1. WINDSOR UNIVERSITY SCHOOL OF MEDICINE
DEPARTMENT OF ANATOMY
Neck
Dr. SREEKANTH THOTA

2. Neck
The neck is a tube providing continuity from the head to the trunk.
It extends anteriorly from the lower border of the mandible to the upper surface of the manubrium of sternum, and posteriorly from the superior nuchal line on the occipital bone of the skull to the intervertebral disc between the CVII and TI vertebrae.

3. Objectives 2. Fascia and Fascial spaces of the neck
1. To study Compartments of the neck.
2. Fascia and Fascial spaces of the neck
3. Anterior triangle of the neck
4. Posterior triangle of the neck
5. Bones of the Neck
6. Vasculatur of the neck
7. Nerves of the neck.
8. Lymphatics of the neck

4. Compartments of the neck
Within the tube four compartments provide longitudinal organization
1. visceral compartment is anterior and contains parts of the digestive and respiratory systems, and several endocrine glands
2. vertebral compartment is posterior and contains the cervical vertebrae, spinal cord, cervical nerves, and muscles associated with the vertebral column
3. Two vascular compartments are lateral and contain the major blood vessels and the vagus nerve [X].

6. Fascia
Superficial fascia: contains a thin sheet of muscle (the platysma)
Deep cervical fascia: organized into several distinct layers
1. Investing layer
2. Prevertebral layer
3. Pretracheal layer
4. Carotid sheath

9. Fascial spaces
Between the fascial layers in the neck are spaces that may provide a conduit for the spread of infections from the neck to the mediastinum.
1. Pretracheal space : passes between the neck and the anterior part of the superior mediastinum
2. Retropharyngeal space : extends from the base of the skull to the upper part of the posterior mediastinum

11. Triangles of the neck
For descriptive purposes the neck is divided into anterior and posterior triangles
1.The anterior triangle of the neck is outlined by the anterior border of the sternocleidomastoid muscle laterally, the inferior border of the mandible superiorly, and the midline of the neck medially.
2. boundaries of the posterior triangle are the posterior border of the sternocleidomastoid muscle, the anterior border of the trapezius muscle, and the middle one-third of the clavicle

14. Anterior Triangle subdivided into smaller triangles by
Posterior Triangle
Submental Triangle
Submandibular Triangle
Carotid Triangle
Anterior Triangle subdivided into smaller triangles by
Digastric muscle
Omohyoid muscle

15. Anterior triangle of the neck
Subdivided into four smaller triangles
1. Submandibular triangle: outlined by the inferior border of the mandible superiorly and the anterior and posterior bellies of the digastric muscle inferiorly
2. Submental triangle: outlined by the hyoid bone inferiorly, the anterior belly of the digastric muscle laterally, and the midline

17. 3.Muscular triangle: outlined by the hyoid bone superiorly, the superior belly of the omohyoid muscle, and the anterior border of the sternocleidomastoid muscle laterally, and the midline
4.Carotid triangle is outlined by the superior belly of the omohyoid muscle anteroinferiorly, the stylohyoid muscle and posterior belly of the digastric superiorly, and the anterior border of the sternocleidomastoid muscle posteriorly.

18. Contents of ant triangle

19. Posterior triangle of the neck

22. Bones of the Neck
The skeleton of the neck is formed by the cervical vertebrae and hyoid bone

23. Cervical Vertebrae
Seven cervical vertebrae form the cervical region of the vertebral column, which encloses the spinal cord and meninges.

25. C1 vertebrae or atlas
Ring-like, kidney-shaped bone lacking a spinous process or body and consisting of two lateral masses connected by anterior and posterior arches.
Its concave superior articular facets receive the occipital condyles.

27. C2 vertebrae or axis
Peg-like dens (odontoid process) projects superiorly from its body

28. Four typical cervical vertebrae (3rd to 6th)
Spinous processes are short and bifid.
Transverse processes of all cervical vertebrae (typical or atypical) include transverse foramina for the vertebral vessel(except for C7, the vertebral artery).

30. C7 vertebra or vertebra prominens
So-named because of its long spinous process, which is not bifid.
Its transverse processes are large, but its transverse foramina are small.

32. HYOID BONE Anterior neck C3
Suspended from the styloid process of the temporal bone by the stylohyoid ligament
Serves as an attachment for suprahyoid and infrahyoid muscles and the investing deep fascia
It serves as a prop to keep the airway open

33. Important Muscles of Neck

34. Superficial Muscles of the Neck
1. Sternocleidomastoid Muscle
Origin:Sternal head: anterior surface of manubrium of sternum Clavicular head: superior surface of medial third of clavicle
Insertion :Lateral surface of mastoid process of temporal bone and lateral half of superior nuchal line
N. supply:Spinal accessory nerve (CN XI, motor)
Action :Two muscles acting together extend head and flex neck; one muscle rotates head to opposite side

35. Congenital Torticollis
Torticollis is a contraction of the cervical muscles that produces twisting of the neck and slanting of the head.
The lesion, like a normal unilateral SCM contraction, causes the head to tilt toward, and the face to turn away from, the affected side

36. Spasmodic Torticollis
Cervical dystonia commonly known as spasmodic torticollis, usually begins in adulthood.
Characteristics of this disorder are sustained turning, tilting, flexing, or extending of the neck .

37. Muscles
The muscles in the anterior triangle of the neck can be grouped according to their location relative to the hyoid bone:
1. Muscles superior to the hyoid are classified as suprahyoid muscles.
2. Muscles inferior to the hyoid are infrahyoid muscles.

38. Suprahyoid muscles Digastric Stylohyoid Geniohyoid Mylohyoid
Styloid process to hyoid bone
Geniohyoid
Inferior mental spine (on back of symphysis menti) to hyoid bone
Mylohyoid
Mandible to hyoid bone
Stylohyoid muscle- With post belly of digastric muscle supplied with facial nerve.
Geniohyoid- C1 running with hypoglossal nerve.
Mylohyoid muscle- With anterior belly of digastric muscle supplied with mylohyoid nerve (arises from mandibular division of trigeminal nerve). 38

40. Action of Supra & Infrahyoid Muscles
Direction of pull; effect on hyoid; swallowing: epiglottis closes over larynx; Function of elevators and depressors is therefore v. imp!

41. Infrahyoid Muscles Strap muscles Sternothyroid Sternohyoid Thyrohyoid
Sternum to thyroid cartilage
Sternohyoid
Sternum to hyoid bone
Thyrohyoid
Thyroid cartilage to hyoid bone
Omohyoid
Superior border of scapula to hyoid bone
All infrahyoid muscles are innervated by ansa cervicalis from cervical plexus (C1-3) EXCEPT for thyrohyoid muscle, which is innervated by C1 fibers running with hypoglossal nerve 41

43. Scalene Muscles Elevation of rib I and II
Anterior, middle, and posterior scalene muscles
Attach to transverse processes of cervical vertebrae and to rib 1 and 2
Action
Elevation of rib I and II
Innervated by spinal nerves C3-C8
Also called lateral vertebral muscles 43

44. Subclavian artery Common carotid artery ICA ECA
Arteries of the Neck
Subclavian artery
Common carotid artery
ICA
ECA

45. Subclavian Arises from
Right side- brachiocephalic trunk
Left side- arch of aorta
Arches laterally over cervical pleura and apex of lung and grooves on 1st rib between anterior and middle scalene muscles
Divided into three parts in relation to anterior scalene muscle
Becomes axillary artery at lateral border of 1st rib

46. First part of Subclavian artery
The first part extends from the origin of the artery to the anterior scalene muscle.
1. Vertebral artery
2. Thyrocervical trunk
3. Internal thoracic artery
Thyrocervical trunk
Inferior thyroid artery
Transverse cervical artery
Suprascapular artery

48. Second part of the subclavian artery.
Costocervical trunk
1. Deep cervical artery
2. Supreme intercostal artery

49. Common carotid artery Arises from
Brachiocephalic trunk on right
Arch of aorta on left
Divides into internal & external carotid arteries
At superior border of thyroid cartilage (C4)

50. Carotid Pulse Important site for pulse taking
Pulsation in common carotid artery are felt just below its bifurcation
Bifurcation happens at the level of superior border of thyroid cartilage
Against transverse process of 6th cervical vertebra (carotid tubercle)

51. Internal carotid artery
No branches in neck
External carotid artery
Gives eight branches
Four or five arise in carotid triangle
Ends within parotid gland by dividing into maxillary and superficial temporal arteries

52. Superficial venous drainage
The external jugular and anterior jugular veins are the primary venous channels for superficial venous drainage of the neck

54. Nerves
Several nerves and components of the nervous system pass through the neck.
1. Cervical plexus
2.Phrenic nerves
3. Vagus nerves [X]
4. Recurrent laryngeal nerves
5. Sympathetic nervous system

55. Cervical plexus
The cervical plexus is formed by the anterior rami of cervical nerves C2 to C4, and possibly a contribution from the anterior ramus of cervical nerve C1.
Muscular (or deep) branches
Cutaneous (or superficial) branches

57. Phrenic nerve
The phrenic nerves are branches of the cervical plexus and arise on each side as contributions from the anterior rami of cervical nerves C3 to C5 come together.

59. Vagus nerves [X]
The vagus nerves [X] descend through the neck within the carotid sheath, posterior to and just between the common carotid artery and the internal jugular vein.
In the root of the neck, each vagus nerve [X] passes anterior to the subclavian artery and posterior to the subclavian vein as it enters the thorax

60. Recurrent laryngeal nerves
The right recurrent laryngeal nerve is a branch of the right vagus nerve [X] on reaching the lower edge of the first part of the subclavian artery in the root of the neck
The left recurrent laryngeal nerve is a branch of the left vagus nerve [X] as it crosses the arch of the aorta in the superior mediastinum. It passes below and behind the arch of the aorta and ascends beside the trachea to the larynx.

62. Sympathetic nervous system
Various components of the sympathetic nervous system are visible as they pass through the root of the neck. These include:
1. cervical part of the sympathetic trunk;
2. ganglia associated with the cervical part of the sympathetic trunk;
3.cardiac nerves branching from the cervical part of the sympathetic trunk

65. Lymphatics Thoracic duct
The thoracic duct is a major lymphatic channel that begins in the abdomen, passes superiorly through the thorax, and ends in the venous channels in the neck.

66. Termination of lymphatic trunks in the root of the neck.
1.Jugular trunk from the head and neck
2.Subclavian trunk from the right upper limb
3.Bronchomediastinal trunk

67. Lymphatics of the neck 1. occipital nodes
2. mastoid nodes (retroauricular/posteri or auricular nodes)
3. pre-auricular and parotid nodes
4. submandibular nodes
5. submental nodes
Superficial cervical lymph nodes
Deep cervical lymph nodes

69. Deep cervical lymph nodes
From the deep cervical nodes, lymphatic vessels form the right and left jugular trunks, which empty into the right lymphatic duct on the right side or the thoracic duct on the left side.