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Anatomy of the neck- divided into triangles. Relevant info for ENT and head and neck surgeons.

Published in: Health & Medicine
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  1. 1. Dr. Juveria Majeed MS ENT, Govt. ENT Hospital/Osmania Medical College TRIANGLES OF NECK 1
  2. 2.  The side of the neck is roughly quadrilateral in outline.  It is bounded  Anteriorly by –Anterior Median Line  Posteriorly- Anterior border of Trapezius  Superiorly- Base of the Mandible, a line joining angle of the mandible & mastoid process, superior nuchal line.  Inferiorly- Clavicle  This quadrangular space is divided obliquely by SCM muscle into anterior and2
  3. 3. STERNOCLEIDOMASTOID  Origin: a) Sternal head b) Clavicular head  Insertion: a) Lateral process of mastoid process b) Lateral half of the superior nuchal line of occipital bone  Nerve Supply: Spinal Accessory Nerve  Blood Supply: One br from sup thyroid A. and suprascapular A. Two br from occipital A. 3
  4. 4. STERNOCLEIDOMASTOID 4  One of the most important landmark in neck.  Actions-  When one muscles contracts-  When both muscles contracts  To make scm taut on one side, the pt is asked to turn the head to opp. side against resistance.
  5. 5. Layers of the Neck 5  Skin  Superficial fascia  Deep fascia (Fascia Colli)  Deep Structures a) lying above the hyoid bone b) lying below the hyoid bone
  6. 6. SKIN 6  Loosely attached anteriorly.  Posteriorly, the skin is very thick and adherent to the underlying structures with numerous sebaceous glands.  Well supplied with blood vessels and has transverse lines.  Nerve supply: 2nd 3rd 4th cervical nerves.  Anterolateral part: anterior primary rami thru ant. cutaneous, great auricular, lesser occipital and supraclavicular nerves.  Posterior part supplied by dorsal posterior primary rami.
  7. 7. Skin, subcutnaeous fat, superficial fascia containing platysma, deep fascia 7
  8. 8. PLATYSMA 8  It is a subcutaneous muscle forming a wide, thin fleshy sheet running upwards and medially in the neck from deltoid and pectoral fasciae to the base of mandible.  Supplied by cervical br. of facial nerve.
  9. 9. DEEP FASCIA (FASCIA COLLI) 9  Investing Layer  Pretracheal Fascia  Prevertebral fascia  Carotid sheath  Buccopharyngeal Fascia  Pharyngobasilar Fascia
  10. 10. DEEP FASCIA 10
  11. 11. Anterior Triangle of Neck 11  Boundaries: Medially: Ant median plane of neck Laterally: SCM Superiorly: Base of the mandible and a line joining the angle of the mandible n mastoid process  Subdivisions: The ant triangle is subdivided by the digastric belly and sup belly of omohyoid into: a) Submental b) Digastric c) Carotid and d) Muscular Triangles
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  15. 15. SUPRAHYOID MUSCLES 15 MUSCLE ORIGIN INSERTION NERVE SUPPLY DIGASTRIC Anterior belly from digastric fossa Post belly from mastoid notch Intermediate tendon held by a pulley to hyoid bone Ant belly by nerve of mylohyoid Post belly by facial nerve STYLOHYOI D Posterior surface of styloid process Junction of body and greater cornua of hyoid bone Facial nerve MYLOHYOID Mylohyoid line of mandible Body of hyoid bone Two m. muscle of both side form median raphe Nerve to mylohyoid GENIOHYOI D Inferior mental spine(Genial tubercle) Ant surface of body of hyoid bone C1 thru hypoglossal nerve
  16. 16. SUBMENTAL TRIANGLE 16  This is a median triangle.  Boundaries: Either side- Anterior belly of corresponding digastric muscles Base- Body of hyoid bone Apex- at the chin Floor- Rt and Lt Mylohyoid muscle
  17. 17. CONTENTS OF SUBMENTAL TRIANGLE 17  It contains:  one or two lymph glands, the submental lymph nodes  some small veins; the latter unite to form the anterior jugular vein  The lymph nodes of the submental triangle receive lymph from the skin of the chin, the lower lip, the floor of the mouth, and the tip of the tongue. They send lymph to the submandibular and jugular chains of nodes. They belong to Level 1 gr of LNs
  18. 18. DIGASTRIC TRIANGLE 18  The submandibular triangle (or submaxillary or digastric triangle) corresponds to the region of the neck immediately beneath the body of the mandible.  Boundaries: Anteroinf: Ant belly of digastric Posteroinf: Post belly of digastric and stylohyoid. Superiorly: Base of the mandible. Roof : Skin, superficial fascia with platysma muscle, deep fascia
  19. 19. Floor of digastric triangle 19
  20. 20. CONTENTS OF DIGASTRIC TRIANGLE 20  ANTERIOR PART OF TRIANGLE  Strucures superficial to mylohyoid are:Superficial part of submandibular gland, Facial vein , Subman. LN (belong to Level 1 gr of LNs), Facial A.,Submental A., Mylohyoid nerve and vessels.  Structures superficial to hyoglossus: Subman.gland,Intermedia te tendon of digastric and
  21. 21. CONTENTS OF DIGASTRIC TRIANGLE 21  POSTERIOR PART OF TRIANGLE:  Superficial Structures: Lower part of parotid, ECA before it enters parotid.  Deep structures: Styloglossus, stylopharyngeus, glossopharyngeal N, Pharyngeal br of vagus, Styloid process, a part of parotid
  22. 22. CONTENTS OF POSTERIOR PART OF DIGASTRIC TRIANGLE 22  Deepest structures: a) Internal carotid A. b) Internal jugular vein c) Vagus N. • Submandibular LNs: Belong to Level 1 gr of LNs • Clinically important because of their wide area of drainage. They are very commonly enlarged. • They drain: a) center of forehead b) Nose with Max. Frontal & Ethmoid sinuses c) Inner canthus of the eye d) Upper lip and the ant part of cheek with adjoinin gums e)Outer part of lower lip with gums and teeth excluding incisors f)Ant 2/3rd of tongue and floor of mouth
  23. 23. CAROTID TRIANGLE 23  Boundaries:  Anterosup: Post belly of digastric  Anteroinf: Sup belly of omohyoid  Posteriorly: Ant border of SCM  Roof: skin, superficial fascia, investing layer of deep fascia  Floor: Thyrohyoid M, hyoglossus, Middle and Inf. constrictors of pharynx
  24. 24. CONTENTS OF CAROTID TRIANGLE 24  ARTERIES:  Common caortid A. with carotid sinus and carotid body at its termination  Internal carotid A.  External carotid A. with br.- Ant br-sup thyroid, lingual facial Post br- Occipital , post. Auricular Medial- Asc. Pharyngeal Terminal –Maxillary , Superficial Temporal.
  27. 27. CONTENTS OF CAROTID TRIANGLE 27  VEINS:  Internal Jugular V.  Common Facial V.  Pharyngeal V  Lingual V. all draining in to internal jugular vein directly or via facial vein
  28. 28. CONTENTS OF CAROTID TRIANGLE 28  NERVES:  Vagus running vertically downwards  Sup L.N of vagus dividing into ext n int L.N  Spinal Accessory N  Hypoglossal N  Sympathetic chain  Carotid sheath and its contents  Lymph Nodes: Jugulo- digastric and jugulo- omohyoid
  30. 30. ANSA CERVICALIS 30  Also known as Ansa Hypoglossi.  This is a thin nerve loop that lies embedded in the ant wall of carotid sheath.  FORMATION: Superior Root:continuation of descending br of hypoglossal N. Inferior Root: 2nd and 3rd cervical spinal N. • Supplies Infrahyoid muscles.
  31. 31. MUSCULAR TRIANGLE 31  Also known as inferior carotid triangle.  Boundaries:  Anteriorly: ant median line of neck  Posterosup: Sup belly of omohyoid  Posteroinf: Ant border od SCM Contents: Infra hyoid Muscles are the chief contents of this triangle.They also form the floor of the triangle
  32. 32. Infrahyoid / Strap / Ribbon muscles32
  33. 33. INFRAHYOID MUSCLES 33 Muscle Origin Insertion Innervation Sternohyoid Post surface of manubrium sterni Medial part of lower border of hyoid bone Ansa cervicalis Sternothyr oid -Post surface of manubrium sterni Oblique line on lamina of thyroid cartilage Ansa cervicalis Thyrohyoid Oblique line on lamina of thyroid cartilage Body and greater cornua of hyoid bone C1 thru hypoglossal N Omohyoid Sup and inf bellies Upper border of scapula near suprasternal notch Lower border of body of hyoid bone Ansa cervicalis
  34. 34. POSTERIOR TRIANGLE 34  The boundaries are:  Anterior: Post. Border of SCM  Posterior: ant border of the trapezius muscle (Fig. 1-21)  Inferior or Base: Middle 1/3rd of clavicle  Apex: Lies on the sup nuchal line where scm and trapezius meet.  Roof: Investing layer of the deep cervical fascia, ext jugular vein
  36. 36. FLOOR OF POSTERIOR TRIANGLE36  Floor: prevertebral layer of deep cervical fascia, covering following muscles a) Splenius capitus muscle, b) Levator scapulae c) Scalenus medius d) Occassionally scalenus posterior
  37. 37. Subdivisions of posterior triangle of neck 37  Subdivided by inf. belly of the omohyoid into a) Larger upper triangle- Occipital triangle b) Smaller lower triangle- Supraclavicular or Subclavian triangle
  38. 38. TRIANGLE 38  Nerves • Accessory nerve • Root, trunks of brachial plexus and their branches : Nerves to rhomboideus(dorsal scapular n) Nerves to serratus anterior(long thoracic n) Nerves to subclavius Suprascapular nerve  Cervical nerves Greater occipital nerve Great auriclular nerve Lesser occipital nerve Transverse cervical nerve of neck Supraclavicular nerve • 3rd and 4th cervical nerves supplying trapezius
  40. 40. ARTERIES OF POSTERIOR TRIANGLE 40  Arteries  Occipital artery  Third part of subclavianartery & branches of subclavianartery  Suprascapular  Transverse cervical
  41. 41. VEINS IN POSTERIOR TRIANGLE 41  Lower part of External jugular vein & its tributaries  Superficial cervical vein  Subclavian vein is lower down and not in the triangle
  42. 42. LYMPH NODES OF POSTERIOR TRIANGLE 42  Supraclavicularl ymph nodes are present on posteriorborder of sternocleidomas toid  Occipital nodes  The nodes of posterior triangle belong to 5th level of
  43. 43. Levels of lymph nodes 43 • Level I: Ia-Submentalgroup Ib-Submandibulargroup  Level II: around upper third of IJV &adjacent to SAN IIa-located anteriorlyto SAN IIb-located posteriorlyto SAN  Level III: around middle third of IJV  Level IV: around lower third of IJV  Level V (posterior triangle group):spinal accessory nodes, nodes around transverse cervical vessels & supraclavicular node  Level VI: pre & paratracheal, precricoid & those around reccurent laryngeal nerves  Level VIII: Mediastinal Lymph nodes
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