Triangular Compartments Of The Neck Flashcards
What is the innervation of the plastysma muscle and when is it seen?
It is innervated by a branch of the facial nerve (CN VII).
It is seen when contracted in activities such as shaving
Where are the vocal cords located?
At the level of the middle of the thyroid cartilage
Where is the laryngeal prominence (Adams apple) of the thyroid cartilage of the larynx located?
In the midline
Can be felt when looking up and palpating the neck from superior to inferior
Where is the cricoid cartilage located?
Immediately belo the laryngeal prominence, follow by the trachea
Where is the hyoid bone located?
About an inch above the thyroid cartilage
It can be felt in the angle between the chin and anterior part of the neck, at the level of the 4th cervical vertebra
What is unique about the hyoid bone?
It does not have any connections to the bony skeleton
I.e. It is maintained in position by muscle attachments
What is indicative of strangulation in forensics?
A broken hyoid bone
What is the most prominent muscle in the neck and from where does it extend?
The sternocleidomastoid m: from the mastoid process of the temporal bone to a sternal head on the manubrium and a clavicular head on the middle third of the clavicle
Where does the SCM produce movement?
At the cranio-vertebral joints
What are the actions of the SCM?
- Unilateral contraction rotates head sideways so that the ear approaches the should on the same side while the chin is turned toward the opposite side
- The bilateral contraction flexes the neck (main flexor of the neck)
What is the innervation of the SCM?
Ventral primary rami of c3-c4 and the spinal accessory nerve (CNXI)
What is torticolis? (Wry neck)
A slanting of the head most commonly cause by a fibrous tumor on the SCM or by damage toCNXI
What is the carotid tubercle and its significance?
The anterior tubercle of the transverse process of the 6th cervical vertebrae can be felt deep in the neck at the anterior border of the SCM
It is the point of preference for compressing the common carotid a. To stop bleeding
How many muscles innervate the hyoid bone and what innervate those muscles?
10 muscles innervated from CN V3, VII, and XII and the cervical plexus.
What are the suprahyoid muscles?
Post. Belly of the digastric
Stylohoid
Ant. Belly of the digastric
Mylohyoid
Geniohyoid
What suprahyoid muscles are innervated by the facial nerve (CNVII)?
Post. Belly of digastric and stylohyoid
What suprahyoid muscles are innervated by CN V3?
Anterior belly of digastric (the stylohyoid m divides where it intersects the digastric muscles)
Mylohyoid
What suprahyoid muscles are innervated by C1 from cervical plexus and the hyoglossus from CN XII?
The geniohyoid
What do the suprahyoid muscles do?
Elevate (and protract) the hyoid-laryngeal complex during swallowing.
What are the infrahyoid muscles and their actions?
- Sternohyoid m -lowers hyoid
- Thyrohyoid m - raises larynx
- Sternothyroid m - lowers larynx
- Omohyoid m - courses from the scapular notch to hyoid via two bellies
What innervates the infrahyoid muscles?
The cervical plexus (motor division)
What is the main function of the infrahyoid muscles?
Depress the hyoid bone-larynx during speaking and after swallowing.
What are the prevertebral muscles of the neck?
Anterior, middle and posterior scalene muscles
What nerve courses over the anterior scalene?
Phrenic
Where do the scalene muscles attach to?
To the tubercles of the transverse process of the cervical vertebrae and the first rib
What do the scalene muscles assist in?
In extreme inspiratory effort by elevating the first nod second ribs. When accompanied by labored breathing this is an indication of respiratory distress
What innervates the scalene muscles?
The ventral primary rami of the cervical spinal nerves
What is the attachment, action and innervation of the levator scapulae?
- Arises from the tubercles on the transverse processes of the upper 4 cervical vertebrae and inserts on the superior angle of the scapula
- Elevates the shoulder
- Ventral primary rami of the cervical spinal nerves (dorsal scapular nerve)
Where dos the common carotid arise from?
From the aortic arch on the left and the brachiocephalic trunk on the right.
Each bifurcate into an internal and external branch.
What does the internal carotid supply?
The brain
Note: it does not have any branches in the neck
What happens when there is disruption of the blood flow to the brain?
Causes unconsciousness in seconds and irreversible damage in minutes. Death occurs when the brain ceases functioning.
What are the branches of the external carotid in the neck?
Mnemonic: Some Anatomists like freaking out poor medical students
S: Superior thyroid artery A: Ascending pharyngeal artery L: Lingual F: Facial artery O: Occipital artery P: Posterior auricular artery M: Maxillary artery S: Superficial temporal artery
What does the superior thyroid artery supply and what branch does it have?
Supplies the thyroid gland and has a superior laryngeal branch that accompanies the internal laryngeal nerve of CNX to the larynx
What path does the facial artery take and what does it supply?
Passes across the submandibular gland.
Main supply to the face and lips. Ends as the angular artery at the medial angle of the eye.
What does the facial artery end as?
The angular artery
What is the path of the lingual artery and what does it supply?
Passes deep to the hyoglossus muscle to supply the tongue.
Note: can arise in common with the facial artery
Where does the ascending pharyngeal artery arise from and what does it supply?
From the carotid bifurcation.
Supplies part of the pharynx
What does the occipital artery supply?
The occipital region of the scalp
What does the superficial temporal artery supply?
Supplies the scalp and part of the face as a terminal artery
Clinical: important source of blood for skin flaps in facial reconstruction surgery.
What does the maxillary artery supply?
Structures in the infratemporal fossa
What is the path of the vertebral arteries to become the basilar artery and supply the circle of Willis?
Each arises from the subclavian and passes through the transverse foramin of the cervical vertebrae.
The vertebral arteries join to form the basilar artery and supply blood to the brain via the circle of Willis
What does the basilar artery supply in order to supply the brain?
The circle of Willis
What does the thyro-cervical trunk divide into? (Branch of the subclavian)
Into a suprascapular artery and a cervicodorsal trunk
Where does the internal jugular vein receive blood from?
The brin and delivers it to the superior vena cava.
It is joined by veins from the face, larynx, thyroid gland, etc.
Where does the external jugular vein arise from?
Near the angle of the mandible by the confluence of the retromandibular and the posterior articular vein.
When does the external jugular vein become prominent?
When venous pressure rises such as in CHF (congestive heart failure), the vein becomes prominent all along its course.
Note: it’s normally visible just above the clavicle
The external jugular vein drains most of the scalp via what vein?
The superficial temporal branch
Where does the external jugular vein terminate and what does it give off?
In the subclavian vein, near the termination it gives off subscapular and cervico-dorsal veins that parallel their respective arteries.
In what locations are lymph nodes not found?
There are no lymph nodes in the scalp and none in the face (except for around the parotid gland)
Where re the superficial cervical lymph nodes found?
Along the external jugular vein
Where does lymph from the scalp, face and neck drain into?
The superficial ring of nodes
What drains the cheek, the side of the nose, the upper lip, part of the lower lip, the gums and part of the tongue?
The 3-6 submandibular nodes
What drains the floor of the mouth and apex of the tongue?
Where are these nodes located?
The submental nodes between the anterior bellies of the digastric muscles
Where are the deep cervical nodes located?
Along the internal jugular vein
What nodes enlarge when the tonsils or pharynx are inflamed?
The jugulo-digastic node
What’s drains the occipital portion of the scalp, the back of the neck, tongue, larynx, thyroid gland? (Etc.)
The superior nodes
What drains the posterior scalp and neck, the superficial pectoral region and part of the arm?
The inferior nodes
The lymphatic system is the major route by which _____ (e.g.metasrases from epithelial tissues) travel.
Carcinomas
What can cause enlargement of the deep cervical nodes?
Metastasis from thorax and abdomen
What nodes are called the cervical sentinel nodes?
Deep cervical nodes
Where does lymph from the head and elk on the left side enter?
The left jugular lymphatic trunk
Where does the lymph drain after it has drained into the left jugular lymphatic trunk (received from the head and neck on the left side)?`
Either the thoracic duct or the left internal jugular vein.
Where does the thoracic duct enter the left brachiocephalic vein?
At the left venous angle (the junction of the left subclavian and IJV)
Where does lymph drain from the head and neck on the right side?
Into the jugular lymphatic trunk
What does the right jugular lymphatic trunk join after receiving draining from the right head and neck?
The right venous angle (the junction of the IJV and subclavian v)
What are the boundaries of the posterior triangle?
Posterior edge of SCM
Anterior edge of trapezius
Base: middle third of the clavicle
The apex is at the occipital bone
Floor- scalene, ms, splenius capitis and levator scapulae
Where can the subclavian artery and some of its branches be accessed?
The lower part of the posterior triangle where the inferior belly of the omohyoid crosses
When can CN XI be disconnected to be placed in another part of the body?
When the innervation from C3, C4 is sufficient to activate the muscles
What structure in the posterior triangle is in danger when cancer metastasize to the superficial cervical lymph nodes?
The cervical plexus
Note: the superficial lymph nodes lie along the EJV.
What are the contents of the posterior triangle?
5 muscles- anterior, middle and posterior scalene, levator scapulae, splenius capitis
4 nerves- phrenic, CN XI, trunks of brachial plexus, cutaneous branches of cervical plexus
3 boundaries- SCM, traps, clavicle
2 vessels- subclavian artery/vein and EJV
Where is the EJV in the posterior triangle?
Enters the anterior part of the triangle and empties into the subclavian vein.
What tributaries of the EJV form a plexus above the subclavian artery in the posterior triangle?
Transverse scapular and transverse cervical
Where is the brachial plexus located in the posterior triangle?
Crosses the lower part of the triangle
Where is the subclavian artery? (3rd part)
The medial part of the posterior triangle
Where is the most common place for ligation of the subclavian artery?
The medial part of the triangle where the arch of the artery may rise above the clavicle
What are the cutaneous branches of the cervical plexus within the posterior triangle? (What do they innervate)
- Supraclavicular: shoulder
- Lesser occipital: lower occipital region
- Great auricular: region around the ear
- Transverse cervical: anterior neck
The cervical plexus contains fibers from what spinal nerves?
C1-c5 anterior ventral primary rami
The motor and sensory branches of the cervical plexus are separated by the SCM such that the _____ branches are ventral (anterior) and the _____ branches are dorsal (posterior).
- Sensory
2. Motor
What do the motor branches of the cervical plexus supply?
Infrahyoid
What innervates the geniohyoid?
C1 axons from the hypoglossal nerve (superior root)
How is the ansa cervicalis formed?
An inferior root is formed by axon from C2-C4 (varies) and the two roots join to form the ansa cervicalis
Why is pain from the phrenic nerve referred to the shoulder? (Origination)
The phrenic nerve originates from C3-C5 where the supraclavicular nerves also originates from.
Note: supraclavicular is cutaneous to shoulder
What is superficial cervical plexus block?
Anesthesizing of the skin from the cervical plexus
When is superficial cervical plexus block used?
This is done for carotid endarterectomy when there is a buildup of art hero sclerotic plaque in the carotid artery.
What are the four subdivisions of the anterior triangle?
The submandibular
Su mental
Muscular
Carotid
What are the boundaries of the anterior triangle?
Base of the mandible
Anterior border of the SCM
the ventral midline
What are the boundaries of the digastric (submandibular) triangle?
“MANDible”
M: Mandible is the base (top).
A: Anterior (front)
N: N(and) posterior (below w/ stylohoid) belly of
D: Digastric
What makes the floor of the submandibular (digastric) triangle?
Mylohyoid and hyoglossus
What are the contents of the submandibular (digastric) triangle?
Anterior: submandibular gland that is crossed by the anterior facial vein/artery
Deep to gland: submental artery, mylohyoid artery and mylohyoid nerve (CN V3)
Hypoglossal nerve
The facial nerve (CN VII) and deeper, the internal jugular v and vagus nerve (CNX)
What does the hypoglossal nerve found in the submandibular triangle innervate?
Extrinsic and intrinsic muscles of the tongue except the palatoglossus (which is innervated by CNX)
What do the submandibular lymph glands drain that lie on either side of the submandibular gland?
Upper lip and lateral parts of the lower lip
To what structure can you gain access to from the submandibular triangle that is deep to the parotid gland and superficial to the internal carotid artery.
External carotid and its branches (posterior auricular, superficial temporal and maxillary branches)
Where do the submandibular exocrine glands have superficial and deep regions?
Around the mylohyoid
What do the submandibular exocrine glands secret?
Mucin for lubrication and amylase to break down start
Where does the saliva exit into the mouth from the submandibular gland?
Adjacent to the frenulum of the tongue
What is the path of saliva to the mouth from the submandibular gland?
Saliva courses along the Wharton’s duct to the front of the mouth where it opens through a papilla adjacent to the frenulum of the tongue.
What accounts for 80% of all salivary duct calculi? (Possible because it’s duct is up-sloping)
The submandibular gland
What gland is a small almond shaped gland that lies beneath the oral mucosa between the mandible and genioglossus muscle?
The sublingual gland
Where do the sublingual gland ducts open into?
Into the floor of the mouth along the sublingual folds (many)
What innervates the sublingual and submandibular glands?
Direct innervation from parasympathetic
Indirect from sympathetic
Where are the preganglionic neurons that innervate the submandibular and sublingual gland located?
Superior salivatory nucleus
How do the parasympathetic neurons of the superior salivatory nucleus enter the oral region? (Submandibular and sublingual gland)
Through the cords tympani nerve
Where do the parasympathetic neurons synapse before reaching the submandibular and sublingual glands to activate secretion of saliva?
The submandibular ganglion. . . .
How do the sympathetic nerves exert influence on the submandibular and sublingual glands?
By vasoconstriction of the blood vessels to the gland producing saliva enriched in mucins.
What are the boundaries of the submental triangle?
“CHIN”
C: chin is the apex
H: hyoid bone is the base
IN: In between the ant. Belly of digastric (sides)
Note: the midline splits the triangle in the middle
What makes the floor of the submental triangle?
The mylohyoid muscle
What are the contents of the submental triangle?
- Submental lymph nodes
2. Small tributaries of the anterior jugular vein
What do the submental lymph nodes within the submental triangle drain?
The floor of the mouth, tip of the tongue, mid lower lip, and central incisors
What are the boundaries of the carotid triangle?`
“SO PDFS”
SO: superior belly of omohyoid (anterior)
PD: posterior belly of digastric (superior)
FS: Front of sternocleidomastoid (posterior)
Idk where stylohyoid goes, sad face :(
The cutaneous cervical nerves and the cerval branch of the facial nerve course through the layers of which triangle?
The carotid triangle
What are the contents of the carotid triangle?
Carotid sheath
Vagus nerve
Cervical sympathetic trunk
Carotid sinus and body
What is within the carotid sheath? (In the carotid triangle)
The carotid artery, internal jugular vein and vagus nerve
What nerves does the vagus give good below the hyoid in the carotid triangle?
External and internal laryngeal branches
What lies just behind the carotid sheath in the carotid triangle?
The cervical sympathetic trunk
The paired carotid sinuses contain baroreceptors which sense?
They are stretch-sensitive mechanoreceptors
Distensión of the sinuses by an increase in blood pressure results in the activation of the baroreceptors and the generation of action potentials in afferent axons of what nerve?
The glossopharyngeal nerve (CN IX)
What is the nucleus responsible for most afferent, non-conscious information?
Nucleus of the solitary tract
Where do the cell bodies of 1st order neurons for the carotid body/sinus reside?
The inferior glossopharyngeal ganglion
Where do the action potential from the baroreceptors in the carotid body and sinus travel to?
The nucleus of the solitary tract
What is the most direct effect of the stretch reflex from the baroreceptors found in the carotid sinus/body?
Activation of the preganglionic neurons in the dorsal motor nucleus of the vagus. The axons of these neurons travel in the vagus nerve to the heart where they release acetylcholine to slow down the heartbeat.
When can sinus hypersensitivity occur?
In vascular disease
What kind of patients should not receive a carotid pulse due to gentle external pressure on the carotid sinus causing brachycardia (slowing of the heart rate) and potential fainting (syncope)?
Those with cardiac or vascular disease
When blood pressure is low, action potential discharge from the glossopharyngeal nerve is reduced. What does this result in?
Signals to the preganglionic sympathetic neurons in lamina VII, in the thoracic spinal cord.
These neurons activate the postganglionic neurons to the heart to release norepinephrine and increase the heart rate.
Note: signals also go to constrict blood vessels and to the adrenal medulla to release adrenalin
What are the boundaries of the muscular triangle?
“MuSCular”
M: Median line of the neck (front)
S: Superior belly of omohyoid (behind)
SC: SCM (below)
What lies beneath the subcutaneous fascia, platysma, deep fascia, sternohyoid and the sternothyroid in the muscular triangle?
The isthmus of the thyroid gland, the larynx, and the trachea
These structures can be reached by moving what laterally? They are: the lower part of the common carotid artery in the carotid sheath with the internal jugular vein and vagus nerve, the ansa cervicalis, the sympathetic trunk, the recurrent laryngeal nerve and the esophagus.
the SCM
Where do you do carotid massage for tachycardia?
In the carotid triangle. Useful for slowing the heart
What receives all visceral afferent information?
Nucleus of solitary tract
