Exam 4 Root of Neck

Question 1

Bony/Cartilagenous Landmarks

Answer 1

• Thyroid cartilage (level C4/C5)
• Thyroid gland
• Tracheal rings
• Jugular notch (T2)
• Body of 1st rib

Question 2

Boundaries of root of neck

Answer 2

• Lateral: First pair of ribs and costal cartilages
• Anterior: Manubrium of sternum
• Posterior: Body of T1 vertebrae

Question 3

Cricothyroid muscle

• Proximal Attachment
• Distal Attachment
• Action
• Innervation

Answer 3

• Proximal Attachment: Arch of cricoid cartilage
• Distal Attachment: Inferior horn of thyroid cartilage
• Action: Tenses vocal cords
• Innervation: External laryngeal nerve

Question 4

Longus colli muscle

• Proximal Attachment
• Distal Attachment
• Action
• Innervation

Answer 4

• Proximal Attachment: Transverse processes of T2-T3
• Distal Attachment: Vertebral bodies of C2-C3
• Action: Flexes and rotates head
• Innervation: C5-C8

Question 5

Branches of subclavian artery

Answer 5

• First segment: Medial to anterior scalene
  
  • Vertebral: B/w anterior scalene and longus colli
  • Internal thoracic: Descends through thorax
  • Thyrocervical trunk: Short trunk that divides into:
    
    • Suprascapular (1st branch)
    • Transverse cervical (2nd branch)
    • Inferior thyroid (3rd branch)
• Second segment: Posterior to anterior scalene
  
  • Costocervical trunk: arises posterior, divides into:
    
    • Deep cervical
    • Supreme intercostal
• Third segment: Lateral to anterior scalene
  
  • Dorsal scapular

Question 6

Veins of root of neck

Answer 6

• Anterior jugular vein drains into ->
• External jugular vein drains into ->
• Subclavian veins draininto ->
• Brachicephalic veins

Question 7

Sumpathetic trunk

• What type of fibers are found in this?
• What are its cervical ganglia?
  
  • Where are they located>
• What is the ansa subclavia?

Answer 7

• Pre and postganglionic sympathetic fibers and visceral afferent fibers found here
• Superior cervical ganglion: Largest of cervical ganglia, lies in front of transverse processes of C1-C2, posterior to internal carotid
  
  • Synapse for postganglionic sympathetics traveling to head
• Middle cervical ganglion: Lies at level of cricoid cartilage (C6 vertebral level)
  
  • Provides synapse for sympathetic innervation to heart and lungs
• Inferior cervical ganglion: Results as fusion of inferior cervical ganglion with 1st thoracic ganglion
  
  • Lies anterior to neck of 1st rib, posterior to subclavian artery
• Ansa subclavia: Cord connecting middle and inferior cervical ganglia
  
  • Loops around 1st portion of subclavian artery
  • Aids in connecting middle and inferior ganglion that contribute to cardiac and pulmonary plexuses

Question 8

Other nerves found in root of the neck…

Answer 8

• Vagus nerve: gives off left and right recurrent laryngeal nerves
  
  • Right recurrent laryngeal wraps around brachiocephalic trunk
  • Left recurrent laryngeal wraps around aortic arch
• Phrenic nerve: Arises from C3, C4, C5 ventral rami near ansa cervicalis
  
  • Travels superficial to anterior scalene

Question 9

Visera of the Neck

• What are the layers?
• What is found in each layer?

Answer 9

• Alimentary layer (deepest layer): Consists of pharynx and esophagus
• Respiratory layer (middle layer): Consists of larynx and trachea
• Endocrine layer (superficial layer): Consists of thyroid and parathyroid glands

Question 10

Tracheotomy

• What is it?
• Where is it performed?

Answer 10

• Surgical opening of trachea
• Performed at 3rd and 4th rings of trachea
  
  • Accessed by midline skin incision from jugular notch to thyroid notch of thyroid cartilage

Question 11

Cricothyrotomy

• What is it?
• What is its clinical importance?

Answer 11

• Incision through skin and cricothyroid membrane
• Emergency relief of respiratory obstruction

Question 12

Thyroid gland

• What does it produce?
• Structure
• Arterial blood supply
• Venous drainage

Answer 12

• Endocrine organ that produces thyroxine and thyrocalcitonin
• Right and left lobes connected by isthmus (crosses 2nd, 3rd, and 4th trachea rings)
• Arterial blood supply:
  
  • Superior thyroid: Supplies superior and anterior portion of thyroid
  • Inferior thyroid: Supplies inferior and posterior portion of thyroid and parathyroid glands
  • Thyroid ima: Supplies middle inferior aspect of thyroid (variable branch off brachiocephalic trunk)
• Venous drainage:
  
  • Superior thyroid vein
  • Middle thyroid vein
  • Inferior thyroid vein

Question 13

Goiter

• What is it?
• What causes it?
• What is it associated with?
• Treatments

Answer 13

• Enlargement of thyroid gland causing swelling in front part of neck
• Caused by iodine deficiency
• Associated with both hyperthyroidism (Graves’ disease) and hypothyroidism
• Treatments:
  
  • Thyroid hormone replacement pills if caused by hypothyroidism
  • Radioactive iodine to shrink gland caused by hyperthyroidism
  • Surgery to remove all or part of gland

Question 14

Parathyroid glands

• What are they?
• What is their function?
• Blood supply

Answer 14

• 2-6 small ovoid bodies that lie against dorsum of thyroid under its sheath but within their own capsules
• Vital for calcium and phosphorus metabolism
• Blood supply: Inferior thyroid artery

Question 15

Parathyroidectomy

• Why is it performed?
• What can happen as a complication?
• Symptoms experienced after surgery?

Answer 15

• Removal of parathyroid glands as part of total thyroidectomy OR targeted due to parathyroid tumor
• Can be fatal if parathyroid hormone, calcium, or vitamin D is not provided as treatment
• Calcium plasma levels decrease after removal, causing increased neuromuscular activity (such as muscle spasms and nervous hyperexcitability, or tetany)

Question 16

Superficial (investing) layer

• What does it envelope?
• Where does it run?
• Where does it attach?

Answer 16

• Most superficial layer; splits at trapezius and SCM to completely invest these muscles
• Superior attachment: External occipital protuberance; superior nuchal line
• Lateral attachment: Mastoid process and zygomatic arch
• Inferior attachment: Scapular spine, acromion, clavicle, and manubrium

(Light blue tube)

Question 17

Pre-tracheal layer

• What does it envelope?
• Where does it run?
• What are its parts?

Answer 17

• Envelops trachea, esophagus, thyroid gland, and infrahyoid muscles
• Runs from hyoid down to superior thorax
  
  • Fuses with pericardium
• Splits into:
  
  • Visceral part: encloses thyroid gland, trachea, esophagus
  • Muscular part: encloses infrahyoid muscles

(Red tube)

Question 18

Buccopharyngeal fascia

• What does it envelope?
• Where does it run?
• Where does it attach?

Answer 18

• Envelopes constrictor muscles of pharynx and buccinator muscle
• Runs parallel to carotid sheaths, along medial aspect
• Attaches to pre-vertebral layer by loose connective tissue allowing for distension, forming retropharyngeal space

(Royal blue tube)

Question 19

Carotid sheaths

• What does it envelope?
• Where does it run?

Answer 19

• Contains common/internal carotid arteries, internal jugular vein, vagus nerve, and deep cervical lymph nodes
• Extends from base of skull to first rib and sternum

Question 20

Pharyngobasilar fascia

• Where does it run?
• What is its function?

Answer 20

• Lines inner surface of pharyngeal wall
• Along with buccopharyngeal fascia, reinforces pharyngeal wall where muscle is deficient

(Gray tube)

Question 21

Pre-vertebral fascia

• What does it envelope?
• Where does it attach?

Answer 21

• Surrounds vertebral column and muscles (scalenes, pre-vertebral, and deep muscles of back)
  
  • Surrounds brachial plexus and subclavian artery
• Anterior attachment: Transverse processes and vertebral bodies of vertebral column
• Posterior attachment: Ligamentum nuchae

(Yellow tube)

Question 22

Where can infection spread in neck?

Answer 22

• If infection is anterior to pre-vertebral fascia:
  
  • Can erode through prevertebral fascia and drain into retropharyngeal space (between pretracheal and pre-vertebral fascia)
  • Retropharyngeal space extends into thorax, and drainage of pus into thorax can lead to infection of mediastinal contents.
• If infection is between superficial investing fascia and visceral part of pre-tracheal fascia:
  
  • Infection can spread inferiorly to chest, causing infection anterior to pericardium.