Answer
1. Obicularis oris. This muscle is located in lips and encircles the opening of the mouth cavity. It has several roles: it closes the mouth, protrudes the lops and aids in speech. Its origin is the modiolus of the mouth, and it is inserted in the submucosa and dermis of the lips. It is innervated by cranial nerve number seven (CN VII), that is the facial nerve.
2. Levator labii superioris. This muscle is located in the upper lip. Its role is to evertthe the upper lip in sad, sneering or serious expression. . Its origin is on the zygomatic and maxilla nearthe infra orbital margin. Its isinserted into the muscles of the upper lip. Supplied by CN VII.
3. Levator anguli oris. . This muscle elevates the angle of the mouth during the act of smiling. Its origin is on the maxilla below the infraorbital foramen. . Insertion is in the muscles at the angle of the mouth, It is supplied by CN VII.4.
4. Zygomaticus major and minor. --Attached to modiolus: It draws the angle of mouth up and laterally in laughing laughing . Origin is zygomatic bone and insertion is in the tissues in the superolateral angle of the mouth
5. Zygomaticus minor : Attached to modiolus. It elevates upper lip ; exposes upper teeth in smiling or
sneering. Origin is on the zygomatic bone and it is inserted in the muscles of the upper lip. Inervation for both zygomaticus major, and zygomaticus minor is the facial nerve.
Work Step by Step
6. Risorius. This muscle is also connected to the modiolus. Its origin is the zygomatic arch and fascia near the ear and its insertion is in the modiolus. It draws the muscles of the mouth laterally in laughing and in expressions of horror and disdain.
7. Depressor anguli oris. Attached to modiolus(insertion); origin inferior margin of body of the mandible. It draws the angle of the mouth laterally and downward in opening the moth or in the making of a sad expression. Innervation is by CN VII.
8. Depressor labii inferioris. This muscle draws the lower down and laterally in the act of chewing and in sad
or doubtful expressions. Its origin is on the mandible era the mental protuberance and it insertion is in
the skin and mucosa of the lower lip. It is innervated by CN VII.
9. The mentalis. This muscle is located in the region of the chin. It elevates and protracts the lower lip in drinking , pouting, and in expressions of doubt and disdain; it also elevates and wrinkles the skin of the chin. Its origin is on the mandible near he lower incisors and it inserts in the skin of the chin near the mental protuberance. It is innervated by the facial nerve (CN VII)
The modiolus is an area of fibrous tissue in the corner of the mouth were eight muscles meet.
Mentalis/ or mental means related to the chin.
