ANATOMY OF NECK.pptx
- 1. ANATOMY OF NECK AASTHA MOZA 1stYR PG
- 2. Cervical fascia is divided into superficial and deep layers. The superficial fascia is immediately deep to the dermis and it ensheathes the platysma as well as the muscles of facial expression. The superficial musculoaponuerotic system (SMAS).It extends from the cranium down to the thorax and axilla. The deep layer is divided into superficial, middle, and deep layers. Fascial spaces of the neck
- 3. The neck is the area between the base of the skull and inferior border of the mandible and the superior thoracic aperture.
- 4. The SLDCF: outer margin of odontogenic deep space neck infections (DSNI). SLDCF Posteriorly at the nuchal ridge and spreads laterally& anteriorly splitting to envelop the trapezius and sternocleidomastoid (SCM),attaches to the hyoid bone anteriorly. It envelops both the parotid and submandibular glands. It fuses with the fascia, covering the anterior bellies of the digastric and mylohyoid forming the inferior margin of the submandibular space. At the mandible, the fascia splits and the internal layer covers the medial surface of the pterygoid muscles up to the skull base . The external layer covers the masseter muscle and inserts into the zygomatic arch. Inferiorly, it inserts into the clavicles, sternum, and acromion of the scapula.
- 5. (MLDCF) is also known as the Pretracheal fascia It often forms the base of deep space infections of the neck, thus creating a barrier to the extension of infection into the pulmonary, tracheobronchial tree, esophagus, and prevertebral space. The muscular division surrounds the sternothyroid, sternohyoid, and thyrohyoid muscles. The visceral layer of the MLDCF envelops the thyroid, trachea, and oesophagus. It extends inferiorly into the upper mediastinum and joins the fibrous pericardium. The middle layer also encloses the pharyngeal constrictors and the buccinator muscles. The visceral layer of the MLDCF is the pathway to mediastinitis.
- 6. The deep layer of the deep cervical fascia (DLDCF) separates into a posterior prevertebral division and an anterior alar division. The prevertebral division is adherent to the anterior aspect of the vertebral bodies from the base of the skull down the spine. It extends posteriorly around the spine and the muscles of the deep neck, the vertebral muscles, muscles of the posterior triangle, and the scalene muscles. It envelops the brachial plexus and subclavian vessels, extending laterally into the axillary sheath. The alar division is located between the visceral division of the middle layer and the prevertebral division of the deep layer. The deep layer corresponds to the posterior boundary of the retropharyngeal space, extending down to the level of T2, where it fuses with the visceral fascia. Thus the DLDCF is important in providing the posterior boundary for extension of infection to the mediastinum. The DLDCF is rarely perforated by infection, but when this occurs, it can result in cervical spine osteomyelitis or epidural abscess following head and neck infection.
- 7. Monson and colleagues Zone I extends from the level of the clavicles and sternal notch at the thoracic inlet to the cricoid cartilage. Includes the arch of the aorta, proximal carotid arteries, vertebral arteries, subclavian vessels, innominate vessels, apices of the lungs, esophagus, trachea, brachial plexus, and thoracic duct. Zone II is the largest and most exposed area, and extends from the level of the cricoid cartilage to the angle of the mandible . Includes the common, internal, and external carotid arteries, the jugular veins, various cranial nerves, the larynx, hypopharynx, and proximal esophagus. Zone III extends from the level of the angle of the mandible to the base of the skull.
- 8. MUSCLE ORIGIN INSERSION NERVE SUPPLY ACTION Digastric Anterior belly Posterior belly Diagastric fossa Of mandible Notch on medial surface of mastoid process of temporal bone Two bellies joined by an intermediate tendon held in a fibrous sling attached to hyoid bone at junction of body and greater cornu Anterior belly By mandibular nerve Posterior belly By facial nerve Depression and retraction of mandible Elevation of hyoid bone Stylohyoid By tendinous fibers from posterior side of styloid process of the temporal bone Body of hyoid bone at junction with greater cornu facial nerve Elevation and retraction of hyoid bone Mylohyoid Entire length of mylohyoid line of mandible Anterior and middle fibers decussate in median fibrous raphe between symphysis menti and midpoint on body of hyoid bone Mylohyoid branch from inferior dental branch of mandibular division of trigeminal nerve Elevation of hyoid bone and depression of mandible Geniohyoid Lower mental spine Anterior surface of body of hyoid bone Anterior ramus C1 Pulls mandible downward, pulls hyoid bone forward
- 9. MUSCLE ORIGIN INSERTION NERVE MUSCLE ORIGIN INSERTION NERVE SUPPLY ACTION Sternohyoid Posterior surface of manubrium sterni Medial portion of lower border of body of hyoid bone Ansa cervicalis Descendens hypoglossi carrying C1 via XII nerve Depression of hyoid Omohyoid Superior belly with intermediate tendon of inferior belly of omohyoid muscle Into lateral portion of inferior border of body of hyoid bone C1 – C3 Depression of hyoid bone Sternothyroid Posterior surface of manubrium sterni below attachment of sternohyoid Into oblique line on external surface of thyroid cartilage C1-C3 Depression of hyoid bone and larynx Thyrohyoid Oblique line on external surface of thyroid cartilage Inferior border of the body of hyoid bone and greater cornu of hyoid C1 through XII nerve Elevation of larynx and Depression of hyoid bone
- 10. Posterior triangles of the neck Boundaries: Anterior: Posterior border of sternocleidomastoid muscle Posterior: Anterior border of trapezius muscle Inferior: Superior surface of the middle third of clavicle Apex: at the point where SCM and trapezius muscles approximate towards each other over the occipital bone Floor: Splenius capitis Levator scapulae Scalenus posterior Scalenus medius Scalenus anterior
- 11. Nerves: Spinal accessory nerve Branches of cervical plexus Phrenic nerve C3-C5 Roots and trunks of brachial plexus Vessels: Subclavian artery Transverse cervical artery Suprascapular artery External jugular vein
- 12. Lymph nodes: Occipital Supraclavicular Muscles: Inferior belly of omohyoid muscle Anterior scalene , Middle , posterior scalene Levator scapulae muscle Subdivisions Occipital triangle Supraclavicular
- 13. Diagastric/ Submandibular triangle Boundaries: Superior: Base of mandible, line extending from mandible to mastoid process. Posteroinferior: posterior belly of diagastric and stylohyoid muscles Anteroinferior: Anterior belly of diagastric muscle Roof: skin, superficial fascia, deep cervical fascia Floor: mylohyoid and hyoglossus muscle 3 triangles within submandibular triangle: Lesser’s triangle Pirogoff’s triangle Beclard’s triangle
- 14. Carotid triangle: Boundaries: Posterior: Anterior border of sternocleidomastoid muscle Anteroinferior: Superior belly of omohyoid muscle Superior: Stylohyoid muscle Posterior belly of digastric muscle Floor: Thyrohyoid Hyoglossus Middle constrictor Roof: skin, superficial fascia, platysma , deep cervical fascia. Anterior angle: level of hyoid bone
- 15. Muscular triangle : Also called omotracheal Boundaries: • Anterior border of sternocleidomastoid • Superior omohyoid • Midline Floor of the triangle is composed of : Sternohyoid Sternothyroid Roof: • Skin • Superficial fascia • Deep cervical fascia
- 16. Boundaries: Submental triangle: Anterior diagastric on right and left Body of hyoid bone Floor of the triangle: Mylohyoid Roof: • Skin • Superficial fascia with platysma • Deep cervical fascia Major contents are anterior jugular vein and submental lymph nodes.
- 17. VASCULAR SUPLLY OF NECK
- 18. VASCULAR SUPPLY OF NECK
- 19. NERVE SUPPLY OF NECK
- 20. ANATOMY OF NECK II Aastha Moza 1st year PG
- 21. Need for lymph node classification • Lymph node status is the single most important prognostic factor in head and neck cancer because lymph node involvement basically decreases overall survival by 50%. Unfortunately, approximately 40% of patients with oral cancer will harbor cervical lymph node metastasis at presentation. • Removal of the atrisk lymphatic basins serves two important purposes. • Allows the removal and identification of occult metastasis in patients in whom cervical metastasis are a risk, which is referred to as an elective neck dissection. • Secondly, it allows the removal of disease in patients in whom metastasis are highly suspected based on imaging, clinical examination or fine needle aspiration, which is referred to as a therapeutic neck dissection.
- 22. Classification by the American Head and Neck Society:
- 23. Level I Anatomic boundaries: Level I a: level I b: SUPERIOR INFERIOR ANTERIOR POSTERIOR Symphysis of mandible Body of hyoid Anterior belly of contralateral diagastric muscle Anterior belly of ipsilateral diagastric muscle SUPERIOR INFERIOR ANTERIOR POSTERIOR Body of mandible Posterior belly of diagastric muscle Anterior belly of diagastric muscle Stylohyoid muscle
- 24. Drainage • Floor of the mouth • Anterior oral tongue • Lower lip and mandibular alveolar ridge.
- 25. Drainage • oral cavity • midface soft tissues • submandibular gland • Anterior nasal cavity.
- 26. Level II contains the upper jugular lymph nodes that surround the upper third of the internal jugular vein and the spinal accessory nerve. It includes the jugulodigastric node also known as the principle node of Kuttner. Level II a: Level II b: Nodal tissue within level II receives efferent lymphatics : parotid, submandibular, submental, and retropharyngeal nodal groups. SUPERIOR INFERIOR ANTERIOR POSTERIOR Skull base Horizontal plane defined by inferior body of hyoid one Stylohyoid muscle InVertical plane by spinal accessory nerve SUPERIOR INFERIOR ANTERIOR POSTERIOR Skull base Horizontal plane defined by inferior body of hyoid one InVertical plane by spinal accessory nerve Lateral border of sternocleidomast oid muscle
- 27. Drainage • oral cavity • nasal cavity • nasopharynx, oropharynx, hypopharynx, larynx, and parotid gland. • Subclassified into IIA and IIB by a vertical plane created by the spinal accessory nerve. Level IIA is anterior and level IIB is posterior to the spinal accessory nerve.
- 28. Level III Level III encompasses node-bearing tissue surrounding the middle third of the internal jugular vein. Level III contains the dominant omohyoid node. SUPERIOR INFERIOR ANTERIOR POSTERIOR Inferior border of hyoid Inferior border of cricoid Lateral border of sternohyoid muscle Lateral border of sternocleidoma stoid muscle
- 29. Drainage: • oral cavity • nasopharynx, oropharynx, hypopharynx, larynx, and parotid gland.
- 30. Level IV Nodal tissue surrounding the inferior third of the internal jugular vein. It extends from the inferior border of level III to the clavicle. The retropharyngeal, pretracheal, hypopharyngeal, laryngeal and thyroid lymphatics also make a contribution. DRAINAGE: Hypopharynx Thyroid Oesophagus, and larynx. SUPERIOR INFERIOR ANTERIOR POSTERIOR Inferior border of level III node grp Clavicle Lateral border of sternohyoid muscle Lateral border of sternocleidom astoid muscle
- 31. Level V makes up the posterior triangle. Level V a: Level V b: Oropharyngeal cancers, however, such as tongue base and tonsillar primaries can spread to level V nodes. Drainage: nasopharynx, oropharynx cutaneous structures from the neck and posterior scalp. SUPERIOR INFERIOR ANTERIOR POSTERIOR Apex of convergence of sternocleido mastoid and trapezius Horizontal plane, lower border of cricoid Posterior border of sternocleidom astoid muscle Anterior border of trapezius SUPERIOR INFERIOR ANTERIOR POSTERIOR Horizontal plane, lower border of cricoid Clavicle Posterior border of sternocleidom astoid muscle Anterior border of trapezius
- 32. Level VI The anterior compartment lymph node group. It is made up of the lymph node bearing tissue occupying the visceral space. Prelaryngeal prethyroid, and pretracheal and paratracheal nodal groups. It begins at the hyoid bone, extends inferior to the suprasternal notch, and laterally is bound by the common carotid arteries. Drainage: Thyroid gland, Larynx Piriform sinus Oesophagus
- 33. INCISIONS FOR NECK DESSECTION McFee incision Martin incision Three-quarter H incision De Quervain incision Lahey incision Modified hockey-stick
- 35. Classifications of neck dissection ACADEMY’S CLASSIFICATION Radical neck dissection (RND) Modified radical neck dissection (MRND) Selective neck dissection (SND) Extended neck dissection AAO- HNS CLASSIFICATION 1991 2001 Radical neck dissection (RND) Radical neck dissection (RND) Modified radical neck dissection (MRND) Modified radical neck dissection (MRND) Selective neck dissection (SND) Divided into anterior/ posterolateral/lateral/ supraomohyoid Selective neck dissection (SND) ( each variation is denoted by SND, sublevels of lymph nodes removed) Extended neck dissection Extended neck dissection
- 36. MEDINA CLASSIFICATION 1989 Comprehensive neck dissection Radical neck dissection Modified Radical neck dissection MRND I - Preserve spinal accessory MRND II – Preserve spinal accessory and sternocleidomastoid but sacrifice internal jugular vein. MRND III- Preservation of all the structures. Selective neck dissection Supraomohyoid neck dissection Jugular neck dissection Anterior triangle neck dissection Central compartment neck dissection Posterolateral neck dissection
- 37. RADICAL NECK DESSECTION Refers to the removal of all ipsilateral cervical lymph node groups extending from the inferior border of the mandible to the clavicle, from the lateral border of the sternohyoid muscle, hyoid bone, and contralateral anterior belly of the digastric muscle medially, to the anterior border of the trapezius. Included are levels I– V. This entails the removal of three important, non- lymphatic structures: the internal jugular vein, the sternocleidomastoid muscle, and the spinal accessory nerve.
- 38. MODIFIED RADICAL NECK DESSECTION Modified radical neck dissection (MRND): Refers to removal of the same lymph node levels (I–V) as the radical neck dissection, but with preservation of the spinal accessory nerve, the internal jugular vein, or the sternocleidomastoid muscle.
- 39. MODIFIED RADICAL NECK DESSECTION Oblique incision extending from the mastoid inferiorly and crossing the sternocleidomastoid muscle then extending across the neck in a natural neck crease at approximately the level of the cricoid cartilage allows adequate access in most cases. HOCKEY STICK INCISION
- 40. SELECTIVE NECK DESSECTION Selective neck dissection (SND) Refers to the preservation of one or more lymph node groups normally removed in a radical neck dissection.
- 41. CAROTID BODY TUMOR It is a small, reddish-brown, oval structure, located in the posteromedial aspect of the carotid artery bifurcation. The gland is highly vascular and receives its blood supply from feeder vessels running through external carotid artery, typically the ascending pharyngeal artery. It is innervated by the Hering nerve, originating from the glossopharyngeal nerve about 1.5 cm distal to the jugular foramen. Shamblin describes 3 different types or stages of carotid body tumors. 1. Type I consists of a small tumor that is easily dissected from the adjacent vessels in a periadventitial plane. 2. Type II tumors are larger and more adherent and partially surround the vessel. 3. Type III tumors are large and completely surround the carotid bifurcation.