Chapter 4 muscles

Cricothyroid Muscle Attachments

Anterior/lateral cricoid cartilage to inferior margin and inferior horn of thyroid cartilage

Cricothyroid Muscle Course

Located on the external surface of the larynx.

Cricothyroid Muscle Innervation

External branch of the Superior Laryngeal Nerve (SLN)

Cricothyroid Muscle Function

Lengthens and tenses vocal folds, increasing pitch

Posterior Cricoarytenoid Muscle Attachments

Posterior cricoid lamina to muscular process of arytenoid cartilage

Posterior Cricoarytenoid Muscle Course

Covers most of the posterior cricoid lamina

Posterior Cricoarytenoid Muscle Innervation

Recurrent Laryngeal Nerve (RLN)

Posterior Cricoarytenoid Muscle Function

Abducts the vocal folds (only vocal fold abductor)

Lateral Cricoarytenoid (LCA) Muscle Attachments

Superior border of cricoid arch to muscular process of arytenoid

Lateral Cricoarytenoid (LCA) Muscle Course

Runs upward and backward from cricoid to arytenoid

Lateral Cricoarytenoid (LCA) Muscle Innervation

Recurrent Laryngeal Nerve

Lateral Cricoarytenoid (LCA) Muscle Function

Adducts membranous vocal folds

Transverse Arytenoid Muscle Attachments

One arytenoid cartilage to the opposite arytenoid cartilage

Transverse Arytenoid Muscle Course

Horizontal muscle spanning the posterior surfaces of the arytenoids

Transverse Arytenoid Muscle Innervation

Recurrent Laryngeal Nerve

Transverse Arytenoid Muscle Function

Adducts arytenoids and closes posterior glottis

Oblique Arytenoid Muscle Attachments

Muscular process of one arytenoid to apex of opposite arytenoid

Oblique Arytenoid Muscle Course

Forms an X-shape across posterior arytenoids

Oblique Arytenoid Muscle Innervation

Recurrent Laryngeal Nerve

Oblique Arytenoid Muscle Function

Adducts arytenoids and assists sphincteric closure

Thyroarytenoid Muscle Attachments

Inner thyroid cartilage to arytenoid cartilage

Thyroarytenoid Muscle Course

Runs parallel to the vocal folds

Thyroarytenoid Muscle Innervation

Recurrent Laryngeal Nerve

Thyroarytenoid Muscle Function

Shortens and relaxes vocal folds, lowering pitch

Aryepiglottic Muscle Attachments

Continuation of oblique arytenoid muscle into aryepiglottic fold

Aryepiglottic Muscle Function

Narrows laryngeal inlet during swallowing

Thyroepiglottic Muscle Attachments

Thyroid cartilage to epiglottis

Thyroepiglottic Muscle Function

Helps widen the laryngeal inlet

Suprahyoid Muscles Function

Elevate the hyoid bone and larynx during swallowing

Digastric Muscle Attachments

Mandible and temporal bone via intermediate tendon attached to hyoid

Digastric Muscle Function

Moves the hyoid up & forward/backward and elevates the larynx

Mylohyoid Muscle Attachments

Mandible to hyoid bone.

Geniohyoid Muscle Attachments

Mandible to hyoid bone

Stylohyoid Muscle Attachments

Styloid process to hyoid bone

Infrahyoid Muscles Function

Lower the hyoid bone and larynx

Sternohyoid Muscle Attachments

Sternum to hyoid bone

Omohyoid Muscle Attachments

Scapula to hyoid bone

Sternothyroid Muscle Attachments

Sternum to thyroid cartilage

Thyrohyoid Muscle Attachments

Thyroid cartilage to hyoid bone

Thyrohyoid Muscle Function

Can elevate the larynx or depress the hyoid