4 - Anterior triangle, thyroid and parathyroid Flashcards
(48 cards)
What are the borders of the anterior triangle?
- inferior border of mandible
- anterior border of SCM
- midline of neck
What forms the roof of the anterior triangle?
Deep investing cervical fascia around the muscles
What forms the floor of the anterior triangle?
Pretracheal fascia and carotid sheath
What are the subdivisions of the anterior triangle?
- submandibular
- submental
- carotid
- muscular (omotracheal)
What is contained in the submandibular triangle?
- digastric
- submandibular gland
- lymph nodes
- parts of CN XII (hypoglossal)
- mylohyoid nerve
- parts of facial artery and vein
What is contained in the submental triangle?
- submental lymph nodes
- small veins (unite to form anterior jugular)
What is contained in the carotid triangle?
- thyroid gland
- larynx
- pharynx
- carotid sheath
- branches of the cervical plexus
- superior root of the ansa cervicalis
- parts of CN XI and XII
- deep cervical lymph nodes
What is contained in the muscular triangle?
- sternohyoid
- sternothyroid
- thyroid
- parathyroid glands
What are the suprahyoid muscles?
- mylohyoid
- diagastric
- stylohyoid
- geniohyoid
What are the infrahyoid muscles?
- sternohyoid
- sternothyroid
- omohyoid
- thyrohyoid
What is the origin of mylohoid?
Mylohyoid line on mandible
What is the insertion of mylohyoid?
- body of the hyoid
- fibres of the opposite mylohyoid
What is the insertion of digastric?
Both bellies insert at the attachment of their intermediate tendon at hyoid (fascial sling)
What is the action of mylohyoid?
- elevate hyoid and the floor of the mouth
- reinforces floor of oral cavity
What is the action of the suprahyoid muscles?
- elevate the hyoid (swallowing)
- elevate the larynx (tone production)
- form floor the mouth
What is the origin of the digastric?
Anterior belly - digastric fossa on lower medial aspect of mandible
Posterior belly - mastoid notch of medial side of mastoid process
What is the action of the digastric?
Anterior belly - raises hyoid and opens mouth by lowering mandible
Posterior belly - elevates and retracts hyoid
What is innervation of mylohyoid?
CN V3, via inferior alveolar branch, “nerve to mylohyoid”
What is the innervation of digastric?
Anterior belly - nerve to mylohyoid (CN V3)
Posterior belly - digastric branch of CN VII
What is the origin of stylohyoid?
Styloid process
What is the insertion of stylohyoid?
Body of hyoid (laterally)
What is the innervation of stylohyoid?
CN VII
What is action of stylohyoid?
Pulls hyoid bone upwards (posterosuperior)
What is the origin of geniohyoid?
Inferior mental spine of mandible
