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Depressor anguli oris | |
---|---|
Details | |
Origin | Tubercle of mandible |
Insertion | Modiolus of mouth |
Artery | Facial artery |
Nerve | Marginal mandibular branch of the facial nerve |
Actions | Depresses angle of mouth |
Identifiers | |
Latin | musculus depressor anguli oris |
TA98 | A04.1.03.026 |
TA2 | 2076 |
FMA | 46828 |
Anatomical terms of muscle |
The depressor anguli oris muscle (triangularis muscle) is a facial muscle. It originates from the mandible and inserts into the angle of the mouth. It is associated with frowning, as it depresses the corner of the mouth.
The depressor anguli oris arises from the lateral surface of the mandible. [1] Its fibers then converge. It is inserted by a narrow fasciculus into the angle of the mouth. [1] At its origin, it is continuous with the platysma muscle, and at its insertion with the orbicularis oris muscle and risorius muscle. Some of its fibers are directly continuous with those of the levator anguli oris muscle, and others are occasionally found crossing from the muscle of one side to that of the other; these latter fibers constitute the transverse muscle of the chin.
The depressor anguli oris muscle receives its blood supply from a branch of the facial artery.
The depressor anguli oris muscle is supplied by the marginal mandibular branch of the facial nerve. [1]
The depressor anguli oris muscle is a muscle of facial expression. [1] It depresses the corner of the mouth, which is associated with frowning. [1]
Damage to the marginal mandibular branch of the facial nerve may cause paralysis of the depressor anguli oris muscle. [1] This may contribute to an asymmetrical smile. [1] This may be corrected by resecting (cutting and removing) the depressor labii inferioris muscle, which has a more significant impact on smiling. [1]
Underdevelopment (hypoplasia) or complete absence (aplasia) of the depressor anguli oris can occur. [2] Similarly to paralysis, individuals with these conditions will have an asymmetric smile.[ medical citation needed ] These conditions are rare, and develop at or before birth (congenitally).
This gallery of anatomic features needs cleanup to abide by the medical manual of style. |
The buccinator is a thin quadrilateral muscle occupying the interval between the maxilla and the mandible at the side of the face. It forms the anterior part of the cheek or the lateral wall of the oral cavity.
In human anatomy, the orbicularis oris muscle is a complex of muscles in the lips that encircles the mouth. It is not a true sphincter, as was once thought, as it is actually composed of four independent quadrants that interlace and give only an appearance of circularity.
The lips are a horizontal pair of soft appendages attached to the jaws and are the most visible part of the mouth of many animals, including humans. Vertebrate lips are soft, movable and serve to facilitate the ingestion of food and the articulation of sound and speech. Human lips are also a somatosensory organ, and can be an erogenous zone when used in kissing and other acts of intimacy.
The platysma muscle is a superficial muscle of the human neck that overlaps the sternocleidomastoid. It covers the anterior surface of the neck superficially. When it contracts, it produces a slight wrinkling of the neck, and a "bowstring" effect on either side of the neck.
The depressor labii inferioris is a facial muscle. It helps to lower the bottom lip.
The zygomaticus major muscle is a muscle of the face. It arises from either zygomatic arch (cheekbone); it inserts at the corner of the mouth. It is innervated by branches of the facial nerve.
The levator anguli oris (caninus) is a facial muscle of the mouth arising from the canine fossa, immediately below the infraorbital foramen. It elevates angle of mouth medially. Its fibers are inserted into the angle of the mouth, intermingling with those of the zygomaticus, triangularis, and orbicularis oris. Specifically, the levator anguli oris is innervated by the buccal branches of the facial nerve.
The mentalis muscle is a paired central muscle of the lower lip, situated at the tip of the chin. It originates from the mentum of the mandible, and inserts into the soft tissue of the chin. It is sometimes referred to as the "pouting muscle" due to it raising the lower lip and causing chin wrinkles.
The facial artery is a branch of the external carotid artery that supplies structures of the superficial face.
In facial anatomy, the modiolus is a dense, compact, mobile, fibromuscular tissue mass of facial muscles formed by the interlacing of a number of muscles just lateral to the angle of the mouth opposite the second upper premolar tooth.
The mental foramen is one of two foramina (openings) located on the anterior surface of the mandible. It is part of the mandibular canal. It transmits the terminal branches of the inferior alveolar nerve and the mental vessels.
The mental nerve is a sensory nerve of the face. It is a branch of the posterior trunk of the inferior alveolar nerve, itself a branch of the mandibular nerve (CN V3), itself a branch of the trigeminal nerve (CN V). It provides sensation to the front of the chin and the lower lip, as well as the gums of the anterior mandibular (lower) teeth. It can be blocked with local anaesthesia for procedures on the chin, lower lip, and mucous membrane of the inner cheek. Problems with the nerve cause chin numbness.
The infraorbital artery is a small artery in the head that arises from the maxillary artery and passes through the inferior orbital fissure to enter the orbit, then passes forward along the floor of the orbit, finally exiting the orbit through the infraorbital foramen to reach the face.
The marginal mandibular branch of the facial nerve arises from the facial nerve in the parotid gland at the parotid plexus. It passes anterior-ward deep to the platysma and depressor anguli oris muscles. It provides motor innervation to muscles of the lower lip and chin: the depressor labii inferioris muscle, depressor anguli oris muscle, and mentalis muscle. It communicates with the mental branch of the inferior alveolar nerve.
The buccal branches of the facial nerve, are of larger size than the rest of the branches, pass horizontally forward to be distributed below the orbit and around the mouth.
The submental artery is the largest branch of the facial artery in the neck. It first runs forward under the mouth, then turns upward upon reaching the chin.
The buccal space is a fascial space of the head and neck. It is a potential space in the cheek, and is paired on each side. The buccal space is superficial to the buccinator muscle and deep to the platysma muscle and the skin. The buccal space is part of the subcutaneous space, which is continuous from head to toe.
The facial muscles are a group of striated skeletal muscles supplied by the facial nerve that, among other things, control facial expression. These muscles are also called mimetic muscles. They are only found in mammals, although they derive from neural crest cells found in all vertebrates. They are the only muscles that attach to the dermis.
The following outline is provided as an overview of and topical guide to human anatomy:
This article incorporates text in the public domain from page 383 of the 20th edition of Gray's Anatomy (1918)