Triangles of the Neck Flashcards
1
Q
- thin CT that lies between the dermis and investing layer of deep cervical fascia
- contents: sensory nerves, blood and lymph vessels, superficial lymph nodes, fat, platysma muscle (muscle of facial expression, innervation by facial N.)
A
subcutaneous layer
2
Q
What are the major landmarks within the neck?
A
- cervical C7 vertebra
- hyoid bone (body at C3-4 axial level, suspended by muscles, has greater and lesser horns)
- thyroid and cricoid cartilages (cricoid at C6 level)
- clavicle and sternum
- mandible
3
Q
- superficial vein of the neck (overlies surface of investing fascia)
- junction of superficial temporal vein and maxillary vein
- runs deep within parotid gland
A
retromandibular vein
4
Q
- superficial vein of the neck (overlies surface of investing fascia)
- crosses over upper 2/3’s of SCM muscle
- may be absent
A
external jugular vein
5
Q
- superficial vein of the neck (overlies surface of investing fascia)
- runs off the midline to the root of the neck and connects w/ the subclavian vein
A
anterior jugular vein
6
Q
- superficial cutaneous nerve that originates from cervical plexus and emerges from posterior margin of mid-SCM muscle
- runs along border of SCM relaying scalp sensory information
A
lesser occipital N. (C2, C3)
7
Q
- superficial cutaneous nerve that originates from cervical plexus and emerges from posterior margin of mid-SCM muscle
- crosses SCM
- supplies skin overlying anterior triangle of neck
A
transverse cervical N. (C2, C3)
8
Q
- superficial cutaneous nerve that originates from cervical plexus and emerges from posterior margin of mid-SCM muscle
- runs w/ EJV on surface of SCM muscle
- supplies posterior auricle and area extending from mandibular angle to mastoid process
A
greater occipital N. (C2, C3)
9
Q
- superficial cutaneous nerve that originates from cervical plexus and emerges from posterior margin of mid-SCM muscle
- supplies root of neck in area of clavicle, acromion, and sternum
A
supraclavicular N. (C3, C4)
10
Q
What is the nerve point of neck?
A
area around the mid-SCM that is used as the site of application anesthetic
11
Q
- fascia of neck
- most superficial, surrounds entire neck and encloses SCM and trapezius muscles and parotid and submandibular glands
A
investing fascia
12
Q
- fascia of neck
- located in anterior of neck and bleds w/ pericardium
- contains infrahyoid muscles and buccopharyngeal fascia
A
pretracheal fascia
13
Q
- fascia of neck
- encloses vertebral column and associated muscles
- extends laterally as axillary sheath into arm
A
prevertebral fascia
14
Q
- fascia of neck
- covers carotids, IJV, and vagus N.
A
carotid sheath
15
Q
- fascia of neck
- posterior to pharynx and esophagus
- bounded by buccopharyngeal and prevertebral fascia and carotid sheath
- extends from base of skull to mediastinum
- permits movement of pharynx, larynx and esophagus during swallowing
- easy route for URI or oral infections to spread
A
retropharyngeal space
16
Q
What are the borders of the anterior triangle of the neck?
A
- midline of neck (anterior)
- sternocleidomastoid M. (posterior)
- inferior border of mandible (superior)
17
Q
What are the borders of the posterior triangle of the neck?
A
- sternocleidomastoid M. (anterior)
- trapezius M. (posterior)
- clavicle (inferior)
18
Q
What muscle breaks the posterior triangle into two triangles?
What is the posterior triangle floor?
What is the posterior triangle nervous and vascular components?
A
- broken into two triangles by inferior belly of omohyoid M. (occipital triangle which is larger and superior to supraclavicular triangle)
- floor is prevertebral fascia
- nerves: spinal accessory N., cutaneous nerves (lesser occipital, greater auricular, transverse cervical, suprascapular)
- vasculature: EJV and suprascapular A., subclavian A. and occipital A.
19
Q
What are the muscles of the posterior triangle?
A
- splenius capitis M.
- levator scapulae M.
- posterior scalene M.
- middle scalene M.
- inferior belly of omohyoid M.
sometimes inferior portion of anterior scalene (hidden under SCM)
20
Q
What are the prevertebral muscles and their OIAN?
A
- posterior scalene: posterior tubercles of C5-7 transverse processes to 2nd rib; flexes neck laterally and elevates rib during deep inspiration
- middle scalene: posterior tubercles of C2-7 transverse processes to superior 1st rib; laterally neck and elevates rib during deep inspiration
- anterior scalene: anterior C3-6 transverse processes to 1st rib; laterally flexes and rotates neck, elevates rib during deep inspiration
- longus capitis and coli: spans between vertebral bodies and transverse processes of cervical vertebrae (longus capitis inserts on occipital bone); forward and lateral flexion, rotation of the head
- rectus capitis lateralis and anterior: complementary to rectus capitis posterior and obliquus capitis; stabilize atlanto-occipital joint and flex head
*all posterior to retropharyngeal space and innervated by cervical and/or brachial plexus*
21
Q
sternocleidomastoid M.
- origin:
- insertion:
- action:
- innervation:
A
sternocleidomastoid M.
- origin: two heads: sternal head attached to manubrium, flatter clavicular head attached to medial third of clavicle
- insertion: muscle runs superiorly and inserts onto mastoid process
- action: bilaterally flexes neck; w/ neck extensors (deep cervical M.) protrudes head and thrusts it forward; unilaterally flexes head, rotates head and neck contralaterally, tilts head to one side
- innervation: accessory N. (CN XI) and branches of cervical plexus (C2-4)
22
Q
- pathology of SCM muscle causing head to turn to side and face to turn away from affected side
- congenital: fibrous tissue tumor within SCM that develops in utero; shortens SCM muscle
- muscular: SCM muscle may be injured during difficult birth, tearing fibers leading to hematoma that develops into fibrotic mass that entraps part of CN XI denervating it; stiffness of neck results from fibrosis and shortening of SCM; may require surgical detaching of SCM
A
torticollis
23
Q
What is the very general origin and route of the cervical plexus?
A
- originates from ventral rami of C1-4
- divides into ascending and descending branches (except C1) that forms a loop with the next one
- loops lie anterolateral to levator scapulae and middle scalene muscles
- forms cutaneous nerves of posterior triangle but also supplies adjacent prevertebral muscles, phrenic nerve, and strap muscles (ansa cervicalis)
24
Q
What is the course of the phrenic N.?
What are the nerve roots of the phrenic N.?
What occurs w/ phrenic N. damage?
A
- course: runs anterior to surface of anterior sclene M., descends obliquely w/ IJV deep to prevertebral fascia and posterior to suprascapular and transverse scapular cervical As. off thyrocervical trunk, runs posterior to subclavian V. but anterior to internal thoracic A. as it enters the thorax
- roots of C3 and C4 of cervical plexus and ventral rami of C5 combine to form phrenic N.
- damage: severance or nerve block causes paralysis of that side of diaphragm
25
What are the 3 parts of the subclavian A.?
- first: lies medial to anterior scalene and at apex of lung and cervical pleura; branches are internal thoracic and vertebral As. and thyrocervical trunk (inferior thyroid, transverse scapular, suprascapular As.)
- second: posterior to anterior scalene; branch is costocervical trunk (superior intercostal and deep cervical As.)
- third: lateral to anterior scalene, lies anterior to brachial plexus within posterior triangle, artery is in contact w/ first rib; compression against rib can control bleeding in upper limb; branch is often dorsal scapular A.
26
What are the branches off the subclavian A.?
* first part
* internal thoracic
* vertebral
* thyrocervical trunk
* inferior thyroid
* suprascapular
* transverse cervical
* ascending cervical branch and deep cervical branch (30% of the time this is dorsal scapular)
* second part
* costocervical trunk
* superior intercostal
* deep posterior ascending cervical
* third part
* dorsal scapular
27
What are the borders and subtriangles of the anterior triangle?
* borders
* midline of the neck (anterior)
* mandible (superior)
* SCM (posterior)
* subtriangles
* **submandibular**: anterior and posterior bellies of digastric and mandible
* **submental**: unpaired; both anterior bellies of digastric and hyoid bone
* **carotid**: SCM, superior belly of omohyoid, posterior belly of digastric
* **muscular**: SCM, superior belly of omohyoid, and midline from hyoid to manubrium
28
What are the contents of the **submental** (submandibular - suprahyoid region) **triangle**? (if muscles, name OIAN)
- **myohyoid M.**: originates on inner mandible and inserts into common raphe and hyoid bone; supports and elevates tongue and hyoid bone during swallowing, speaking, and tongue protrusion; innervated by mylohyoid N. (branch of inferior alveolar N., CN V3)
- **geniohyoid M.**: superior to mylohyoid; originates on mental spine and inserts on anterior surface of hyoid bone; pulls hyoid anteriosuperior, shortens floor of mouth, and widens pharynx; innervated by C1 via hypoglossal N.
- **diagastric M.**: two bellies separated by intermediate tendon; originates on mastoid process and inserts on mandible; depresses mandible, elevates hyoid during chewing and swallowing; innervated by mylohyoid nerve (inferior alveolar nerve, CN V3) for anterior belly and digastric branch (facial nerve, CN VII) for posterior belly
- **submandibular gland**: lies wrapped around free border of posterior border of myloghyoid M.; easily palpated especially if tense mylohyoid M.
- **submental lymph nodes** and small veins that unite to form **anterior jugular vein**
29
What are the contents of the **submandibular triangle** (digastric region)?
- **digastric M.**: two bellies separated by intermediate tendon, sling is made from investing fascia that allows it to slide; depresses mandible, raises hyoid bone, steadies it during swallowing and speaking; two embryological origins thus innervated by trigeminal N., CN V (anterior belly) and facial N., CN VII (posterior belly)
- **stylohyoid M.**: parallels posterior digastric and splits on either side of insertion of posterior digastric; originates on styloid process and inserts onto hyoid bone; elevates and retracts hyoid bone; innervated by CN VII
- **hypoglossal M.**: from hyoid bone to lateral tongue; depresses tongue and shortens it; innervated by CN XII
- **submandibular gland** almost fills entire triangle
- **submandibular lymph nodes**
- **hypoglossal N. (CN XII)**
- **mylohyoid N.**
- parts of **facial A. and V.**
30
What are the infrahyoid muscles and their OIAN?
- **sternohyoid**: originates off manubrium and clavicle, inserts on body of hyoid; depresses hyoid after elevation due to swallowing; innervated by C1-3 of ansa cervicalis
- **omohyoid**: two bellies united by intermediate tendon, connected to clavicle by fascial sling; inferior belly (origin is superior border of scapula near suprascapular notch and inserts at intermediate tendon), superior belly (origin is intermediate tendon and inserts on lower border of hyoid bone); depresses, retracts, and steadies hyoid; innervated by C1-3 of ansa cervicalis
- **sternothyroid**: originates off posterior surface of manubrium, inserts on oblique line of thyroid cartilage; depresses thyroid cartilage and pulls hyoid down; covers lateral lobe of thyroid; innervated by C2 and C3 via ansa cervicalis
- **thyrohyoid**: originates off oblique line of thyroid cartilage, inserts on inferior border of body and greater horn of hyoid; depresses hyoid and elevates larynx; innervated by C1 via hypoglossal N.
- **cricothyroid**: cricoid cartilage to thyroid cartilage; important in vocalization; innervated by external laryngeal N. (branch of vagus N.)
31
Where is the ansa cervicalis derived from?
What muscles does it innervate?
Where does the superior part originate from?
Where does the inferior part originate from?
- derived from **anterior branches off ventral rami of cervical plexus**, forming a loop that vary in length
- innervates **infrahyoid muscles** (sternohyoid, sternothyroid, thyrohyoid, and omohyoid) and **geniohyoid muscle**
- **superior part**: originates from C1 of the cervical plexus that joins hypoglossal N. (fibers run w/ hypoglossal for 2-3 cm then leave to descend in front of internal carotid As. as superior limb (loop) of the ansa cervicalis; the limb gives off nerve to thyrohyoid (C1) and geniohyoid (C1); superior limb swings down to meet inferior limb giving off a branch to superior omohyoid belly)
- **inferior part**: formed by branches of C2 and C3; descends behind carotid sheath and winds laterlward and emerges from behind carotid sheath to join superior limb
32
What are the contents of the carotid triangle?
- **carotid sheath**: fasica surrounding **IJV**, **carotid A.**, and **vagus N.** (runs along then under anterior border of SCM; IJV is most lateral and vagus N. most posterior within sheath)
- division of **common carotid** into **internal** and **external carotid As.**
- branches of **vagus N.** to larynx
- hypoglossal N. (CN XII) and superior root of ansa cervicalis
- spinal accessory N. (CN XI)
- thyroid gland, larynx, and pharynx
- deep cervical lymph nodes
- branches of cervical plexus
33
What are the arteries present in the anterior triangle?
- **carotid sinus**: located at site of **bifurcation of common carotid**, contains chemoreceptors and baroreceptors for monitoring of O2 and BP levels
- **internal carotid**: no branches in the neck
- **external carotid**: terminates by dividing into maxillary and superficial temporal As.
- **external carotid branches**: ascending pharyngeal, superior thyroid, lingual, facial, occipital, posterior auricular
34
- lies deep to sternothyroid and sternohyoid Ms. from levels C5 to T1
- consists of two lobes that are anteriolateral to larynx and trachea
- has isthmus uniting lobes overlying trachea at 2nd/3rd tracheal rings
- dense CT attaches it to the cricoid cartilage and superior tracheal rings
- blood supply: inferior and superior thyroid As. and Vs.
- parathyroid lies on posterior aspect of gland in its own capsule
thyroid gland
35
- upaired cartilages of larynx:
- paired cartilages of larynx:
- ligaments/membranes of larynx:
- **upaired cartilages of larynx**: thyroid (thyroid prominence C4 level, superior thyroid notch), epiglottis-elastic cartilage type, cricoid (located at C6 level, signet ring shaped)
- **paired cartilages of larynx**: arytenoid (vocal cords attached), corniculate, cuneiform
- **ligaments/membranes of larynx**: vocal ligament (lies under vocal cord), thyrohyoid membrane, cricothyroid membrane
36
- contain elastic vocal ligaments running between thyroid and arytenoid cartilages
- generate sound by vibrating as air passes by
- force of air controls volume, tension of folds determines pitch
- tension is regulated by intrinsic muscles innervated by vagus N. (CN X)
- ventricular folds (false cords): brought together when holding your breath while straining, do not contain vocal ligaments
vocal folds (cords)
37
What are disorders of the vocal cords?
- dysphonia: disorder of the voice
- hoarseness: inflammation of vocal cords
- laryngitis: inflammation of vocal cords where they no longer vibrate
38
What are intrinsic laryngeal muscles involved in sound production?
- adductors: lateral cricoarytenoid and transverse arytenoid Ms.
- abductors: posterior cricoarytenoid M.
- sphincters: transverse arytenoid, oblique arytenoid, and aryepiglottic Ms.
- tensors: cricothyroid M.
- relaxers: thyroarytenoid and vocalis Ms.
\*control tension of and spacing between vocal cords\*
39
What is the neurovascularization of the larynx?
- **neuro**: **vagus N.** (CN X) \> **superior laryngeal N.** (internal - sensory, external - motor to cricothyroid M.) and **inferior laryngeal N.** (terminal branch of recurrent laryngeal N., motor to intrinsic laryngeal Ms.)
- **vascularization**: **superior laryngeal A.** off superior thyroid A. and **inferior laryngeal A.** off inferior thyroid A.
40
What is the vascularization of the thyroid gland?
- superior thyroid A. from external carotid A.
- inferior thyroid A. from thyrocervical trunk
- parallel veins
- sometimes thyroid ima A. (branch directly off brachiocephalic trunk to inferior thyroid gland, 10% of the time)
41
- no white rami in neck (presynaptic fibers from superior spinal nerves)
- fibers pass to cervical spinal nerves via gray rami or leave as visceral branches (splanchnic) into thorax; branches to head run via vascular plexus
- three cervical ganglia: superior ganglia, middle ganglia, and inferior ganglion
cervical sympathetic chain
42
What are the three cervical ganglia?
- **superior ganglia**: level of C1/C2; post-synaptic fibers from internal carotid periarterial plexes that enters cranium, also sends fibers to cervical plexus and cardiopulmonary splanchnic nerves
- **middle ganglia**: may be absent; lies over inferior thyroid A. at level of cricoid cartilage and transverse process of C6, distributed via periarterial plexes and cardiopulmonary splanchnic nerves
- **inferior ganglia**: lies anterior to transverse process of C7 just superior to neck of 1st rib; some post-ganglionic fibers enter brachial plexus, others run to heart (inferior cervical cardiac nerve), others go to periarterial plexus of vertebral A.
43
What are the lymphatic specifics of the neck?
- **superficial cervical nodes**: located along EJV draining superficial tissues of neck
- **inferior deep cervical nodes**: drain lateral cervical area and run along path of CN XI
- all drain into nodes and lymphatics running along IJV, lymphatics join to form lymphatic trunks that then join to form lymphatic ducts that empty into subclavian vein near its junction w/ IJV
