Neck muscles and triangles

1. The Neck 1

2. is relatively narrow and flexible portion between the head above and the chest below Functions: 1. transports a food tube, an air tube, and a neurovascular bundle between the head and chest. 2. the upper limbs originate from the cervical region during their embryological development, 3. passageway for the blood vessels and nerves to and from the upper limb. 2

3. Boundaries of the Neck 3

4. A. Superior 1. Anterior - lower border of the mandible 2. Lateral - line between the gonion and the mastoid temporal, 3. Posterior - inion and superior nuchal line 4

5. B. Inferior 1. Anterior - jugular or suprasternal notch 2. Lateral - superior border of the clavicle, 3. Posterior- transverse line from the acromioclavicular joint to the spinous process of the 7 th cervical vertebra 5

6. Surface Anatomy of the Neck 6

7. Contour well-rounded in women and children and is more angular in men natural upright position of the neck is midway between flexion and extension 7

8. Structures Palpated in the Midline body of the hyoid bone thyroid cartilage cricoid cartilage Trachea isthmus of the thyroid gland suprasternal notch 8

9. Structures Palpated Posteriorly Inion Nuchal goove Vertebra prominence Ligamentum nuchae which covers spines of C2 to C6 9

10. Structures Palpated Laterally Sternocleido-mastoid muscle Trapezius muscle External jugular veins 10

11. The Muscles and Triangles of the Neck 11

12. Regions of the Neck To facilitate the seemingly complicated area, the neck is divided into two major areas, or triangles, by the sternocleidomastoid muscle . These are: 1. anterior triangle - the area anterior to the SCM and below the inferior border of the mandible 2. posterior triangle - the area posterior to the SCM and is limited posteriorly by the trapezius muscle 12

13. Sternocleidomastoid Muscle Origin Insertion Action Nerve Supply Two heads: Sternal head – manubrium sterni Clavicular head - Medial 2/3 of the clavicle Mastoid process of the of the temporal bone and lateral half of the superior nuchal line. Bilateral: Flex the neck Single: Flex the head and laterally rotate to the opposite side 1. Spinal accesory nerve 2. Anterior primary rami of spinal nerves C2 and C3. 14

14. Trapezius Muscle Origin Insertion Action Nerve Supply External occipital protruberance , the medial half of the superior nuchal line, the ligamentum nuchae , and the lower cervical and all the thoracic spines Fibers originating from the head insert into the lateral third of the clavicle, and the remaining fibers insert into the acromion process and spine of the scapula Contract to rotate and elevate the scapula. Its cervical portion, acting bilaterally, can extend the head and singly, it can rotate the head and face to the opposite side 1. Spinal accessory nerve 2. Anterior primary rami of the spinal nerves C3 and C4. 15

15. The Anterior Triangle of the Neck 16

16. Muscles of the Anterior Triangle of the Neck 17

17. I. Infrahyoid Muscles Muscle Origin Insertion Action Nerve Supply Omohyoid Inferior belly: Superior border of the scapula Superior belly: Intermediate tendon Inferior belly: Intermediate tendon Superior belly: Lower border of the body of the hyoid bone Depresses the hyoid bone and larynx Ansa cervicalis (APR of C1, C2, C3) Sternohyoid Manubrium of the sternum, posterior aspect Lower border of the body of the hyoid bone Depresses the hyoid bone and larynx Ansa cervicalis (APR of C1, C2, C3) 18

18. Infrahyoid Muscles Muscle Origin Insertion Action Nerve Supply Sternothyroid Manubrium of the sternum, posterior aspect Oblique line of thyroid cartilage Depresses the larynx Ansa cervicalis (APR of C1, C2, C3) Thyrohyoid Oblique line of thyroid cartilage Body and greater horn of hyoid bone, lower border Depresses the hyoid bone Thyrohyoid branch of the hypoglossal nerve 19

19. II. Suprahyoid Muscles Muscle Origin Insertion Action Nerve Supply Stylohyoid Styloid process Greater horn of hyoid bone Elevates hyoid bone Facial nerve Digastric (Posterior belly) Digastric notch of the temporal bone at the base of the skull Intermediate tendon Raises the hyoid bone Facial nerve Digastric (anterior belly) Intermediate tendon Digastric fossa of the mandible Elevates the hyoid bone Nerve to the mylohyoid muscle 20

20. Suprahyoid Muscles Muscle Origin Insertion Action Nerve Supply Mylohyoid Mylohyoid line on the medial aspect of mandibular body Median raphe and body of hyoid Elevates the hyoid bone, base of the tongue, and floor of the mouth Nerve to mylohyoid muscle Geniohyoid muscle Inferior border genial tubercle of the mandible Body of hyoid bone Elevates hyoid bone, protracts hyoid bone APR of C1 21

21. Boundaries of the Anterior Triangle 22

22. Anterior - median line of the neck Posterior – anterior border of the sternocleidomastoid muscle Superior - inferior border of the mandible Roof - skin, superficial fascia, platysma, and investing layer of deep cervical fascia 23

23. Subdivisions of the Anterior Triangle 24

24. Digastric Triangle Carotid triangle Muscular or inferior carotid triangle Submental triangle 25

25. 1. Digastric Triangle Boundaries: Superior- lower border of the mandible Anterior – anterior belly of the digastric Posterior – posterior belly of the digastric Floor - mylohoid and hyoglossus muscles and superior contrictor muscle of the pharynx 26

26. Structures: 1 . Glands – parotid and submandibular 2. Arteries - Internal and external carotid, facial, submental, posterior auricular, superficial temporal and lingual. 3. Veins - anterior facial and internal jugular. Nerves – vagus, glossopharyngeal, facial, and hypoglossal. 27

27. 2. Carotid Triangle Boundaries: Superior – posterior belly of the digastric Inferior – superior belly of omohyoid 3. Posterior – anterior border of the SCM Floor - thyrohyoid muscle, hyoglossus muscle, and the middle and inferior constrictor muscles of the pharynx. 28

28. Structures: Organs – larynx and pharynx (lower part) Arteries - CCA, facial, occipital, acending pharyngeal, superior thyroid, and lingual. Veins - internal jugular, superior thyroid, lingual, facial, occipital and ascending pharyngeal. Nerves - vagus, accessory, hypoglossal, ansa hypoglossi, external and internal laryngeal. 29

29. Muscular or Inferior Carotid Triangle Boundaries: Supero -posterior - superior belly of omohyoid Infero -posterior - anterior border of SCM Anterior - median line of the neck Floor - sternohyoid and sternothyroid 30

30. Structures: Organs – thyroid and parathyroid glands, trachea Arteries - inferior thyroid Veins - internal jugular Nerves - vagus , recurrent laryngeal, sympathetic n. 31

31. 4. Submental Triangle Boundaries: Lateral - two anterior bellies of the digastric Inferior - body of the hyoid bone Structures: Submental lymph glands Beginning of the anterior jugular vein 32

32. The Posterior Triangle of the Neck 33

33. Boundaries : Anterior - posterior border of the SCM. Posterior - anterior border of the trapezius muscle. Inferior - superior border of the intermediate 1/3 of trhe clavicle. 34

34. Superior - meeting of the trapezius and SCM at the superior nuchal line. Roof - formed by the skin, superficial fascia, platysma and investing layer of the deep cervical fascia. Floor - formed by several muscles – semispinalis capitis , splenius capitis , levator scapulae, and scalene muscles 35

35. Muscles of the Posterior Triangle of the Neck 36

36. 37 Muscle Origin Insertion Action Nerve Platysma Superficial fascia of the deltoid and pectoral regions Inferior border of the mandible, some fibers sweep upward and blend with risorius Stretches tight the skin of the neck, depresses the mandible Facial nerve Splenius capitis Lower part of the ligamentum nuchae, lower cervical spines Mastoid process and the superior nuchal line Bilateral: Extends the head Individual: Flexes the head laterally Cervical spinal nerves

37. 38 Muscle Origin Insertion Action Nerve Levator scapulae Transverse processes of C1 to C4 Superior portion of the vertebral border of the scapula Elevates and rotates the scapula Dorsal scapular nerves Scalenius posterior Transverse processes of C5 and C6 Superior aspect of the second rib Flexes the neck APR of C5 to C8 Scalenius Medius Transverse processes of C2 to C7 Superior aspect of the first rib Flexes the neck APR of C3 and C4 Scalenius anterior Transverse processes of C3 to C6 Scalene tubercle of the first rib Participates in forced inspiration by elevating the ribs and sternum APR of C5 to C8

38. Subdivisions of the Posterior Triangle Occipital Triangle Supraclavicular Triangle 39

39. 1. Occipital Triangle Boundaries: Anterior - posterior border of SCM Posterior - anterior border of the Trapezius M. Superior - meeting between the trapezius and SCM Inferior - superior border of the inferior belly of omohyoid 40

40. 2. Supraclavicular or Subclavian or Omoclavicular Triangle Boundaries: Anterior - posterior border of SCM Superior - inferior border of the inferior belly of omohyoid Inferior - superior border of the intermediate 1/3 of the clavicle 41

41. Contents of the Posterior Triangle Arteries - subclavian artery, transverse cervical artery, occipital artery and suprascapular artery. Veins - external jugular vein, anterior jugular vein, transverse cervical vein, suprascapular and subclavian veins. Nerves - spinal accessory nerve, cutaneous and muscular branches of the cervical plexus, ansa cervicalis and root, trunk and divisions of the brachial plelxus. Lymph glands - supraclavicular lymph glands, and the lateral superior deep cervical lymph glands. 42