level 2 a and 2b cervical lymph node CV LN LEVELS

CERVICAL LYMPH NODE DISSECTION.

14TH FEBRUARY 2015

Lymph Nodes draining tissues of the head and neck are located in 
the fibrofatty tissue that lies between 
      the superficial (investing)layer of the deep fascia and 
      the deeper visceral and prevertebral layers . 

In this space the nodes lie aggregated around certain neural and vascular structures such as 
1- Internal jugular vein, 
2-Spinal accessory nerve, and
3- Transverse cervical artery.
4- Trachea and Throid -(not included in Radical or Modified Radical Neck dissections)

Much about the details of the anatomy (location) and the drainage zones of these nodes have been elucidated 
First through Lymhangiography studies done in the past three decades.–and later on through image based studies using CTScans and MRI.

Based on these studies the earlier anatomic classification of these nodes initially got redefined into     5 categories: namely -      
Junctional, Jugular,(superficial and Deep) Spinal, Supraclavicular, and Retroauricular.

However, the nomenclature in popular use today comes from  the study of the patterns of metastatic dissemination observed in patients who were treated at the center with radical neck dissection.  (The Memorial Sloan Kettering Cancer Center studies).

 In this nomenclature, Lymph nodes in the neck are grouped into levels I-V, 
 Level 1- Submental and Submandibular nodes.
 Levels II, III, IV - Upper, Middle, and Lower jugular nodes ; 
 Level V -Posterior triangle nodes 
 Level VI – Midline of the Neck

The 6 levels of the neck nodes with sublevels.

Ref Medscape

Level I

Boundaries-
Superiorly -The lower border of theBody of the mandible , 
Inferiorly -A line running horizontally from the inferior border of the hyoid bone.
Anteriorly -The anterior belly of the digastric muscle on the contralateral side . 
Posteriorly -the vertical plane marked by the posterior edge of the submandibular gland is used as a boundary between levels I and II. -(2008) ---- 
The earlier posterior boundary was The stylohyoid muscle,

Subdivisions 
Level I may be divided into

Level Ia, which refers to the nodes in the submental triangle (bound by the anterior bellies of the digastric muscles and the hyoid bone), and
Level Ib, which refers to the submandibular triangle nodes (see image ).

www.pixshark.com

Closely related, to the level Ib group of nodes, are The perifacial nodes, related to the facial vessels above the mandibular margin, and The buccinator nodes, (see image below)

www.studyblue.com

Drainage areas - 
The nodes of level Ia drain  -
The floor of mouth, / Anterior tongue,/ Anterior mandibular alveolar ridge, and Lower lip

The nodes of Level Ib - The oral cavity, / Anterior nasal cavity/, Skin and soft tissue structures of the midface,  and Submandibular gland. 

The prefacial and Buccinator nodes may become involved with metastasis from tumors in the 
Buccal mucosa,/ Nose, and  Skin and Soft tissues of the cheek and lips -

Level II

Boundaries Extend from 

The skull base Superiorly to Inferiorly the inferior border of the hyoid bone 

They are related to the upper third of the jugular vein,. 

The anterior border of level II is the vertical plane marked by the posterior edge of the submandibular gland

The 2008 classification revision proposed that the vertical plane marked by the posterior edge of the submandibular gland be used as an alternative to the stylohyoid muscle boundary 

The posterior border of level II is the posterior border of the sternocleidomastoid muscle,

www.pocketdentistry.com

Subdivisions 
The spinal accessory nerve, which travels obliquely across this area, is used as a landmark to subdivide this group 
 IIa, the part that lies anteroinferiorly and closer to the internal jugular vein 
 IIb, the portion above and behind the nerve,

Drainage areas - . The oral cavity,/  Nasal cavity,/  Nasopharynx, Oropharynx, Hypopharynx, Larynx, and Parotid gland. (see image below)

www.vocalclinic.org

Level III

Boundaries

Superiorly The Hyoid Bone 
Inferiorly -a horizontal plane defined by the inferior border of the cricoid cartilage. This line also traverses the OmoHyoid muscle at this level.

Anterior border -The sternohyoid muscle 

The posterior border is posterior border of the sternocleidomastoid muscle  .

Subdivisions -Nil

The nodes at this level lie around the middle third of the Internal Jugular vein.

Drainage areas - Oral cavity, Nasopharynx, Oropharynx, Hypopharynx, and Larynx.-
(see image below)

www.medicalgeek.com

Level IV

Boundaries -

Superior boundary – Inferior border of the Cricoid cartilage- 
Inferior boundary -The Clavicle. 
Anterior boundary -SternoHyoid muscle. 
Posterior boundary -Posterior border of the Sternomastoid muscle.

These nodes at this level lie in relation to the lower third of the jugular vein.

Subdivisions -Nil.

Drainage areas - The larynx, hypopharynx, thyroid, and cervical esophagus as shown below.

www.kuleuven.be

Level V

This refers to the lymph nodes located in the posterior triangle of the neck.(see image below)

www.rahulgladwin.com

Boundaries

Superior boundary - The apex of the convergence of the sternocleidomastoid and trapezius muscle
Inferior boundary – Clavicle. 
Anterior Boundary - Posterior border of the Sternomastoid muscle 
Posterior boundary - The anterior border of the Trapezius muscle

Subdivisions -subdivided by a plane defined by the inferior border of the cricoid cartilage into 
level Va superiorly and 
level Vb inferiorly.

Level Va contains the nodes associated with the Spinal accessory nerve, and
Level Vb contains the Transverse cervical and Supraclavicular nodes.

Drainage areas - The nasopharynx, oropharynx, and skin of the posterior scalp and neck.
                            The Supraclavicular nodes connect with the Mediastinal group of Nodes

Level VI

This refers to lymph nodes of the anterior, or central, compartment of the neck.

Boundaries

 Superiorly – The hyoid bone. 

www.youtube.com

 
 Inferiorly – The Suprasternal  notch. 
 Laterally – Carotid arteries.

Subdivisions -Nil

Drainage areas

Thyroid gland, 
Subglottic larynx,
Cervical trachea, 
Hypopharynx, and   
Cervical esophagus                     .

Lymph nodes in this compartment are located in 
 1-The tracheoesophageal groove (paratracheal nodes),  
 2-In front of the trachea (pretracheal nodes), 
 3-Around the thyroid gland (Para-Thyroidal nodes), and 
 4-On the cricothyroid membrane (Precricoid or Delphian node). 

www.surgicalcore.org

(Level VII- Mediastinum)

WATCH VIDEO ON EXAMINATION OF THE CERVICAL LYMPH NODES.

Summary of drainage areas of Cervical Lymph Nodes.