Muscle of the Terminal Notch

Ear · Head & Neck

Muscle of the Terminal Notch belongs to the Ear group of the Head & Neck. It arises from Margins of the terminal (incisural) notch of the auricle, between the tragus and crus of the helix and attaches to Adjacent auricular cartilage across the terminal notch. Functionally, it modifies the shape of the auricle (vestigial). Innervation is provided by the Facial nerve (CN VII).

Origin, Insertion, Action & Nerve

Origin

Margins of the terminal (incisural) notch of the auricle, between the tragus and crus of the helix

Insertion

Adjacent auricular cartilage across the terminal notch

Action

Modifies the shape of the auricle (vestigial)

Nerve

Facial nerve (CN VII)

Attachments explained

The Muscle of the Terminal Notch 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.

Origin

Margins of the terminal (incisural) notch of the auricle, between the tragus and crus of the helix

Insertion

Adjacent auricular cartilage across the terminal notch

Action & function

When the Muscle of the Terminal Notch 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 Muscle of the Terminal Notch receives its nerve supply from the Facial nerve (CN VII).

Because a muscle can only contract when its nerve is intact, injury to the Facial nerve can weaken or paralyse the Muscle of the Terminal Notch, 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 Muscle of the Terminal Notch (the OIANS method)

OIANS stands for Origin, Insertion, Action and Nerve, the four facts that uniquely define every skeletal muscle. To learn the Muscle of the Terminal Notch, work through them in order: picture its origin, trace the muscle to its insertion, reason out the action that shortening between those two points must create, then add the nerve that drives it.

Most students remember the Muscle of the Terminal Notch fastest by linking its action back to its attachments rather than memorising each fact in isolation. Once the origin and insertion make sense, the action usually follows logically.