Unit I Triangles of the Neck Flashcards
The SCM, when viewed laterally, divides these two triangles
the anterior and posterior triangles
The anterior boundary of the posterior triangle is
the posterior border of the SCM
the posterior boundary of the posterior triangle is
the anterior border of the trapezius
The inferior boundary of the inferior triangle is
the superior border of the middle 1/3 of the clavicle
The superior boundary of the anterior triangle is
the inferior border of the mandible
The anterior border of the anterior triangle is
the anterior midline
The posterior border of the anterior triangle is
the anterior border of the SCM
List the subdivisions of the anterior triangle
submental, submandibular (digastric), carotid, and muscular triangles
What is the only unpaired triangle of the subdivisions of the anterior traingle?
the submental triangle
List the boundaries of the submental triangle
left and right anterior bellies of the digastric, and the body of the hyoid
What is the floor of the submental triangle?
the mylohyoid muscle
What is contained in the submental triangle?
minor veins and lymph nodes
What are the boundaries of the submandibular triangle?
inferior border of mandible, anterior belly of the digastric, and the posterior belly of the digastric
What is the floor of the submandibular triangle?
mylohyoid and hyoglossus muscles
What is contained in the submandibular triangle?
the submandibular gland, internal carotid artery, facial artery, internal jugular vein, glossopharyngeal nerve (CN IX), and vagus nerve (CN X)
What are the boundaries of the carotid triangle?
the posterior belly of digastric, superior belly of omohyoid, and anterior border of the SCM
What makes the floor of the carotid triangle?
portions of the thyrohyoid, hyoglossus, and inferior and middle contrictor muscles
What is contained within the carotid triangle?
parts of the common and internal carotid arteries, the external carotid artery and three of its branches, and tributaries of the internal jugular vein.
What are the three branches of the external carotid artery included within the cartoid traingle?
superior thryroid artery, lingual artery, and facial artery
What are the boundaries of the muscular triangle?
superior belly of omohyoid, anterior midline of the neck, and anterior border of the SCM
What makes the floor of the muscular triangle?
posterior layer of the pretracheal fascia
What is contained within the muscular triangle?
sternohyoid and sternothyroid muscles, thyroid gland, trachea, and esophagus
What bone is often broken in strangulation cases of murder?
the hyoid bone
Where is the hyoid located?
between the mandible and larynx
What is the primary function of the infrahyoid muscle?
they move the hyoid and larynx
List the infrahyoid muscles
omohyoid, sternohyoid, sternothyroid, and thyrohyoid
What muscles make up the superficial layer of the infrahyoid muscles?
omohyoid and sternohyoid
What muscles make up the deep layer of the infrahyoid muscles?
sternohyoid and sternothyroid
What is the origin of the inferior belly of the omohyoid?
the upper border of the sacpula
Where does the inferior belly of the omohyoid end?
an intermediate tendon deep to the SCM
What is the origin of the superior belly of the omohyoid?
it extends upwards from the intermediate tendon where the inferior belly ends
What is th insertion of the omohyoid?
body of the hyoid bone
What is the innervation of the omohyoid?
the ansa cervicalis (C1-C3)
Function of the omohyoid
depresses hyoid and larynx
Origin of the sternohyoid
posterior surface of manubrium, and medial end of the clavicle
Insertion of the sternohyoid
body of the hyoid
Innervation of the sternohyoid
ansa cervicalis (C1-C3)
Function of the sternohyoid
depresses hyoid and larynx
Origin of the sternothyroid
posterior surface of manubrium, and inferior to origin of sternohyoid
Insertion of sternothyroid
oblique line on lamina of thyroid cartilage
Innervation of sternothyroid
ansa cervicalis (C1-C3)
Function of sternothyroid
depresses the larynx
Origin of thyrohyoid
oblique line on lamina of thyroid cartilage
Insertion of thyrohyoid
body of hyoid
Innervation of thyrohyoid
C1 through hypoglossal
Function of thyrohyoid
depresses hyoid bone
Why do we need the muscles to depress the hyoid and larynx?
Swallowing, talking, respiration, and if hyoid is fixed, the digastric depresses the mandible