Head Neck And Lymph Nodes

Platysma Origin – fascia overlying the pectoralis major and deltoid muscle.Surgical considerations :Increases blood supply to skin flaps.Absent in the midline of the neck.Fibers run in an opposite direction to the sternocleidomastoid muscle. Platysma Sternocleidomastoid : Origin – medial third of the clavicle(clavicular head) manubrium (sternal head) Insertion– mastoid tip Surgical considerations: Enclosed by superficial layer of deep cervical fascia Lateral retraction exposes the submuscular recess Sternocleidomastoid Sternal head is a thick tendon which attaches to the anterior and lateral surface of the sternum, clavicular head is muscular and attaches to the medial 3rd of the clavicle and superiorly to the Mastoid tip and superior nuchal line. Nerve supply is by spinal accessory nerve Omohyoid : Origin – upper border of the scapula Insertion –1) via the intermediate tendon onto the clavicle2) hyoid bone lateral to the sternohyoid muscle Omohyoid Inf belly common tendon and superior belly, inf belly from he upper border of scapula at the scapular notch. The central tendon lies on the internal jugular vien at the level of the cricoid cartilage and is bound to the clavicle by fascial pulley Superior belly by superior root of ansa cervicalis, inf belly by ansa cervicalis Surgical considerations : Absent in 10% of individualsLandmark demarcating level III from IVInferior belly lies superficial toThe brachial plexusPhrenic nerveTransverse cervical vesselsSuperior belly lies superficial toIJV Digastric muscle : Origin – digastric ridge medial aspect of Mastoid tipInsertion – Digastric fossa on the inner surface of the mandible Digastric muscle Post belly runs anteroinferiorly and becomes a tendon which runs through a sling tht is attached to the lesser cornu of the hyoid. Ant belly runs antero superirly to insert into digastric fossa on the inner surface of the mandible.Post belly supplied by the facial nerve and anterior belly by the mandibular division of the trigeminal nerve Surgical considerations : Posterior belly is superficial to:ECAHypoglossal nerveICAIJVAnterior belly (Between the 2 anterior bellies lies the submental lymph node.) :Landmark for identification of mylohyoid for dissection of the submandibular triangle § Trapezius : Origin – 1) medial 1/3 of the superior nuchal line.2) external occipital protuberance.3) ligamentum nuchae.4) spinous process of C7 and T1-T12.Insertion – 1) lateral 1/3 of the clavicl2) acromion process3) spine of the scapula. It has a wide origin, superior fibers insert into the lateral 1/3rd of clavicle and acromion– inferior fibres insert into the spine of scapula Trapezius Surgical considerations : Posterior limit of Level V neck dissectionDenervation results in shoulder drop and winged scapula. Spinal Accessory Nerve : In 70% cases it lies lateral to IJV.Crosses lateral to the transverse process of the atlas.Descends obliquely in level II (forms Level IIa and IIb). Spinal Accessory Nerve Formed in the posterior cranial fossa by the union of spinal and cranial parts. Spinal part is formed by the rootlets tht emerge from the upper 5 cervical segments, it forms 2 segments one on either side and enters the posterior fossa through the foramen magnum and joind cranial part and exits from the jugular foramen lateral to vagus nerve. Cranial part seperates and joins the vagus. It runs along the ijv then enters scm muscle and supplies it and exits at the erbs point. Courses inferiorly to reach lateral surface of SCM at Erb’s point, and at 5cm above the clavicle it disappears under the anterior border of trapezius. Spinal Accessory Nerve Erbs point: point on posterior border of sternocleiodomastoid muscle where 4 superficial brnaches of the cervical plexus meet:Greater auricular, lesser occipital, transverse cervical and supreclavicular nerves meet and emerge behind the muscle Thoracic Duct : Conveys lymph from the entire body back to the blood.Begins at the cisterna chyli.Enters posterior mediastinum between the azygous vein and thoracic aorta.Courses to the left into the neck anterior to the vertebral artery and vein.Enters the junction of the left subclavian and the IJV. Thoracic Duct Common Carotid Artery : Arises from Brachiocephalic on right side and Arch of aorta on the left side Bifurcates at the level of greater cornu of the hyoid Internal Jugular vein lies medial and deep to CCA Vagus nerve lies inbetween CCA and IJV in the carotid sheath Common Carotid Artery Internal Jugular Vein : It is the continuation of sigmoid sinus and is the thin walled capacitance vessel IVJ joins the subclavian vein to form brachiocephalic vein at the level of sternal end of the clavicle Tributaries are: inferior petrosal vein, facial, lingual, pharyngeal, superior and middle thyroid veins Internal Jugular Vein Relations : Posteriorly: prevertebral muscles, transverse process of atlas, phrenic nerve, thyrocervical trunk Medially: vagus nerve, common and internal carotid arterySuperficially: deep cervical group of lymph nodes Sternocleidomastoid musclePosterior belly of digastric and superior belly of omohyoid are important surgical land marks Lymph Node levels/Nodal Relations : Developed by Memorial Sloan-Kettering Cancer Center(1981).It made the description of regional nodal involvement in cancer of the head and Neck easy and uniform. Lymph Node levels/Nodal Relations Lymph node levels : Level I: Submental and submandibular nodes. Level II: Upper jugular nodes.Located around upper third of IJV.Level III: Middle jugular lymph nodes. Level IV: Lower jugular lymph nodesLevel V: Posterior triangle lymph nodes. Level VI:Central compartment group of lymph nodes (perithyroidal,paratracheal, precricoid). Level VII: Upper mediastinal group of lymph nodes Lymph node levels Boundaries - hyoid bone (clinical landmark) or carotid bifurcation (surgical landmark).Submental group of lymph nodes are inferior to mandible between anterior bellies of digastric musclesUpper jugular nodes sup- lower level of bony margin of jugular fossa, : upto the greater cornu of the hyoid bone Boundaries - Inferior border of level II to lower border of cricoid arch (clinical landmark) or where the omohyoid muscle tendon crosses the IJV(surgical landmark). Boundaries- inferior border of level III to clavicle,Boundaries - posterior border of SCM, clavicle and anterior border of trapezius. Rationale for subzones : Suggested by Suen and Goepfert (1997) & American head and neck society (2001). Biologic significance for lymphatic drainage depending on site of tumor. Lymph Node Subzones : Lymph Node Subzones Level I subzones. Lower lip, floor of mouth, ventral tongue – Ia.Other oral cavity – IbLevel II subzones: Oropharynx , larynx and hypopharynx drain in to these group of lymph nodeLevel V subzonesNasopharynx – Va.Thyroid Gland – Vb. Named lymph nodes : Jugulo-digastric nodes-Within upper deep cervical group at lower end of level II & upper end of level III ,in a triangle formed by IJV, facial vein & posterior belly of digastric. Jugulo-omohyoid nodes -At the junction of middle & lower deep cervical group where omohyoid crosses IJV. Organ specific drainage Organ specific drainage Organ specific drainage Organ specific drainage Organ specific drainage Lymphatics of Head & Neck : Waldeyer’s internal ring Waldeyer’s internal ring Waldeyer’s internal ring is scattered throughout the pharynx in its subepithelial layer is the lymphoid tissue which is aggregated at places to form masses collectively called as waldeyers ring. 1. Nasopharyngeal tonsil or the adenoids 2. Palatine tonsils or simply the tonsils 3. Lingual tonsil 4. Tubal tonsils (in fossa of Rosenmuller) 5. Lateral pharyngeal bands 6. Nodules (in posterior pharyngeal wall). Superficial system-two circles of lymph nodes -In head nodes situated around skull base. (occipital, postauricular, parotid/preauricular buccal/facial). -In neck superficial cervical,submandibular, submental,anterior cervical Deep system -Junctional nodes -Upper, middle &lower group of lymph nodes along IJV -Spinal accessory group -Nuchal nodes -Visceral nodes -Upper mediastinal nodes Drainage : Superficial system and Deep system Lymphatic drainage of Head and Neck Lymphatic drainage of Head and Neck Staging of The Neck: “N” classification – UICC(Union for international cancer control) (1997) Consistent for all mucosal sites except the nasopharynx. Thyroid and nasopharynx have different staging based on tumor behavior and prognosis. Based on extent of disease prior to first treatment. NX: Regional lymph nodes cannot be assessed. N0: No regional lymph node metastasis. N1: Metastasis in a single ipsilateral lymph node, <3cm. N2a: Metastasis in a single ipsilateral lymph node 3 to 6cm.N2b:Metastasis in multiple ipsilateral lymph nodes, less than 6 cm.N2c: Metastasis in bilateral or contralateral nodes < 6cm.N3: Metastasis in a lymph node more than 6 cm in greatest dimension. Staging of The Neck: Staging of The Neck: Nodal staging-thyroid : Regional nodes -cervical &upper mediastinal Nx-regional nodes cannot be assessed. N0-no regional nodal metastasis. N1-regional nodal metastasis. N1a-metastasis in ipsilateral cervical nodes. N1b-metastasis in bilateral, midline, contralateral & mediastinal nodes Nodal staging-nasopharynx : Nx-nodes cannot be assessed. No-no evidence of nodal metastasis. N1-Unilateral metastasis in a node 6cm or less above supraclavicular fossa. N2-Bilateral metastasis in a node 6cm or less above supraclavicular fossa. N3-metastasis in lymph nodes- a)>6cm. b)In supraclavicular fossa. Examination of neck : Careful inspection of both sides of neck essential. Neck nodes are better palpated while standing at back of the patient & neck slightly flexed. Both hands should be used to palpate each side of neck simultaneously. In addition, parotid region, postauricular region & thyroid are also palpated. For complete OSCE Examination kindly see our OSCE Examination Youtube channel Radiological Imaging : USG: 1)Can detect lymph node size, 2)Cannot differentiate between malignant /benign lymph node. Absent hilar echoes and incres in the short axis length are considered as the metastatic nodes. Alone usg sensitivity is 70 to 90%. ALONG with fnac sensitivity is increased to more than 90% CT scanning of neck : Indications - Neck scanned as part of assessment of primary tumour. In presence of significant ipsilateral disease when presence of deep fixation or contralateral spread can change management. To assess difficult neck. Restaging of recurrent tumours. Suspicious nodes on imaging : Size >1cm. Central necrosis(Central necrosis: as the lymph node enlarges the centre of the LN dies and becomes necrosed, and there will be inflammation around the edge leading to rim enhancement). Rim enhancement following IV contrast. Spherical shape. 80% overall accuracy rate achieved on CT. Drawbacks of CT Scan: May miss low volume disease. Efficacy is doubtful in recurrent/residual disease following surgery and irradiation If the size of the node is less then 8mm Suspicious nodes on imaging Other Investigations: MRI: -Accuracy is similar to CT.-Useful for perineural or extracapsular spread-Criteria for diagnosis is similar to CT scan-Better in evaluating N0 neck FNAC Sentinel node mapping : Gained popularity –cutaneous melanomasMucosal cancers of upper aerodigestive tractAccurate histopathologic assessmentMost minute foci of microscopic cancerMolecular level Routine frozen section analysisParaffin section analysis of excised lymph nodeSerial sectioning of the lymph nodeImmunohistochemical techniquesMolecular techniques with PCR 3 techniques of Sentinel node mapping Radioisotope scan imaging Injection of blue dye Use of hand held isotope tracer probe for localization Combination of techniques increase accuracy Risk of nodal metastasis : Depends on various factors- Site Size T-stage Location of primary tumor Histomorphological features of primary tumor Tumor invasion -Risk increases on progression from anterior to posterior aspect of upper aerodigestive tract, lips< oral cavity< oropharynx< hypopharynx. -For tumors of larynx & pharynx, risk increases from centre of laryngopharyngeal compartment to periphery. -Endophytic tumors more inclined to metastasize than exophytic tumors.