Unit 5: Lecture 4 (Part 2: Start Layers of Neck Viscera)

Investing layer

What is the most superficial of the deep layers of cervical fascia?

Investing layers

What layer of the deep cervical fascia encircles the entire neck, enclosing the sternocleidomastoid and trapezius muscles?

Pretracheal fascia

What is the middle layer of the deep cervical fascia that is limited to the anterior part of the neck?

Pretracheal layer

What layer of the deep cervical fascia surrounds structures within the visceral compartment, including the trachea, esophagus, thyroid gland, and infrahyoid muscles (in its muscular portion)?

Carotid sheath

What is the tubular fascial compartment that encloses major neurovascular structures: the common and internal carotid arteries, internal jugular vein, and vagus nerve (CN X)?

Alar fascia

What is the thin layer situated between the carotid sheath and prevertebral fascia, helping to define the retropharyngeal space?

Prevertebral fascia

What is the deepest layer of the deep cervical fascia, which surrounds the vertebral column and the prevertebral muscles (longus colli, longus capitis, scalenes, and other deep cervical musculature)? It extends laterally to form the axillary sheath, which contains the brachial plexus and subclavian artery.

Suboccipital nerve

What nerve innervates the suboccipital triangle?

Flex the head and neck, contribute to postural control, and assist in fine-tuned stabilization of the cervical spine.

What do prevertebral muscles of the neck primary do?

Flexes the head

What action does the longus capitis perform?

Longus capitis

Weakness or delayed activation in what muscle has been associated with impaired deep cervical flexor function, particularly in patients with whiplash-associated disorders and chronic neck pain?

Flexes the head and neck; contributes to contralateral neck rotation when acting unilaterally.

What actions do the longus colli perform?

Longus colli

In patients with chronic neck pain, what muscle often demonstrates reduced activation and atrophy, which can compromise segmental stability in the cervical spine?

Pharynx

What is the muscular tube that serves as a shared pathway for both the respiratory and digestive systems?

Flexes the head at the atlanto-occipital joint.

What action does the rectus capitis anterior perform?

Rectus capitis anterior

What muscle plays a critical role in stabilizing the atlanto-occipital joint; minor trauma or strain may provoke cervicogenic headaches?

Extends from the transverse process of the atlas (C1) to the jugular process of the occipital bone.

What action does the rectus capitis lateralis perform?

Longus capitis, longus colli, rectus capitis anterior, rectus capitis lateralis, and scalenes

What muscles make up the prevertebral muscles of the neck?

Thyroid and parathyroid glands

What glands make up the endocrine layer of the neck?

Thyroid gland

Enlargement of what gland (goiter) can compress the trachea or esophagus, causing symptoms such as dyspnea or dysphagia? Cross-sectional imaging is essential for preoperative evaluation.

Metabolic homeostasis

What does the thyroid gland regulate?

Calcium homeostasis

What does the parathyroid gland regulate?

Larynx, trachea, and pharynx

What is included in the respiratory layer of the neck?

Larynx

What acts as the voice box and is continuous inferiorly with the trachea?

Trachea

What serves as the airway passage?

Pharynx

What structure is part of both the respiratory and alimentary layers of the neck?

Alimentary layer

What is the deepest layer of the visceral compartment, which includes the pharynx (shared with the respiratory layer) and the esophagus, which begins around the level of the cricoid cartilage (C6) and continues into the thorax?

Pharynx and esophagus

What two structures make up the alimentary layer of the neck?

Thyroid hormone (T3 and T4), which regulates basal metabolic rate and Calcitonin, which lowers blood calcium levels by inhibiting osteoclast activity in bone.

What two primary hormones are produced by the thyroid?

Thyroid

Enlargement of what gland may distort tracheal alignment or cause compression symptoms?

Parathyroid hormone (PTH), which increases blood calcium levels by stimulating osteoclast-mediated bone resorption, increasing renal calcium reabsorption, and promoting activation of vitamin D to increase intestinal absorption of calcium.

What hormone is produced by the parathyroid gland?

Superior and inferior thyroid arteries

What arteries supply the thyroid gland?

Superior, middle, and inferior thyroid veins

What veins drain the thyroid gland?

Alar fascia

What layer of fascia connects the two carotid sheaths?

True

(T/F) Dysfunction of the pharyngeal constrictor muscles, or neural impairment (e.g., vagus nerve lesions), may lead to dysphagia and aspiration.

Larynx

What structure functions primarily to guard the airway during swallowing and to generate sound via vibration of the vocal cords? Structurally, it consists of cartilage (including the thyroid, cricoid, and arytenoid cartilages), intrinsic muscles, and the vocal folds.

Trachea

What begins at the level of the inferior border of the cricoid cartilage (C6) and descends into the thorax where it bifurcates into the main bronchi? It is supported by C- shaped cartilaginous rings that keep the airway open and is posteriorly adjacent to the esophagus.

Endocrine, respiratory, and alimentary layers

What are the visceral layers of the neck from superficial to deep?

Pharynx

What is the muscular tube that connects the nasal and oral cavities to the esophagus?

Thyroid, cricoid, and epiglottic cartilages

What are the 3 unpaired cartilages of the laryngeal skeleton?

Arytenoid, corniculate, and cuneiform cartilages

What are 3 paired cartilages of the laryngeal skeleton?

Thyroid cartilage

What is the largest laryngeal cartilage that forms the anterior and lateral walls of the larynx?

Cricoid cartilage

What is only complete ring of cartilage in the airway, it lies inferior to the thyroid cartilage and articulates with it at the cricothyroid joint? It is broader posteriorly and forms the base of the laryngeal skeleton.

Epiglottic cartilage

What is the leaf-shaped elastic cartilage that projects posterosuperiorly from the thyroid cartilage? It functions as a protective flap during swallowing, deflecting food and liquids away from the airway.

Arytenoid cartilages

What are the pyramid-shaped cartilages that rest on the superior border of the posterior cricoid lamina? They serve as the posterior attachment site for the vocal cords and rotate and glide to change vocal fold position during phonation.

Corniculate cartilages

What are the small, horn-like cartilages that sit on the apices of the arytenoids? They help reinforce the aryepiglottic folds.

Cuneiform cartilages

What cartilages are embedded within the aryepiglottic folds and provide structure to the mucosal tissue in this region? They are not always visible on imaging or in dissection.

Arytenoid cartilages

Malposition or dysfunction of what cartilages can lead to vocal fold paralysis, causing hoarseness or aspiration risk?

Vocal folds

What laryngeal folds extend from the thyroid cartilage anteriorly to the arytenoid cartilage posteriorly and are known as the "true vocal cords?"

Rima glottidis

What is the space between the vocal folds?

Vestibular folds

What laryngeal folds are located superior to the vocal folds, the vestibular folds are composed of the vestibular

ligament and a mucous covering and are known as "false vocal folds?"

True

(T/F) The vestibular folds (False vocal cords) are not typically involved in sound production, but serve a protective role by helping to seal the airway during swallowing.

Aryepiglottic folds

What laryngeal folds run from the arytenoid cartilages to the lateral edges of the epiglottis and form the superior border of the laryngeal inlet? Together with the epiglottis, they form a seal that protects the airway during swallowing.

Glottis

What consists of the vocal folds and the rima glottidis—the opening between them?

Producing sound

What is phonation?

Forced inspiration; phonation

The rima glottidis is widest during ____ ____ and narrowest during ____.

Vestibule, ventricle, and infraglottic cavity

What are the three main regions of the laryngeal cavities?

Respiratory epithelium (psuedostratified ciliated columnar epithelium)

What type of epithelium lines the mucosal layer of the larynx?

Vestibule

What part of the laryngeal cavity is the portion of the cavity above the vestibular folds, extending to the laryngeal inlet?

Ventricle

What part of the laryngeal cavity is a small lateral recess between the vestibular and vocal folds?

Infraglottic cavity

What part of the laryngeal cavity is the space below the vocal folds that extends to the inferior border of the cricoid cartilage?

Vagus nerve

What nerve innervates all intrinsic larynx muscles?

Recurrent laryngeal nerve (branch of vagus nerve)

What nerve innervates all intrinsic larynx muscles except for he cricothyroid?

Cricothyroid

What muscle is located on the external surface of the larynx, between the anterior cricoid and thyroid cartilages? Known as the 'bowtie muscle' on cadavers.

Hyaline cartilage

What type of cartilage makes up the thyroid cartilage?

Cricothyroid

What muscle stretches and tenses the vocal ligament?

External branch of superior laryngeal nerve

Injury to the what nerve can impair pitch modulation, especially in professional voice users (cricothyroid)?

Lateral cricoarytenoid

What muscle adducts the vocal folds?

Lateral cricoarytenoid

Weakness of what muscle may result in incomplete glottic closure and contribute to hoarseness or aspiration?

Posterior cricoarytenoid

What muscles abducts the vocal folds?

Elastic cartilage

What type of cartilage make up the epiglottis?

Posterior cricoarytenoid

What is the only muscle that opens the rima glottidis? Bilateral paralysis can cause airway obstruction and require tracheostomy.

Thyroarytenoid (including vocalis)

What muscle relaxes vocal ligament, allowing for lower pitch?

Transverse and oblique arytenoids

What muscle adduct arytenoid cartilages, closing posterior rima glottidis?

Non-keratinized stratified squamous epithelium

What type of epithelium lines the vocal folds

They close

What happens to the vocal folds when you are about to cough or sneeze?

Hyaline cartilage

What type of cartilage is arytenoid cartilage?