Head and Neck Muscles

Describe the Neck

Extends from → lower border of mandible to manubrium / superior nuchal line of occipital bone to intervertebral disc of C7-T1

Divided into 4 compartments - Visceral, Vertebral, and Vascular(2)

What are the compartments of the Neck

Visceral Compartment:

Anterior, Organs of digestive and respiratory systems, and Endocrine glands

What are the compartments of the Neck

Vertebral compartment:

Posterior, Cervical vertebrae, Spinal cord, Cervical nerves, Muscles associated with vertebral column

What are the compartments of the Neck

Vascular Compartments (2)

Left and Right, Lateral, Contain major bv, vagus nerv

What are the components of the Neck

Anterior and Posterior Triangle

What are the boundaries of the Posterior Triangle

Posterior border of sternocleidomastoid, Anterior border of trapezius, Clavicle

What are the boundaries of the Anterior Triangle

Anterior border of sternocleidomastoid, Inferior border of mandible, Midline of neck

What does the Anterior Triangle muscle contain

Muscles - suprahyoid + infrahyoid muscles

BV - common carotid A and branches + jugular Vs

Cranial nerves

Thyroid and parathyroid glands

Pharynx and laryn

What does the Pharynx do and what is it divided into

Links oral and nasal cavity in head to larynx and esophagus in neck

Common pathway for air and food

Divided into → Nasopharynx, Oropharynx, and Laryngopharyn

What is this compartment of the Pharynx

Nasopharynx

From posterior apertures (choanae) of nasal cavities to soft palate

Continuous with oropharyn

What is this compartment of the Pharynx

Oropharynx

Posterior part of oral cavity

Inferior to soft palate, superior to epiglottis

Houses palatoglossal folds that house palatine tonsi

What is this compartment of the Pharynx

Laryngopharynx

Superior margin of epiglottis to top fo esophagus (C6)

What does the pharynx house

Houses tonsils

Pharyngeal tonsils → Adenoids and Nasopharynx

Palatine tonsils → Oropharynx

Describe the Larynx

Opens to pharynx

Continues with trachea

Valve to close lower respiratory tract

Instrument to produce sound

Describe the structures of the Larynx

Cartilages + Membranes/Ligaments

Suspended from Hyoid bone, attached to trachea

Lvl of C4 to C6

Keep airway open by routing food and drink into esophagus

Voice box - sound production

What does the Larynx do during swallowing

Larynx move up and forward to facilitate closing of the laryngeal inlet and open the esophagus

No food/drink in larynx

Describe the Thyroid Cartilage

Unpaired Cartilage

Lvl of C4 and C5

Has Laryngeal Prominence (Adam’s Apple)

Describe the Thyroid Notch

Superior to laryngeal prominence

Signifies superior margin of thyroid carilage

Describe the horns off the Hyoid

They come off of the Thyroid Cartilage

Superior - attachment for thyrohyoid ligament

Inferior - articulation with cricoid cartilage

What is this Membrane

Thyroid Membrane

B/T Hyoid bone and Thyroid cartilage

What is this Cartilage

Cricoid Cartilage

Lvl of C6

Below Thyroid Cartilage

Unpaired Cartilage

What is this ligament

Cricothyroid Ligament

B/T thyroid cartilage and cricoid cartilage

What is this

Epiglottis

Unpaired cartilage

Closes off trachea so food and drink does not enter

Attached by narrow stem by ligament to thyroid cartilage - Thyro-epiglottic ligament

What is this

Corniculates

Paired cartilage

Small

Sit atop arytenoids

What is this

Arytenoids

Paired cartilage

Articulate inf with cricoid cartilage

Slide and rotate on the criocoid cartilage

Involved in sound production

Describe the Vocal Ligament

Sup margin of cricothyroid ligament thickened to from Vocal lig

Attached to internal surface of thyroid cartilage and vocal process of arytenoids

Vocal ligaments flank glottis

Arytenoids rotate and slide on cricoid cartilage, change how air passes out of glottis

Vocal lig enclosed in vocal folds

Describe the Larynx - Vocal Cords

Within larynx

2 vocal cords/folds

Vocal Fold/True Vocal cord (produces sound + inferiorly placed)

Vestibular Fold/False Vocal Cord (modifies sound produced by vocal fold)

Describe the thyroid gland

Large gland with distinct anatomy → left and right lobes, connected by narrow Isthmus

Endocrine

Flanking trachea, inferior to larynx

How do you find the parts of the Thyroid Gland

R/L lobes best palpated by finding laryngeal prominence, move inferiorly to cricoid cartilage

Move posteriolateral to larynx

Isthmus lies on surface of trachea

Palpate isthmus by finding cricoid cartilage, move inferiorly to palpate along trachea

Describe the Parathyroid Glands

Small

Embedded in posterior surface of thyroid gland

Produces parathyroid hormone (Ca lvls in blood)

ID/Describe

Sternocleidomastoid

Origin - Clavicular head-medial 1/3 of Clavicle / Sternal head-Manubrium

Insertion - Clavicular head-lateral ½ superior nuchal line / Sternal ehad-Mastoid process

Fxn - Unilateral contraction-ipsilateral lateral flecion / Unilateral contraction-contralateral head rotation / Bilateral-neck flexion

N - Accessory N

ID/Desciribe

Scalenus Anterior (anterior to brachial plexus and subclavian A

Origin - TP of C3-C6

Insertion - Upper surface of rib 1, scalene tubercle

Fxn - Elevate rib 1

N - Ant rami of C4-C7

ID/Describe

Scalenus Medius (posterior to brachial plexus and subclavian A

Origin - TP of vert C2-C7

Insertion - Upper surface of rib 1, posterior to groove for subclavian A

Fxn - Elevate rib 1

N - Ant rami of C3-C7

ID/Describe

Scalenus Posterior (posterior to brachial plexus and subclavian A)

Origin - TP of vert 

Insertion - Upper surface of rib 2

Fxn - Elevate rib 2

N - Ant rami of C5-C7

What do the muscles of the face do

Move the skin, lips, nostrils, and eyelids in diff facial expressions

All innervated by the Facial N

ID/Describe

Platysma (large, thin, sheetlike muscle)

Origin - Clavicle

Insertion - Mandible

Fxn - Draws corners of mouth down / Grimace / Tenses skin of neck

N - Facial N

ID/Describe

Orbicularis Oris

Origin - Facial muscles / Mandible / Maxilla

Insertion - Ellipse around mouth

Fxn - Closes lips / Protrudes lips / Presses lips against teeth / Pouting / Kissing

N - Facial N

ID/Describe

Zygomaticus Major

Origin - Zygomatic bone

Insertion - Corners of mouth

Fxn - Raises upper lip / smiling

N - Facial N

ID/Describe

Zygomaticus Minor

Origin - Zygomatic bone

Insertion - Upper lip medial to corner of mouth

Fxn - Raises upper lip

N - Facial N

ID/Describe

Levator Labii Superioris

Origin - Infraorbital margin of maxilla

Insertion - Upper lip

Fxn - Raises upper lip

N - Facial N

ID/Describe

Orbicularis Oculi (3 portions)

Origin - Encircles orbit

Insertion - Encircles orbit

Fxn - Closes eyelids / Draws eyebrows medially and downward

N - Facial N

What are the 3 portions of the Orbicularis Oculi

1 Orbital portion

2 Palpebral portions (superior placed - upper eyelid)(inferior placed - lower eyelid)

ID/Describe

Occipitofrontalis

Two muscle bellies - Frontal belly (forehead) + Occipital belly

Connected by aponeurosis - Epicranial aponeurosis

ID/Describe

Frontal Belly

Origin - Epicranial Aponeurosis

Insertion - Skin of eyebrows

Fxn - Draws eyebrows upward / Wrinkles skin of forehead

N - Facial N

ID/Describe

Occipital Belly

Origin - Superior nuchal line of occipital bone / Mastoid process temporal bone

Insertion - Epicranial aponeurosis

Fxn - Draws scalp backward

N - Facial N

ID/Describe

Buccinator (pierced by parotid duct)

Origin - Posterior parts of maxilla and mandible

Insertion - Blends with orbicularis oris and lips

Fxn - Presses cheek against teeth / Helps position food against teeth during chewing

N - Facial N

ID/Describe

Masseter

Origin - Zygomatic arch / Maxillary process of zygomatic bone

Insertion - Lateral surface of ramus of mandible

Fxn - Elevate mandible

N - Mandibular branch of trigeminal N

ID/Describe

Temporalis

Origin - Temporal bone / Temporal fascia

Insertion - Coronoid process of mandible / Anterior marign of ramus of mandible

Fxn - Elevate mandible / Retract mandible

N - Mandibular branch of trigeminal N

ID/Describe

Lateral Pterygoid (2 heads - Upper + Lower)

Origin - U-infratemporal fossa / L-lateral side of lateral pterygoid plate 

Insertion - Temporomandibular joint capsule / neck of mandible

Fxn - Protrude mandible / Move mandible side to side

N - Mandibular branch of trigeminal N

ID/Describe

Medial Pterygoid (2 heads - Superficial + Deep)

Origin - S-palatine bone + maxilla / D-medial surface of lateral pterygoid plate

Insertion - Medial surface of mandible near angle

Fxn - Elevate mandible / move mandible side to side

N - Mandibular branch of trigeminal N

ID/Describe

Genioglossus

Origin - Mental spines on back of mandible

Insertion - Forms bulk of tongue / Some fibers to hyoid

Fxn - Protrudes tongue

N - Hypoglossal N

ID/Describe

Hypoglossus

Origin - Hyoid bone

Insertion - Fibrous tissue of tongue near dorsum

Fxn - Flattens (depresses) tongue

N - Hypoglossal N

ID/Describe

Styloglossus

Origin - Styloid process

Insertion - Lateral side of tongue / Body of hyoid bone

Fxn - Retracts tongue upward and backward

N - Hypoglossal N

What do muscles of the hyoid move

Muscles that move the hyoid will move the larynx

b/c of membranous/muscular connection between the two

What are the 2 types of muscles that move the hyoid + larynx

Suprahyoid muscles → attach to superior margin of hyoid

Infrahyoid muscles → tatach to inferior marign of hyoid

ID/Describe

Stylohyoid (suprahyoid)

Origin - Styloid process

Insertion - Body of hyoid

Fxn - Elevates hyoid during swallowing

N - Facial N

ID/Describe

Digrastic (2 bellies - Ant + Post)(Suprahyoid)

Origin - A-lower margin of mandible / P-Mastoid process

Insertion - Tendon B/T two bellies to body of hyoid bone

Fxn - A-Elevates hyoid during swallowing and opening of mouth, depresses mandible / P-elevates hyoid during closing of mouth

N - A-Mylohyoid N / P-Facial N

ID/Describe

Mylohyoid (Suprachyoid)

Origin - Internal surface of mandible / Mylohyoid line of mandible

Insertion - Hyoid bone

Fxn - Helps form floor of oral cavity / Elevation of floor of mouth / Elevation of hyoid

N - Mylohyoid N (off branch of mandibular division of trigeminal N)

ID/Describe

Geniohyoid (Suprahyoid)

Origin - Mental spine of mandible

Insertion - Body of hyoid bone

Fxn - Supports and elevates floor of oral cavity / Depresses mandible when hyoid fixed / Elevates hyoid when mandible fixed

N - Ant ramus C1

ID/Describe

Omohyoid (2 bellies)(Infrahyoid)

Origin - Superior border of scapula

Insertion - Lower border of body of hyoid bone

Fxn - Depressing hyoid bone during vocalization and end of swallowing / Fixes hyoid bone

N - Ant rami of C1-C3

ID/Describe

Sternohyoid (Infrahyoid)

Origin - Manubrium / Clavicle

Insertion - Lower border of hyoid bone

Fxn - Depress hyoid bone during vocalization and end of swallowing / Fixes hyoid bone

N - Ant rami of C1-C3

ID/Describe

Thyrohyoid (Infrahyoid)

Origin - Thyroid cartilage 

Insertion - Lower border of hyoid bone

Fxn - Depresses hyoid bone / Raise larynx while swallowing

N - Ant ramus of C1

ID/Describe

Sternothyroid

Origin - Manubrium / Medial part of first costal cartilage

Insertion - Front of thyroid cartilage

Fxn - Depresses larynx

N - Ant rami of C1-C3

Describe the Parotid Gland

Large salivary gland

Ant to ear, much of cheek region

Parotid duct comes off - Pierces buccinator to enter oral cavity

Describe the Submandibular Gland

Salivary gland below mandible

On L and R side

Drained by submandibular duct

Describe the Sublingal Gland

Salivary gland below tongue

On L and R side