Neck Anatomy Flashcards
Pharynx vs larynx
What contributes to the Adam’a apple in males?
in males, after puberty, the thyroid cartilage becomes more prominent and the prominence constitutes Adam’s apple.
Larynx functions
Organ of phonation, part of air passage of air in inspiration
How may cartilages are there of the larynx?
9 cartilages
Internaally coevred by mucus and cilia
Boundaries of larynx?
From root of tongue to beginning of trachea
Approximately from C3 to C6 (higher in females
Which cartilages of the larynx are paired and unpaired?
3 UNPAIRED:
Thyroid
Cricoid
Epiglottis
3 PAIRED:
Arytenoid
Corniculate
Cuneiform
What are the:
Cornu
and central laryngeal prominence?
The thyroid cartilage has a superior and inferior pair of horns (cornu) and a central laryngeal prominence (better visible in previous picture). It is open posteriorly.
What 2 muscles are closely linked with the vocal cords?
The vocalis muscle
The thyroarytenoid muscle
Extrinsic laryngeal muscles
Theextrinsicmuscles act to elevate or depress the larynx during swallowing:
They are comprisedof the suprahyoid and infrahyoid groups, and the stylopharyngeus. As a general rule, the suprahyoid muscles and the stylopharyngeuselevate the larynx, whilst the infrahyoid muscles depress the larynx.
Intrinsic laryngeal muscles
The intrinsic muscles act tomove the individualcomponents of the larynx – playing a vital role in breathing and phonation.
They control the shape of the rima glottidis (such as the thyroarytenoid muscle).
What are the intrinsic laryngeal muscles?
A. Thyroarytenoid: soften voice by relaxing vocal cords
B. Lateral Cricoarytenoid: adduction of vocal cords
C. Transverse Arytenoid : adduction of vocal cords
D. Posterior Cricoarytenoid: abduction of vocal cords
E. Oblique Arytenoid : adduction of vocal cords
F. Cricothyroid : forceful speech and alteration of tone of voice (singer’s muscle) by stretching vocal cords
What are all intrinsic laryngeal muscles innervated by?
Recurrent laryngeal nerve
except the cricothyroid muscle, which is innervated by the external branch of the superior laryngeal nerve (a branch of the vagus).
Extrinsic laryngeal muscle innervation?
Innervations of the extrinsic laryngeal muscles vary and include the following nerves: ansa cervicalis, trigeminal nerve, facial nerve, glossopharyngeal nerve, and hypoglossal nerve.
Left recurrent laryngeal nerve vs right laryngeal nerve
Note how the left recurrent laryngeal nerve curves medially around the aortic arch. In contrast, the right recurrent laryngeal nerve courses around the right subclavian artery
Laryngeal blood supply
Blood supply to the larynx is derived from the external carotid and subclavian artery.
The external carotid gives rise to the superior thyroid artery, from which the superior laryngeal artery departs.
This artery courses with the superior laryngeal nerve through the thyrohyoid membrane to supply the supraglottic region (upper part of the larynx).
The inferior thyroid artery, derived from the subclavian artery, terminates as the inferior laryngeal artery.
This vessel travels with the recurrent laryngeal nerve and supplies the infraglottic larynx (below the rima glottis).
What divides the neck into anterior and posterior triangles?
THE STERNOCLEIDOMASTOID MUSCLE (SCM) divide the neck into an anterior and a posterior triangles
What structures define the posterior triangle of the neck?
Trapezius
SCM
Clavicle
What structures define the posterior triangle of the neck?
Trapezius
SCM
Clavicle
What structures define the anterior triangle of the neck?
Mandible
SCM
Anterior midline
What is the anterior triangle divided into?
4 triangles (surprise surprise)
Carotid triangle
Submental triangle
Submandibular triangle
Muscular triangle
Carotid triangle
Carotid Triangle: the main contents of the carotid triangle are the common carotid artery (which bifurcates within the carotid triangle into the external and internal carotid arteries), the internal jugular vein, and the vagus nerve.
In the carotid triangle, many of the vessels and nerves are relatively superficial, and so can be accessed by surgery. The carotid arteries, internal jugular vein, vagus nerves are frequent targets of this surgical approach.
Submental triangle
Submental Triangle: is situated underneath the chin. It contains the submental lymph nodes, which filter lymph draining from the floor of the mouth and parts of the tongue.
Submandibular triangle
Submandibular Triangle: is located underneath the body of the mandible. It contains the submandibular gland (salivary), and lymph nodes. The facial artery and vein also pass through this area.
Muscular triangle
Muscular Triangle: contains some muscles and organs – the infrahyoid (or strap) muscles, the pharynx, and the thyroid and parathyroid glands.
Describe the structure of the posterior triangle
The omohyoid muscle splits the posterior triangle of the neck into two:
The larger, superior part is termed theoccipital triangle.
The inferior triangle is known as the subclavian triangle (or supraclavicular triangle or omoclavicular triangle) andcontains the distal portion of the subclavian artery.
Vasculature of posterior triangle
Other important vasculature in the posterior triangle is the external jugular vein (supraclavicular triangle), one of the major veins of the neck region. Within the posterior triangle, the external jugular vein pierces the investing layer of fascia and empties into the subclavian vein.
Innervation of posterior triangle
Important nerves in the posterior triangle are:
Accessory nerve CN XI : supplies motor innervation to neck muscles
The cervical plexus and the brachial plexus
Carotid triangle boundaries
Boundaries:
Posteriorly by the anterior border of the Sternocleidomastoid.
Inferiorly, by the superior belly of the Omohyoid muscle.
Superiorly by the posterior belly of the digastric muscle.
What does the carotid triangle contain?
The carotid sheath a protective
layer of fascia that surrounds the following structures:
The common carotid artery The internal jugular vein The vagus nerve
Submental triangle boundaries
Boundaries:
Medially by the midline of the neck.
Inferiorly by the hyoid bone.
Laterally by the digastric muscle.
Contains the submental lymph nodes.
Submandibular triangle: Boundaries and contents
Boundaries:
Superiorly, by the lower border of the body of the mandible.
Inferiorly by the Digastricus muscle.
Contains the submandibular gland (salivary), and lymph nodes.
Muscular triangle boundaries
Boundaries:
The muscular triangle (or inferior carotid triangle) is bounded:
- superiorly, by the hyoid bone
- medially, by the median line of the neck from the hyoid bone to the sternum;
- laterally, superior belly of omohyoid and anterior border of sternocleidomastoid
Muscular triangle contents
Contains the following muscles: thyrohyoid, sternothyroid, sternohyoid. COLLECTIVELY THESE ARE CALLED THE STRAP MUSCLES (OR INFRAHYOID MUSCLES).
It also contains the thyroid gland, larynx, trachea and oesophagus.
What does the omohyoid muscle split the posterior triangle into?
The omohyoid muscle splits the posterior triangle of the neck into two minor triangles:
the superior occipital triangle
and the inferior supraclavicular triangle
Superior occipital triangle boundaries
Boundaries:
anteriorly, by the posterior border of Sternocleidomastoideus;
posteriorly, by the anterior border of Trapezius;
inferiorly, by the inferior belly of omohyoid muscle;
superiorly, by the occipital bone.
Superior occipital triangle contents
Contains the accessory nerve CN XI and the cervical plexus and upper most part of brachial plexus.
Inferior supraclavicular triangle boundaries
Boundaries:
Superiorly, by the inferior belly of the omohyoid muscle.
Inferiorly, by the clavicle;
anteriorly, by the posterior border of the sternocleidomastoid muscle;
posteriorly by the Trapezius.
Inferior supraclavicular triangle contents
Contains the subclavian artery, which curves lateralward and downward. The lower portion of the brachial plexus of nerves lies above the artery, and in close contact with it. The external jugular vein runs vertically downward to join the subclavian vein.
The superior occipital and inferior supraclavicular triangles
Action of posterior cricoarytenoid?
Widens aperture for inhalation
