Suprahyoid Anterior Neck Triangles

Question 1

boundaries of submental triangle

Answer 1

Base (posteriorly): body of hyoid bone
Anterolaterally: anterior bellies of both digastric muscles
Floor: mylohyoid muscles

[Diagram: Submental triangle]

Question 2

contents of submental triangle

Answer 2

(a) origin of anterior jugular veins
(b) submental group of cervical lymph nodes (level Ia); drain the lower lip, tip of the tongue and the floor of the mouth [pathologies in these regions may cause enlargments of the submental lymph nodes]

Note:
The contents of the triangle actually lie in the superficial fascia over the roof of the submental triangle.

[Diagram: Submental triangle]

Question 3

boundaries of submandibular/digastric triangle

Answer 3

superiorly/base: base of mandible and its imaginary projection to mastoid process
posteroinferiorly: posterior belly of digastric and stylohyoid muscles
anteroinferiorly: anterior belly of digastric muscle
floor: mylohyoid (ant.) and hyoglossus (post.)
superficially: platysma, cervical branch of the facial nerve, transverse cutaneous nerve of the neck

[Diagram: Submandibular triangle]
[8-minute video: Cadaveric demonstration of the digastric triangle]

Question 4

contents of submandibular/digastric triangle

Answer 4

Anterior aspects:
✔ submandibular gland
✔ facial artery and vein
✔ submental artery [branch of facial artery]
✔ artery and nerve to mylohyoid muscle [mandibular nerve ⇒ inferior alveloar nerve ⇒ nerve to mylohyoid], [maxillary artery ⇒ inferior alveolar artery ⇒ artery to mylohyoid]
✔ submandibular group of cervical lymph nodes [level Ib nodes]

Posterior aspects
✔ lower part of parotid gland
✔ external carotid artery

[Diagram: Submandibular triangle]
[8-minute video: Cadaveric demonstration of the digastric triangle]

Question 5

List the suprahyoid muscles of the neck.

Answer 5

The suprahyoid muscles comprise following four paired muscles.
1. Digastric
2. Stylohyoid
3. Mylohyoid
4. Geniohyoid

Further notes:
✔ Genial tubercles: Genial tubercles (GTs), also known as spinae mentalis, genial apophysis and mental spines GTs are small eminences of bone found on the lingual side of the mandible at the midline and are important landmarks for maxillofacial surgeons, radiologists, prosthodontists and general dentists.
✔ Appreciate the mylohyoid line too.

Question 6

Suprahyoid neck extends from the hyoid bone to base of skull. List the suprahyoid neck spaces.

Answer 6

1. Submandibular, sublingual and submental spaces
2. Masticator and buccal spaces
3. Parotid space
4. Parapharyngeal space
5. Pharyngeal mucosal space
6. Retropharyngeal and danger spaces
7. Carotid space
8. Posterior cervical space
9. Perivertebral space

[Diagram 1] [Diagram 2] [Diagram 3] [Radiograph 1] [Radiograph 2] [Radiograph 3] [Radiograph 4]