Hyoid

C3 level

suspended via attachments of muscle

no articulation with bones

greater and lesser horns

body

THYROID CARTILAGE

hyaline cartilage

larygeal prominence - adam's apple

thyroid notch

Cricoid Cartilage

hyaline cartilage

articulates with thyroid cartilage

complete ring

found between larynx and trachea

Jugular (suprasternal) Notch

fossa between sternal heads of SCM

Thyroid Gland

thyroid is deep to infrahyoid muscles, 2 lobes and isthmus bridge, 

Endocrine Function- growth, temp regulation, sympathetic activity, secretes T3, T4 and calcitonin

Parathyroid Glands

Four small glands located in each lobe of thyroid gland,

Endocrine function - critical role in maintaining calcium and phosphate balance

Pharynx- nasopharynx, oropharynx, laryngopharynx

function- pass food to esophagus an conduct air to larynx and trachea, two layers of muscles (constrictors and inner longitudinal), innervation of these muscles is CN 10 (vegus), during swallowing epiglottis will move over and close to prevent food from going down trachea

Larynx

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Connects pharynx to trachea, voice production via complex mechanism consisting of cartilage, ligaments and small (but important) laryngeal muscles

inferior laryngeal nerve innervates all of the intrinsic muscles of the larynx except one

lesion of the recurrent laryngeal nerve causes paralysis of vocal folds!

Posterior Triangle[image]

Can be split into occipital and supraclavicular triangles - separated by omohyoid inferior belly.

Contains- EJV, transverse cervical artery, subclavian artery, suprascapular artery, trunks of brachial plexus, CN11, cutaneous branches of cervical plexis, inferior belly of omohyoid muscle, floor is medial and posterior scalenes, levator scapula and splenius capitis, also contains cervical and supraclavical lymph nodes

Anterior Triangle

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Contents- hyoid muscles, arteries, veins, nerves, lymph nodes and viscera

4 subdivisions- 1. Submandibular triangle (digastric), 2. carotid triangle, 3. muscular triangle, 4. submental triangle

Submental Triangle

A part of the Anterior Triangle

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Contents- submental lymph nodes

Submandibular/Digastric Triangle

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has submandibular lymph nodes and gland (saliva to tongue),

borders- anterior and posterior bellies of digastric muscle and the mandible

contents- submandibular gland/duct, submandibular lymph nodes, CN12 (hypoglossal nerve)

Carotid Triangle[image]

Contents- CCA, ECA, IJV, CN10, 11 and 12- superior root of ansa cervicalis, branches of cervical plexus, thyroid, larynx and pharynx

Muscular Triangle

A section of the anterior triangle

Contents- infrahyoid muscles, thyroid and parathyroid glands

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Supraclavicular Fossa

depression overlying the supraclavicular triangle

pressure point of subclavian artery

palpate subclavian pulse just posterior to triangle

SCM

sternal and clavicular attachments up to mastoid process

Superficial Lymph Nodes

located throughout head and neck

drain superficial structures and eventually drain into deep cervical lymph nodes

Deep Cervical Lymph Nodes

tend to follow IJV and are located deep to SCM

drain into R/: brachiocephalic veins

Drainage into Brachicephalic Veins

Thoracic duct: drains at bifurcation of L IJV and subclavian v. as they merge into brochiocephalic

R Lyphatic duct: drains near bifurcation of R IJV and subclavian v. as they merge into brochiocephalic v.

thin layer of subcutaneous connective tissue

contains platysma muscle

Investing Layer of Deep Cervical Fascia

Most superficial of deep dervical fascia

invests SCM and Traps..."Four Corner"

Prevertebral Fascia

contains: 

scalnes and prevertebral muscles

posterior muscles of the neck

cervical vertebral column

Pretracheal Fascia

top: muscular portion of the pretrachial fascia, invests suprahyoid and infrahyoid muscles

bottom: visceral portion of pretrachial fascia, invests larynx, trachea, and thyroid gland

Cervical Plexus

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4 Sensory Branches- 1. lessor occipital nerve (C2) supplies posterior skull, 2. greater auricular nerve (C2-3) supplies anterior to ear, 3. transverse cervical nerve innervates sin of anterior triangle, 4. Supraclavicular nerve divides into three branches (anterior, middle and posterior)

2 Motor Branches- 1. Ansa Cervicalis- innervates infrahyoid muscles (except thyrohyoid), 2. Phrenic Nerve- motor supply to diaphragm

Carotoid Sheath

contains:

CCA (common carotid atery)

ICA (internal carotid artery)

IJV (internal jugular vein)

CN 10 (vagus)

Retropharyngeal Space

smooth, friction-less

between buccopharyngeal fascia and pre-vertebrial fascia

potential sight for swelling due to trauma/infection: would impair speech and swalowing

Phrenic Nerve

motor supply to diaphragm

Motor Branch of the cervical plexus

Brachial Plexus

Clinically- potential site for entrapment- referred pain

Located between anterior and middle scalene- dorsal and scapular nerves and thoracic nerves are here

Left side- CCA and Subclavian arise directly from aortic arch (CCA on to head, Subclavian to body)

Right side- Brachiosephalic trunk arises from aortic arch THEN CCA and Subclavian come from that trunk (again CCA going up to head, Subclavian going outward)

Thyrohyoid

Inf: oblique line of thyroid cartilage

Sup: body and greater horn of hyoid

N: C1 via CNX11 (hypoglossal nerve)

A: depresses the thyroid cartilage (larynx)

Common Carotid Artery

Carotid sinus (baroreceptor) and Carotid Body (Chemoreceptor) are at biforcation, they then split into Internal Carotid Artery- NO branches in neck, ascends up to carotid canal of temporal bone to supply brain

and

External Carotid Artery- gives into 8 branches as it ascends into neck (superior thyroid artery, lingual artery, facial artery, ascending pharyngeal artery, occipital artery, posterior auricular artery, maxillary artery, superficial temporal artery)

Sternohyoid

inf: posterior manubrium of sternum

sup: oblique line of throid cartilage

n: ansa cervicalis

a: depresses the thyroid carilage (larynx)

Omohyoid

superior belly (top): intermediate tendon to body of hyoid

inferior belly (bottom): superior border scapula to intermediate tendon

N: ansa cervicalis

A: depresses, retracts and stabilizes hyoid

3/8 branches of external carotid artery that supply face

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Subclavian Artery and Branches

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Vertebral Artery- branches supply spinal cord, brainstem and cerebellum

Thyrocervical Trunk- branches into inferior thyroid artery, transverse cervical artery and suprascapular artery

Internal Thoracic Artery- upt to upper six costal cartilages

Dorsal Scapular Artery- really a branch of thyrocervical

Mylohyoid (suprahyoid muscle)

sup: mylohyoid line of mandible

Inf: raphe and body of hyoid

N: mylohyoid n

A: elevates hyoid and tongue and during speech and swallowing

Genohyoid

sup: inferior mental spine of mandible

inf: body of hyoid

N: branch of C1 via C12

a: pulls hyoid anterosuperiorly (widens pharynx during deglutition)

Stylohyoid

sup: styloid process of temporal bone

inf: body of hyoid

n: CN7 facial nerve

a: elevates and retracts hyoid (elongates floor of mouth)

Digastric

Anterior Belly

Posterior Belly

n: anterior: mylohyoid n

posterior: CN 7

a: depresses mandible, elevates hyoid

Anterior Scalene

sup: transverse processes C3-6

inf: 1st rib

a: lateral flexion of c spine, assists in rotating neck to opposite side

Scalene Medius

sup: transverse processes of C2-7

inf: superior surface of 1st rib

a: elevates 1st rib (inspiration)

lateral flexion of cervical spine

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External Jugular Vein- distention with cardiovascular pressure

Anterior Jugular Vein- drains into EJV

Internal Jugular Vein- right IJV is site for cardiac catheterization, distention with increased cardiovascular pressure as well

Scalenus Posterior

sup: transverse processes C4-C6

inf: outer surface 2nd rib

a: lateral flexion of cervical spine

elevates 2nd rib (inspiration)

Longus Coli

inf: vertebral bodies of C5-T3 and transverse processes of C3-C5

sup: body C2-4, transverse processes C5-6 

a: flexes head and neck (forward movement)

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Brachiosephalic Vein- Inferior thyroid vein, IJV, subclavian ein, AJV and lymphatics (left thoracic duct and right lymphatic duct) all drain into this

Superior Vena Cava- descends to heart 

Longus Capitis

inf: transverse processes C3-C6

sup: base of skull

a: flexes head and neck

Subclavian Vein- clinically site for central line and right subclavian for cardiac catheterization

Rectus Capitis Anterior

inf: lateral mass of atlas

sup: base of skull anteior to occipital condyle

a: flexes head

Rectus Capitis Lateralis

inf: transverse process of atlas

sup: jugular process of occipital bone

a: flexes head