Neck Levels.. a presentation of the various Neck Levels

Neck Levels

1. Neck Levels By Dr. Devan P P

2. The  lymph nodes  in the neck have historically been divided into at least six anatomic  neck lymph node levels  for the purpose of head and neck cancer staging and therapy planning. Differing definitions exist across specialties  1-4 . The following is a synthesis of radiologically useful boundaries for each level.

3. Level I: submental and submandibular superiorly:  mylohyoid muscle  and  mandible inferiorly: inferior border of the  hyoid bone anteriorly:  platysma muscle posteriorly: posterior border of the  submandibular gland

4. Level I: submental and submandibular superiorly:  mylohyoid muscle  and  mandible inferiorly: inferior border of the  hyoid bone anteriorly:  platysma muscle posteriorly: posterior border of the  submandibular gland

5. There are two sublevels: level Ia   (submental nodes): anteromedial between the anterior bellies of both  digastric muscles level Ib   (submandibular nodes): posterolateral to the anterior belly of the digastric muscles

6. Level II: upper internal jugular (deep cervical) chain superiorly:  base of the skull  at the  jugular fossa inferiorly: inferior border of the hyoid bone anteriorly: posterior border of the submandibular gland posterolaterally: posterior border of the  sternocleidomastoid muscle medially: medial border of the  internal carotid artery

7. Level II: upper internal jugular (deep cervical) chain superiorly:  base of the skull  at the  jugular fossa inferiorly: inferior border of the hyoid bone anteriorly: posterior border of the submandibular gland posterolaterally: posterior border of the  sternocleidomastoid muscle medially: medial border of the  internal carotid artery

8. ​There are two sublevels: level IIa:  inseparable from or anterior to the posterior edge of the  internal jugular vein ; includes  jugulodigastric nodal group level IIb:  posterior to and separable by a fat plane from the internal jugular vein

9. ​There are two sublevels: level IIa:  inseparable from or anterior to the posterior edge of the  internal jugular vein ; includes  jugulodigastric nodal group level IIb:  posterior to and separable by a fat plane from the internal jugular vein

10. Level III: middle internal jugular (deep cervical) chain superiorly: inferior border of the hyoid bone inferiorly: inferior border of the  cricoid cartilage anteriorly: anterior border of the sternocleidomastoid muscle posterolaterally: posterior border of the sternocleidomastoid muscle medially: medial border of the  common carotid artery

11. Level IV: lower internal jugular (deep cervical) chain superiorly: inferior border of the cricoid cartilage inferiorly: level of the  clavicle anteriorly: anterior border of the sternocleidomastoid muscle posterolaterally: oblique line drawn through the posterolateral edge of the sternocleidomastoid muscle and the lateral edge of the  anterior scalene muscle   2 medially: medial border of the common carotid artery includes medial  supraclavicular nodes  including  Virchow node   1

12. Level V: posterior triangle superiorly: skull base at the apex of the convergence of sternocleidomastoid and trapezius muscles inferiorly: level of the clavicle anteromedially: posterior border of the sternocleidomastoid muscle posterolaterally: anterior border of the  trapezius muscle

13. ​There are two sublevels: level Va:  superior half, superior to inferior border of the cricoid cartilage (posterior to levels II and III); includes  spinal accessory  nodes level Vb:  inferior half, inferior to inferior border of the cricoid cartilage (posterior to level IV); includes lateral  supraclavicular nodes   1

14. Level VI: central (anterior) compartment superiorly: inferior border of  hyoid bone inferiorly: superior border of  manubrium  (suprasternal notch) anteriorly:  platysma muscle   8 posteriorly: trachea (medially) and prevertebral space (laterally)  8 laterally: medial borders of both common carotid arteries (medial to levels III and IV) includes anterior jugular, pretracheal, paratracheal, prelaryngeal/precricoid ( Delphian ), and perithyroidal nodes

15. Termination All the levels above eventually drain to the  jugular trunk  of their respective side and then to the  right lymphatic duct  or the  thoracic duct  (left)  10

16. Variant anatomic boundaries Minor variations to the above anatomic boundaries have been described. For example, head and neck surgeons may use different intraoperative landmarks  1,4 :  levels IIa and IIb are separated by the vertical plane defined by the  spinal accessory nerve the medial border of levels III and IV and lateral border of level VI is defined by the lateral border of the  sternohyoid muscle the posterior border of levels II through IV and anterior border of level V may also be defined by the plane of sensory branches of the cervical plexus In addition, radiologists may describe  supraclavicular nodes  separately from levels IV and V using the transverse level of the clavicle as the border

17. Additional neck levels The above classification is not inclusive of several important  nodal groups in the head and neck : superior mediastinal nodes retropharyngeal nodes parotid nodes occipital nodes posterior auricular (mastoid) nodes facial nodes

18. Other classification systems include some of these regions, but a consensus approach has not been reached. For example, with respect to "level VII," radiologists may apply this label to superior mediastinal nodes  2 , radiation oncologists may apply this label to "prevertebral nodes"  and head and neck surgeons omit this level from their nomenclature altogether.  Thus, it is best to name lymph node groups outside of the established levels I-VI. If "level VII" is used for superior mediastinal lymph nodes, it should refer to the extension of the paratracheal chain below the suprasternal notch but above the level of the  brachiocephalic artery