The Head and Neck Triangles of the Neck

The Head and Neck

Triangles of the Neck l Neck subdivided into two triangles l Separated by the sternocleidomastoid muscle l Anterior triangle l Posterior triangle

Triangles of the Neck: Posterior l Boundries: ¡ ¡ ¡ l Anterior - sternocleidomastoid Posterior - trapezius Inferior – clavicle Contents: ¡ ¡ ¡ Nerves: accessory nerve, cranial plexus, phrenic nerve, brachial plexus Artery: Subclavian Vein: External jugular

Triangles of the Neck: Anterior l Boundries: ¡ ¡ ¡ l Anterior - midline Posterior - sternocleidomastoid Superior – inferior margin of the mandible Contents: ¡ ¡ ¡ Glands: Submandibular Muscles: Suprahyoid and infrahyoid muscles Artery: Carotid Vein: Internal jugular, External jugular Nerve: Acccessory

Triangles of the Neck

Lingvalni trokuti su: donji - trigonum linguale (Beclard) i gornji - trigonum linguale Pirogoff - dno oba trokuta je musculus hyoglossus; - granice gornjeg su: intermedijarna tetiva digastrikusa i cornu maius ossis hyoidei - granice donjeg su: intermedijarna tetiva digastrikusa i stražnji rub milohioidnog mišića - lateralno od m. hyoglossus i površno kroz oba trokuta prolazi n. XII s venom pratilicom - medijalno i ispod hyoglossus-a leži a. lingualis

Upper Respiratory Tract l l l Nasal Cavity Nostril Oral Cavity Larynx Pharynx

Nose Only portion of the RT that is externally visible l Functions: l ¡ ¡ ¡ l Provides airway for respiration Moistens and warms air Filters inhaled air Resonating chamber for speech Houses olfactory receptors 2 divisions: ¡ ¡ External nose Internal nasal cavity

Nasal Cavity l Air enters here during breathing ¡ Passes through the nares (nostrils) Divided into R and L by nasal septum l Continuous with the nasopharynx through the internal nares l

Nasal Cavity l Boundries: ¡ ¡ Roof – ethmoid bone (cribiform plate) Floor – maxilla (palatine process) palatine (horizontal plate) ¡ l Hard palate ¡ l Lateral walls – nasal bones, superior and middle nasal conchae (ethmoid bone), inferior nasal conchae, maxilla, palatine bone Palatine bones and maxillary bone Soft palate ¡ Muscular posterior portion

Nasal Cavity l Vestibule ¡ ¡ Superior to nostrils Skin lined with: l Sebaceous glands • • l Greasy secretion Collect dirt Lubricate Kill bacteria Sweat glands • Acidic • Slows growth of bacteria l Hair follicles • Trap small particles of dirt l Vibrissae ¡ ¡ Nose hairs Filter large particles (insects)

Lining of the Nasal Cavity l Olfactory Mucosa ¡ ¡ l Roof of nasal cavity Houses small receptors Respiratory Mucosa ¡ ¡ ¡ Pseudostratified ciliated columnar epithelium Goblet cells Lamina propria l ¡ ¡ Mucous and serous cells Venous plexus Function is to filter and warm inhaled air

Nasal Conchae l l Project medially from each lateral wall 3 structures: Superior ¡ Middle of ethmoid bone ¡ Inferior ¡ l Functions: Filters air ¡ Heats air ¡ Moistens air ¡ Reclaim heat and moisture during exhalation ¡

Paranasal Sinuses Air filled cavities that surround the nasal cavity l Lined by mucosa l Perform same function as nasal cavity and lightens skull l Located in Frontal, Ethmoid, Sphenoid, Maxilla bones l

Pharynx l l l Connects the nasal cavity and mouth to larynx and esophagus Extends from base of skull to level of C 6 vertebra Common passage for food and air (throat) Lined with skeletal muscle Divided into: ¡ ¡ ¡ Nasopharynx Oropharynx Laryngopharynx

Regions of the Pharynx Nasopharynx Oropharynx Laryngopharynx Pg 584

Nasopharynx l Location: ¡ ¡ ¡ Posterior to nasal cavity Inferior to sphenoid bone Superior to level of soft palate ONLY an air passageway l Closed off during swallowing by the soft palates’ uvula l ¡ Giggling! Ciliated pseudostratified epithelium l Contain: l ¡ ¡ Pharyngeal tonsils (adenoids) Tubal tonsils

Oropharynx l Location: ¡ ¡ Postreior to the oral cavity Extends inferiorly from level of the soft palate to level of the esophagus Swallowed food and inhaled air pass through here l Stratified squamous epithelium l Contain: l ¡ ¡ Palatine tonsils Lingual tonsils

Tonsils Lymphoid organ l Swellings of the mucosa lining the pharynx l Form ring around the entrance to the pharynx l 4 groups: l ¡ ¡ Palatine Lingual Pharyngeal Tubal Remove pathogens l MALT l

Laryngopharynx l Location: ¡ ¡ Lies posterior to larynx Continuous with the esophagus and larynx Common passageway for food and air l Stratified squamous epithelium l

Larynx l l l l “Voice box” Extends from C 4 to C 6 Attachments: ¡ Hyoid bone superiorly ¡ Continuous with trachea inferiorly Functions: ¡ Vocalization ¡ Provides open airway ¡ Switches to route air and food into proper channels Innervation: Vagus Superior part = stratified squamous epithelium Below vocal cords= ciliated pseudostratified columnar

Larynx l Composed of 9 cartilages connected by membranes and ligaments: ¡ ¡ ¡ 1 Thyroid 1 Cricoid 1 Epiglottis 2 Arytenoid 2 Corniculate 2 Cuneiform

Laryngeal Cartilages l Thyroid Cartilage ¡ ¡ Large Shield shaped Formed by 2 plates Composed of laryngeal prominence l Adam’s Apple!!

Laryngeal Cartilages l Cricoid ¡ ¡ ¡ Inferior to thyroid cartilage Forms a complete ring Perched on top of the trachea

Laryngeal Cartilages l Epiglottis ¡ ¡ ¡ Composed of elastic cartilage Covered by mucosa Projects upward from anterior wall of laryngeal inlet to level of base of tongue

Vocal Cords Located in the larynx l Mucosal folds formed by vocal ligaments l ¡ ¡ l Exhaled air passes over them and causes vibration ¡ ¡ l Composed of elastic fibers Run from arytenoid cartilages to the thyroid cartilages Force of air = volume Length & tension of folds = pitch False vocal cords ¡ Vestibular folds (superior to true)

Thyroid Gland l Location: ¡ ¡ l 2 lateral lobes ¡ l l In anterior neck On trachea, inferior to larynx Connected by the isthmus Butterfly shape Largest endocrine gland in body ¡ Produces TH l ¡ Increases metabolic rate Calcitonin l Depresses excess levels of Ca+ in blood

Thyroid Gland l Internally, composed of follicles ¡ Follicular cells l ¡ Parafollicular cells l l TH Calcitonin Blood supply ¡ Superior thyroid arteries l ¡ Branches of external carotids Inferior thyroid arteries l Branches of subclavians

Hyoid Bone l Location: ¡ ¡ l Inferior to mandible In anterior neck Associated with the skull ¡ Only bone in skeleton that does not articulate directly to another bone!!! Attaches via ligaments to temporal bone, larynx l Composed of: l ¡ ¡ l Body 2 pairs of horns Functions: ¡ ¡ Moveable base for tongue Points of attachment for larynx and neck muscles l Sternohyoid, thyrohyoid,

Mouth and Associated Organs Mouth l Tongue l Salivary glands l Teeth l

Mouth - Oral Cavity Food enters alimentary canal through here l Mucosa-lined l ¡ l Boundaries: ¡ ¡ ¡ l Thick stratified squamous epithelium, with keratinization in some areas Lips anteriorly Cheeks laterally Palate superiorly Tongue inferiorly Oropharynx posteriorly Mouth divided into 2 parts: ¡ ¡ Vestibule Oral cavity proper

Mouth l Lips (labia) and Cheeks ¡ ¡ Keep food inside mouth during chewing Composed of skeletal muscle surrounded by skin Lips formed by orbicularis oris muscle Cheeks; Muscles of Mastication (pg 266 -67) l l l Temporalis & Masseter (elevate mandible, close mouth) Buccinator (chewing) Digastric (lower mandible against resistance, opens mouth) Pterygoids (lateral movements) Palate: forms the roof of the mouth ¡ ¡ Soft palate (posterior) rises to close off nasopharynx during swallowing; made of muscle Hard palate (anterior) provides surface for tongue to force food against during chewing

Tongue l Functions ¡ ¡ ¡ l l l Grips and moves food between teeth during chewing Mixes food with saliva = BOLUS Moves bolus down pharynx Speech production Houses taste buds (= gustation) Creates floor of mouth Attachments: hyoid, mandible, styloid process, soft palate Made of Skeletal muscle with a CT septum ¡ ¡ Intrinsic muscles (change shape; rolling) Extrinsic muscles (movement; protrude, retract) Motor = Hypoglossal (CN XII) Sensory = Mandibular (CN V 3), Facial (CN VII), Glossopharyngeal (CN IX)

Swallowing Voluntarily initiated (pharynx) l Peristalsis = propulsion l ¡ ¡ Involuntary Alternate waves of contraction and relaxation of muscles in organ walls (e. g. esophagus) Squeezes food from one organ to next Some mixing

Salivary Glands Compound tubuloalveolar glands l Intrinsic salivary glands l ¡ ¡ l In mucosa of tongue, palate, lips and cheeks Keeps mouth moist at all times Extrinsic salivary glands ¡ ¡ Lie external to mouth Connected by ducts Secrete only during eating or prior to (“mouth watering”) 3 paired glands: l l l Parotid Submandibular sublingual

Salivary Glands l Produce saliva ¡ ¡ ¡ ¡ Mixture of water, ions, mucus and enzymes Moistens mouth Dissolves food for taste Binds food into a bolus Enzymes digest starch Bicarbonate buffer neutralizes acids Kill microorganisms Contains proteins to promote growth of beneficial bacteria

Teeth – From Eruption to Edentate l Teeth lie in sockets (alveoli) in gumcovered margins in mandible and maxilla l Have 2 sets of teeth (dentitions) ¡ Primary dentition / deciduous (milk) teeth ¡ Permanent dentition (21 years; 32 teeth) Incisors (8): rip, cut l Canines (4): tear and pierce l Premolars (8): grinding l Molars (12): grinding l

Teeth l Function: ¡ l Ingestion and mechanical breakdown of food Periodontal ligaments (collagen fibers) anchor tooth in bony socket ¡ ¡ Gomphosis - form of immovable articulation; a peglike part fits into a cavity Continous with gingiva (gum)

Teeth l Regions: ¡ Crown l l ¡ ¡ Neck (gumline) Root l l Covered with enamel Area above gingiva Area below neck in alveolus Pulp cavity ¡ ¡ ¡ Center of tooth Loose CT with vessels and nerves Supplies nutrients to hard tissues

Teeth l Root Canal ¡ l Apical foramen ¡ l Opening into the root canal at the tip of each root Blood supply ¡ l Portion of the pulp cavity in the root Superior/Inferior Alveolar artery, branches of External Carotid artery Innervation ¡ ¡ Maxilla = Superior Alveolar Nerves Mandible = Inferior Alveolar Nerves

Teeth Substances l Enamel ¡ ¡ l Dentin ¡ ¡ ¡ l Made of calcium salts Avascular, acellular Not renewed or replaced HARDEST substance in body!!!! Underlines enamel Forms bulk of tooth Made of minerals and collagen Maintained during life Harder than bone Cementum ¡ ¡ Calcified external surface Attaches tooth to periodontal ligament

Teeth at Birth Number of erupted teeth = 0 l Jaws covered by gingiva (gums) l ¡ Lots of drooling!!!

First Teeth – 6 Months l Lower central incisors first to appear ¡ ¡ 8 Incisors = 6 -10 months 4 Canines = 16 -20 months 4 1 st Molars = 12 -16 months 4 2 nd Molars = 20 -24 months 20 deciduous teeth emerge by age 2 l Dental formula l ¡ Deciduous teeth dental formula: Describes the number and position of classes of teeth (half of the mouth) 2 I, 1 C, 2 M X 2 = 20 ****No premolars!

Adolescence – Adult l Permanent teeth enlarge and develop ¡ ¡ Roots of deciduous teeth reabsorbed Teeth loosen and fall out Begin to erupt from 7 -13 years of age Third molars (wisdom teeth) emerge from 17 -25 years l ¡ May be absent!! Adult dental formula: 2 I, 1 C, 2 P, 3 M X 2 = 32

Tooth Troubles l Cavities (caries) ¡ ¡ ¡ Demineralization of enamel by bacteria In severe cases, erodes the dentin of tooth Most severe cases erosion penetrates pulp cavity

Tooth Troubles l Gingivitis ¡ ¡ l Inflammation of the gingiva caused by plaque accumulation Leads to……. Periodontitis ¡ ¡ Infection of periodontal ligament leading to its destruction along with the bone around the teeth Leads to……………