They are of two types, intrinsic, which attach laryngeal
cartilages to each other, and extrinsic, which attach
larynx to the surrounding structures.
1. Intrinsic muscles. They may act on vocal cords or
(a) Acting on vocal cords
Abductors: Posterior cricoarytenoid
Adductors: Lateral cricoarytenoid lnterarytenoid (transverse
arytenoid) Thyroarytenoid (external
Tensors: Cricothyroid Vocalis ( internal part of thyroarytenoid)
(b) Acting on laryngeal inlet
Openers of laryngeal inlet: Thyroepiglottic (part of thyroarytenoid)
Closers of larylngeal inlet: Interarytenoid (oblique part)
Aryepiglottic (posterior oblique
part of interarytenoids)
2. Extrinsic muscles. They connect the larynx to the
neighbouring structures and are divided into elevators
or depressors of larynx.
(a) Elevators. Primary elevators act directly as they
are attached to the thyroid cartilage and include
stylopharyngeus, salpingopharyngeus, palatopharyngeus
Secondary elevators act indirectly as they are
attached to the hyoid bone and include mylohyoid
(main), digastric, stylohyoid, geniohyoid.
(b) Depressors. They include sternohyoid, sternothyroid