Anatomy of the Neck

1. Anatomy of the Neck

2. Anterior triangle • Midline of the neck • Sternocleidomastoid muscle • Lower border of the mandible

3. Subunits of ant. triangle • Submandibular triangle • Submental triangle • Carotid triangle • Muscular triangle

4. Submandibular triangle • Anterior & posterior bellies of digastric muscle • Lower border of the mandible

5. Submental triangle • Anterior bellies of the digastric muscle • Hyoid bone

6. Posterior triangle • Anterior border of the trapezius m. • SCM • Middle third of the clavicle

7. Subunits of post. Triangle • Subclavian triangle • Occipital triangle

8. Fascial layer of the neck The cervical fascia represents a condensation of connective tissue that extends between anatomic structures

9. Superficial Fascia • Lies just below the dermis • Deep portions of this layer encase the platysma muscle as well as the voluntary muscles of the face & scalp

10. Deep cervical fascia • Superficial layer • Middle layer • Deep layer

11. Superficial layer of deep cervical fascia • Begins from the vertebral spinous processes and splits to enclose the trapezious • Again it splits to invest SCM as well as strap muscle • Superior attachment : occipital protuberance , superior nuchal line & zigomatic arch

12. Between parotid & submandibular glands the two layer rejoin to form the stylomandibular ligament • Inferiorly the fascia split and attach to the anterior and posterior surface of the sternum : Suprasternal space of Burns

13. Middel layer of the deep cervical fascia • It encloses the thyroid gland , trachea , pharyngeal constrictor muscle & esophagus • It extends from the hyoid bone down to the sternal attachments and is continuous with fibrous pericardium

14. Deep layer of the deep cervical Fascia • Anterior to the vertebral bodies • Tips of transverse process • Vertebral spines posteriorly • From the skull base until the coccyx

15. Prevertebral layer • Alar layer ( until first thoracic vertebra )

16. Danger space • A potential space is created between the alar and prevertebral fascias because it communicates directly with the mediastinum

17. Prevertebral space Between the prevertebral fascia and vertebral body

18. Retropharyngeal space Between alar and the visceral fascia

19. Tissue space of the neck Between cervical fascia exist potential spaces

20. Because superficial and deep layers of the deep cervical fascia fuse at the hyoid bone infection in the spaces above the hyoid does not spread directly to spaces below the hyoid

21. Communication along the entire length of the neck occurs posteriorly along the retropharyngeal and prevertebral spaces .

22. Submandibular space • Between outer space of of mylohyoid muscle and superficialstructure within submandibular triangle • Along the posterior free edge of the mylohyoid muscle it continuous with the sublingual space • It also communicate with submental and contralateral submandibular space `

23. Intrapharyngeal space • Inner surface of the superior constrictor muscle and the pharyngeal mucosa • It also known as peritonsillar space

24. Parapharyngeal space • Medial : superior constrictor m. • Lateral : pterygoid muscles and fascia of the parotid gland • Inferior : Fascial attachment to the hyoid

25. Posteromedially this space communicates with the retropharyngeal space providing a route to spread infection

26. Retropharyngeal space • Entire length of the neck • Between visceral fascia and alar fascia • From the skull base down to the T1

27. Danger space • Between alar fascia and prevertebral fascia • Retropharyngeal space→ danger space →mediastinum

28. Prevertebral space • Between prevertebral fascial and vertebral column • From the skull base to the lower thoracic area

29. Artery of the neck

30. Common carotid artery • Right side from brachiocephalic artery • Left side from aortic arch • It crosses by omohyoid muscle , , superior & middle thyroid vein

31. Internal carotid artery • it crosses by hypoglossal nerve , occipital artery & posterior belly of digastric muscle • Near skull base it crosses by glossopharyngeal nerve ,stylohyoid , stylopharyngeous ,styloglossus muscle and styloid process

32. External carotid artery • It crosses superficially to styloglossus and stylopharyngeous muscle • Terminal branches passing behind the condylar process

33. Superior thyroid artery • At the level of greater horn hyoid bone • Superior part of thyroid gland , larynx and SCM

34. Ascending pharyngeal artery • At the level of sup. Thyroid artery posteriorly • Supply pharynx , palate , tonsil , middle ear and meninges

35. Lingual artery • Above the superior thyroid artery • Runs anterior and superior • Passes beneath the hyoglossus muscle to enter the tongue

36. Facial artery • On the anterior surface of carotid , deep to the digastric muscle • Passes through the submandibular gland , crosses the inferior border of the mandible • Branches in the neck : ascending palatine artery , tonsillar artery , branches of the submandibular gland , submental artery

37. Occipital artery • From posterior surface of the external carotid artery the hypoglossal nerve hooks around it • Supply suboccipital region of the scalp , SCM , digastric and stylohyoid muscle

38. Posterior auricular artery • Posteriorly at the level of the upper border of digastric muscle • Passes between the mastoid and ear • Branches to the parotid gland , auricle and scalp

39. Terminal branches • Superficial temporal : toward the scalp • Maxillary artery : infratemporal fossa → pterygopalatine fissure → pterygopalatine fossa

40. Thyrocervical thrunk • Arises from the first part of the subclavian artery just anterior to the scalenus anrerior muscle • Transverse cervical branch → SCM , trapezius • Inferior thyroid artery : deep to the carotid sheath • Supply inferior portion of the thyroid , sup. & inf. Parathyroid gland and a portion of larynx and trachea • Inter the thyroid at the level of cricoid

41. Vein of the neck

42. Internal jugular vein • Sigmoid sinus → intrenal jugular vein → subclavian vein • Major tributaries :inferior petrosal sinus Common facial vein lingual vein superior thyroid vein middle thyroid vein

43. External jugular vein Posterior auricular vein + posterior branch retromandibular vein Deep to the platysma but superficial to the SCM Terminate in the subclavian vein At its midportion it joined by posterior external jugular vein

44. Anterior jugular vein • Confluence of the vein in the submandibular region • Drain to the external jugular or subcalavian vein

45. Nerve of the neck

46. Glossopharyngeal nerve • Sensory , motor , parasympathic component • It has superior and inferior ganglion • Anterior to the internal and deep to the external carotid artery • Pass between superior and middle constrictor muscle • Innervate tonsil , pharynx and tongue

47. Tympanic nerve • Arises from inferior ganglion • Tympanic canaliculus → middle ear (jacobson nerve ) • Sensory fiber to the middle ear , eustachian tube and mastoid cavity

48. Lesser petrosal nerve • Preganglionic parasympathetic fibers • Tympanic plexus → floor of middle cranial fossa → foramen oval → infratemporal fossa → otic ganglion • In the otic ganglion it synapsis with postganglionic fiber of parasympathic that supply the parotid gland

49. Carotid branch • Arises from IX nerve just below the skull base • Unit with carotid branch of vagus nerve and carries sensory information back from the carotid body and carotid sinus

50. Pharyngeal branch • Reach to the pharyngeal plexus on the middle constrictor muscle • Sensory innervation