1. Triangles of the Neck
Sanjaya Adikari
Department of Anatomy

2. Boundaries of the neck
Spinous process of C7
Acromian

3. Compartments of the neck
Neck has 4 major compartments
Vertebral compartment
Cervical vertebrae and associated muscles
Visceral compartment
Parts of respiratory and digestive tracts, important glands (thyroid, parathyroid and thymus)
Two vascular compartments
Contains major blood vessels and vagus nerve

4. Compartments of the neck

5. Cervical fascia Superficial Deep
Contains platysma muscle, cutaneous nerves, superficial veins and superficial LNs
Deep

6. Deep cervical fascia Consists of 4 parts Investing layer
Encircles the neck completely
Pretrachial fascia
Encircles the visceral compartment
Prevertebral fascia
Encircles the vertebral compartment
Carotid sheaths
Enclose the two vascular compartments

7. Investing layer Splits to enclose the parotid gl.
Superficial layer forms parotid fascia & attached to zygomatic arch
Mandible
Mastoid p.
E.O. protuberance & s. nuchal line
Acromian & spine
L. nuchae
Clavicle
Manubrium

8. Investing layer
Deep layer forms stylomandibular ligament between styloid process & angle of mandible
Stylomandibular ligament
Mandible
Mastoid p.
E.O. protuberance & s. nuchal line
Acromian & spine
L. nuchae
Clavicle
Manubrium

9. Prevertebral fascia Lies in front of prevertebral muscles
Extends from skull base to T4 body getting attached to anterior longitudinal ligament
Extends around the subclavian artery and brachial plexus and becomes axillary sheath
Phrenic nerve lies behind
Sympathetic trunk lies in front
Cutaneus branches of Cx plexus pierce it

10. Pretrachial fascia

11. Carotid sheath
Anterior
Vagus nerve

12. Triangles of the neck

15. Posterior triangle - contents
External jugular vein after piercing the investing layer.
Accessory nerve
Branches of Cx plexus
Lesser occipital
Great auricular
Transverse cervical
Supraclavicular

16. Floor of the posterior triangle
Prevertebral fascia lying on the muscles
Semispinalis capitis
Splenius capitis
Levator scapulae
Scalenus medius
Scalenus anterior

17. Anterior triangles of the neck

18. Anterior triangle of the neck
Suprahyoid muscles
Digastric: poterior belly by facial N. & anterior belly by nerve to mylohyoid
Stylohyoid: by facial nerve
Mylohyoid: by nerve to mylohyoid, a branch of inferior alveolar nerve (mandibular division)
Geniohyoid: by C1 through hypoglossal nerve

19. Anterior triangle…. Infrahyoid muscles Sternohyoid Omohyoid Thyrohyoid
Sternothyroid
These are depressors of the larynx. Supplied by ansa cervicalis (C1-C3)

20. Carotid triangle
Tip of the greater horn of hyoid is an important reference point
Note the relationships of hypoglossal nerve

21. Root of the neck
All structures that pass between the head and thorax or upper limb and thorax must pass through the root of the neck

22. Subclavian Artery 1st part of subclavian artery
Vetebral A
Internal thoracic A
Thyrocervical trunk
2nd part of subclavian artery
Costocervical trunk
3rd part of subclavian artery
Dorsal scapular A

23. Thoracic duct in the neck
Join the junction between the left subclavian and internal jugular veins