L2: Organisation of the head and neck

Question 1

What structures do you find in the neck?

Answer 1

• blood vessels and nerves
• cervical vertebrae (C1-7)
• muscles
• cartilages
• glands
• muscular tubes (aerodigestive tract)

Question 2

What is the aerodigestive tract?

Answer 2

• pharynx connects the oral cavity, any fluid/food that passes through here, goes through to the oesophagus and then the stomach
• air through nasal/oral cavity is directed into the larynx and down into the trachea and lungs

Question 3

What structures can you see/palpate when you tilt your neck back?

Answer 3

(sometimes below your chin you can feel the hyoid bone)
-first lump is the thyroid cartilage (Adam’s apple)
-second lump is the cricoid cartilage
(then you would find the thyroid gland- this is not palpable)
-

Question 4

What are the muscles of the neck?

Answer 4

• platysma
• trapezius
• sternocleidomastoid
• scalene muscles
• supra/infra-hyoids

Question 5

Where would you find the supra/infra-hyoids?

Answer 5

Located above (supra) and below (infra) the hyoid
bone. They are important in moving the hyoid bone up and down.

Question 6

What nerves supply the supra/infra-hyoids?

Answer 6

Supra: cranial nerves
Infra: cervical nerves (C1-3)

Question 7

What is the most superficial neck muscle?

Answer 7

Platysma (immediately beneath the skin)

Question 8

Where is the platysma muscle found?

Answer 8

• 2 either side of the midline
• start from the mandible
• extend down towards the anterior chest covering up the clavicle

Question 9

What is the function of the platysma?

Answer 9

• contract to made the skin taut (used when shaving your neck)
• upper parts contracts and can draw down the lower parts of the mouth causing a grimace

Question 10

Where is the sternocleidomastoid (SCM) muscle found?

Answer 10

• below the platysma
• has 2 heads: one comes from the sternum, one from the clavicle
• the 2 heads join and attach to a bony prominence just below your ear: mastoid process
• run obliquely across the neck from a more lateral position to a medial position

Question 11

What is the function of the sternocleidomastoid muscle?

Answer 11

-when it contracts it rotates the chin in the opposite direction

Question 12

Which fibres of the trapezius are found in the neck?

Answer 12

Superior fibres, which are split by a midline called the nuchal ligament.
They extend out laterally and insert into scapula and clavicle
(involved in movements of the shoulder)

Question 13

What classification of muscle does the platysma fit into?

Answer 13

Muscles of facial expression, despite it being located in the neck

Question 14

What nerve supplies the platysma?

Answer 14

Facial nerve- probably the cervical branch

Question 15

What nerve supplies the sternocleidomastoid muscle?

Answer 15

Cranial nerve 11 (accessory nerve)

Question 16

What nerve supplies the trapezius muscle?

Answer 16

Cranial nerve 11 (accessory nerve)

Question 17

What action is associated with testing the trapezius muscle?

Answer 17

Shrugging of the shoulders, with resistance

Question 18

What are the 2 triangles of the neck called?

Answer 18

-anterior triangle
-posterior triangle
There are two of both

Question 19

What are the borders of the anterior triangles?

Answer 19

Lateral boundary: anterior border of SCM
Medial boundary: imaginary mid sagittal line
Superior boundary: inferior border of the mandible
There are 2 anterior triangles

Question 20

What are the borders of the posterior triangles?

Answer 20

The platysma muscle overlies this triangle.
Anterior boundary: posterior border of the SCM
Posterior boundary: anterior border of the trapezius muscle
Inferior boundary: clavicle

Question 21

What structures are found in the anterior triangles?

Answer 21

Structures coursing b/w the head and the thorax e.g. aerodigestive tract

Question 22

What structures are found in the posterior triangles?

Answer 22

Structures coursing b/w the thorax/neck to the upper limb

Question 23

What venous structure runs through the posterior triangles?

Answer 23

External jugular vein (within the subcutaneous tissue/superficial cervical fascia.
It is found in a similar plane to the platysma muscle, but it is found deeper than the platysma.

Question 24

What forms the floor of the posterior triangles?

Answer 24

• scalene muscles (3 of them)
• trunks of the brachial plexus which emerge through the scalene muscles
• subclavian vessels (artery & vein), these continue over the first rib and run into the upper limb
• omohyoid muscle

Question 25

What muscle runs obliquely across the posterior triangles?

Answer 25

Omohyoid muscle (infrahyoid muscle): inferior belly

• it has 2 bellies
• origin is the hyoid bone

Question 26

What is the structure of the omohyoid muscle?

Answer 26

• superior belly takes origin from the hyoid bone, adn descends and disappears beneath the SCM
• inferior belly is then seen again in the posterior triangle

Question 27

What structures are found in the anterior triangles?

Answer 27

• long strap like muscles (infrahyoid muscles)
• thyroid gland (strap muscles lie anterior to the gland)
• suprahyoid muscles (including the digastric muscle)

Question 28

How many bellies does the digastric muscle have?

Answer 28

2

-anterior & posterior bellies

Question 29

What shape is the digastric muscle?

Answer 29

V shaped, with an attachment onto the hyoid bone

Question 30

What is one of the superficial veins of the neck?

Answer 30

External jugular vein

Question 31

What are the deep vessels than run along the neck?

Answer 31

Contained within a connective tissue sheath (carotid sheath)

• internal jugular vein
• common carotid artery
• vagus nerve: cranial nerve 10 (slightly posteriorly to the vessels)

Question 32

Where does the vagus nerve emerge from?

Answer 32

Brain stem, and emerges from the base of the skull and runs down the neck to reach various structures it will be innervating.

Question 33

What are the boundaries of the carotid triangle?

Answer 33

Carotid triangle is a subtriangle within the anterior triangle
Superior boundary: posterior belly of the digastric muscle
Anterior boundary: superior belly of the omohyoid muscle
Lateral boundary: Anterior border of the SCM

Question 34

Why is the carotid triangle important?

Answer 34

This is where the bifurcation of the common carotid artery into its internal/external carotid artery. Here you find a slight swelling at the internal carotid artery: carotid sinus- baroreceptors to monitor pressure

Question 35

What is a carotid sinus massage?

Answer 35

Direct pressure is applied to area of the carotid sinus to stimulate the baroreceptors: slows HR of patients with supraventricular tachycardias
-you can also easily detect a pulse here

Question 36

What is the carotid body?

Answer 36

Chemoreceptor to monitor blood pH/pCO2/pO2