Antitragicus

Origin, Insertion, Action & Nerve

Attachments explained

The Antitragicus is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.

Action & function

When the Antitragicus contracts, it produces the following movement: Modifies the shape of the auricle (vestigial).

As part of the Ear group of the Head & Neck, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.

Nerve supply & clinical relevance

The Antitragicus receives its nerve supply from the Posterior auricular branch of facial nerve (CN VII).

Because a muscle can only contract when its nerve is intact, injury to the Posterior auricular branch of facial nerve can weaken or paralyse the Antitragicus, impairing the movements it normally produces (modifies the shape of the auricle (vestigial)). This is why knowing the innervation is central to localising nerve lesions in clinical practice.

How to study the Antitragicus (the OIANS method)

Learn the antitragicus by its landmark, the antitragus, and by its partnership with the tragicus across the intertragic notch; the antitragicus spreads from the antitragus toward the antihelix and the tail of the helix. As with all the intrinsic ear muscles, its position rather than its negligible action is what you need to retain.

The distinguishing detail is its nerve: whereas most intrinsic ear muscles take the temporal branch, the antitragicus is supplied by the posterior auricular branch of the facial nerve, the same branch serving the auricularis posterior. Holding the antitragicus and the auricularis posterior together as the posterior auricular pair is a clean way to remember both the exception and the group.

Frequently asked questions

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