Unit 1 Triangles & Deep Structures of the Neck Flashcards
What is the anterior boundary of the posterior triangle?
Posterior border of the SCM
What is the posterior boundary of the posterior triangle?
Anterior border of the trapezius
What is the inferior boundary of the posterior triangle?
Superior border of the middle third of the clavicle
What is the superior boundary of the anterior triangle?
Inferior border of the mandible
What is the anterior boundary of the anterior triangle?
Anterior midline
What is the posterior boundary of the anterior triangle?
Anterior border of the SCM
Where is the apex of the anterior triangle located?
Inferiorly at the jugular notch
What is the roof of the anterior triangle formed by?
The investing layer of the deep cervical fascia, the superficial cervical fascia, and the platysma
What are the four subdivisions of the anterior triangle?
Submental, submandibular, carotid, and muscular triangles
Which subdivision of the anterior triangle is unpaired?
Submental
What are the boundaries of the submental triangle?
The left and right anterior bellies of digastric and the body of the hyoid bone
What makes up the floor of the submental triangle?
Mylohyoid muscle
What are the contents of the submental triangle?
Minor veins and lymph nodes
Which subdivision of the anterior triangle must be palpated carefully due to its vital structures?
Submandibular triangle
What are the boundaries of the submandibular (digastric) triangle?
Inferior border of the mandible, anterior belly of digastric, and posterior belly of digastric
What makes up the floor of the submandibular triangle?
Mylohyoid and hyoglossus muscles
What are the contents of the submandibular triangle?
Submandibular gland, internal carotid artery, facial artery, internal jugular vein, glossopharyngeal nerve, and vagus nerve
In what triangle does the common carotid artery bifurcate?
Carotid
What are the boundaries of the carotid triangle?
Posterior belly of digastric, superior belly of omohyoid, and the anterior border of SCM
What makes up the floor of the carotid triangle?
Portions of the thyrohyoid, hyoglossus, and inferior and middle constrictor muscles
What are the contents of the carotid triangle?
Parts of the common and internal carotid arteries the external carotid artery and three of its branches: the superior thyroid artery, lingual artery, and facial artery
What are the boundaries of the muscular triangle?
Superior belly of omohyoid, anterior midline of the neck, and the anterior border of SCM
What makes up the floor of the muscular triangle?
Posterior layer of pretracheal fascia
What are the contents of the muscular triangle?
Sternohyoid and sternothyroid muscles, thyroid gland, trachea, and esophagus
What is the hyoid bone located?
Between the mandible and larynx
What is the forensic significance of the hyoid bone?
Often broken in cases of strangulation
What part of the hyoid bone is the attachment site for the stylohyoid ligament?
Lesser horn
What are the four infrahyoid muscles?
Omohyoid, sternohyoid, sternothyroid, and thyrohyoid
What two infrahyoid muscles make up the superficial layer?
Omohyoid and sternohyoid
What two infrahyoid muscles make up the deep layer?
Sternothyroid and thyrohyoid
What is the origin of omohyoid?
Inferior belly of omohyoid originates from the upper border of the scapula. It ends in an intermediate tendon located deep to the SCM. The superior belly of omohyoid extends upward from this tendon
What is the insertion of omohyoid?
Body of the hyoid
What is the innervation of omohyoid?
Ansa cervicalis (C1-C3)
What is the function of omohyoid?
Depresses the hyoid bone and larynx
What is the origin of sternohyoid?
Posterior surface of the manubrium and the medial end of the clavicle
What is the insertion of sternohyoid?
Body of the hyoid bone
What is the innervation of sternohyoid?
Ansa cervicalis
What is the function of sternohyoid?
Depresses the hyoid bone and larynx
What is the origin of sternothyroid?
Posterior surface of the manubrium, inferior to the origin of the sterohyoid
What is the insertion of sternothyroid?
Oblique line on the lamina of the thyroid cartilage
What is the innervation of sternothyroid?
Ansa cervicalis
What is the function of sternothyroid?
Depresses the larynx
What is the origin of thyrohyoid?
Oblique line on the lamina of the thyroid cartilage
What is the insertion of thyrohyoid?
Body of the hyoid bone
What is the innervation of thyrohyoid?
C1 through hypoglossal nerve
What is the function of thyrohyoid?
Depresses the hyoid bone
Why else do we need all these muscles to depress the hyoid bone and larynx (infrahyoid muscles)?
Swallowing, speech, breathing
If the hyoid bone is fixed, how is the mouth opened?
Digastric depressed the mandible
What are the four subdivisions of the deep cervical fascia of the neck?
Investing layer, pretracheal, prevertebral, and carotid sheath
Which subdivision of the deep cervical fascia encloses the SCM and trapezius?
Investing layer
What subdivision of the deep cervical fascia encloses the thyroid gland, trachea, and esophagus?
Pretracheal
What subdivision of the deep cervical fascia encloses the vertebral column and the deep muscles of the back?
Prevertebral fascia
What does the carotid sheath enclose?
Common carotid artery, internal carotid artery, internal jugular vein, vagus nerve, and deep cervical lymph nodes
What is the function of the fascial layers of the neck?
To provide a slippery surface to reduce friction during gross movements of the head and neck and swallowing
What can happen to the fascial layers of the neck leading to neck pain?
Adhesion of the layers (myofacial release helps with this)
What is the clinical significance of the fascial layers of the neck?
May serve as a channel for infection, cancer of the deep cervical lymph nodes can compress the internal jugular vein (ICP)
Infection in the pretracheal fascia can travel where?
To the mediastinum
What is the superior thoracic aperture (thoracic inlet)?
Opening through which structures of the neck pass into the thorax
What are the boundaries of the superior thoracic aperture?
First thoracic vertebra, first ribs and their cartilages, manubrium of sternum
What is the shape of the superior thoracic aperture?
Reniform
What major arteries pass through the superior thoracic aperture?
Brachiocephalic trunk, left common carotid artery, left subclavian artery, internal thoracic artery
What vein passes through the superior thoracic aperture?
Brachiocephalic
What nerves pass through the superior thoracic aperture?
Phrenic, vagus, and recurrent laryngeal nerves, sympathetic trunk
What viscera passes through the superior thoracic aperture?
Trachea, esophagus, cervical pleura, apex of lung, thymus
Because the apex of the lung is within the superior thoracic inlet, what can occur when a broken first rib or penetrating wound to the neck?
Atelectasis (lung collapse)
The thymus is a part of what body system?
Immune
What does the thymus produce?
T-lymphocytes
What happens to the thymus gradually after puberty?
Involutes (thus a reduced immune response with age)
Where is the thymus located?
Behind the manubrium and body of sternum
What muscles lie anterior to the thymus and thyoid glands?
Sternothyroid and sternohyoid
The thymus is inferior to which gland?
Thyroid
What is the blood supply of the thymus gland?
Internal thoracic artery
What is the innervation for the thymus gland?
Stellate ganglion of sympathetic trunk and vagus
What does thyroid mean in Greek?
Shield-shaped
What types of organ is the thyroid gland?
Endocrine
What does the thyroid gland produce?
Thyroxine and calcitonin
Which substance made in the thyroid gland is mainly active in children?
Calcitonin
At what vertebral level does the thyroid gland lie?
C5-T1
What is the typical shape of the thyroid gland?
H or U-shaped
How could one live without the thyroid gland?
Thyroxine tablets
Secretions from the thyroid gland enter what to carry out its endocrine function?
Bloodstream
What connects the right and lefts lobes of the thyroid gland?
Isthmus
About what percent of thyroid glands also have a pyramidal lobe?
50
What is a common muscular variation involving the thyroid gland?
Levator glandulae thyroideae connecting the isthmus with the hyoid bone
What is the innervation of levator glandulae thyroideae?
Ansa cervicalis
Which gland of the neck is known for being highly vascular?
Thyroid
What two arteries are associated with the thyroid gland?
Superior and inferior thyroid arteries
The superior thyroid artery is a branch from where?
External carotid
The inferior thyroid artery is a branch from where?
Thyrocervical trunk
What artery to the thyroid gland from the brachiocephalic trunk is an anatomical variation found in only 10% of the population?
Thyroid ima artery
What is significant about the thyroid ima artery?
May be damaged during a tracheotomy
What are the veins associated with the thyroid gland?
Superior, middle, and inferior thyroid veins
Where does the superior thyroid vein drain into?
Internal jugular
Where does the middle thyroid vein drain into?
Internal jugular
Where does the inferior thyroid vein drain into?
Brachiocephalic
What is the innervation of the thyroid gland?
Superior, middle, and inferior cervical sympathetic ganglia
What is the clinical term for an abnormal enlargement of the thyroid gland that produces swelling in the anterior neck?
Goiter
What type of goiter is due to dietary deficiency of iodine which is needed to make thyroxine?
Endemic
In what type of goiter does the thyroid gland enlarge to increase output but the hormone is largely inactive?
Thyroid
Feeling cold, moon face, and weight gain (symptoms of hypothyroidism) are associated with which type of goiter?
Endemic
What type of goiter is typically present among vegetarians?
Endemic
What type of goiter is due to an autoimmune disease?
Exophtalmic
What type of goiter is more prevalent among females?
Exophtalmic
In what type of goiter do thyroid stimulating immunoglobulins bind to the receptor site causing overactivity of the gland?
Exophtalmic
With what type of goiter is the hormone ACTIVE?
Exophtalmic
What type of goiter shows signs of hyperthyroidism (Grave’s disease)?
Exophtalmic
What is the most important nerve of the neck?
Recurrent laryngeal
What nerve lies first on the posterior surface of the thyroid lobe then deep to it?
Recurrent laryngeal
What glands are essential for life due to its role in calcium regulation?
Parathyroid
What type of glands (functionally) are the parathyroids?
Endocrine
Where are the parathyroid glands located?
Posterior surface of the thyroid gland
How many parathyroid glands are there usually?
4 (could be from 2-6, however)
What arteries supply the parathyroid glands?
Inferior and superior thyroid arteries
What is the innervation for the parathyroid glands?
Inferior or middle cervical sympathetic ganglia
What three things make thyroid surgery quite difficult?
Presence of parathyroid glands, highly vascular, Presence of recurrent laryngeal nerve
What can be an alternative to thyroid surgery?
Radioactive iodine
What is the lay term for the trachea?
Windpipe
At what vertebral level does the trachea begin?
C6 (same as pharynx)
What supports the tracheal walls?
Cartilaginous rings opened posteriorly
Why is it important that the rings be made of cartilage and not bone?
Movement necessary for breathing
What smooth muscle spans the posterior opening of the cartilaginous rings of the trachea?
Trachealis
What is the blood supply to the trachea?
Inferior thyroid artery
What is the innervation of the trachea?
Recurrent laryngeal nerve
What else does the opening of the trachea allow?
Expansion of the esophagus posteriorly during swallowing
What two things does the esophagus connect?
Pharynx and stomach
At what vertebral level does the esophagus begin?
C6
Where is the esophagus located?
Posterior to the trachea
Which branch of the common carotid artery lies more anterior?
External carotid
What branch of the common carotid artery lies more posterior?
Internal carotid
Which branch of the common carotid artery is accompanied by numerous branches?
External
Which branch of the common carotid artery enters the skull through the carotid canal to supply blood to the brain?
Internal carotid
Which branch of the common carotid artery is the main source of blood to the structures of the neck, face, and scalp?
External carotid
What are the eight branches of the external carotid artery?
Superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, superficial temporal, and maxillary arteries
Which branches of the external carotid artery represent the terminal branches of the external carotid artery?
Superficial temporal and maxillary
What is the slight dilation of the internal carotid artery where it joins the common carotid artery typically called?
Carotid sinus
What is the innervation of the carotid sinus?
Carotid sinus nerve (branch of the glossopharyngeal nerve)
What is the function of the carotid sinus?
Acts as a baroreceptor to detect blood pressure and adjust heart rate accordingly (increase BP = decrease HR)
What is the small reddish-brown mass located within or deep to the bifurcation of the common carotid artery?
Carotid body
What is the function of the carotid body?
Acts as a chemoreceptor to detect changes in the chemical makeup of the blood within the carotid (ex: decrease or increase of CO2 leads to increase rate of ventilation)
What is the innervation of the carotid body?
Carotid sinus branch of the glossopharyngeal nerve
What is usually the largest vein of the neck?
Internal jugular
Where does the internal jugular vein drain?
Brachiocephalic
What is the superior jugular bulb?
Dilation of the internal jugular vein at its origin below the jugular foramen
Where does the internal jugular vein begin?
Jugular foramen (continuation of the sigmoid sinus)
What are the tributaries of the internal jugular vein?
Inferior petrosal sinus, pharyngeal veins, facial, lingual, superior and middle thyroid veins
The internal jugular vein lies deep to which muscle?
SCM
What is the inferior jugular bulb?
Dilation of the internal jugular vein near its termination into the brachiocephalic vein
