Muscles of head, lips, and cheeks

Muscles of head, lips, and cheeks

• The orbicularis oris muscle is a sphincter muscle of the mouth that is located between the skin and mucous membrane of the lips with no direct skeletal insertion.
• The orbicularis oris muscle closes the lips.
• The levator nasolabialis muscle originates from the frontal and nasal bone and has an insertion on the superior lip and lateral and nasal wing commissure of the lips.
• The levator nasolabialis muscle elevates the superior lip and the commissure and dilates the nostril openings.
• The levator labii superioris proprius muscle originates from the lacrimal, malar, and maxillary bones at the point of union and has an insertion on the superior lip by a common tendon with the opposite side.
• Contraction of the levator labii superioris proprius muscle elevates the upper lip.
• The zygomaticus muscle originates in the fascia covering the masseter muscle and has an insertion on the labial commissure that blends the buccinator.
• The zygomaticus muscle retracts and elevates the corner of the mouth.
• The incisivus superior muscle originates on the alveolar border of the premaxilla from the second incisive to the first molar and has an insertion into the upper lip.
• The incisivus superior muscle depresses the superior lip.
• The incisivus inferior muscle originates on the alveolar border of the mandible from the second incisor to a point located near the first molar on each side of the body of the mandible, it inserts on to the skin of the lower lip and the prominence of the beard.
• The incisivus inferior muscle elevates the lower lip.
• The mentalis muscle originates on each side of the body of the mandible and has an insertion on the skin of the chin.
• The mentalis muscle elevates and wrinkles the skin where it is inserted.
• The depressor labii inferioris muscle originates on the alveolar border of the mandible near the coronoid apophysis, and the maxillary tuberosity and has an insertion on the lower lip.
• The depressor labii inferioris muscle depresses and retracts the lower lip.
• The buccinator muscle originates on the lateral face of the maxilla above the interalveolar space and molars, alveolar border of the mandible and raphe pterygomandibular. Its insertion is the corner of the mouth and the orbicularis oris.
• The buccinator muscle flattens the cheeks, thus rejecting foods against the teeth and retracting the corner of the mouth.

Muscles of the wings of the nose

• The levator nasolabialis acts as a muscle of the wings of the nose.
• The dilator naris lateralis muscle originates in the maxilla, very close to the anterior end of the facial crest.
• The dilator naris lateralis muscle inserts into the lateral wing of the nose, therefore dilating of the nostrils.