Lecture 1- Muscles of the neck

Question 1

Two very important muscles in the neck are the

Answer 1

sternocleidomastoid and trapezius muscles. Not only do they play a significant role in moving your head and neck but they also define boundaries of triangles that doctors use to visually divide the neck into subsections.

Question 2

most important triangles of the neck

Answer 2

anterior, posterior and carotid triangles

Question 3

key muscles of the neck

Answer 3

Platysma, Sternocleidomastoid (SCM), trapezius, suprahyoids and infrahyoids, scalene muscles (anterior, middle and posterior)

Question 4

suprahyoids are

Answer 4

above the hyoid bones- attached to jaw or base of skull to hyoid bone - elevate tjhe hyoid, depress the mandible

Question 5

infra hyoids are

Answer 5

strap like they overlie the larynx and thyroid gland depress the hyoid and help stabilise it

Question 6

neck muscles

Answer 6

Question 7

• Supra hyoid supplied by

Answer 7

• supplied by cranial nerves

Question 8

Infrahyoid supplied by

Answer 8

cervical nerves (C1-3)

Question 9

platysma

Answer 9

A thin sheet-like muscle that lies superficially within the anterior aspect of the neck. It arises in the upper thoracic and shoulder regions from a fascia that covers the pectoralis major and deltoid muscles. Its fibers ascend superomedially over the anterolateral aspect of the neck, to attach on the mandible and the skin and subcutaneous tissue of the lower face. Contained within the superficial cervical fascia, which is a zone of loose connective tissue between the dermis and deep cervical fascia.

Origin

• Passes over the clavicle and ascends through the anterolateral sides of the neck

Insertion

• Mandible (skin of the lower lip)
• Perioral region
• Muscles surrounding the mouth

Innervation- cervical branch of the facial nerve (CN VII)

Blood supply- facial artery

Function

• Producing a myriad of facial expressions:
  
  • sadness
  • surprise
  • horror by lowering the corners of the mouth and lower lip.

Due to its attachment on the mandible, the platysma can also assist in depressing the mandible and therefore help to open the mouth

Question 10

SCM

Answer 10

Origin- manubrium and medial portion of the clavicle

Insertion- mastoid process of the temporal bone, superioral nuchal line

Blood supply- occipital artery and superior thyroid artery

Nerve supply- the accessory nerve.

Function - rotate the head to the opposite side or obliquely rotate the head. It also flexes the neck. When both sides of the muscle act together, it flexes the neck and extends the head. When one side acts alone, it causes the head to rotate to the opposite side and flexes laterally to the same side (ipsilaterally).

Question 11

Trapezius

Answer 11

Innervation- accessory nerve (CN XI)

Blood supply- upper part (descending) supplied by occipital artery

Function- stabilises the scapula, movement of the head and neck

Question 12

superor border of the anterior triangle

Answer 12

inferior border of the mandible

Question 13

lateral border of the anterior triangle

Answer 13

anterior border of the sternocleidomastoid

Question 14

medial border of the AP

Answer 14

imaginary sagittal line down the midline of the neck

Question 15

carotid triangle is a

Answer 15

subdivision of the anteiror triangle

Question 16

superior border of the carotid triangle

Answer 16

posterior belly of the digastric muscle.

Question 17

lateral border of the carotid triangle

Answer 17

medial border of the sternocleidomastoid muscle.

Question 18

inferior border of the the carotid triangle

Answer 18

• superior belly of the omohyoid muscle.

Question 19

The main contents of the carotid triangle are

Answer 19

the common carotid artery (which bifurcates within the carotid triangle into the external and internal carotid arteries C4?), the internal jugular vein, and the hypoglossal and vagus nerves.

Question 20

posteiror triangle

Answer 20

Located in the lateral aspect of the neck and covered by the investing layer of fascia. Floor is formed by prevertebral fascia.

Question 21

anterior border of the PT

Answer 21

posterior border of the SCM

Question 22

posterior border of the PT

Answer 22

terior border of the trapezium muscle

Question 23

inferior border of the PT

Answer 23

middle 1/3 of the clavicle

Question 24

Contents of the PT

Answer 24

• Muscles
  
  • Omohyoid muscle
    
    • Two bellies (split by a tendon)
    • Inferior belly crosses the posterior triangle trvalling in an supero-medial direction and splitting the triangle in two. The corsses underneath the SCM to enter the anterior triangle
  • Vertebral muscles which form the floor
    
    • Splenius capitis
    • Levator scapulae
    • Anterior, middle and posterior scalenes
• Blood supply
  
  • External jugular vein
    
    • Within the PT this pierces the investing layer of fascia and empties into the subclavian vein
  • Transverse cervical ands suprascapular veins also lie in the posterior triangle
  • Distal part of the subclavian artery
• Nerves
  
  • Accessory nerve (CN XI)