. Axial CT images demonstrating tiny metallic foreign bodies with hematoma (dotted arrow) surrounding left internal carotid artery (short arrows on A and B). Note that left internal jugular vein is obliterated on A and B. Left side of tongue (thick arrows on A) and left thyrohyoid muscle (long arrow on C) are atrophic due to hypoglossal nerve injury. Atrophy of left vocal cord (asterisk on D) and left side of hypopharyngeal wall (arrowhead on C) suggest vagus nerve injury. Atrophy of left sternocleidomastoid muscle (long arrow on D) and left trapezius muscle (empty arrow on D) implies damage to spinal accessory nerve.

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