Functional Anatomy of Respiration and Phonation: Musculature and Innervation Flashcards
6 intrinsic muscles of the larynx
- Posterior cricoarytenoid
- Lateral cricoarytenoid
- Transverse arytenoid
- Oblique arytenoid
- Thyroarytenoid
- Cricothyroid
Function of posterior cricoarytenoid
- Rotates arytenoids laterally
- Abducts vocal cords
Function of lateral cricoarytenoid
- Rotates arytenoids medially
- Adducts vocal cords
Function of transverse arytenoid
- Adducts arytenoids
- Adducts vocal cords
Function of oblique arytenoid
- Adducts arytenoids
- Adducts vocal cords
Function of thyroarytenoid
Shortens vocal ligaments
Function of cricothyroid
- Flexion of cricothyroid joint
- Lengthens vocal ligaments
Which nerve supplies all branches to the intrinsic muscles of the larynx?
Vagus nerve
Which nerve branches from the vagus superior to the hyoid to supply the larynx?
Superior laryngeal nerve
Branches of the superior laryngeal nerve
- External branch
- Internal branch
Where do each of the branches of the superior laryngeal nerve pass and to innervate what?
- E = inferiorly to innervate cricothyroid
- I = pierces through thyrohyoid membrane to innervate mucous membrane superior to and including vocal fold
Which nerve branches off the vagus more inferiorly to innervate the larynx?
Recurrent laryngeal nerve
Where does the left recurrent laryngeal nerve branch and pass?
- Level of arch of aorta
- Loops posteriorly under the arch and passes superiorly to larynx
Where does the right recurrent laryngeal nerve branch and pass?
- Level of right subclavian artery
- Loops posteriorly under the artery passes superiorly to larynx
What is innervated by the recurrent laryngeal nerve?
- Intrinsic muscles of larynx (except cricothyroid)
- Mucosa of infraglottic space
Which artery supplies the upper regions of the larynx?
Superior laryngeal artery
Origin of superior laryngeal artery
Common carotid –> External carotid –> Superior thyroid –> Superior laryngeal
Where does the superior laryngeal artery pass to enter the larynx?
Through thyrohyoid membrane with internal branch of superior laryngeal nerve
Which artery supplies the lower regions of the larynx?
Inferior laryngeal artery
Origin of inferior laryngeal artery
Subclavian –> thyrocervical trunk –> inferior thyroid –> inferior laryngeal
Superior venous drainage of larynx
Superior laryngeal vein –> superior thyroid vein –> internal jugular vein
Inferior venous drainage of larynx
Inferior laryngeal veins –> left brachiocephalic vein
What does Semon’s law state and why?
- Partial transection of recurrent laryngeal nerve is worse than full transection
- Partial knocks out only abductor but not all adductors of vocal cords
- Vocal cords can be shut but not reopened, so patient cannot breathe
Groups of the extrinsic muscles of the larynx
- Suprahyoid muscles
- Infrahyoid muscles
Suprahyoid muscles
- Digastric
- Stylohyoid
- Mylohyoid
- Geniohyoid
Infrahyoid muscles
- Thyrohyoid
- Sternohyoid
- Sternothyroid
- Omohyoid