Superficial Neck

Question 1

The _____ _______ spread of infection within a fascial space is very easy

Answer 1

north south

Question 2

What is the main action of the platysma?

Answer 2

• draws corners of mouth inferiorly and widens (sadness/fright)
• draws skin of neck superiorly when teeth are clenched

Question 3

What is the main action of the sternocleido-mastoid?

Answer 3

• unilateral: tilts head to same side and rotates it so face is turned superiorly toward opposite side
• bilateral: extends neck at atlanto-occipatal joint, flexes cervical vertebrae so chin goes down, extends superior cervical vetrebrae while flexing inferior vertebrae so chin is trust forward

Question 4

What is the main action of the trapezius?

Answer 4

• elevates retracts and rotates scapulae superiorly
• descending fibers: elevate sacpulae/shoulders (against gravity)
• transverse fibers: retract scapulae
• ascending fibers: depress scapulae/shoulders
• descending and ascending: rotate spinous process of scapulae superiorly
• with shoulders fixed: bilateral contraction extends neck, unilateral contraction produces lateral flexion to same side

Question 5

What is the innervation for the platysma?

Answer 5

• cervical branch of facial nerve (CN VII)

Question 6

What is the innervation for the sternocleido mastoid?

Answer 6

• spinal acessory nerve; CN XI (motor)
• C2 and C3 nerves (pain and proprioception)

Question 7

What is the innervation for the trapezius?

Answer 7

• spinal acessory nerve; CN XI (motor)
• C2 and C3 nerves (pain and proprioception)

Question 8

What is the main action of the mylohyoid?

Answer 8

elevates hyoid, floor of mouth, and tongue during swallowing and speaking

Question 9

What is the innervation of the mylohyoid?

Answer 9

inferior alveolar nerve from CN V3

Question 10

What is the main action of the geniohyoid?

Answer 10

pulls hyoid anterosuperiorly; shortens floor of mouth; widens pharynx

Question 11

What is the innervation of the geniohyoid?

Answer 11

C1 via hypoglossal nerve (CN XII)

Question 12

What is the main action of the stylohyoid?

Answer 12

elevates and retracts hyoid, thus elongating floor of mouth

Question 13

What is the innervation of the stylohyoid?

Answer 13

stylohyoid branch of the facial nerve (CN VII)

Question 14

What is the innervation of the digastric?

Answer 14

• digastric branch of facial nerve (CN VII)
• nerve to mylohyoid, a branch of inferior alveolar nerve

Question 15

What is the main action of the digastric nerve?

Answer 15

working with infrahyoid muslces, depresses mandible against resistance; elevates and steadies hyoid during swallowing and speaking

Question 16

What is the innervation of the sternohyoid and omohyoid?

Answer 16

C1-C3 by branch of ansa cervicalis

Question 17

What is the innervation of the sternothyroid?

Answer 17

C2 and C3 by a branch of ansa cervicalis

Question 18

What is the innervation of the thyrohyoid?

Answer 18

C1 via hypoglossal nerve (CN XII)

Question 19

What is the main action of sternohyoid?

Answer 19

depresses hyoid after elevation during swalloing

Question 20

What is the main action of omohyoid?

Answer 20

depresses, retracts, and steadies hyoid

Question 21

What is the main action of sternothyroid?

Answer 21

depresses hyoid and larynx

Question 22

What is the main action of thyrohyoid?

Answer 22

depresses hyoid and elevates larynx