BMS271 - Neck

Question 1

Platysma

Answer 1

Attachments:
- subcutaneous tissue of inferior and superior to clavicle
- mandible, cheek, inferior lip, orbicularis oris
Action:
- depresses mandible (against resistance)
Innervation
- facial nerve (Cervical branch)

Question 2

Sternocleidomastoid

Answer 2

Attachments:
2 heads, clavicular and sternum
- mastoid process and occipital bone
- manubrium and medial third of clavicle
Action:
- unilateral: laterally flexes and superiorly rotates neck
- bilateral: extends atlanto-occipital joints
- bilateral: flexes neck
- bilateral: extends superior cervical vertebrae while flexing inferior cervical vertebrae
Innervation
- accessory nerve (CN XI)

Question 3

Suprahyoid Muscles

Answer 3

Proximal attachments:
- digastric: base of cranium
- stylohyoid: styloid process
- mylohyoid: body of mandible
- geniohyoid: body of mandible	
Distal attachments:
- hyoid bone 
Action:
- elevate hyoid
- depress mandible (against resistance)
Creates floor of mouth - genioglossus sits on top

Question 4

Infrahyoid Muscles

Answer 4

Proximal attachments:
- omohyoid: scapula
- sternohyoid: manubrium
- sternothyroid : manubrium
- thyrohyoid: thyroid cartilage	
Distal attachments:
- hyoid bone (except sternothyroid: thyroid cartilage) 
Action:
- fix or depress hyoid bone (and larynx: sternothyroid)

Question 5

Scalene Muscles

Answer 5

Proximal attachments:
- anterior: transverse processes C3-C6
- middle: transverse processes C5-C7
- posterior: transverse processes C5-C7 	
Distal attachments:
- anterior and middle: 1st rib
- posterior: 2nd rib
Action:
- anterior: flexes head
- middle and posterior: laterally flex neck and elevate 1st and 2nd ribs during forced inspiration

Question 6

Thyroid Gland

Answer 6

Sits deep to sternothyroid and sternohyoid muscles
Right and left lobes connected by isthmus
Has thin fibrous capsule which extends into the gland
Parathyroid glands (usually 4) are on the posterior surface of the thyroid external to the capsule

Question 7

Larynx

Answer 7

9 cartilages, many ligaments and membranes
Produces sound: phonation
Guards air passages:
- can block air flow
- can block fluid/food from entering during swallowing
Cartilages: 3 single, 3 pairs
- single: thyroid, cricoid, epiglottic
- paired: arytenoid, corniculate, cuneiform

Question 8

Vagus Nerves

Answer 8

Travel between internal jugular vein and common carotid artery

Question 9

Recurrent laryngeal nerves are branches of vagus

Answer 9

Right loops inferior to right subclavian artery
Left loops inferior to arch of aorta
Recurrent laryngeal nerves supply trachea, oesophagus and muscles of larynx (except cricothyroid)

Question 10

Phrenic nerves

Answer 10

C3,4,5 keeps you alive
Formed at lateral border of anterior scalene
Descend on anterior surface of anterior scalene deep to SCM and internal jugular vein

Question 11

Sympathetic trunk

Answer 11

Anterolateral to vertebral column
Three ganglia: superior, level of C1 – C2
Middle, level of C6
Inferior, level of C7, may fuse with 1st thoracic