The anterior triangle is a region of the
neck
The neck is the part of the body on many vertebrates that connects the head with the torso. The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In ...
.
Structure
The triangle is inverted with its apex inferior to its base which is under the chin.
Investing fascia covers the roof of the triangle while
visceral fascia
A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organs. ...
covers the floor.
Anatomy
Muscles:
*
Suprahyoid muscles
The suprahyoid muscles are four muscles located above the hyoid bone in the neck. They are the digastric, stylohyoid, geniohyoid, and mylohyoid muscle, mylohyoid muscles. They are all pharyngeal muscles, with the exception of the geniohyoid muscle. ...
- Digastric (Ant and Post Belly), mylohyoid, geniohyoid and Stylohyoid.
*
Infrahyoid muscles
The infrahyoid muscles, or strap muscles, are a group of four pairs of muscles in the anterior (frontal) part of the neck. The four infrahyoid muscles are the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles.
Excluding the sternothyr ...
- Omohyoid, Sternohyoid, Sternothyroid, and Thyrohyoid.
Nerve supply
2 Bellies of Digastric
* Anterior:
Mylohyoid nerve
The mylohyoid nerve (or nerve to mylohyoid) is a nerve of the head. It is a branch of the inferior alveolar nerve. It supplies the mylohyoid muscle, and the Anterior belly of digastric, anterior belly of the digastric muscle. It may also supply m ...
* Posterior:
Facial nerve
The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of tas ...
Stylohyoid: by the facial nerve, by a branch from that to the posterior belly of digastric.
Mylohyoid: by its own nerve, a branch of the inferior alveolar ( from the mandibular division of trigeminal nerve), which arises just before the parent nerve enters the mandibular foramen, pierces the sphenomandibular ligament, and runs forward on the inferior surface of the mylohyoid, supplying it and the anterior belly of the digastric.
Geniohyoid: by a branch from the hypoglossal nerve consisting of fibres from the C1 nerve.
Sternohyoid, Omohyoid, Sternothyroid are supplied by Ansa cervicalis.
Thyrohyoid: by a branch of hypoglossal nerve but the fibres are all 'hitch-hiking' from C1.
Development
* Anterior: 1st
Pharyngeal arch
The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arch ...
* Posterior: 2nd
Pharyngeal arch
The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arch ...
Divisions
This space is subdivided into four smaller triangles by the
Digastricus
The digastric muscle (also digastricus) (named ''digastric'' as it has two 'bellies') is a small muscle located under the jaw. The term "digastric muscle" refers to this specific muscle. However, other muscles that have two separate muscle belli ...
above, and the superior belly of the
Omohyoideus
The omohyoid muscle is a muscle that depresses the hyoid. It is located in the front of the neck, and consists of two bellies separated by an intermediate tendon. The omohyoid muscle is proximally attached to the scapula and distally attached to t ...
.
These smaller triangles are named:
* the
muscular triangle
The inferior carotid triangle (or muscular triangle), is bounded, in front, by the median line of the neck from the hyoid bone to the sternum; behind, by the anterior margin of the sternocleidomastoid; above, by the superior belly of the omohyoid ...
* the
carotid triangle
The carotid triangle (or superior carotid triangle) is a portion of the anterior triangle of the neck.
Coverings and boundaries
It is bounded:
* Posteriorly by the anterior border of the Sternocleidomastoid;
* Anteroinferiorly, by the superior be ...
* the
submandibular triangle
The submandibular triangle (or submaxillary or digastric triangle) corresponds to the region of the neck immediately beneath the body of the mandible.
Boundaries and coverings
It is bounded:
* ''above'', by the lower border of the body of the man ...
* the
submental triangle
The submental triangle (or suprahyoid triangle) is a division of the anterior triangle of the neck.
Boundaries
It is limited to:
* Lateral (away from the midline), formed by the anterior belly of the digastricus
* Medial (towards the midline), f ...
Additional images
File:Musculussternocleidomastodieus.png, Sternocleidomastoid muscle
The sternocleidomastoid muscle is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the access ...
File:Gray386.png, Muscles of the neck. Anterior view.
File:Gray512.svg, The triangles of the neck. (Anterior triangles to the left; posterior triangles to the right. Suprahyoid labeled at left.)
See also
*
Posterior triangle of the neck
Posterior may refer to:
* Posterior (anatomy), the end of an organism opposite to its head
** Buttocks, as a euphemism
* Posterior horn (disambiguation)
* Posterior probability, the conditional probability that is assigned when the relevant evidenc ...
References
External links
* ()
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{{Authority control
Human head and neck
Triangles of the neck