Anterior triangle of the neck
Globally, the anterior triangle is an extensive region bounded by three clear landmarks:
- Anteriorly, the boundary is formed by the midline of the neck.
- Posteriorly, the region is bounded by the m. sternocleidomastoideus.
- Superiorly, it is enclosed by the mandible.
For a detailed understanding of the topography, this zone is subdivided into 4 smaller triangles, three of which are highlighted in detail.
1. Submental triangle (trigonum submentale)
Located in the uppermost part of the neck. Its boundaries are formed by the anterior bellies of the digastric muscle (m. digastricus) on both sides, with the body of the hyoid bone serving as its base. The primary contents of this area are lymph nodes.
2. Submandibular triangle (trigonum submandibulare)
This zone is wedged between the margin of the mandible and both bellies (anterior and posterior) of the m. digastricus. The submandibular salivary gland lies within the triangle, and the facial vessels pass through it.
3. Carotid triangle (trigonum caroticum)
A critically important anatomical region named after the major vessels passing through it.
Boundaries of the carotid triangle:
- Posterior belly of the m. digastricus.
- Superior belly of the omohyoid muscle (m. omohyoideus).
- Anterior margin of the m. sternocleidomastoideus.
Contents: this is where the common carotid artery (a. carotis communis) and the site of its division (bifurcatio carotidis) are located. In addition, the internal jugular vein (v. jugularis interna), vagus nerve (n. vagus), and ansa cervicalis (ansa cervicalis) lie within the triangle.
Posterior triangle of the neck
The posterior region of the neck also has a triangular shape, bounded anteriorly by the posterior margin of the m. sternocleidomastoideus, posteriorly by the anterior margin of the trapezius muscle (m. trapezius), and resting inferiorly on the clavicle.
Using the omohyoid muscle, this large area is divided into two smaller topographical zones.
| Name of the triangle | Latin term | Boundaries and contents |
|---|---|---|
| Omoclavicular triangle | trigonum omoclaviculare (or supraclaviculare) | Located between the inferior belly of the m. omohyoideus and the clavicle. The subclavian artery (a. subclavia) and structures of the brachial plexus (plexus brachialis) pass through it. |
| Omotrapezoid | trigonum omotrapezoideum | Located between the m. omohyoideus and the m. trapezius. Here, branches of the cervical plexus (plexus cervicalis) and the accessory nerve (n. accessorius) can be found. |
Briefly: answers to topical questions
Which smaller triangles make up the anterior triangle of the neck?
The anterior (medial) triangle of the neck comprises four smaller triangles.
- Submental triangle (trigonum submentale) — unpaired, located in the suprahyoid region.
- Submandibular triangle (trigonum submandibulare) — located above the hyoid bone.
- Carotid triangle (trigonum caroticum) — located in the infrahyoid region.
- Omotracheal triangle (trigonum omotracheale) — also located below the hyoid bone.
Which vessels and nerves form the contents of the carotid triangle?
The contents of the carotid triangle are formed by the main neurovascular bundle of the neck and its branches.
- Common carotid artery (a. carotis communis) — located medially; the carotid bifurcation (bifurcatio carotidis) is also situated here.
- Internal jugular vein (v. jugularis interna) — lies laterally.
- Vagus nerve (n. vagus) — located between the artery and vein, posterior to them.
- Ansa cervicalis (ansa cervicalis) — formed superficially to the fascial sheath of the bundle.
What anatomical structures make up the contents of the submandibular triangle?
The contents of the submandibular triangle include glandular, neurovascular, and lymphatic structures.
- Submandibular salivary gland (gl. submandibularis) — located in its own fascial bed.
- Facial artery and vein (a. et v. facialis) — pass within the boundaries of the triangle.
- Hypoglossal nerve (n. hypoglossus) — located in the cleft between the muscles of the floor of the mouth.
- Lymph nodes (nodi lymphoidei submandibulares) — anterior, middle, and posterior groups.
Also within this region lies Pirogov's triangle, containing the lingual artery and vein.
What are the boundaries of the muscular (omotracheal) triangle?
The boundaries of the muscular, or omotracheal, triangle (trigonum omotracheale) are formed by the following anatomical landmarks.
- Superiorly — the inferior belly of the omohyoid muscle (m. omohyoideus).
- Laterally — the anterior margin of the sternocleidomastoid muscle (m. sternocleidomastoideus).
- Medially — the midline of the neck.
Within these boundaries lie the thyroid gland, larynx, and trachea.
Which vessels and nerves pass through the omoclavicular triangle?
The following vascular and neural formations, enclosed in a fascial sheath, pass through the omoclavicular triangle (trigonum omoclaviculare):
- Subclavian artery (a. subclavia) — its third part is located here.
- Brachial plexus (plexus brachialis) — its supraclavicular part is represented here.
The syntopy of the structures is such that the trunks of the brachial plexus are located superiorly and posteriorly to the subclavian vessel.
Where is Pirogov's triangle (lingual triangle) located and what are its boundaries?
Pirogov's triangle is located within the submandibular triangle of the neck. Its boundaries are formed by:
- Superiorly — the hypoglossus nerve (n. hypoglossus).
- Anteriorly — posterior border of the mylohyoid muscle (m. mylohyoideus).
- Inferiorly and posteriorly — tendon of the posterior belly of the digastric muscle (m. digastricus).
The floor of the triangle is formed by the hyoglossus muscle (m. hyoglossus), beneath which lies the lingual artery.
Class and exam questions
Which muscles bound the carotid triangle?
The carotid triangle is bounded by the posterior belly of m. digastricus, the superior belly of m. omohyoideus, and the anterior border of m. sternocleidomastoideus.
Where is the submandibular gland located?
It is located in the submandibular triangle (trigonum submandibulare), which is wedged between the mandible and both bellies of m. digastricus.
What passes through the omoclavicular triangle?
In this triangle (trigonum omoclaviculare) lie the subclavian artery (a. subclavia) and the brachial plexus (plexus brachialis).
Which muscle serves as the common boundary for the anterior and posterior triangles of the neck?
This is the sternocleidomastoid muscle (m. sternocleidomastoideus). Its anterior border bounds the anterior triangle, and its posterior border bounds the posterior one.
What else to study on this topic
- Fourth small triangle of the anterior neck region (muscular / omotracheal triangle)
- Topography and branches of the cervical plexus (plexus cervicalis)
- Course and distribution of the accessory nerve (n. accessorius) in the neck
- Formation and branches of the brachial plexus (plexus brachialis)
- Relationship of the facial vessels to the submandibular salivary gland
Study the complete topic in the Anatomy course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Triangles of the Neck" and 1,363 other subject pages
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 295 video lessons by subject
Other topics in the "Myology" section
Free video lessons: AnatomyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.