Lecture 18 - Neck

Question 1

What are the different hypaxial muscle groups in the neck?

L18 S5

Answer 1

Rectus cervicis (rectus abdominal equivalent):

• sternothyroid
• thyrohyoid
• sternohyoid
• omohoyoid

Geniohyoid (floor of mouth)

Scalene muscle (intercostals equivalent):

• anterior scalene (C3-6 -> 1st rib)
• middle scalene (C5-7 -> firs rib)
• posterior scalene (C5-7 -> second rib)

Levator scapulae (part of stratus laver)

Prevertebral (no equivalent)

• rectus capitis lateralis
• rectus capitis anterior
• longus capitis
• longus colli

Question 2

What are the borders of the anterior triangle of the neck and what are its subdivisions?

L18 S10

Answer 2

Borders:

• superior: mandible
• posterior: sternocleidomastoid
• anterior midline of neck

Subdivisions:

• muscular triangle
• submandibular triangle
• carotid triangle

Question 3

What is the origin, innervation, and action of the different bellies of the digastric muscle?

L18 S11

Answer 3

Anterior belly:

• origin: digastric fossa of mandible
• innervation: CN V-3
• action: elevate hyoid and tongue; open mouth; depress mandible

Posterior belly:

• origin: mastoid notch of temporal bone
• innervation: mylohyoid nerve CN VII
• action: elevates hyoid and tongue; open mouth; depress mandible

Question 4

What is the origin, insertion, action and innervation of the stylohyoid muscle?

L18 S12

Answer 4

Origin:
-styloid process

Insertion:
-body of hyoid

Action:
-elevates and retracts hyoid

Innervation:
-CN VII

Question 5

What is the origin, insertion, action and innervation of the mylohyoid muscle?

L18 S12

Answer 5

Origin:
-mylohyoid line of mandible

Insertion:
-raphe/body of hyoid

Action:
-elevates hyoid

Innervation:
-CN V-3

Question 6

What is the origin, insertion, action and innervation of the geniohyoid muscle?

L18 S12

Answer 6

Origin:
-inferior mental spine of mandible

Insertion:
-body of hyoid

Action:
-elevates hyoid

Innervation:
-C1 via hypoglossal nerve

Question 7

What is the origin, insertion, action and innervation of the sternohyoid muscle?

L18 S12

Answer 7

Origin:
-manubrium

Insertion:
-body of hyoid

Action:
-depresses hyoid and larynx

Innervation:
-ansa cervicalis

Question 8

What is the origin, insertion, action and innervation of the sternothyroid muscle?

L18 S13

Answer 8

Origin:
-manubrium

Insertion:
-thyroid cartilage

Action:
-depresses hyoid and larynx

Innervation:
-ansa cervicalis

Question 9

What is the origin, insertion, action and innervation of the thyrohyoid muscle?

L18 S13

Answer 9

Origin:
-thyroid cartilage

Insertion:
-body and greater horn of hyoid

Action:

• depresses hyoid
• elevates larynx

Innervation:
-C1 via hypoglossal nerve

Question 10

What is the origin, insertion, action and innervation of the omohyoid muscle?

L18 S13

Answer 10

Origin:

• body of hyoid (superior belly)
• upper border of scapular (inferior belly)

Insertion:
-intermediate tendon attached to clavicle and rib 1

Action:
-depresses hyoid

Innervation:
-ansa cervicalis

Question 11

What is the blood supply of the lower neck?

L18 S14

Answer 11

Branches of subclavvian artery:

• vertebral artery
• internal thoracic artery
• costocervical trunk
• thyrocervical trunk

NOT THE COMMON CAROTID

Question 12

What are the contents of the carotid sheath?

L18 S15

Answer 12

• carotid artery
• internal jugular vein
• part of vagus nerve

Question 13

What is the superior cervical ganglion?

L18 S23

Answer 13

Lies on longus capitis muscle

At level of C1/2

Innervates all smooth muscle and glands of head