This document describes the anatomy of the anterior triangle of the neck, including the digastric triangle and submandibular triangle. The digastric triangle is bounded above by the lower border of the mandible and behind by the posterior belly of the digastric muscle. It contains the submandibular gland, facial vein, facial artery and branches, submandibular lymph nodes, and parts of cranial nerves. The submandibular triangle is below the body of the hyoid bone, bounded by the anterior bellies of the digastric muscles. It contains submental lymph nodes and branches of the anterior jugular veins. Infrahyoid muscles such as the omo

1. ANTERIOR
TRIANGLE OF NECK
–II
DR. SUNDIP CHARMODE
ASSOCIATE PROFESSOR
DEPARTMENT OF ANATOMY
AIIMS RAJKOT

2. DIGASTRIC TRIANGLE
• Above: Lower border of body of mandible and line
extending from angle of mandible to mastoid process
• Below and behind: Posterior belly of digastric and
stylohyoid
• Below and front: Anterior belly of digastric

5. DIGASTRIC TRIANGLE
ROOF
• Skin
• Superficial fascia
containing platysma
• Cervical branch of the
facial nerve
• Transverse cutaneous
nerve of neck
• Deep cervical fascia
splits to enclose
submandibular gland

6. DIGASTRIC TRIANGLE
FLOOR
• Anteriorly:
Mylohyoid
• Posteriorly:
Hyoglossus
• Still posteriorly:
Middle constrictor
of pharynx

8. DIGASTRIC TRIANGLE
• Digastric triangle/Submandibular triangle is subdivided
by stylo-mandibular ligament into:
• Anterior part and
• Posterior part

10. ANTERIOR PART - CONTENTS
1. Superficial part of submandibular gland
2. Facial vein
3. Submandibular lymph nodes
4. Facial artery
5. Mylohyoid vessels and nerve
6. A part of hypoglossal nerve

20. FACIAL VEIN & SM LYMPH NODES
• Facial vein and submandibular lymph nodes lie
superficial to gland
• Nodes are clinically important:
– Wide area of drainage
– Enlarged in infection or metastatic spread

24. FACIAL ARTERY
• Facial artery lies deep to gland
• winds around lower border of mandible
• Ascending part of loop – lodges in a groove
• Descending part of loop – between gland & fossa
• Summit of loop – rests on superior constrictor

25. FACIAL ARTERY - BRANCHES
• At summit of loop of facial artery – gives Ascending
palatine and Inferior tonsillar arteries
• At lower border of mandible:
– Gives Sub-mental branch
– Crossed by marginal mandibular branch

30. MYLOHYOID VESSELS AND NERVE
• Mylohyoid nerve – branch of inferior alveolar branch
of mandibular nerve
• Mylohyoid vessels- branches of third part of
maxillary artery
• They pass undercover of gland and supply mylohyoid
muscle and anterior belly of digastric muscle.

31. MYLOHYOID VESSELS

32. MYLOHYOID NERVE

33. POSTERIOR PART - CONTENTS
1. Lower part of parotid gland – overlap the posterior
belly of digastric
2. External carotid artery: Enters parotid gland
3. Carotid sheath containing ICA, IJV and Vagus nerve:
Pass deep beneath the parotid gland and styloid
process

36. SUB-MENTAL TRIANGLE
BOUNDARIES
• Apex: Lower border of Symphysis Menti
• Base: Body of Hyoid bone
• Sides: Anterior belly of Digastric muscles of both
sides
• Floor: Mylohyoid muscles meeting at a median
fibrous raphe forming the Diaphragma oris.

40. CONTENTS
1. Sub-mental lymph nodes:
– 3-4 in number
– In superficial fascia below the chin
– Drains lymph from central part of lower lip,
adjoining gum, floor of mouth, tip of tongue.
2. Commencement of Anterior Jugular veins

41. MUSCLES OF FRONT REGION OF NECK
1. Supra-hyoid muscles
1. Digastric
2. Geniohyoid
3. Stylohyoid
4. Mylohyoid
2. Infra-hyoid muscles
1. Omohyoid
2. Thyrohyoid
3. Sternothyroid
4. Sternohyoid

42. INFRA-HYOID MUSCLES/RECTUS
CERVICIS
• Arranged in superficial and deep planes
• Morphologically correspond rectus abdominis
• Supplied by C1, C2, C3 via hypoglossal nerve and
ansa cervicalis

43. INFRA-HYOID MUSCLES

48. SUPRA-HYOID MUSCLES
STERNOHYOID
• O – Posterior aspect of
OMOHYOID

54. CLINICAL CORRELATION
• Wry neck – deformity of neck caused due to shortening
of sternocleidomastoid
• Torticollis - repeated painful contractions of SCM and
trapezius of one side.
• Posterior belly of digastric:
– Key muscle of neck
– Vagus, accessory and hypoglossal nerves pass under it
– ICA, IJV and ECA pass under it

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