2. Posterior and anterior triangles of the neck, thyroid, parathyroid Flashcards

1
Q

Boundaries of the anterior triangle of the neck?

A

Bounded by inferior border of mandible, anterior border of SCM & midline of neck

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2
Q

What fascia forms the roof and floor of the anterior triangle?

A
Roof= Deep investing fascia around muscles
Floor= Pretracheal fascia and carotid sheath
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3
Q

What are the 4 subdivisions of the anterior triangle?

A

Submandibular, submental, carotid & muscular triangles

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4
Q

What are the contents of the submandibular subdivision of the anterior triangle?

A

Contains submandibular gland, lymph nodes, (parts of) CN XII, mylohyoid nerve & parts of the facial artery & vein

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5
Q

What are the contents of the submental subdivision of the anterior triangle?

A

Submental lymph nodes

Small veins

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6
Q

What are the contents of the carotid subdivision of the anterior triangle?

A

Contains thyroid gland, larynx, pharynx, carotid sheath (& its contents), branches of cervical plexus, superior root of the ansa cervicalis, deep cervical lymph nodes & (parts of) CN XI & XII

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7
Q

What are the contents of the muscular subdivision of the anterior triangle?

A

Muscles: Sternothyroid and Sternohyoid
Glands: Thyroid and parathyroid

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8
Q

Which bone divides the muscles of the anterior compartment?

A

The hyoid bone, all are either:

  • above and connect to skull or mandible
  • Below and connect to inferior structure (e.g. sternum, scapula, thyroid, cartilage)

Except: Sternothyroid

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9
Q

Name the 8 muscles above and below the hyoid bone in the anterior compartment of the neck?

A

Suprahyoid muscles

  • Mylohyoid
  • Digastric
  • Stylohyoid
  • Geniohyoid

Infrahyoid muscles

  • Sternohyoid
  • Omohyoid
  • Thyrohyoid
  • Sternothyroid*

*Sternohyoid doesn’t attach to the hyoid bone. Attaches from sternal notch to the thyroid cartilage

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10
Q

Action of suprahyoid muscles

A

Raise the hyoid bone as required during swallowing

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11
Q

Attachment and action of the mylohyoid bone?

A

Mylohyoid originates at mylohyoid line on mandible; inserts into body of hyoid & fibres of opposite mylohyoid

Actions:
Elevates the hyoid & the floor of the mouth
Supports floor of mouth

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12
Q

Digastric:
Bellies?
Attachments?
Actions?

A

Bellies: Anterior and posterior

ANTERIOR BELLY
Attachment: From digastric fossa on lower meal aspect of mandible to intermediate tendon at hyoid
Action: Raises hyoid and opens mouth by lowering mandible

POSTIOR BELLY
Attachment: Mastoid notch on medial side of mastoid process to the intermediate tendon at the hyoid bone
Action: Elevates and retracts hyoid bone

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13
Q

Innervation of mylohyoid?

A

Nerve to mylohyoid i.e. inferior alveolar branch of CN V3

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14
Q

Innervation of anterior belly of digastric?

A

Nerve to mylohyoid i.e. inferior alveolar branch of CN V3

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15
Q

innervation of posterior belly of digastric?

A

Digastric branch of CN VII

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16
Q

Stylohyoid:
Attachment?
Action?
Innervation?

A

Stylohyoid originates at the styloid process & inserts into body of hyoid (laterally)
Action: Pulls hyoid bone upward (posterosuperior direction)
Innervation via CN VII

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17
Q

Innervation of surpahyoid muscles?

A

Suprahyoid muscles

  • Mylohyoid: inferior alveolar branch of CN V3
  • Digastric: Ant belly (inferior alveolar branch of CN V3), Post belly (Digastric branch of CN VII)
  • Stylohyoid: CN VII
  • Geniohyoid: Anterior ramus of C1 (travels via CN XII)
18
Q

Geniohyoid muscle:
Attachment?
Action?
Innervation?

A

Geniohyoid originates from the mandible (mental spine) & inserts at body of hyoid (located superior to mylohyoid)

Actions:
Fixed mandible – elevates & pulls hyoid forward
Fixed hyoid – pulls mandible downward & inward

Innervation:
Anterior ramus of C1 (travels via CN XII)

19
Q

Role of infrahyoid muscles?

A

Depress or fix hyoid bone
+
Provide attachment for suprahyoid muscles

20
Q

Attachment of sternohyoid?

Action?

A

Sternohyoid originates at posterior surface of sternoclavicular joint & manubrium; inserts into body of hyoid medially
Action: Depresses hyoid after elevation during swallowing

21
Q

Omohyoid:
Bellies?
Attachment?
Action?

A

Bellies: Inferior and superior

SUPERIOR BELLY: Attaches from intermediate tendon and inserts as body of hyoid laterally.

INFERIOR BELLY:
originates at superior border of scapula & inserts/ends at its intermediate tendon in posterior triangle)

Note: intemediate tendon attaches to the clavicle with a fascial sling

Actions: Depresses and fixes the hyoid

22
Q

Thyrohyoid:
Attachment?
Actions?

A

Thyrohyoid originates at oblique line on thyroid cartilage; inserts into greater horn & adjacent body of hyoid

Actions:
Depresses the hyoid
Raises larynx when hyoid is fixed

23
Q

Sternpthyroid:
Attachment?
Action?

A

Sternothyroid originates at posterior surface of manubrium; inserts into oblique line on thyroid cartilage
Action: Draws the larynx downward

24
Q

Innervation of the infrahyoid muscles in the anterior triangle?

A

Sternohyoid, omohyoid & sternothyroid are innervated by anterior rami of C1 to C3 (through the ansa cervicalis )

Thyrohyoid: From anterior rami of C1 but fibres run with CN XII

25
Q

What structures make up the thyroid gland?

A

• Composed of 2 lateral lobes (right & left)
(extends from thyroid cartilage to 5th
tracheal ring)
• Midline isthmus (level of 3rd tracheal ring)
• Midline pyramidal lobe (variably present,
remnant of thyroglossal duct)

26
Q

What compartment is the thyroid gland within?

A

within the visceral compartment surrounded by pretracheal fascia

27
Q

Arterial supply to thyroid artery?

A

Arterial supply:
• Superior thyroid artery (1st
branch of external CA)
• Inferior thyroid artery (branch of thyrocervical trunk from subclavian)

28
Q

Venous drainage of the thyroid artery?

A
Venous drainage (thyroid venous plexus):
• Superior thyroid vein (into
IJV)
• Middle thyroid vein (into IJV)
• Inferior thyroid vein (into
brachiocephalic)
29
Q

Position of the parathyroid gland?

A

Two pairs (superior & inferior) of small glands usually on posterior surface of thyroid, but exact position varies

4 in total/

30
Q

Arterial supply and venous drainage of parathyroid artery?

A

Arterial supply:
Inferior thyroid arteries (branch of thyrocervical trunk from subclavian)

Venous drainage (same as thyroid gland):
• Superior thyroid vein (into
IJV)
• Middle thyroid vein (into IJV)
• Inferior thyroid vein (into
brachiocephalic)
31
Q

Innervation of the parathyroid and thyroid gland?

A

From the thyroid branches of the cervical (symp) glanglia

32
Q

Border of the posterior triangle?

A

Anterior: Post border of SCM
Posterior: Ant borfer of trapezius
Inferior: Middle 1/3 of clavicle Superior: occipital bone

Is in direct continuity with upper limbs

33
Q

Which fascia for the roof and floor of the posterior triangle of the neck?

A

Roof: deep investing fascia around muscles (SCM & trapezius)
Floor: (muscular) prevertebral fascia surrounding splenius capitus, levator scapulae, scalenes

34
Q

Innervation of roof and floor muscles of the posterior triangle of the neck?

A

Roof: SCM & trapezius from CN XI
Floor: Splenius capitus, levator scapulae, scalenes from cervical nerves

35
Q

Sternocleidomastoid:
Attachment?
Action?
Innervation?

A

• Sternal head originates at
manubrium of sternum & inserts lateral half of the superior nuchal line
• Clavicular head originates at medial 3rd of clavicle & inserts into lateral surface of mastoid process

Actions: Draws the head forward (both SCMs); or tilts head toward ipsilateral shoulder while turning face contralaterally (one SCM)

Innervated by spinal accessory nerve (CN XI)

36
Q

Trapezius:
Attachment?
Action?
Innervation?

A

rapezius originates at superior nuchal line, external occipital protuberance, ligamentum nuchae & spinous processes (C7-T12); inserts into lateral 3rd of clavicle, acromion & spine of scapula

Actions: Assists in rotating scapula during abduction of humerus; upper fibres elevate, middle adduct & lower depress scapula

Innervated by spinal accessory nerve (CN XI)

37
Q

Levator scapulae:
Attachment?
Action?
innervation?

A

Levator scapulae originates at C1-C4 (transverse processes); inserts into scapula (upper medial border)

Action: Elevates scapula

Innervated by C3, C4, & dorsal scapular nerve (C4, C5)

38
Q

Anterior scalene:
Attachment?
Action?
Innervation?

A

Anterior scalene originates at C3-C6 (anterior tubercle of transverse processes); inserts into upper surface of rib 1 & scalene tubercle

Action: Elevates 1st rib

Innervation: Anterior rami of C3-C7

39
Q

Middle scalene:
Attachment?
Action?
Innervation?

A

Middle scalene originates at C4-C7 (transverse processes); inserts into upper surface of rib 1, posterior to groove for SCA

Action: Elevates 1st rib

Innervation: Anterior rami of C4-C7

40
Q

What are the cutaneious and muscular branches of the anterior rami of C1-C4 of the cervical plexus?

A
Muscular branches: 
Phrenic nerve (C3, C4, C5) 
Ansa cervicalis (C1, C2, C3) branches to prevertebral & vertebral muscles

Cutaneous branches:
C2 – lesser occipital nerves
C2, C3 – great auricular & transverse cervical nerves
C3, C4 – supraclavicular nerves

**great auricular supplies the angle of the mandible*

41
Q
Ansa Cervicalis (anterior rami of C1-C3) Superior & inferior roots 
Innervates which muscle of the anterior triangle?
A

Infrahyoid muscles

42
Q

Difference in drainage of anterior and external jugular vein?

A

Anterior jugular vein drains into the external jugular vein

External jugular vein drains into the subclavian vein