Triangles of the Neck/Root of the Neck
Terms in this set (49)
What is the key landmark in the neck?;
The sternocleidomastoid muscle.
What are the boundaries of the anterior triangle of the neck? ;
Superior: inferior border of the mandible; posterior: anterior border of the sternocleidomastoid; anterior: an imaginary midline drawn vertically through the neck.
What are the three divisions of the deep cervical fascia?;
From superficial to deep: the investing layer of deep cervical fascia; the pretracheal fascia, and the prevertebral fascia.
Which of these fascial divisions are related to the anterior triangle? ;
The investing layer forms the roof and the pretracheal layer (as well as the middle layer of cervical facsia that harnesses the infrahyoid mm.) forms the floor of the anterior triangle.
Why is the lower extent of these fasciae clinically important? ;
These fascial layers extend down into the thorax and allow for "tracking" of pus/infection from the head and neck down into the thorax.
Which spinal cord levels are involved in the cervical plexus?
What are the sensory branches of the cervical plexus?
The lesser occipital, great auricular, transverse cervical and supraclavicular nn. (note that C1 has NO sensory contribution to the plexus)
Where is a cervical block administered? Why?
About 1/2 the way up the posterior border of the sternocleidomastoid. The bolus of anesthestic diffuses around the point of exit of the nerves of the cervical plexus from behind the muscle.
What muscles form the floor of the posterior triangle?
From anterior to posterior - Scalenus anterior, scalenus medius, levator scapulae, splenius capitis, semispinalis capitis
What are the boundaries of the Submandibular triangle?
anterior and posterior bellies of the digastric and the inferior border of the mandible;
What are the boundaries of the Submental triangle?
anterior bellies of contralateral digastric mm. and the hyoid bone;
What are the boundaries of the Carotid triangle?
posterior belly of digastric, anterior border of the sternocleidomastoid and the lateral border of the superior belly of the omohyoid;
What are the boundaries of the Muscular triangle?
medial border of the superior belly of the omohyoid, anterior border of the sternocleidomastoid and the imaginary vertical midline axis of the neck.
List the important structural contents of the submandibular triangle?
the submandibular gland, facial artery and lymph nodes
List the important structural contents of the submental triangle?
List the important structural contents of the carotid triangle?
common carotid artery, internal jugular vein, vagus nerve, and hypoglossal nerve
List the important structural contents of the muscular triangle?
nothing - midline viscera located below the muscular floor.
List the suprahyoid muscles:
Anterior belly of digastric, posterior belly of digastric, stylohyoid, mylohyoid, and geniohyoid.
What innervates the Anterior belly of digastric ?
n. to the mylohyoid - V3
What innervates the posterior belly of digastric ?
facial n. - VII
What innervates the stylohyoid ?
facial n. - VII
What innervates the mylohyoid ?
n. to the mylohyoid - V3
What innervates the geniohyoid ?
C1 via XII
List the infrahyoid muscles:
Sternohyoid , (superior belly of) omohyoid, sternothyroid and the thyrohyoid
What innervates the Sternohyoid ?
What innervates the (superior belly of the) omohyoid ?
What innervates the sternothyroid ?
What innervates the thyrohyoid ?
C1 via XII
What are the superficial groups of the infrahyoids?
sternohyoid and omohyoid
What are the deep groups of the infrahyoids?
sternothyroid and thyrohyoid
What is the function of the suprahyoid muscles.?
With the hyoid bone stabilized by the infrahyoids, the suprahyoids act as accessory mm. of mastication by assisting in depression of the mandible.
What is the function of the infrahyoid muscles.?
With the hyoid stabilized by the suprahyoids, the infrahyoids assist in elevating the larynx during swallowing.
How is the ansa cervicalis formed?
From the descendens hypopglossus (superior root) from C1 fusing with the descendens cervicalis (inferior root) from C2/3.
Over what structure is the ansa formed?
The internal jugular vein within the carotid sheath
What does the ansa do?
It supplies 3 of the 4 infrahyoid muscles of the neck with motor innervation.
Which branches form the descendens cervicalis
Contributions from C2 and C3
What are the contents of the carotid sheath?
The common carotid artery, internal jugular vein and the vagus nerve
Which of the contents of the carotis sheath lies on the medially? on the laterally? and posteriorly?
Medially - common carotid artery, Laterally - internal jugular vein and Posteriorly - vagus nerve.
Which cranial nn. have an anatomical relationship with the branches of the external carotid?
The accessory nerve (XI) swing posteriorly over the internal jugular vein. The hypopglossal nerve (XII) swings anteriorly over the top of the external carotid a. and hooks just under the lingual artery.
The carotid sinus is
a swelling on the initial portion of the internal carotid. It is a baroreceptor regulating blood pressure the thinner walled cerebral artery. and It is innervated principally by the glossopharyngeal nerve (CN IX).
The carotid body is
found in the birfucation of the common carotid, is a chemoreceptor that senses the CO2 content of the blood (increasing respiration if CO2 content is high) and is innervated by CN IX and X.
List the sources of blood supply to the thyroid gland
Superior thyroid (off external carotid); inferior thyroid (off the thyrocervical trunk) and thyroidea ima artery (off the arch of the aorta).
Why is the thyroid richly supplied with blood?
It is an endocrine organ (an organ that secretes hormones into the bloodstream).
What is the relationship of the parathyroids to the thyroid gland?
They are embedded into the posterior region of the capsule of the thyroid gland.
Name one other clinically important relationship in the posterior region of the thyroid.
The recurrent laryngeal nerves run behind the lobes of the thyroid on their way to the larynx. Thyroidectomy with damage to these nerves results in either hoarseness (one nerve cut) to inability to speak (both nerves cut).
What is the functional significance of the deep cervical group of lymph nodes?
They are the destination for all the superficial lymph drainage from the head and neck and are less palpable (deeper in location) than the superficial groups.
Where are the deep cervical nodes located?
They run inside the carotid sheath close to the internal jugular vein.
Which groups of superficial nodes can be palpated under the inferior border of the mandible?
The submental (under the apex) and the submandibular (under the lateral aspects).
What regions do these submandibular lymph nodes drain?
Tongue, lips, nose, oral regions and the submandibular glands