Muscular system · Head and neck
Mentalis !
The mentalis is a small muscle in the chin; it wrinkles the chin skin and pushes the lower lip out, as in a pout.
Official name: Mentalis muscle
Opens in the Durgical app, no sign-up needed.
What it is
A small muscle in the chin.
What it does
Wrinkles the chin and pushes the lower lip out (pout).
Key facts
- Origin
- Incisive fossa of the mandible
- Insertion
- Skin of the chin
- Action
- Wrinkles the chin, pushes the lower lip out
- Nerve
- Facial nerve (CN VII): marginal mandibular branch
- Blood supply
- Facial artery branches
Relations
- Superficial
- Skin of the chin, firmly tied to the muscle, so it dimples when the muscle contracts
- Deep
- Incisive fossa of the mandible below the lower incisor roots, and the bony chin
- Lateral
- Depressor labii inferioris; further out the mental foramen and the mental nerve
- Above
- Labial gingiva and the lower lip with the orbicularis oris
How to find it
Asked to pout or push the lower lip out, the chin skin wrinkles and puckers over a firm pad on each side of the midline.
Examination
- Pouting or wrinkling the chin; with the lower-lip depressor test it helps place a lesion on the marginal mandibular branch (both weak) or the cervical branch (mentalis spared)
On imaging
Imaging is rarely needed for it. On CT or MRI it is a small paired muscle in the chin pad, in front of the mandibular symphysis and below the roots of the lower incisors. After a genioplasty or chin implant, CT shows the soft tissue in front of the symphysis, a collection or a displaced implant; a sagging chin after an intraoral approach is a clinical diagnosis.
Clinical notes
- Strain of the mentalis to close the lips over protruding front teeth shows a dimpled «cobblestone» chin; it fades when the bite is corrected
- Intraoral incisions for symphysis fractures and genioplasty go through it; it is closed in layers to keep the chin from drooping
- Weakening by botulinum toxin injection is used for a dimpled chin; spread to the lower-lip depressors can cause lip asymmetry
Development
Second pharyngeal arch muscle.
Test yourself
Think of the answer, then tap the question to see it.
What is the unique action of the mentalis?
It is the only muscle that raises and pushes out the lower lip; it also lifts and wrinkles the chin soft tissue.
Why must the mentalis be reattached after an intraoral approach to the chin?
Otherwise the chin soft tissue sags (witch's chin).
What is the cobblestone chin?
A dimpled chin from mentalis strain when closing the lips over protruding front teeth; it fades when the bite is corrected.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- musculus mentalis TA2 2087
- Official Spanish (DeCS)
- Músculo mentoniano
- English (TA2)
- Mentalis muscle
Related
Sources: Terminologia Anatomica (TA2); Anatomy, Head and Neck: Facial Muscles; Anatomy, Head and Neck, Lips.
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.
