Anterior Triangle Flashcards
What are the general boundaries of the anterior triangle
- superiorly - inferior border of the mandible
- laterally - anterior border of the Sternocleidomastoid
- medially - sagital line down the midline of the neck
What covers the roof of the anterior triangle
Investing fascia
What covers the flow of the anterior triangle
Visceral fasia
What is contained in the anterior triangle
- muscles
- nerves
- arteries
- veins
- lymph nodes
How are the muscles in the neck divided
They are divided as to where they lie in relation to the hyoid bone
What muscles are located superiorly to the hyoid bone
Suprahyoid muscles located superiorly
What muscles are located inferiority to the hyoid bone
Infrahyoid muscles
What blood vessels are found in the anterior triangle
Common carotid artery bifurcates within the triangle into the external and internal carotid branches, the internal jugular vein can also be found here
What cranial nerves are found in the anterior triangle
Facial (VII), glossopharyngeal (IX), vagus (X), accessory (XI) and hypoglossal (XII)
What are the suprahyoid muscles
- stylohyoid
- digastric
- mylohyoid
- geniohyoid
What are the infrahyoid muscles
- omohyoid, sternohyoid, thyrohyoid, sternothyroid
The anterior triangle is divided into … triangles
4
What are the 4 subdivisions of the anterior triangle
- carotid triangle
- submental triangle
- submandibular triangle
- muscular triangle
Describe the carotid triangle
Boundaries
- superior - posterior belly of the digastric muscle
- lateral - medial border of the Sternocleidomastoid muscle
- inferior - superior belly of the omohyoid muscle
What are the main contents of the carotid triangle
- common carotid artery
- internal jugular vein
- hypoglossal and vagus nerve
Describe the submental triangle
- situated underneath the chin
- contains the submental lymph nodes
Bounded - inferiority - hyoid bone
- medially - midline of the neck
- laterally - anterior belly of the digastric
What is the floor of the submental triangle formed by
The mylohyoid muscle
Describe the submandibular triangle
- located underneath the body of the mandible
- contains submandibular gland
- the facial artery and vein pass through here
Boundaries - superior - body of the mandible
- anteriorly - anterior belly of the digastric muscle
- posteriorly - posterior belly of the digastric muscle
Explain the muscular triangle
Situated more inferiority than the subdivisions
Four boundaries -
- medially - midline of the neck
- superio-laterally - superior belly of the omohyoid muscle
- inferio-laterally - inferior portion of the Sternocleidomastoid muscle
What does the muscular triangle contain
- infrahyoid muscle
- pharynx, thyroid, parathyroid
What general muscles are found in the anterior triangle
Mylohyoid
Anterior belly of digastric
Infrahyoid
What is the function of the mylohyoid muscles
Forms the floor of the mouth, arises from the mandible and attaches onto the hyoid bone and floor of the mouth
Explain the anterior belly of digastric muscle
One of two muscles ( posterior one too) arises from mandible and passes to the mastoid process, pulls down the mandible and raises the hyoid bone
Explain the infrahyoid muscles
Named after where they attach, depress hyoid bone and the larynx, or pull it down during swallowing (degultition) and speaking
What are the skeletal elements of the anterior triangle
- thyroid cartilage
- cricoid cartilage (only one that wraps around the larynx)
- hyoid bone
How many laryngeal cartilages are there
9
What glands are contained within the anterior triangle
- thyroid gland
- parathyroid glands
- submandibular glands
What does the thyroid gland secrete
Thyroid hormones T3 and T4
What is the role of the thyroid hormones
- raise metabolic rate
- influences synthesis of proteins
- responsible for nerve growth and development
What are the two lobes of the thyroid gland linked by
Isthmus
What is the pyramidal lobe
Embryological remmenet of where the thyroid gland developed at the foramen caecum of the tongue
What nerves innervate the anterior triangle
- vagus
- phrenic
- hypoglossal
What is the role of the vagus nerve
Innervates muscles of the larynx, pharynx and soft palate
What are the sensory roles of the vagus nerve
Taste in epiglottis and roof of the tongue
