1. Anterior Neck TrianglesBy
Dr. Adel Sahib Al-Mayaly
Head & Neck Surgery

4. Muscular triangle
It is one of the anterior neck triangles that is found in the infrahyoid region. It is bounded by the superior belly of omohyoid m. superiorly, SCM inferiorly & mid line of neck anteriorly.
It contains the infrahyoid muscles

5. Muscular Triangle Boundaries:-
Superiorly; superior belly of omohyoid m.
Inferiorly: anterior border of SCM
Anteriorly: midline of neck.
Roof: investing layer.
Floor: Infrahyoid muscle.

6. Contents of muscular triangle infrahyoid muscles
1- sternohyoid m.
2- omohyoid m.
3- sternohyoid m.
4- thyrohyoid m.
They are supplied by Ansa cervicalis n( C 1,2,3)
They depress the hyoid bone & eventually the larynx so that they narrow the upper esophageal opening.

9. Infrahyoid muscles

10. Ansa cervicalis
is a loop of nerves that are part of the cervical plexus+
It lies superficial to the internal jugular vein in the carotid triangle.
Its name means "handle of the neck" in Latin.
Branches from the ansa cervicalis innervate most of the infrahyoid muscles

11. Roots of ansa cervicalis
1- Superior root:- (descendens hypoglossi).
It is derived from anterior primary rami of C1
It supplies the thyrohyoid muscle & superior belly of omohyoid m.

12. Ansa cervicalis 2-The inferior root(C2,3) (descendens cervicalis)
gives off branches to
1- inferior belly of omohyoid muscle
2- sternothyroid.
3- sternohyoid.

13. Hyoid Bone
A horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage.
At rest, it lies at the level of the third cervical vertebra (C3).
Unlike other bones; is only articulated to other bones by muscles or ligaments.

15. Attachments of hyoid Superior attachment Inferior attachments
1- Middle pharyngeal constrictor muscle
2-Hyoglossus muscle
3-Genioglossus
4-Intrinsic muscles of the tongue
5-Suprahyoid muscles
6-Digastric muscle
7-Stylohyoid muscle
8-Geniohyoid muscle
9-Mylohyoid muscle
Inferior attachments
Thyrohyoid muscle
Omohyoid muscle
Sternohyoid muscle

16. Submental triangle Boundaries;-
is a division of the anterior triangle of the neck.
Boundaries;-
Medially: midline raphe of the neck
Laterally: anterior belly of the two digastric muscles
Posteriorly: hyoid bone
Floor : Mylohyoid muscle.
Contents:- Submental L.N, Submental veins.

19. Contents of Submental triangle

20. Submandibular triangle
Boundaries:-
1- anteriorly:- anterior belly of digastric m.
2- posteriorly:- posterior belly of digastric muscle.
3- superiorly:- body of mandible.

22. contents 1- Arteries:- Facial & lingual.
2- Nerves:- hypoglossal & nerve to mylohyoid.
3- Glands:- submandibular & its duct.
4- Submandibular L.Ns
5- Suprahyoid muscles.

23. Suprahyoid muscles

25. Lingual Artery. • Is the third branch ECA .
• Origin: external carotid artery at the level of hyoid bone.
• May give origin to the ascending pharyngeal artery or the facial artery.
• Course:
Ascends deep to the digastric and stylohyoid muscles against the lateral wall of the pharynx
It Continues anteriorly until it plunges into the hyoglossus muscle

26. Facial (External Maxillary) Artery
• Is the fourth branch.
• Origin: anteriorly at the lower border of the digastric muscle beneath the angle of the mandible.
• Course: ascends anterosuperiorly deep to the digastric and the stylohyoid muscles to traverse the sub mandibular triangle in contact with the glands' posterior surface .
• Its cervical branches include
1-Ascending palatine
2-Tonsillar
3-Branches to the submandibular gland.
4-Submental branch to the mylohyoid muscle and adjacent tissue
5-Masticator branches

27. Hypoglossal Nerve (CN XII)
Emerges from the skull through the hypoglossal (anterior condylar) canal in the occipital bone.
Lies medial to the internal jugular vein and the internal carotid artery.
Near its emergence from the skull, receives branches from the upper cervical nerve (C-1).
These cervical fibers leave the nerve as the superior root of the ansa cervicalis.
Innervates the muscles of the tongue.