Areas - Anterior Triangle

Question 1

Where is the anterior triangle located?

Answer 1

Front of the neck.

Question 2

Borders?

Answer 2

Superiorly - inferior border of mandible

Laterally - anterior border of the sternocleidomastoid

Medially - sagittal line down the middle of neck

Roof of the triangle - investing fascia

Floor of the triangle - visceral fascia

This triangle can be broken down into four more triangles…

Question 3

Carotid triangle

Answer 3

Boundaries

Superiorly - posterior belly of digastric muscle

Laterally - medial border of the sternocleidomastoid

Inferiorly - superior belly of the omohyoid

Contents

Common carotid artery (bifurcates in the carotid triangle), internal jugular vein, hypoglossal and vagus nerves.

Question 4

Clinical relevance - medical uses of the carotid triangle

Answer 4

Many of the structure lie superficial in the vessels and nerves, and do can be accessed by surgery.

The carotid sinus is also contained with this triangle - it contains specific sensory cells, called baroreceptors - these detect stretch as a measure of blood pressure. The glossopharyngeal nerve feeds this information to the brain, and this is used to regulate blood pressure.

In some people, baroreceptors are hypersensitive to stretch. In these people, external pressure on the carotid sinus can cause slowing of the heart rate and a decrease in blood pressure. The brain becomes underperfused, and syncope results. Checking carotid pulse is not advised.

Question 5

Submental triangle

Answer 5

This is situated underneath the chin. Contains the sub-mental nodes that drain the lymph from the tongue and floor of the mouth.

Border

Inferiorly - hyoid bone

Medially - midline of the neck

Laterally - anterior belly of the digastric

Floor - mylohyoid muscle - mandible to the hyoid bone.

Question 6

Submandibular triangle

Answer 6

Located under the body of the mandible. It contains the submandibular gland (salivary), and lymph nodes. The facial artery and vein pass through this area.

Boundaries

Superiorly - body of the mandible

Anteriorly - anterior belly of the digastric muscle

Posteriorly - posterior belly of the digastric muscle

Question 7

Muscular (not really) triangle

Answer 7

More inferior to other subdivisions. It has four boundaries. Contains the infrahyoid muscles, pharynx, thyroid and parathyroid glands.

Superiorly - hyoid bone

Medially - imaginary midline of the neck

Supero-laterally - superior belly of the omohyoid muscle

Inferolaterally - inferior portion of the sternocleidomastoid