Head and Neck Anatomy PDF

Larynx Relations: Laryngopharynx via laryngeal inlet (gated by epiglottis) Trachea at C5-6  Larynx “La”-rynx lets you sing - its functions are: Structure: made up of Respiration - diameter of airway Unpaired cartilage - epiglottis, thyroid, cr...

Larynx Relations: Laryngopharynx via laryngeal inlet (gated by epiglottis) Trachea at C5-6  Larynx “La”-rynx lets you sing - its functions are: Structure: made up of Respiration - diameter of airway Unpaired cartilage - epiglottis, thyroid, cricoid Phonation - vibration of vocal folds Paired cartilage - arytenoid, corniculate, cuneiform Effort closure - such as during heavy lifting Swallowing - moves up and forward Larynx Laryngeal Cartilages Cricoid ○ thick lamina posteriorly, narrow arch ant ○ 2 depressions on posterior surface for oesophagus at centre and posterior cricoarytenoid m. Thyroid ○ Superior and inferior horns ○ Laryngeal prominence = adam’s apple ○ Oblique line - site of attachment for extrinsic muscles of larynx (sternothyroid, thyrohyoid, inferior constrictor) Epiglottis - attachment via thyroepiglottic ligament to thyroid cartilage Arytenoids ○ Base - articulates with cricoid cartilage ○ Apex - articulates with corniculate cartilage ○ Attachment of vocal l., vocalis m., vestibular l. And cricoarytenoid m. Cuneiform - floats in quadrangular membrane  Laryngeal Ligaments Extrinsic Ligaments Hyoepiglottic and thyroepiglottic l. Thyrohyoid membrane ○ Forms median and lateral thyrohyoid l. Cricotracheal l. Intrinsic Ligaments Quadrangular Cricothyroid ligament membrane Forms Vestibular ligament Vocal ligament (true (false vocal cord) vocal cord) Is attached to Epiglottis to thyroid Lateral epiglottis to cartilage and arytenoids thyroid and arytenoid cartilage Covered by Vestibular fold Vocal fold Triangular Space is Rima vestibuli Rima glottidis called The vocal and vestibular folds divide the laryngeal cavity into the: vestibule, middle (bulges to form laryngeal ventricle + saccule producing mucus for lubrication), and infraglottic space  Laryngeal Muscles All innervated by vagus n. [X] Cricothyroid via external branch of superior laryngeal n. (of vagus n.) All others via recurrent laryngeal branch Made up of: Cricothyroid Vocalis Thyroarytenoid Cricoarytenoids - lateral and posterior Arytenoids - transverse and oblique  Laryngeal Muscles All innervated by vagus n. [X] Cricothyroid via external branch of superior laryngeal n. (of vagus n.) All others via recurrent laryngeal branch Cricothyroid Tense vocal l. Vocalis Relax vocal l. (runs adjacent Thyroarytenoids to vocal l.) Lateral cricoarytenoids Adduct arytenoids (closes Transverse arytenoids rima glottidis) Oblique arytenoids Posterior cricoarytenoids Abducts arytenoids (opens rima glottidis)  Neurovasculature Superior Branches Inferior Branches Arteries Superior laryngeal Inferior laryngeal (external carotid) (thyrocervical trunk) Veins Superior laryngeal Inferior laryngeal → superior thyroid → IJV → Inferior thyroid v. → brachiocephalic v. Lymph n. Superior deep cervical Inferior deep cervical Nerves Superior laryngeal Recurrent laryngeal (turning - External branch into inferior laryngeal) (All [X] Inferior constrictor of sensory below vocal branches) pharynx folds Cricothyroid m. motor to all other - Internal branch muscles sensory down to Travels around arch of vocal folds aorta (left) or under subclavian artery (right)  Neurovasculature Superior Branches Inferior Branches Arteries Superior laryngeal Inferior laryngeal (external carotid) (thyrocervical trunk) Veins Superior laryngeal Inferior laryngeal → superior thyroid → IJV → Inferior thyroid v. → brachiocephalic v. Lymph n. Superior deep cervical Inferior deep cervical Nerves Superior laryngeal Recurrent laryngeal (turning - External branch into inferior laryngeal) (All [X] Inferior constrictor of sensory below vocal branches) pharynx folds Cricothyroid m. motor to all other - Internal branch muscles sensory down to Travels around arch of vocal folds aorta (left) or under subclavian artery (right)  Hoarseness Symptom - not a disease Aetiology: Overuse - screaming, singing, excessive coughing Toxins - tobacco, caffeine, alcohol Polyps on vocal cords Throat, thyroid, lung cancer Nerve or muscle conditions - recurrent laryngeal n. ○ Left often affected during cardiac surgery ○ Right - apical lung tumour, thyroid cancer, aortic aneurysm Stomach acid reflux  Thyroidectomy Structures at risk: External superior laryngeal n. → cricothyroid m. weak (usually tenses vocal cord) → weak voice, inability to sing, lower pitch Recurrent laryngeal n. During dissection of inferior thyroid a. → vocal cord toward miline ○ Unilateral → hoarse voice ○ Bilateral → airway obstruction and need for tracheostomy Parathyroid glands → hypocalcaemia Post thyroidectomy haemorrhage Thyroid is beneath deep cervical fascia and strap muscle layer Leads to increase in pressure on venous/lymphatic system → swelling of submucosa and airway obstruction Tx: open neck on ward to relieve pressure (need to cut through aforementioned layers)  Common Sites of Foreign Body Lodgement Piriform Fossa Vallecula On either side of laryngeal inlet Depression anterior to epiglottis Branches of internal laryngeal and recurrent laryngeal n. at risk Dehiscence of Killain Rima Glottidis Narrowest part of larynx Object or removal of object can damage vocal chords