Anatomy of Root of the Neck in a Nutshell

Anatomy of Root of the Neck

Clinical case: Cervical mass at cervical bifurcation

• No change in mass size since discovery
• No symptoms
• Differential
  • Carotid body tumor (chemodectoma)
  • Tumor of tail of parotid gland (large salivary gland)
• MRI: offers new diagnoses: carotid body tumor, schwannoma, neoplasm assoc. with branchial cleft tract epithelium
• Carotid angiography shows well circumscribed mass splaying apart the ICA and ECA.
• Ended up being cervical sympathetics: removal of tumor resulted in right Horner’s syndrome.

Boundaries:

1. Laterally: Rib 1 on each side
2. Anteriorly: Manubrium
3. Posteriorly: T1 vertebral body

Subclavian artery:

• 3 parts
  • First part: medial to anterior scalene
  • Second part: posterior to anterior scalene
  • Third part: lateral to anterior scalene
• Becomes axillary artery at inferior border of rib 1

Branches of the Subclavian artery:

• First part:
  • Vertebral artery:

1. 1. • Ascends in the neck. Is mot medial branch
      • As it approaches the cervical vertebrae, it goes through transverse foramen of C vertebrae.

• • • Does not enter the transverse foramen of C7.

1. • Internal thoracic

1. 1. • Heads inferiorly into the thorax
      • Branches at about the same place as vertebral

1. • Thyrocervical trunk: Several branches

• • • Inferior thyroid artery:
      1. Heads superiorly then arches medially to supply inferior aspect of thyroid
      2. Note that superior thyroid is branch of common carotid and anastomoses with inferior thyroid
      3. Gives off branch = ascending cervical artery which sits right on the C vertebrae to supply those V bodies and spine.
    • Suprascapular artery:
      1. Arises from trunk and courses posteriorly over the suprascapular notch to enter the supraspinous fossa to supply tissues there, and then move inferiorly to supply muscles around scapula (supraspinatus, infraspinatus)
      2. It may arise from the subclavian 2^nd / 3^rd parts as a variation.
      3. Is joined by suprascapular nerve

• • • Transverse cervical artery:
      1. When present: arises from trunk and course transversely / posteriorly to the base of the neck
      2. Passes over the cervical plexus when have true transverse cervical (thus when lacking subclavian-originating dorsal scapular)
      3. Gives off a superficial branch: heads in superior direction
      4. Gives off deep branch:
         1. Heads inferiorly to course along the medial border of the scapula.
         2. This is similar to Dorsal scapular.
         3. The deep branch of transverse cervical artery is the dorsal scapular by definition.
    • Usually do not have this branching pattern with deep / superficial branches (is only 25%): normally have separate dorsal scapular artery arising directly from subclavian itself.

• Second part: Costocervical trunk
  • Branches after 1 cm into
  • Deep cervical artery: heads superiorly along vertebral column to supply V bodies and spinal cord.
  • Supreme (highest) intercostal artery: supplies highest intercostal spaces (muscles, bone etc.)
• Third part: dorsal scapular (75%)
  • Supplies Rhomboids, levator scapulae, inferior aspect of trapezius
  • Can arise from 2^nd / 3^rd part of subclavian (75% of the time) to head posteriorly then inferiorly along medial border of scapula

1. 1. • When this happens, the transverse cervical artery is a branch off of the thyrocervical trunk that courses transversely and then is directed upward
      • There is no deep branch in this case, thus only the superficial branch is present.

• • • Thus, there is no true transverse cervical artery, only a superficial cervical artery.

• • When vessel gets to rhomboids, it is still called dorsal scapular, regardless of how it arises.
    • Dorsal scapular artery (when lacking transverse cervical) will cut right through the brachial plexus if it arises from the subclavian

Subclavian vein:

• Is behind the clavicle
• Behind the subclavian vein, have attachment of anterior scalene to rib 1
• Posterior to anterior scalene (at rib 1 level) have the subclavian artery
• Thus, the anterior scalene separates subclavian artery from subclavian vein.

Nerves:

• Phrenic (C3-5)
• Vagus:
  • Can see recurrent branch under subclavian artery on R side in the tracheoesophageal groove
• Sympathetic trunk / ganglia
  • No white rami communicans
  • Preganglionic (presynaptic) fibers are from the upper thoracic trunk- they ascend and then synapse in cervical ganglia
  • Ganglia

1. 1. • Superior cervical ganglion (SCG) at C1-2
      • Middle cervical ganglion at C6 (level of cricoid cartilage)

• • • Inferior cervical ganglion at C7
      1. In 80%, is fused with 1^st thoracic ganglion
      2. When fused, referred to as stellate ganglion

Thyroid Gland:

• Consists of 2 lateral lobes (L / R) connected by portion called the Isthmus
• May have small pyramidal lobe
  • Extends superiorly
  • May go all the way up to the tongue
  • Is a remnant of the path taken by the thyroid gland as it developed form an area called the foramen cecum of the tongue→follows thyroglossal duct
  • May be present / may not be
• Arterial supply:
  • Superior thyroid artery:

1. 1. • From external carotid
      • Comes to superior pole

1. • Inferior thyroid artery:

1. 1. • From thyrocervical trunk
      • Ascends, loops, and descends back to the thyroid gland

1. • Thyroid ima artery

1. 1. • Arises from various locations
      • Rare (10%)

• • • Usually unpaired

• Veins:
  • Superior: drains to internal jugular vein
  • Middle: drains to internal jugular vein
  • Inferior: drains into left brachiocephalic vein
• Nerve:
  • Fibers of Vagus travel on blood vessels to gland
  • These are vasomotor nerves (control vasculature), not secretomotor
• Has a fibrous capsule (is thus an encapsulated gland)

Parathyroid glands

• Found in posterior aspect of thyroid gland
• Usually 4, with 2 on each side (may have 6-8)
• Not always right on the back of the gland, they may extend and be found inferiorly as far down as the superior mediastinum.

Lymphatics of the head / neck:

• Basic drainage pattern: superficial nodesà deep nodes
• Superficial nodes are along external / internal jugular veins
  • Occipital nodes toward occipital area
  • Mastoid near mastoid process
  • Pre-auricular and parotid
  • Submandibular
  • Submental
• Deep nodes: along internal jugular vein
  • Superior deep cervical nodes
  • Inferior deep cervical nodes
• Sentinal nodes
  • Along transverse cervical artery
  • Especially important in breast cancer (and other cancer in general) as a pathway to the brain.
  • Palpating lumps hear are early warning.
• In the root of the neck
  • Lymphatics converge at junction of subclavian veins with internal jugular veins
  • The thoracic duct comes in to this region from the thorax to empty to left subclavian
  • Subclavian trunks drain upper limbs and empty here
  • Jugular trunks that drain deep cervical nodes drain into the central venous system as well.

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