Triangles of the Neck: mm & vasculature

Question 1

Subtriangles of the Anterior Cervical Triangle

Answer 1

1. Muscular Triangle
2. Carotid Triangle
3. Submandibular (digastric) triangle
4. Submental (suprahyoid) triangle

Question 2

Cervical Muscles (2)

Answer 2

Platysma m.

Sternocleidomastoid m.

Question 3

Platysma m.

Answer 3

O: superficial fascia over part of deltoid and pec. major
I: Mandible; skin and muscles over mandible and angle of mouth
Inn: Facial n. (CN VII)
A: Depresses lower jaw/lip and angle of mouth; wrinkles skin of neck

Question 4

Sternocleidomastoid m.

Answer 4

O: manubrium and medial 1/3 of clavicle
I: mastoid process and lateral half of superior nuchal line
Inn: Spinal Accessory n. (CN XI)
A: Singly turns face toward opposite side; together flex head, raise thorax

Question 5

Suprahyoid mm. (4)

Answer 5

Digastric m
Mylohyoid m
Stylohyoid m
Geniohyoid m

Question 6

Digastric m.

Answer 6

O: ant. belly - digastric fossa of mandible; post. belly - mastoid notch
I: Median raphe and body of hyoid bone
Inn: Ant. belly - n. to mylohyoid from trigeminal n. (CN V); post. belly - facial n. (CN VII)
A: Elevates hyoid and tongue; depresses mandible

Question 7

Mylohyoid m

Answer 7

O: mylohyoid line of mandible
I: median raphe and body of hyoid bone
Inn: n. to mylohyoid from trigeminal n (CN V)
A. Elevates hyoid and depresses mandible

Question 8

Stylohyoid m.

Answer 8

O: styloid process
I: Body of Hyoid
Inn: Facial N. (CN VII)
A: Elevates hyoid

Question 9

Geniohyoid m.

Answer 9

O: Genial tubercle of mandible
I: Body of hyoid
Inn: C1 via hypoglossal n (CN XII)
A: Elevates hyoid and tongue

Question 10

Infrahyoid mm. (4)

Answer 10

Sternohyoid m
Sternothyroid m
Thyrohyoid m
Omohyoid m (superior belly)

Question 11

Sternohyoid m

Answer 11

O: manubrium and medial end of clavicle
I: Body of hyoid
Inn: ansa cervicalis
A: depresses hyoid and larynx

Question 12

Sternothyroid m

Answer 12

O: Manubrium and 1st costal cartilage
I: Oblique line of thyroid cartilage
Inn: ansa cervicalis
A: depresses thyroid cartilage and larynx

Question 13

Thyrohyoid m

Answer 13

O: oblique line of thyroid cartilage
I: Body and greater horn of hyoid
Inn: C1 via Hypoglossal n. (CN XII)
A: Depresses and retracts hyoid and larynx

Question 14

Omohyoid m (superior belly)

Answer 14

O: intermediate tendon
I: Body of hyoid
Inn: Ansa cervicalis
A: depresses and retracts hyoid and larynx

Question 15

Boundaries of the Anterior Cervical Triangle

Answer 15

Superior border - inferior margin of mandible
Inferior border - jugular notch
Medial border - anteriomedian line of the neck
Lateral border - Anterior margin of sternocleidomastoid m.
Anterior border (roof) - platysma m. and investing layer of deep cervical fascia

Question 16

Branches of the External Carotid Artery (8 in ant. triangle)

Answer 16

Superior Thyroid, Lingual, Facial, Ascending Pharyngeal, Occipital, Post. Auricular, Maxillary, Superficial temporal

Question 17

Retromandibular v

Answer 17

• Formed by the superficial temporal and maxillary veins
• Anterior branch joins facial v to form common facial v.
• Post. Branch joins post. auricular v to form ext. Jugular v.

Question 18

External Jugular Vein

Answer 18

• Crosses the sternocleidomastoid obliquely under platysma m.
• Ends in the Subclavian vein or the internal jugular vein
• Recieves the suprascapular v, transverse cervical v, ant. jugular v

Question 19

Cervical Plexus

Answer 19

formed by the ventral primary rami of C1-C4

Question 20

Motor branches of Cervical plexus

Answer 20

• Arise from Ansa Cervicalis
  1. n. to Omohyoid (superior belly)
  2. n. to Sternothyroid
  3. n. to Sternohyoid
  4. n. to omohyoid (inferior belly)

Question 21

Ansa Cervicalis

Answer 21

loop formed by superior root of C1 and/or C2 with inferior root of C2/3

Question 22

Sensory Branches of Cervical Plexus

Answer 22

• Great Auricular Nerve (C2-3)

- Transverse Cervical Nerve (C2-3)

Question 23

Lymphatic Drainage of the Head

Answer 23

Superficial nodes of the head, superficial cervical nodes all drain into deep cervical nodes

Question 24

Boundaries of the Posterior Triangle

Answer 24

Anterior: Post. margin of Sternocleidomastoid
Posterior: Ant. margin of Trapezius
Inferior: Middle 1/3 of Clavicle
Roof: Platysma m. and investing layer of deep cervical fascia
Floor: Splenius Capitus, Levator Scapulae, Scalenes

Question 25

Danger area of the posterior cervical triangle

Answer 25

- Clinically important area located between the trapezius m. and sternocleidomastoid m., inferior to the accessory n. - Many nerves and vessels close to the skin

Question 26

Splenius Capitus

Answer 26

O: Spinous processes C7-T3 I: Mastoid process, Superior nuchal line Inn: Dorsal Primary rami C2-C6 A: Extend neck and head

Question 27

Levator Scapulae

Answer 27

O: Transverse processes of C1-C4 I: Medial border of scapula Inn: nerves to levator scapulae (C3/4), dorsal scapular n A: Elevates scapula

Question 28

Scalenus Medius

Answer 28

O: Transverse processes of C2-C7 I: Upper surface of first rib Inn: C5-C8 A: Elevates first rib, bends neck

Question 29

Scalenus Posterior

Answer 29

O: transverse processes of C4-C6 I: Outer surface of second rib Inn: C6-C8 A: Elevates second rib, bend neck

Question 30

Scalenus Anterior

Answer 30

O: Transverse processes of C3-C6 I: Scalene tubercle of first rib Inn: C5-C8 A: elevates first rib, bend neck

Question 31

Omohyoid (inferior belly)

Answer 31

O: Medial lip of suprascapular notch; suprascapular ligament I: Intermediate tendon Inn: Ansa Cevicalis A: depresses and retracts hyoid and larynx

Question 32

Subclavian Artery

Answer 32

Gives rise to the thyrocervical trunk at the medial margin of the ant. scalene muscle

Question 33

Suprascapular Artery

Answer 33

1st branch from thyrocervical trunk | - passes in front of the ant. scalene m, parallel and inferior to the transverse cervical a.

Question 34

Transverse Cervical artery

Answer 34

2nd branch from thyrocervical trunk | - passes laterally on ant. scalene m, in front of phrenic n, passies deep to trapezius

Question 35

Venous supply of the Posterior triangle

Answer 35

- External Jugular - Transverse cervical - Suprascapular

Question 36

Motor branches of the posterior triangle

Answer 36

- Spinal Accessory (CN XI) - Supraclavicular portion of brachial - dorsal scapular n. - long thoracic n.

Question 37

Sensory branches of the Posterior triangle

Answer 37

- Lesser Occipital n | - Supraclavicular

Question 38

Congenital Torticollis

Answer 38

- aka Wryneck - presents a contracted state of cervical mm, especially SCM, which results in twisting of the neck and protrusion of the chin to the side opposite of the lesion/ contracture - caused by injury to the SCM or avulsion of CN XI at birth - congenital torticollis - SCM fibrosis resulting in no lengthening during development

Question 39

Cervical plexus block

Answer 39

- Regional anesthesia may be achieved bby injeting agent into the nerve point of the neck, which lies along the posterior margin of SCM, ~at the superior and middle 1/3 of the neck

Question 40

Supraclavicular nerve block

Answer 40

- For anesthesia of the upper limb, anesthetic agent may be applied to the supraclavicular portion of the brachial plexus with the main injection site superior to the midpoint of the clavicle

Question 41

Internal Jugular Vein Puncture

Answer 41

- The Right internal jugular Vein may be punctured or instrumented by aiming at the apex of the triangle between the sternal and clavicular heads of the SCM