TRIANGLES OF THE NECK Khalid M. Khan Department of Anatomy Kuwait University December 09, 2013

Reference & Reading Assignment Clinically Oriented Anatomy, 7 th ed., Moore & Dalley, pp Objectives  Describe the surface landmarks of the neck  Describe the boundaries of the triangles of the neck  Describe the contents of the triangles of the neck  Describe the organization of cervical plexus and course and distribution of its branches

The Neck  is a transitional area that joins the head to the trunk and limbs.  is a cylindrical structure that serves as a major conduit for structures passing between them.  has many structures crowded together in a narrow space.  is relatively slender to allow flexibility to position the head to maximize efficiency of sensory organs.  is vulnerable to injury as it is devoid of bony protection. In order to provide support the cervical structures are surrounded by superficial fascia and are compartmentalized by layers of deep cervical fascia.

TRANSVERSE SECTION OF NECK

SURFACE ANATOMY OF THE NECK

PLATYSMA & SUPERFICIAL FASCIA OF NECK

BONES & CARTILAGES OF THE NECK

A – Sternocleidomastoid 1 – Lesser supraclavicular fossa B – Trapezius C – Lateral Cervical Region/Posterior triangle of neck 2 – Occipital triangle 3 – Omoclavicular (subclavian) triangle D – Anterior Cervical Region/Anterior triangle of neck 4 – Submandibular (Digastric) triangle 5 – Submental triangle (unpaired) 6 – Carotid triangle 7 – Muscular (omotracheal) triangle CERVICAL REGIONS/TRIANGLES OF NECK

POSTERIOR CERVICAL REGION/TRIANGLE Boundaries:  Anterior Boundary - Posterior border of Sternocleidomastoid  Posterior Boundary - Anterior border of Trapezius  Inferior Boundary - Middle third of the clavicle  Apex - Meeting point of Sternocleidomastoid and Trapezius on the superior nuchal line of the occipital bone  Roof – Investing layer of the deep cervical fascia  Floor – Muscles covered by the prevertebral layer of deep cervical fascia Subdivisions of Posterior Triangle:  Occipital Triangle – Anterior border of Trapezius, posterior border of Sternocleidomastoid, and superior border of inferior belly of Omohyoid  Omoclavicular (Subclavian) Triangle – Inferior border of inferior belly of Omohyoid, posterior border of Sternocleidomastoid, and superior border of middle third of the clavicle

POSTERIOR CERVICAL REGION/TRIANGLE Roof – Investing layer of the deep cervical fascia

CONTENTS OF THE 0CCIPITAL TRIANGLE OCCIPITAL TRIANGLE 1. Part of External Jugular Vein 2. Posterior branches of cervical plexus 3. Spinal accessory nerve 4. Supraclavicular part of brachial plexus 5. Transverse cervical artery 6. Cervical lymph nodes (not shown)

CONTENTS OF THE SUBCLAVIAN TRIANGLE OMOCLAVICULAR (SUBCLAVIAN) TRIANGLE 1. Subclavian artery (3 rd part) 2. Suprascapular artery 3. Supraclavicular lymph nodes (not shown) 2 1

POSTERIOR TRIANGLE OF THE NECK

ANTERIOR CERVICAL REGION/TRIANGLE Boundaries:  Anterior Boundary - Anterior midline of neck  Posterior Boundary - Anterior border of Sternocleidomastoid  Superior Boundary - Inferior border of the mandible  Apex - Jugular notch in the manubrium  Roof - Subcutaneous tissue containing platysma & investing layer of deep cervical fascia  Floor - Pharynx/esophagus, larynx and thyroid gland Subdivisions of Anterior Triangle:  4. Submandibular Triangle – Inferior border of mandible and the two bellies of Digastric  5. Submental Triangle – Unpaired between left and right anterior bellies of Digastric and hyoid bone  6. Carotid Triangle – Superior belly of Omohyoid, posterior belly of Digastric and anterior border of Sternocleidomastoid  7. Muscular Triangle - Superior belly of Omohyoid, anterior border of Sternocleidomastoid and the median plane of the neck

ANTERIOR CERVICAL REGION/TRIANGLE Boundaries:  Anterior Boundary - Anterior midline of neck  Posterior Boundary - Anterior border of Sternocleidomastoid  Superior Boundary - Inferior border of the mandible  Apex - Jugular notch in the manubrium  Roof - Subcutaneous tissue containing platysma & investing layer of deep cervical fascia  Floor - Pharynx/esophagus, larynx and thyroid gland

CONTENTS OF THE ANTERIOR TRIANGLE SUBMANDIBULAR (DIGASTRIC) TRIANGLE Submandibular gland and lymph nodes; Hypoglossal nerve; Mylohoid nerve; parts of facial artery and vein SUBMENTAL TRIANGLE Submental lymph nodes and small veins that unite to form Anterior Jugular vein CAROTID TRIANGLE Carotid sheath containing Common Carotid artery and its branches; Internal Jugular vein and its tributaries; External Carotid artery and some of its branches; Hypoglossal nerve and Superior root of ansa cervicalis; Spinal Accessory nerve; Thyroid gland, Larynx and Pharynx; deep cervical lymph nodes; branches of cervical plexus MUSCULAR (OMOTRACHEAL) TRIANGLE Sternothyroid and Sternohyoid muscles; Thyroid and Parathyroid glands

CONTENTS OF THE CAROTID TRIANGLE -1

CONTENTS OF THE CAROTID TRIANGLE – F/L art. 3 – Sup Thy art 4 – Inf B Om 5 – Inv Lay 6 – Int J V 7 – CC art 8 – EC art 9 – IC art 10 – Sp Ac ner 11 – Hypgl ner 12 – Occ art 2 – F art

ARTERIES OF THE NECK Transverse facial Maxillary Facial Lingual Superior thyroid Omohyoid (Sup. belly) Omohyoid (Inf. belly) Digastric (Post. belly) Inferior thyroid Thyrocervical trunk Vertebral Transverse cervical Suprascapular Common carotid External carotid Internal carotid Occipital Superficial temporal Posterior auricular Ascending pharyngeal

ARTERIES OF THE NECK

INTERNAL JUGULAR VEIN

CERVICAL PLEXUS – SENSORY NERVES