The Neck

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• 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.

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BOUNDARIES OF THE NECK

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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

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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 7th cervical vertebra

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SURFACE ANATOMY OF THE NECK

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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

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Structures Palpated in the Midline

body of the hyoid bone

thyroid cartilage

cricoid cartilage

Trachea

isthmus of the thyroid gland

suprasternal notch

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Structures Palpated Posteriorly

Inion

Nuchal goove

Vertebra prominence

Ligamentum nuchae which covers spines of C2 to C6

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Structures Palpated Laterally

Sternocleido-mastoid muscle

Trapezius muscle

External jugular veins

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The Muscles and Triangles of the Neck

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Regions of the NeckTo 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 muscle12

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 nerve2. Anterior primary rami of spinal nerves C2 and C3.

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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.

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The Anterior Triangle of the Neck

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MUSCLES OF THE ANTERIOR TRIANGLE OF THE NECK

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I. Infrahyoid Muscles

Muscle Origin Insertion Action Nerve Supply

Omohyoid Inferior belly:Superior border of the scapulaSuperior belly:Intermediate tendon

Inferior belly:Intermediate tendonSuperior 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

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

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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

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Suprahyoid MusclesMuscle 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

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BOUNDARIES OF THE ANTERIOR TRIANGLE

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• 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

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SUBDIVISIONS OF THE ANTERIOR TRIANGLE

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1. Digastric Triangle2. Carotid triangle3. Muscular or inferior carotid triangle4. Submental triangle

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1. Digastric TriangleBoundaries:1. Superior-

lower border of the mandible

2. Anterior –anterior belly of the digastric

3. Posterior –posterior belly of the digastric

4. Floor - mylohoid and hyoglossus muscles and superior contrictor muscle of the pharynx

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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.

4. Nerves – vagus, glossopharyngeal, facial, and hypoglossal.

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2. Carotid TriangleBoundaries:1. Superior

– posterior belly of the digastric

2. Inferior – superior belly of omohyoid

3. Posterior – anterior border of the SCM

4. Floor - thyrohyoid muscle, hyoglossus muscle, and the middle and inferior constrictor muscles of the pharynx.

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Structures:

1. Organs – larynx and pharynx (lower part)

2. Arteries - CCA, facial, occipital, acending pharyngeal, superior thyroid, and lingual.

3. Veins - internal jugular, superior thyroid, lingual, facial, occipital and ascending pharyngeal.

4. Nerves- vagus, accessory, hypoglossal, ansa hypoglossi, external and internal laryngeal.

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3. Muscular or Inferior Carotid Triangle

Boundaries:1. Supero-posterior

- superior belly of omohyoid

2. Infero-posterior- anterior border of SCM

3. Anterior- median line of the neck

4. Floor - sternohyoid and sternothyroid

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Structures:

1. Organs – thyroid and parathyroid glands, trachea

2. Arteries- inferior thyroid

3. Veins- internal jugular

4. Nerves- vagus, recurrent laryngeal, sympathetic n.

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4. Submental Triangle

Boundaries:1. Lateral

- two anterior bellies of the digastric2. Inferior

- body of the hyoid bone

Structures:3. Submental lymph glands4. Beginning of the anterior jugular vein

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The Posterior Triangle of the Neck

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Boundaries:

1. Anterior- posterior border of the SCM.

2. Posterior- anterior border of the trapezius muscle.

3. Inferior- superior border of the intermediate 1/3 of trhe clavicle.

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4. Superior - meeting of the trapezius and SCM at the superior nuchal line.

5. Roof - formed by the skin, superficial fascia, platysma and investing layer of the deep cervical fascia.

6. Floor- formed by several muscles – semispinalis capitis, splenius capitis, levator scapulae, and scalene muscles

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Muscles of the Posterior Triangle of the Neck

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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 headIndividual:Flexes the head laterally

Cervical spinal nerves

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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

Subdivisions of the Posterior Triangle

1. Occipital Triangle2. Supraclavicular Triangle

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1. Occipital TriangleBoundaries:1. Anterior

- posterior border of SCM

2. Posterior- anterior border of the Trapezius M.

3. Superior- meeting between the trapezius and SCM

4. Inferior- superior border of the inferior belly of omohyoid

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2. Supraclavicular or Subclavian or Omoclavicular Triangle

Boundaries:

1. Anterior- posterior border of SCM

2. Superior- inferior border of the inferior belly of omohyoid

3. Inferior- superior border of the intermediate 1/3 of the clavicle

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Contents of the Posterior Triangle

1. Arteries- subclavian artery, transverse cervical artery, occipital artery and suprascapular artery.

2. Veins- external jugular vein, anterior jugular vein, transverse cervical vein, suprascapular and subclavian veins.

3. Nerves- spinal accessory nerve, cutaneous and muscular branches of the cervical plexus, ansa cervicalis and root, trunk and divisions of the brachial plelxus.

4. Lymph glands- supraclavicular lymph glands, and the lateral superior deep cervical lymph glands.

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