Surface Anatomy of the Neck

Question 1

Learning outcomes

Answer 1

After this lecture, time spent in the dissecting room, and further private study you should be able to:

1. Describe the general structure of the neck as composed of vertical columns surrounded by fascial sheets with potential spaces between
2. Describe the concept of the anterior and the posterior triangles of the neck, and their boundaries
3. Describe the form and position of the common and internal carotid arteries and the internal jugular vein
4. Describe the form and position of the external carotid artery, external jugular vein and anterior jugular vein
5. Discuss the nerves, lymph nodes and muscles adjacent to the above vessels
6. State the bony and cartilaginous landmarks used to locate and demonstrate the above structures on a living model or patient

Question 2

Describe the general structure of the neck

Answer 2

Posteriorly there is the euro-musculo-skeletal column with prevertebral fascia

Anteriorly there is a visceral column with pretracheal and buccopharangeal fascia

In between there are potential spaces to allow for movement

On each side there is a carotid neuromuscular bundle with carotid sheath

Everything is surrounded by a layer (collar) of surrounding fascia

Question 3

What are the fascial layers of the neck?

Answer 3

Superficially there is the investing (superficial) fascia

Pretrachial fascia

2x carotid sheath

prevertebral fascia

Question 4

Where are some important potential spaces in the neck?

Answer 4

Retropharangeal space

Bounded by the buccopharyngeal fascia anteriorly and the alar fascia posteriorly (sometimes considered a part of prevertebral fascia, sometimes not).

And DANGER space

It is bounded at the top by the skull base, at the front by the alar fascia and behind by the prevertebral fascia. It comes to an end at the level of the diaphragm.

Question 5

Why is the danger space called such a cool name?

Answer 5

The risk of an infection travelling from here to the thorax/mediastinum and its bilateral structure allows infection to spread to either side. It is dangerous

Also dental abscesses can spread into mediastinum

Question 6

What does the “True” Retropharyngeal Space allow?

Answer 6

Movement, as do all potential spaces:
– Permits movement during swallowing of pharynx, oesophagus,
trachea and larynx

Question 7

What are the potential retropharangeal abcesses?

Answer 7

– Nasopharynx, paranasal sinuses or middle ear infections

Question 8

What are the two triangles of the neck?

Answer 8

Posterior triangle

Anterior triangle

Question 9

What are the borders of the posterior triangle?

Answer 9

Anterior 
– posterior border of the SCM
Posterior
– anterior border of the trapezius muscle 
Inferior 
– middle 1/3 of the clavicle

Question 10

What are the borders of the anterior triangle?

Answer 10

Superiorly 
– inferior border of the mandible
Laterally 
– anterior border of SCM
Medially 
– sagittal line down the midline of the neck

Question 11

What is the clinical relevance of the triangles of the neck?

Answer 11

When looking for Neck Lumps

 Location
– Anterior triangle – Posterior triangle – Midline
 Size/Depth
 Pulsatile
 Solitary or multiple lumps 
 Tenderness
 Heat/Inflammation
 Movement
 -Swallowing
 -Sticking out tongue

Question 12

Name the big bony landmarks of the skull

Answer 12

Mastioid

Zygoma and external acoustic meatus

Angle of the mandible

Position of transverse process of the atlas between mastoid and angle of the mandible

Question 13

How many horns does the hyoid bone have?

Answer 13

Two pairs, Lesser and Greater horns

Question 14

Describe the thyroid cartilage

Answer 14

Largest cartilage of the laryngeal skeleton
 Two lamina, lesser and greater horns
 Laryngeal Prominence
– Fusion of inferior 2/3 of two lamina
– Adam’s Apple – prominent in males 
 Articulates with cricoid cartilage
– Rotation and gliding of thyroid cartilage
– Change length/sound of vocal cords

Question 15

What are the branches of the aorta? (sans coronary arteries)

Answer 15

Brachiocephalic trunk leading to right subclavian and right common carotid

Left common carotid
Left subclavian

Question 16

Describe the brachiocephalic trunk

Answer 16

Largest branch of arch of aorta
Anteriorly covered by;
– Right sternohyoid and sternothyroid muscles
Passes superolaterally to the right and divides
– Right common carotid and right subclavian arteries -> posterior to the sternoclavicular joint

Question 17

Describe the subclavian arteries

Answer 17

Passes Rib 1 on way to upper limb
 3 parts, according to the anterior scalene muscle
 1st part
– Vertebral artery
– Thyrocervical trunk
– Internal thoracic artery
 2nd part
– Costocervical trunk
 3rd part
– Dorsal scapular artery
 Becomes the axillary artery

Question 18

Describe the common carotid arteries

Answer 18

Bifurcates at the level of superior border of thyroid cartilage
– Internal carotid artery
– External carotid artery
Proximally covered by muscles
Distally exposed allowing palpation of pulse
– Normally internal carotid artery

Question 19

Describe carotid bifurcation

Answer 19

Level of the superior border of the thyroid cartilage
External carotid artery
Internal carotid artery
– Dilatation of proximal internal carotid artery

Question 20

Describe the carotid body and carotid sinus

Answer 20

Nerve innervation
– Afferent glossopharyngeal
• Carotid sinus nerve
– Efferent Vagus nerve

Carotid Sinus - Baroreceptor
– Reacts to change in arterial blood pressure

Carotid Body – Chemoreceptor
– Monitors the partial pressure of CO2

Question 21

Describe the internal carotid artery

Answer 21

Covered by the carotid sheath
Carotid sheath
– Internal jugular – Internal carotid – Vagus nerve
Supplies intracranial structures

Question 22

Describe the external carotid artery

Answer 22

Shitton of branches, look at a tube map for their path

Acronym:
 Some
 Anatomists 
 Like
 Freaking
 Out
 Poor
 Medical
 Students

 Superior thyroid artery
 Ascending pharyngeal artery  Lingual artery
 Facial artery
 Occipital artery
 Posterior auricular artery
 Maxillary artery
 Superficial temporal artery

Question 23

Describe venous drainage of the neck

Answer 23

Facial veins
– Superficial
– Deep

Cervical veins
– External jugular vein
– Anterior jugular vein
– Vertebral vein

 Cranial veins
– Cerebral veins
– Dural venous sinuses 
– Diplopic veins
– Emissary veins

Question 24

Describe the cranial veins

Answer 24

Drained by
– Dural venous sinuses
• Superior sagittal sinus 
• Inferior sagittal sinus
• Sinus rectus
– Sigmoid sinus
• Becomes internal jugular vein

The posterior compartment of the jugular foramen transmits the sigmoid sinus (becoming the internal jugular vein)

Question 25

Describe the internal jugular vein

Answer 25

Drains intracranial structures, superficial parts of face and neck
Within the carotid sheath
– Vagus and internal carotid artery
Initially lies posterior to the internal carotid artery, moves laterally then anterior of the common carotid
Jugular Venous Pulse Wave is visible along the trajectory of the IJV

Question 26

What is the internal jugular veins relationship with other structures?

Answer 26

Close to many very important structures!

Vagus
Phrenic nerve
Brachial plexus

Question 27

What is the clinical relevance of the internal jugular vein?

Answer 27

Central Venous Access or Central Venous Catheterisation

 Most commonly inserted in the internal jugular vein (sometimes subclavian)
 Measure central venous pressure (CVP)
– Normal CVP is <8 cm H2O
 Administration of fluids, medications

 Complications
– Pneumothorax
– Puncture of subclavian artery
– Nerve injury

Note: Risk of air embolism if external jugular vein used

Question 28

Describe the external jugular vein

Answer 28

 Descends from the angle of the mandible to the middle of the clavicle
 Formed by;
– Posterior division of
the retromandibular vein 
– Posterior auricular vein

• Crosses the SCM obliquely, deep to the platysma, and enters the antero- inferior part of the posterior triange.
• Pierces the investing fascia at the posterior border of the SCM.
• Descends and terminates in the subclavian vein.
• Drains most of the scalp and side of the face.

Question 29

Describe the anterior jugular vein

Answer 29

 Inferior to the hyoid bone
• Drains into external jugular or
subclavian veins
• Anterior jugular veins of both sides join
• Jugular venous arch

Question 30

Describe the nerves of the neck

Answer 30

Cutaneous branches of the cervical plexus

 Erb's point – four cutaneous branches become superficial
– Lesser occipital
– Great auricular nerve
– Transverse cervical 
– Supraclavicular

• Accessory nerve
– Motor control of
trapezius and SCM
– Passes across the posterior triangle

Question 31

Describe the lymph nodes in the neck

Answer 31

• No lymph nodes in the scalp or face

* Except parotid/buccal region