Anterior Triangle

Question 1

Boundaries of Digastric Triangle and contents.

Answer 1

• Anteroinferiorly : Anterior belly of digastric muscle.
• Posteroinferiorly Posterior belly of digastric muscle and stylohyoid muscle.
• Base: base of the mandible and imaginary line joining the angle of the mandible to the mastoid process.
• Apex: intermediate tendon of digastric muscle, bound down to hyoid bone by a fascial sling derived from investing layer of deep cervical fascia.

CONTENTS:
Anterior part of the triangle:
1. Submandibular salivary gland.
2. Submandibular lymph nodes.
3. Hypoglossal nerve.
4. Facial vein (lies superficial to the gland).
5. Facial artery (lies deep to the gland).
6. Submental artery.
7. Mylohyoid nerve and vessels.

Posterior part of the triangle:
1. External carotid artery.
2. Carotid sheath and its contents.
3. Structures passing between the external and internal
carotid arteries

Question 2

Boundaries and contents of Submental triangle.

Answer 2

1. On each side: Anterior belly of digastric muscle. Base: Body of hyoid bone.
2. Apex: Symphysis menti.
3. Floor: It is formed by the two mylohyoid muscles meeting at the median fibrous raphe extending from symphysis menti to the hyoid bone.
4. Roof :Investing layer of deep cervical fascia.

CONTENTS

1. Submental lymph nodes
2. Submental veins which join to form Anterior jugular veins

Question 3

Contents of carotid triangle.

Answer 3

1. Common carotid artery which divides into the Internal and External carotid arteries.
2. Carotid sinus and carotid body.
3. Internal jugular vein.
4. Last three cranial nerves
   (a) Vagus (b) Spinal accessory (c) Hypoglossal.
5. Carotid sheath
6. Ansa cervicalis.
7. Cervical part of the sympathetic chain. 8. Deep cervical lymph nodes.