neck and spine anatomy Flashcards
Airway
Using the model, demonstrate the main features of the larynx
Features you need to know
- Thyroid cartilage
- Cricoid cartilage
- Arytenoid cartilages
- Epiglottis
- Vallecula
- Cuneiform and corniculate cartilages
- Cricothyroid membrane
- Vocal chords
What are the structures in the upper airway that could lead to airway obstruction?
Tongue, tonsils, pharynx, epiglottis, glottis
Demonstrate the landmarks for a cricothyroidotomy.
The thyroid cartilage above, cricoid cartilage below and the cricothyroid membrane
between.
What cartilage in the larynx is fully circumferential?
Cricoid cartilage
Name the muscles of vocalisation
● Cricothyroid - from the anterolateral cricoid to inferior margin and inferior horn of
thyroid
● Thyroarytenoid - from the lower ½ posterior angle of thyroid laminae and
cricothyroid ligament to the anterolateral arytenoid
● Posterior cricoarytenoid - from the posterior surface of cricoid lamina to the vocal
process of arytenoid
● Lateral cricoarytenoid - from the arch of the cricoid to vocal process to the vocal
process of arytenoid
● Transverse and oblique arytenoids - from one arytenoid cartilage to the
contralateral arytenoid
● Vocalis - lateral surface of the vocal process of arytenoid cartilage to the
ipsilateral vocal ligament
Innervation of the airway
What is the motor nerve supply of the larynx?
● All muscles of the larynx are supplied by branches of the Vagus Nerve (X)
● The recurrent laryngeal nerve becomes the inferior laryngeal nerve and supplies
all intrinsic muscles except one - the cricothyroid, which is supplied by the
superior laryngeal nerve.
● The superior laryngeal nerve is a branch of the vagus, which then gives an
internal and external branch. The external branch, called the external laryngeal
nerve supplies the cricothyroid membrane.
What is the sensory supply of the larynx?
● Sensation below the cords = Inferior laryngeal nerve (a branch of the recurrent
laryngeal nerve)
● Sensation above the cords = Internal laryngeal nerve (a branch of the superior
laryngeal nerve)
What is the difference between the course of the right and left recurrent laryngeal
nerve?
Right: hooks around the subclavian artery
Left: hooks around aorta
After looping they ascend in trachea-oesophageal groove to supply intrinsic muscles of
larynx (except the cricothyroid, which, as mentioned above, is supplied by the…superior
laryngeal nerve.
What is the result of an injury to the recurrent laryngeal nerve?
Hoarse voice if unilateral and stridor if bilateral due to inability to abduct the cords as
posterior cricoarytenoids are the only abductors
Identify the major triangles of the neck
● Anterior triangle - which can be further divided into the digastric, submental,
muscular and carotid triangles
● Posterior triangle
Define the boundaries of the anterior triangle of the neck
● Inferior border of the mandible forms the superior border of the triangle
● Midline of the neck is the anterior border
● The lateral border is the anterior part of the sternocleidomastoid muscle
Describe the course of the internal jugular vein.
● IJV is the continuation of the sigmoid sinus
● It is formed by the inferior petrosal and sigmoid dural venous sinuses
● Descends within the carotid sheath with the internal carotid artery and the Vagus
Nerve
● Lies lateral and ventral to artery
● Passes deep to the heads of SCM (sternal and clavicular heads)
● Joins the subclavian vein posterior to the sternal end of the clavicle
● Forms the brachiocephalic vein
What major structures are at risk during insertion of an IJ line?
● External carotid artery
● Common carotid artery
● Vagus nerve
● Other nerves
● Lung, trachea, SCM, thyroid and thoracic duct
Describe the location of the thyroid gland in the neck
● Located anteriorly in the neck at the level of C5 to T1
● Lies deep to sternothyroid and sternohyoid muscles
● Right and left lobes sit anterolateral to the larynx and trachea
● A thin isthmus unites the two lobes across the trachea approximately the 2nd and
3rd tracheal rings
- Carotid Triangle & Vessels
Outline the boundaries of the carotid triangle
● Superior belly of the omohyoid
● Posterior belly of the digastric
● Anterior border of the SCM