Anterior Triangle of the Neck (1) Flashcards
what is the roof of the anterior triangle of the neck
deep investing fascia around muscles
what is the floor of the anterior triangle
pretracheal fascia and the carotid sheath
what are the subdivisions of the anterior triangle
submandibular, submental, carotid and muscular
what is the superior border of the anterior triangle
inferior border of the mandible
what is the posterior border of the anterior triangle
the anterior triangle of the sternocleidomastoid
what is the anterior border of the anterior triangle
midline of neck
what structures are contained in the submandibular region
submandibular gland, lymph nodes, parts of CN XII, mylohyoid nerve and parts of the facial artery and vein
what structures are contained in the submental region
submental lymph nodes and small veins that unite to form the anterior jugular vein
what structures are contained in the carotid region
thyroid gland, larynx, pharynx, carotid sheath, branches of cervical plexus, superior root of ansa cervicalis, parts of CN XI and CN XII and deep cervical lymph nodes
what structures are contained in the muscular region of the anterior triangle
sternohyoid, sternothryoid muscles, thyroid and parathyroid glands
name the suprahyoid muscles (4)
mylohyoid
digastric
stylohyoid
geniohyoid
name the infrahyoid muscles (4)
sternohyoid
omohyoid
thyrohyoid
sternothyroid
what is the origin and insertion of the mylohyoid
origin - mylohyoid line on mandible
insertion - body of hyoid bone and fibres of opposite mylohyoid
what is the action of the mylohyoid
elevates the hyoid and floor of the mouth and reinforces floor of oral cavity
what is the origin points of the digastric
anterior belly - digastric fossa on lower medical aspect of mandible
posterior belly - mastoid notch on medial side of mastoid process
what is the insertion point of the digastric
attachment of intermediate tendon at hyoid
what is the function of the anterior belly of digastric
raises hyoid bone and opens mouth by lowering the mandible
what is the function of the posterior belly of the digastric
elevates and retracts the hyoid bone
what nerve innervates the mylohyoid
the mandibular branch of the trigeminal nerve (nerve to the mylohyoid)
what is the anterior belly of digastric muscle innervated by
nerve to mylohyoid (V3)
what is the posterior belly of the digastric innervated by
digastric branch of the facial nerve
origin and insertion points of stylohyoid
O = styloid process
I - = body of hyoid
innervation of stylohyoid
facial nerve
action of the stylohyoid
pulls hyoid bone upwards
origin and insertion of geniohyoid
O = mandible
I = body of hyoid
action of geniohyoid
elevates and pulls hyoid forward (fixed mandible)
pulls mandible down and inward (fixed hyoid)
innervation of geniohyoid
anterior ramus of C1
what cranial nerve does the anterior ramus of C1
CN XII
what is the group function of the strap muscles
fix hyoid bone and provide attachments for suprahyoid muscles
origin and insertion of sternohyoid
O = posterior surface of sternoclavicular joint of manubrium
I = body of hyoid medially
action of sternohyoid
depress hyoid after elevation due to swallowing
origin and insertion of superior belly of omohyoid
O = intermediate tendon
I = body of hyoid laterally
origin and insertion of inferior belly of omohyoid
O = superior border of scapula
I = intermediate tendon
action of omohyoid
depresses and fixes hyoid bone
origin and insertion of thyrohyoid
O = oblique line of thyroid cartilage
I = greater horn and adjacent body of hyoid
action of thyrohyoid
depresses hyoid and can raise larynx when hyoid is fixed
origin and insertion of sternothyroid
O = posterior surface of manubrium
I = oblique line on thyroid catrilage
action of sternothyroid
draws larynx downward
what muscles do the anterior rami of C1 to C3 innervate through ansa cervicalis
sternohyoid, omohyoid and sternothyroid
what is the thyrohyoid innervated by
anterior rami of C1 but fibres run with CN XII
what is found in the thyroid gland between the left and right lobes
isthmus
what is the pyramidal lobe and where is it
midline
remnant of thyroglossal duct
what arteries supply the thyroid
superior thyroid artery and inferior thyroid artery
what is the venous drainage to the thyroid
superior thyroid vein
middle thyroid vein
inferior thyroid vein
where does the superior thyroid artery arise from
the external carotid artery
where does the inferior thyroid artery arise from
thyrocervical trunk from the subclavian artery
where does the superior thyroid vein and middle thyroid vein drain into
inferior jugular vein
where does the inferior thyroid vein drain into
brachiocephalic vein
what is there in around 10% of the population regarding a vessel of the thyroid
thyroid IMA artery
what is the thyroid IMA artery
small and unpaired arising from brachiocephalic
where are the parathyroid glands usually found
posterior surface of the thyroid - but variable
what is the arterial supply to parathyroid glands
inferior thyroid arteries - branches of thyrocervical trunk from subclavian
what are the thyroid and parathyroid glands innervated by
cervical sympathetic ganglia
what other nerves are closely associated with the thyroid gland
recurrent laryngeal nerves (L and R) from CN X
what could occur as a result of damage to the recurrent laryngeal nerve
hoarseness or aphonia
what is a cricothyrotomy
emergency procedure - needle passed through cricothyroid ligament
what is a tracheostomy
surgical airway - retraction of infrahyoid muscles and incision of thyroid at isthmus