The tragicus muscle is an intrinsic muscle of the outer ear that facilitates the opening of the external auditory canal and assists in minor movement of the tragus.
Summary:
origin: base of tragus
insertion: apex of tragus
blood supply: branches of facial arteries
innervation: facial nerve (CN VII)
action: opening of the external auditory canal, minor movement of the tragus
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Gross anatomy
Origin
The tragicus muscle is a short, flat intrinsic muscle of the auricle, originating at the base of the tragus, positioned lateral to the tragus itself.
Insertion
The muscle inserts vertically on the lateral aspect of the tragus, oriented perpendicularly to the antitragicus muscle.
Arterial supply
The blood supply to the intrinsic muscles of the ear is provided by the anterior auricular branches of the superficial temporal artery, the posterior auricular branch of the external carotid artery, and the occipital artery.
Venous drainage
The primary venous drainage routes for the tragicus muscle include the pterygoid plexus, external jugular vein, and maxillary vein.
Innervation
Innervation of the tragicus muscle is primarily through the temporal and posterior auricular branches of the facial nerve (CN VII).
Action
The primary action of the tragicus muscle is to assist in minor movements of the tragus, which may play a role in modulating sound conduction into the external auditory canal.
Variant anatomy
There is considerable variation in the size, shape, and presence of the tragicus muscle among individuals. In some cases, the muscle may be absent or rudimentary 3.
History and etymology
The term "tragicus" is derived from the Greek word "tragos," meaning "goat," which is thought to be in reference to the hair that commonly grows on the tragus in humans, resembling a goat's beard.