Anterior Triangle Flashcards
borders of anterior triangle
inferior border of mandible
anterior border of SCM
midline of neck
roof and floor of anterior triangle
roof: deep investing fascia around muscles
floor: pretracheal fascia and carotid sheath (posterolaterally)
subdivisions of anterior triangle
submandibular
submental
carotid
omotracheal
what is in submandibular triangle
submandibular gland, lymph nodes, part of hypoglossal nerve (CN VII), mylohyoid nerve, parts of facial artery and vein
what is in submental triangle
submental lymph nodes, small veins that unite to form anterior jugular vein
what is in the carotid triangle
parts of thyroid gland, larynx & pharynx, common and internal carotid artery, internal jugular vein and vagus nerve
what is in omotracheal triangle
sternohyoid and sternothyroid muscles, larger part of thyroid and parathyroid glands
where are the suprahyoid muscles found
located superiorly to the hyoid bone
what do suprahyoid muscles connect to
connect to the skull / mandible as well as the hyoid
what are the suprahyoid muscles
mylohyoid
digastric (right & left)
stylohyoid
geniohyoid
where are the infrahyoid muscles found
located inferiorly to the hyoid bone
what do the infrahyoid muscles attach to
attach to sternum , scapula and thyroid cartilage also hyoid bone but there is 1 exception
what are the infrahyoid muscles
sternohyoid
omohyoid
thyrohyoid
sternothyroid
which infra / suprahyoid muscle does not attach to the hyoid
sternothyroid
group function of suprahyoid muscles
to raise the hyoid during swallowing & to elevate the pharynx during tone production
origin and insertion of mylohyoid
origin - mylohyoid line on the mandible
insertion - body of hyoid
action of mylohyoid
to elevate the hyoid & floor of the mouth
digastric muscle origin & insertion
right & left digastric each have an anterior & posterior belly
anterior - originates at lower medial aspect of mandible
posterior - originates on medial side of mastoid process
insertion of both is the hyoid bone
function of anterior belly of digastric muscle
raises the hyoid & opens mouth by lowering the mandible
function of posterior belly of digastric
elevates and retracts the hyoid bone
innervation of mylohyoid & anterior belly of digastric
CN V3 inferior alveolar branch known as nerve to mylohyoid
innervation of posterior belly of digastric
digastric branch of facial nerve (CN VII)
origin and insertion of stylohyoid
origin: styloid process of skull
insertion: body of hyoid from lateral side
function of stylohyoid
to elevate hyoid in posterosuperior direction
innervation of stylohyoid
via facial nerve CN VII
origin and insertion of geniohyoid
origin: mandible
insertion: body of hyoid superiorly to mylohyoid
innervation of geniohyoid
anterior ramus of C1 which travels with hypoglossal nerve CN XII
function of geniohyoid
if mandible is fixed - elevates + moves hyoid in a forwards direction
if hyoid is fixed - acts to pull mandible down and inwards
group function of infrahyoid muscles
depress or fix hyoid bone & provide attachment for suprahyoid muscles
what 2 planes can infrahyoid muscles be separated into
- superficial - sternohyoid & omohyoid
- deep - sternothyroid & thyrohyoid
origin and insertion of sternohyoid
origin: posterior surface of sternoclavicular joint
insertion: body of hyoid medially
action of sternohyoid
acts to depress hyoid after it has been elevated for swallowing
how are superior & inferior omohyoid bellies connected
by an intermediate tendon