Muscle of the Terminal Notch
Ear · Head & Neck
The muscle of the terminal notch is a small, inconstant intrinsic muscle of the external ear. It occupies the region of the terminal (incisural) notch of the auricle, the gap in the cartilage between the tragus and the crus of the helix, and its fibres bridge the adjacent auricular cartilage across this notch. Like the other intrinsic ear muscles it is vestigial in humans, capable only of slightly modifying the shape of the auricle. In keeping with all the muscles of the ear and face, it is supplied by the facial nerve (CN VII). Because it is variable, it is often absent or poorly developed, and it is chiefly of descriptive and comparative anatomical interest.
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)
Locate this muscle by first learning the landmark it is named for: the terminal or incisural notch is the cartilage gap between the tragus in front and the crus of the helix above. Once you can picture that notch, the muscle is simply the slip of fibres that spans it, so its only possible action is to draw the cartilage together and thereby modify the shape of the auricle. Naming the muscle from its landmark makes both its position and its trivial action self-explanatory.
Remember that this is a variant, often absent muscle, so the safest facts to carry are its facial nerve (CN VII) supply and its vestigial status shared with the other intrinsic ear muscles. Rather than memorising precise attachments, group it with the transverse and oblique auricular muscles as a cluster of functionally silent, facial-nerve-innervated remnants of the mobile mammalian ear.
Frequently asked questions
Where is the Muscle of the Terminal Notch located?
The Muscle of the Terminal Notch is a muscle of the Ear group, located in the Head & Neck.
What is the origin of the Muscle of the Terminal Notch?
Margins of the terminal (incisural) notch of the auricle, between the tragus and crus of the helix
What is the insertion of the Muscle of the Terminal Notch?
Adjacent auricular cartilage across the terminal notch
What movements does the Muscle of the Terminal Notch produce?
Modifies the shape of the auricle (vestigial)
What nerve supplies the Muscle of the Terminal Notch?
Facial nerve (CN VII)
Is the Muscle of the Terminal Notch free to study in OIANS?
The Muscle of the Terminal Notch is always free to browse. Its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory. Quiz and Flashcard practice for the Head & Neck is part of the one-time Lifetime upgrade, though; only the Upper Limb decks are free to test yourself on.
Related muscles
Study the Muscle of the Terminal Notch
Test yourself on Head & Neck muscles with interactive quizzes and flashcards in the free OIANS app.
Quiz yourself → Flashcards Open the OIANS app
Browsing is always free. A one-time Lifetime unlock adds every region's quizzes, flashcards, progress tracking and explore tools.