The document provides information on the anatomy and physiology of the larynx. It discusses the larynx's location in the neck, its composition of cartilages, muscles, and ligaments. The key functions of the larynx are identified as protection of the respiratory tract, respiration, phonation (voice production), fixation of the chest, and closure of the glottis. Diagrams are included showing the anterior and posterior views of the larynx cavities and structures.
05.26.09(b): Development of the Respiratory System and DiaphragmOpen.Michigan
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The development of the respiratory system begins with the formation of lung buds from the foregut endoderm in the fourth week of gestation. The tracheoesophageal septum then separates the respiratory primordium from the esophagus, dividing the foregut into the lung buds and esophagus. The lung buds give rise to the right and left mainstem bronchi which further branch to form the bronchopulmonary segments. Abnormal partitioning of the foregut by the tracheoesophageal septum can result in tracheoesophageal fistulas and esophageal atresias, which are often associated with other birth defects.
The document provides an overview of the anatomy of the larynx and trachea. It describes the development, location, cartilages, joints, muscles, blood supply, nerve supply, lymphatic drainage and functions of the larynx. It also discusses the development, structure, blood supply, nerve supply, lymphatics and functions of the trachea.
The document summarizes the development of the respiratory system from the lower respiratory tract. It describes how the lower respiratory system develops from the median laryngo-tracheal groove in the floor of the pharynx between the 6th pharyngeal arches. This groove deepens to form the laryngo-tracheal diverticulum, whose edges fuse to form the oesophago-tracheal septum and laryngo-tracheal tube. The cranial part becomes the larynx while the caudal part divides into the two principal bronchi. Each bronchus then branches forming the lungs, surrounded by mesoderm forming the stroma and blood vessels. The cartilages and muscles develop
1. Lung development begins in the fourth week of gestation and progresses through five stages - embryonic, pseudoglandular, canalicular, saccular, and alveolar.
2. Key molecular regulators of lung development include fibroblast growth factors, sonic hedgehog, retinoic acid, transforming growth factor beta, Wnts, platelet-derived growth factor and vascular endothelial growth factor.
3. Transcription factors such as NKX2-1, GLI genes, FOX family, GATA6 and SOX family also play important roles in lung development by regulating cell proliferation, branching morphogenesis and epithelial cell differentiation.
1) The lungs develop from the foregut endoderm and associated mesoderm. The endoderm forms the epithelial lining of the trachea, bronchi, and alveoli while the mesoderm forms the cartilage, muscle, and connective tissue.
2) During the 4th week, lung buds form as outgrowths of the foregut endoderm. Tracheo-esophageal ridges then fuse to separate the trachea from the esophagus. Incomplete fusion can lead to tracheo-esophageal fistulas or esophageal atresia.
3) Over successive developmental stages, the lungs continue to branch and the pleural membranes form, separating the pleural
The trachea is a cartilaginous tube that extends from the larynx to the lungs. It divides at the carina into the right and left main bronchi. The right bronchus is wider, shorter and more vertical, while the left is smaller but longer. The bronchi continue dividing within the lungs to form the bronchial tree which supplies the lungs. Each lung has a root, hilum, lobes, borders and surfaces. The lungs are supplied by the pulmonary arteries and veins and are innervated by the pulmonary plexus.
The larynx houses the vocal cords and protects the entrance to the lower respiratory tract. It develops from the foregut in the 4th week of gestation. The larynx is made up of cartilage, including the thyroid, cricoid, and arytenoid cartilages. It attaches to the hyoid bone and contains intrinsic muscles. The larynx has supraglottic, glottic, and subglottic regions and differs in infants due to smaller size and shape. The document provides details on the anatomy, development, features and surgical considerations of the larynx.
The thoracic wall is comprised of skin, fascia, muscles and bones. It protects the thoracic viscera and enables breathing movements. The bony thoracic cage consists of 12 pairs of ribs connected to 12 thoracic vertebrae and the sternum. There are three types of ribs: true ribs that connect to the sternum, false ribs that connect to ribs above, and floating ribs that do not connect to other bones. The thoracic vertebrae are distinguished by demifacets on the vertebral bodies. The sternum consists of the manubrium, body, and xiphoid process. Openings in the thoracic wall include the superior inlet bounded by the clavicle, first
1) The thoracic cage is bounded superiorly by the thoracic inlet and inferiorly by the thoracic outlet and diaphragm. It contains typical intercostal spaces bounded by ribs and atypical spaces.
2) The typical intercostal spaces contain the external, internal, and innermost intercostal muscles as well as the subcostalis and sternocostalis muscles. The intercostal nerves and vessels also course through these spaces.
3) The muscles of respiration that act during inspiration include the diaphragm, external intercostals, and accessory muscles like SCM. During forced expiration, the rectus abdominis, internal intercostals, and serratus posterior inferior
Mastoidectomy is a surgical procedure to access and treat infections of the mastoid air cells behind the ear. Over time, the procedure has evolved from simple cortical mastoidectomies described in the 17th century to more advanced techniques using an operating microscope and drill. Modern mastoidectomies are typically classified as canal wall up or canal wall down depending on whether the bony ear canal wall is preserved. Indications include treatment of cholesteatoma, refractory ear infections, and approaches for other inner ear procedures. The surgery involves an incision behind the ear to access and clean out the infected mastoid air cells.
Viral laryngitis is the most common cause of laryngeal infection and presents with symptoms like dysphonia, odynophagia, and laryngeal trauma from phonation and coughing. Bacterial laryngitis can also occur from pathogens like Streptococcus and Staphylococcus and may result in supraglottitis or epiglottitis. Fungal, mycobacterial, and other infections like leprosy and syphilis can also infect the larynx, especially in immunocompromised patients. Autoimmune conditions such as Wegener's granulomatosis, rheumatoid arthritis, relapsing polychondritis, and pemphigus/pemphigoid can cause
Endoscopic single handed septoplasty with batten graft for caudalDaria Otgonbayar
This study evaluated the effectiveness of an endoscopic single-handed septoplasty technique using a batten graft to correct deviations of the caudal septum. 17 patients underwent the procedure, which uses a modified Killian incision and preserves the L-strut to prevent deformities. Post-operation, CT scans showed significantly improved nasal cavity ratios and patient surveys found improvements in nasal obstruction and other symptoms. The technique provides an easy, minimally invasive option to correct caudal septum deviations in select cases.
Brainstem auditory evoked responses (baer or abrDaria Otgonbayar
This document summarizes information about brainstem auditory evoked responses (BAER or ABR) testing. It provides normative data for BAER wave latencies and intervals. It then discusses using BAER threshold differences as a new diagnostic index for detecting small vestibular schwannomas. The document describes a study of 7 patients with untreated vestibular schwannomas that found all patients had abnormal ABR threshold differences between normal and diseased ears, and 5 patients also had traditional abnormal BAER indices. The mean threshold difference was 41.4 dB for diseased ears and 15.8 dB for normal ears. This suggests threshold differences may help increase BAER sensitivity for detecting small tumors.
Brainstem auditory evoked responses (baer or abrDaria Otgonbayar
1) Brainstem auditory evoked responses (BAER or ABR) testing involves measuring electrical activity in the auditory pathway in response to clicks or tones. It is used to identify sensorineural hearing loss and retrocochlear pathologies like acoustic neuromas.
2) The study evaluated 7 patients with untreated, MRI-confirmed unilateral vestibular schwannomas to determine if using auditory brainstem response threshold differences could increase the sensitivity of ABR testing in detecting small tumors compared to traditional ABR indices.
3) The results found that all 7 patients had an abnormal ABR threshold difference of over 30dB between ears, and 5 patients also showed abnormal traditional ABR indices, indicating threshold
- Three days after traumatic perforation of the rat tympanic membrane, the epithelial layer was thicker with more cell rows. The lamina propria showed disorganized fibroblasts and edema, while inflammation was predominant.
- Between 5-7 days, the healing process was proliferative with closure of the perforation beginning around 7-10 days. By 14 days, healing was complete.
- The study histologically examined the rat tympanic membrane at set time points after traumatic perforation to analyze the inflammatory, proliferative, and remodeling phases of the spontaneous healing process.
The formation and management of middle ear granulationDaria Otgonbayar
This document describes a case of a 55-year-old woman who presented with 40 years of bilateral intermittent otorrhea. Cultures from bilateral granulation tissue samples grew nontuberculous mycobacteria (NTM), specifically Mycobacterium abscessus and Mycobacterium fortuitum. She was treated with intravenous and oral antibiotics based on culture sensitivities. Follow up scans and examinations showed resolution of symptoms and infection. The document discusses NTM as a rare cause of chronic otitis media that is often underdiagnosed due to its slow growth, and outlines the challenges in management through surgical debridement and prolonged multidrug antibiotic therapy.
3. Thyroarytenoid (TA): (RLN) increases vocal
fold tension, vocal fold
ADduction, the medial aspect of the TA is
called the vocalis
Cricothyroid:(external branch of SLN)
ADduction, increases vocal
fold tension and length (chief pitch-changing
muscle)
Interarytenoid: (RLN) only unpaired muscle,
ADduction
4. Laryngeal Cartilage
• Thyroid, Cricoid, and Arytenoids: hyaline cartilage (hyaline
cartilage is the most common, found in most articular
cartilage)
• Epiglottis: fibroelastic cartilage (less strength, elastin),
attaches to
thyroid cartilage
• Corniculate Cartilage: fibroelastic cartilage, above arytenoid
cartilage, provides rigidity to A-E folds
• Cuneiform Cartilage: fibroelastic cartilage, within A-E folds,
provides rigidity
• Trieceous Cartilage: sometimes found in thyrohyoid
ligament,
may be mistaken on x-ray as a foreign body when calcified
5. Laryngeal Joints
• Cricothyroid Joints: synovial, rocks (hinge)
• Cricoarytenoid Joints: synovial, rocking
motion (anteromedially for
vocal fold ADduction and posterolaterally for
vocal fold ABduction)
7. NOTE: the squamous epithelium and superficial layer of the
lamina
propria form the vocal fold cover, the intermediate and deep
lamina
propria form the vocal ligament (transition zone), the
thyroarytenoid muscle complex forms the vocal fold body
NOTE: The gelatinous consistency of the SLP allows for
fluency of
vibration of the cover over the body during voicing (cover-
body concept
of vocal fold vibration). This vibratory activity can be readily
visualized
using videostroboscopy and is referred to as the mucosal
wave.
