Larynx, Trachea and Bronchi

What is the anatomical location of the larynx in the neck?

The larynx lies in the anterior midline of the neck, extending from the root of the tongue to the trachea, opposite the C3–C6 vertebrae.

What is the average length of the larynx in males and females?

Males: 44 mm long; Females: 36 mm long.

What are the paired cartilages of the larynx?

Arytenoid, corniculate, and cuneiform cartilages.

What are the unpaired cartilages of the larynx?

Thyroid, cricoid, and epiglottic cartilages.

What is the shape and structure of the thyroid cartilage?

V-shaped cartilage with right and left laminae, anterior and posterior borders, upper and lower borders, external surface, and piriform fossa on the inner surface.

What is the shape and location of the cricoid cartilage?

Ring-shaped cartilage located at the C6 vertebra; it forms the skeletal foundation of the larynx with an anterior arch and posterior lamina.

What is the shape and attachment of the epiglottis?

Leaf-shaped cartilage; upper end is broad and free, lower end is pointed. Anteriorly connected to the tongue and hyoid bone; posteriorly lined by mucous membrane; lateral borders connect to arytenoid cartilages.

Describe the structure of the arytenoid cartilage.

Paired, pyramidal shape with an apex (articulates with corniculate cartilage), base (rests on cricoid lamina), posterior surface (site of transverse and oblique arytenoideus muscle), anterolateral surface (vocal process), and muscular process (projects laterally and backward).

Where are the corniculate and cuneiform cartilages located?

Corniculate cartilage sits at the apex of the arytenoid; both lie in the aryepiglottic fold. Cuneiform cartilage is rod-shaped and located ventral to the corniculate.

What are the two main synovial joints in the larynx?

The cricothyroid joint and the cricoarytenoid joint.

What structures articulate at the cricothyroid joint?

The inferior cornua of the thyroid cartilage and the side of the cricoid cartilage.

What movements occur at the cricothyroid joint?

Rotatory and gliding movements.

What structures articulate at the cricoarytenoid joint?

The base of the arytenoid cartilage and the lamina of the cricoid cartilage.

What movements occur at the cricoarytenoid joint?

Rotatory and gliding movements.

What is the main extrinsic membrane of the larynx?

The thyrohyoid membrane.

What structures pass through the thyrohyoid membrane?

The internal laryngeal nerve and superior laryngeal vessels.

What are the two broad groups of laryngeal muscles?

Intrinsic and extrinsic muscles.

What is the role of intrinsic laryngeal muscles?

They control sound production by regulating the tension of the vocal cords and the size of the glottis.

What is the function of the posterior cricoarytenoid muscle?

It abducts (opens) the vocal cords and is the only muscle that does so.

What is the function of the lateral cricoarytenoid muscle?

It adducts (closes) the vocal cords.

What is the function of the cricothyroid muscle?

It tenses and elongates the vocal cords, increasing pitch.

What is the function of the thyroarytenoid and vocalis muscles?

They relax the vocal cords, lowering pitch.

What are the main arteries supplying the larynx?

The superior and inferior laryngeal arteries.

What are the branches of the superior laryngeal artery?

It arises from the superior thyroid artery, a branch of the external carotid artery.

The inferior laryngeal artery is a branch of which artery?

The inferior thyroid artery, which arises from the thyrocervical trunk.

What are the sensory and motor nerves of the larynx?

• Sensory above the vocal cords: Internal laryngeal nerve (branch of the superior laryngeal nerve, from vagus). • Sensory below the vocal cords: Recurrent laryngeal nerve (branch of vagus). • Motor to all intrinsic muscles (except cricothyroid): Recurrent laryngeal nerve. • Motor to cricothyroid: External branch of the superior laryngeal nerve.

What happens in vocal cord paralysis?

It is often due to recurrent laryngeal nerve injury; it can lead to hoarseness, voice loss, or airway obstruction.

What is laryngitis?

Inflammation of the larynx, often resulting in hoarseness or loss of voice.

What is a cricothyrotomy?

An emergency airway procedure performed by making an incision through the cricothyroid membrane.

Why is the posterior cricoarytenoid muscle clinically important?

Because it is the only abductor of the vocal cords; bilateral paralysis can cause airway obstruction.

Where does the trachea begin and end?

It begins at the lower border of the cricoid cartilage (C6 level) and ends at the sternal angle (T4/T5), where it bifurcates into right and left bronchi.

What is the average length and diameter of the trachea?

About 10–12 cm long and 2 cm in diameter.

What structure is found posterior to the trachea?

The esophagus.

What is the name of the ridge at the bifurcation of the trachea?

The carina.

What type of cartilage supports the trachea?

Incomplete C-shaped hyaline cartilage rings (about 16–20 in number).

What closes the posterior open part of the tracheal cartilage rings?

The trachealis muscle (a band of smooth muscle).

What are the primary bronchi?

The right and left bronchi, which arise from the trachea at the carina.

Which bronchus is shorter, wider, and more vertical?

The right main bronchus.

Which bronchus is longer, narrower, and more horizontal?

The left main bronchus.

Why is the right bronchus more prone to foreign body aspiration?

Because it is wider, shorter, and more vertical than the left.

How many secondary (lobar) bronchi does the right main bronchus give off?

Three — one for each lobe of the right lung (superior, middle, inferior).

How many secondary (lobar) bronchi does the left main bronchus give off?

Two — one for each lobe of the left lung (superior and inferior).

What are tertiary bronchi also known as?

Segmental bronchi — they supply bronchopulmonary segments