Intro to head and neck

Question 1

Where does the neck begin and end?

*anteriorly and posteriorly

Answer 1

Anteriorly: Lower border of mandible -> upper surface of manubrium of sternum

Posteriorly: superior nuchal line on occipital bone -> IV disc between C7-T1

Question 2

What are the four major compartments of the neck?

List them from anterior-posterior

Answer 2

1. Visceral
2. 2 vascular
3. Vertebral

Question 3

What structures would you penetrate through in the neck to go from skin-> deep cervical fascia?

Answer 3

1. Skin
2. Subcutaneous fat
3. Superficial fascia (one layer)
4. Deep cervical fascia

Question 4

Name the sheath of muscle found only in the superficial layer of the anterior neck, where does it begin and what does it attach to? What movement does it contribute to?

Answer 4

Platysma: Begins in the superficial fascia of the thorax and runs upwards to attach to the mandible, blending with muscles of the face

Part of muscles contributing to facial expression

Question 5

What innervates the platysma muscle?

Answer 5

CN VII: Facial n

Question 6

What does the investing fascial layer of the neck attach to posteriorly?

Answer 6

Ligamentum nuchae and the spinous process of the cervical vertebrae

Question 7

Describe the course of the investing layer of deep cervical fascia as it passes around the posterior-anterior neck

Answer 7

1. Splits as it passes forwards to enclose bilateral trapezius muscles
2. Reunites into single layer forming the roof of the posterior triangle
3. Splits again to surround sternocleidomastoid and the 4 infrahyoid muscles

Question 8

What are the borders of the posterior triangle of the neck? What forms the floor?

Answer 8

Anterior: sternocleidomastoid
Posterior: anterior border of trapezius
Inferior: middle 1/3 of clavicle

Floor formed by prevertebral fascia

Question 9

What innervates the trapezius and sternocleidomastoid muscles?

Answer 9

Accessory nerve (CN XI)

Question 10

Which muscle is responsible for dividing the anterior and posterior triangles of the neck?

Answer 10

Sternocleidomastoid

Question 11

What are the pharyngeal arches?

Answer 11

Externally visible anterior tissue bands underneath the early brain that gives rise to structures of the head and neck

Question 12

What overall structure is the hyoid bone a part of and what does it derive from?

Answer 12

Part of the axial skeleton, derived from the 2nd and 3rd pharyngeal arch

Question 13

What level of vertebra does the hyoid bone correlate with?

Answer 13

C3

Question 14

What suspends the hyoid bone?

Answer 14

The stylohyoid muscle which attaches to the styloid process

Question 15

What suspends from and attaches to the hyoid bone?

Answer 15

Larynx is suspended from it

Attachment point for hyoid muscles (supra and infrahyoid muscles)

Question 16

Name the four suprahyoid muscles, what is their function in general terms?

Answer 16

When they contract they raise the hyoid bone and thus the larynx during swallowing to avoid food, etc going down into the lungs

1. Stylohoid (suspends the hyoid bone)
2. Digastric (anterior and posterior belly)
3. Mylohyoid
4. Geniohyoid

Question 17

Name the four infrahyoid muscles (aka ‘strap muscles’) from posterior-anterior, what is their function in general terms?
Which muscle lies overtop of them?

Answer 17

Stabilize the hyoid bone and thus the larynx and lower it after swallowing 
Arranged in layers:
1. Thyrohyoid
2. Sternothyroid (just below thyrohoid) 
3. Sternohyoid 
4. Omohyoid

Sternocleidomastoid lies overtop

Question 18

How does the prevertebral layer of deep cervical fascia attach to the vertebra? What ‘structure’ lies between its attachments?

Answer 18

Splits into two layers
-anteriorly attaches to transverse processes and vertebral bodies of vertebral column

• between is longitudinal fascial space which contains loose CT extending from the base of the skull through the thorax
• posteriorly attaches to nuchal ligament of vertebral column

Question 19

What structures are enclosed by the prevertebral layer of deep cervical fascia both within and outside the neck?

Answer 19

Within neck: surrounds vertebral column and associated muscles (anterior, posterior, middle scalene and deep muscles of back)

As it exits the neck and travels into the upper limb it extends laterally as the axillary sheath which encloses the axillary artery and brachial plexus

Question 20

Where does the pretracheal layer of deep cervical fascia extend from?

Answer 20

Begins at superior hyoid bone and ends inferiorly in the upper thoracic cavity where it blends with the fibrous pericardium

Question 21

What does the pretracheal layer of deep cervical fascia pass and cover anteriorly, laterally and posteriorly? What does it cover overall?

Answer 21

Overall covers the neck’s viscera:
Muscular layer covers infrahyoid muscles
Visceral layer covers trachea, thyroid and esophagus

Anteriorly: posterior to infrahyoid muscles; covers trachea, thyroid gland and esophagus

Laterally: Continues covering lateral sides of thyroid glands and esophagus, blends with the carotid sheaths

Posterior: known as buccopharyngeal fascia which separates the esophagus from the preVERTEBRAL layer

Question 22

Where does the carotid sheath extend from?

List the structures within the carotid sheath from lateral-medial
*bonus: which vessel is the carotid sheath thinner and thicker around?

Answer 22

From base of cranium -> root of neck

1. Internal jugular (thinner here)
2. Vagus N
3. Common carotid artery inferiorly -> internal carotid artery superiorly (*external carotid isn’t in the sheath)
   (Thicker over the common carotid)

Question 23

What contributes to the carotid sheath posteriorly, anteromedially and anterolateral Ly?

Answer 23

Posteriorly: prevertebral layer
Anteromedially: pretracheal layer
Anterolaterally: Investing layer of cervical fascia

Question 24

What might the fascial spaces allow for?

Answer 24

Infection to spread from neck to mediastinum!

Question 25

Name the three fascial spaces, where/how might an infection spread within them? *Identify which space is the MAJOR pathway for infection to spread from the neck to the thorax

Answer 25

1. Pretracheal fascia: infection might spread inferiorly into the superior mediastinum ANTERIOR to the pericardium 2. Retropharyngeal space: major route for infection - may spread inferiorly into the superior mediastinum POSTERIOR to the pericardium 3. Fascial space within the prevertebral layer

Question 26

What forms the borders of the anterior triangle of the neck?

Answer 26

Anterior: midline of neck Superior: inferior border of mandible Posterior: sternocleidomastoid (its anterior border)

Question 27

What are the four subdivisions of the anterior triangle of the neck?

Answer 27

Divided by the hyoid muscles 1. Submandibular triangle 2. Submental triangle (just below submandibular) 3. Carotid triangle 4. Muscular triangle (Just below submental)

Question 28

What are the two subdivisions of the posterior triangle of the neck?

Answer 28

1. Occipital triangle | 2. Supraclavicular triangle

Question 29

Describe the structure and function of the larynx

Answer 29

Structure: A hollow musculoligamentous structure with a cartilaginous framework Function: a valve (sphincter) which closes entry into the lower resp tract (is continuous with the trachea) and produces sound

Question 30

What does the larynx open into superiorly/posteriorly?

Answer 30

The pharynx

Question 31

How mobile is the larynx and why?

Answer 31

Highly mobile as it can be moved up-down forwards-backwards by extrinsic muscles; comprised of suprahyoid and infrahyoid muscles, as well as stylopharyngeus (a muscle of the pharynx)

Question 32

What happens to the larynx during swallowing?

Answer 32

It’s muscles pull upwards and forwards to help block the laryngeal inlet (epiglottis also moves to block this inlet)

Question 33

What provides motor and sensory innervation to the larynx?

Answer 33

Vagus n

Question 34

What structures do the R and L common carotid arteries pass laterally to as they ascend through the neck in the carotid sheath? Where do they divide into external and internal carotid branches?

Answer 34

Pass laterally to the trachea and esophagus Divide into external and internal carotid branches nearer to the superior edge of thyroid cartilage

Question 35

Which vessels provide superficial venous drainage to the head and neck?

Answer 35

1. External jugular vein (the anterior branch) | 2. Anterior jugular vein

Question 36

Which superficial vein crosses sternocleidomastoid as it descends down the neck?

Answer 36

External jugular vein

Question 37

Which vessel provides deep venous drainage to the head and neck? Which structure does it pass deep to and which structures does it drain?

Answer 37

Internal jugular vein, passes deep to sternocleidomastoid Collects blood from skull, brain, superficial face and neck

Question 38

Which vessels does the internal jugular vein join with? Where does this occur and which vessel is inevitably formed by this fusion?

Answer 38

Posterior to the sternoclavicular joint the internal jugular vein joins with the subclavian veins to form the brachiocephalic vein

Question 39

What are the two parts of the cranium?

Answer 39

1. Neurocranium/cranium: Calvaria (top part of skull) -> skull base (fossae) 2. Viscerocranium: facial skeleton

Question 40

Name the layers of the scalp, which layer of the scalp would you find blood vessels that supply it? Which layers are tightly bound together and which layer tends to be where infections localize and spread?

Answer 40

First 3 are tightly bound together S: skin C: CT (dense, main blood vessels and nerves) A: Aponeurotic layer L: Loose CT, where infections tend to localize and spread P: Pericranium; dense irregular CT

Question 41

What does the pericranium adhere to?

Answer 41

Calvarial bone of the skull

Question 42

What does the aponeurotic layer consist of and what innervates it?

Answer 42

The occipitofrontalis muscle (a muscle of facial expression), therefore innervated by CN VII Has two bellies 1. Occipital belly (near occipital bone) 2. Frontal belly (near frontal bone)

Question 43

What separates/connects the two muscle bellies of occipitofrontalis?

Answer 43

Galea aponeurotica AKA epicranial aponeurosis

Question 44

What is the role of the Loose CT layer of the scalp?

Answer 44

Facilitates movement of the scalp over the calvaria bone

Question 45

Name the two major sources of innervation to the scalp, which general areas of the head to they supply?

Answer 45

1. Cranial nerves (mainly in front of ear) | 2. Cervical nerves (mainly behind ear)

Question 46

Name the four major muscle groups in the face/head and the CN that innervates them. Where do they all lie?

Answer 46

All within the subcutaneous tissue 1. Muscles of facial expression (VII) 2. Muscles of the cheek (buccinators) VII 3. Muscles of scalp (i.e occipitofrontalis, VII) 4. Muscles of mastication (V3 branch)

Question 47

Name the four muscles of mastication, which muscle is not innervates by the V3 branch?

Answer 47

1. Masseter 2. Temporalis 3. Buccinator: innervates by VII 4. Medial and lateral Pterygoid

Question 48

Name the five divisions of CN VII on the face from superior-inferior

Answer 48

To Zanzibar By Motor Car ``` T: Temporal Z: Zygomatic B: Buccal M: Mandibular C: Cervical ```

Question 49

Where does sternocleidomastoid extend from?

Answer 49

One head on the sternum, another on the clavicle - both extend to the mastoid process (behind the ear)

Question 50

Where do the two bellies of the digastric muscle (a suprahyoid muscle) extend from?

Answer 50

Posterior belly: mastoid process - hyoid bone | Anterior belly: hyoid bone - front

Question 51

Which muscle forms the floor of the mouth?

Answer 51

The mylohyoid muscle (a suprahyoid muscle)

Question 52

What might a lymph node in the supraclavicular triangle of the posterior triangle of the neck infer?

Answer 52

Metastasis or a pathology coming up from the stomach

Question 53

Which layer of fascia encloses the parotid and submandibular salivary glands?

Answer 53

The investing layer

Question 54

Which structures does the prevertebral layer of deep cervical fascia extend to and from?

Answer 54

From base of cranium -> 3rd thoracic vertebra

Question 55

What happens if pus behind the prevertebral layer extends laterally in the neck? How might this present?

Answer 55

Can perforate the prevertebral fascia and enter the retropharyngeal space - causing a bulge in the pharynx (retropharyngeal abscess). This many present with dysphagia, difficult speech, fever and malaise

Question 56

Name three common causes of neck pain

Answer 56

Inflamed lymph nodes, muscle strain, displacement/protrusion of IV discs

Question 57

What commonly causes chronic neck pain?

Answer 57

``` Bony abnormalities (i.e cervical osteoarthritis) (Or local trauma) ```

Question 58

Major arteries supplying the face are branches of the ____?

Answer 58

External carotid artery

Question 59

What does the external carotid artery terminate as?

Answer 59

The temporal artery and the maxillary artery

Question 60

Which artery provides the major arterial supply to the face and what vessel does it branch off of? What should you do if one of the arteries (on one side of the face is lacerated)

Answer 60

Facial artery, branches off of external carotid Since the facial artery has many anastomoses with other arteries of the face, if it is lacerated it is necessary to compress both arteries

Question 61

Which veins form the external jugular vein?

Answer 61

The retromandibular and posterior auricular veins

Question 62

Both internal and external jugular veins drain into the ____

Answer 62

Subclavian vein

Question 63

Which vein forms the major venous drainage of the face and which vessel does it drain into?

Answer 63

The facial vein, drains into the internal jugular vein

Question 64

After exiting the skull base, where does the facial branch divide into its terminal branches?

Answer 64

As it passes through the parotid gland

Question 65

What is the most common non-traumatic cause of facial paralysis? What is thought to cause it and what does it result in?

Answer 65

Bell’s palsy, a diagnosis of exclusion through to be due to facial nerve inflammation as it exits the facial canal (and cranium) via the stylomastoid foramen and results in edema and compression of the nerve in the facial canal

Question 66

How might the facial nerve be easily damaged and what would be the inevitable result?

Answer 66

Damage to the facial nerve results in weakness of the face It’s branches are superficial and may be injured due to wounds, cuts or childbirth Since the nerve and its branches pass through the parotid gland they are vulnerable during gland surgery or disease

Question 67

Name three areas that might become painful in parotid gland disease

Answer 67

1. Auricle (external part) of the ear 2. Temporal region 3. Temporomandibular joint (TMJ) 4. External acoustic meatus (ear canal running from outer-middle ear)

Question 68

Where does the auricle arise from?

Answer 68

Swellings forming around the entrance to the meatus (ear canal)

Question 69

How can you make the sternocleidomastoid muscle stand out?

Answer 69

Ipsilateral lateral flexion and rotate head to the opposite side

Question 70

Define the term “fascia” and describe its functions in the neck

Answer 70

It’s a CT - which is a mesenchymal organ that can be “loose” or “dense” In the neck: separates organs so they can move against each other (i.e viscera in pre-tracheal layer glide against others to make swallowing possible), compartmentalizations infections

Question 71

Describe the 2 main divisions of fascia in the neck and their subdivisions from superficial-deep, which layer surrounds all neck structures?

Answer 71

1. Superficial fascia (loose CT) 2. Deep fascia (dense irregular CT), consisting of - investing fascia; surrounds all neck structures - pretracheal - prevertebral - carotid sheath

Question 72

Describe the term “potential space” as it applies to fascial planes of the neck?

Answer 72

Adjacent facial compartments are normally so close there is no space, BUT blood from perforated vessels or pus from infections can collect in between fascial planes and track to other areas, creating “potential spaces”

Question 73

What is the difference between the retropharyngeal space and the danger space? Where are infections likely to spread?

Answer 73

The retropharyngeal space is posterior to the pretracheal fascia and anterior to the fascia surrounding the pharynx The DANGER space is a potential space posterior to the retropharyngeal space. It connects inferiorly to the mediastinum (posterior to the pericardium) so infections of the pharynx may lead here

Question 74

Describe the relationship between the retropharyngeal space and the danger space in a healthy individual

Answer 74

In healthy patients the danger space is indistinguishable from the retropharyngeal space - and is only visible when distended by fluid or pus (below the level of T1-6) (since the retropharyngeal space variably ends at this level)

Question 75

How would a person with a dystonic (hypertonic) Sternocleidomastoid present? What is this condition called?

Answer 75

Head tilt (ipsilateral to lesion) and rotation of the chin (contralateral) Called torticollis (or congenital torticollis in newborns)

Question 76

Name the two sphincter muscles of the face. Briefly describe their functions

Answer 76

Orbicularis oris and oculi They contribute to facial expression AND anchor the majority of other small muscles Orbicularis oculi also protects the cornea

Question 77

What might the loss of orbicularis oris lead to and which condition is this commonly seen in?

Answer 77

Drooling, commonly seen in facial nerve palsy/Belle’s palsy

Question 78

Which cranial nerve supplies the motor innervation to the muscles of the face?

Answer 78

Facial nerve CN VII

Question 79

What nerves provide sensory innervation to the face and neck?

Answer 79

Face: Cutaneous branches of the 3 divisions of Trigeminal (V1 - opthalmic, V2 - maxillary, V3 - mandibular) Neck: cutaneous branches of the cervical nerves from the cervical plexus

Question 80

Name three conditions of the head and neck which commonly affect children

Answer 80

1. Enlarged adenoids 2. Cleft lip and palate 3. Ear infections

Question 81

Name three conditions of the head and neck which commonly affect the elderly

Answer 81

1. Presbyacusis - age related hearing loss 2. Presbyopia - far sightedness (loss of elasticity in lens of eye) 3. Macular degeneration (macula is central part of retina, therefore results in distorted/loss of central vision)

Question 82

Why are pregnant women at an increased risk of gingivitis and gum disease?

Answer 82

Increased volume of blood and hormonal changes effect the soft tissues around the body during pregnancy

Question 83

Why are pregnant women at an increased risk of acid reflux?

Answer 83

Pregnancy hormones relax the lower esophageal sphincter and the size of the baby increases the pressure on the stomach

Question 84

What is ostosclerosis and what can it be exacerbated by?

Answer 84

Hereditary disorder causing progressive deafness due to overgrowth of bone in the inner ear, can be exacerbated by pregnancy (likely due to estrogen)

Question 85

When does a wound to the scalp gape? How long would it take to remove sutures from the scalp/head (or face) region and why?

Answer 85

Gapes IF the wound is deep enough to involve the aponeurosis as the muscle bellies on either side of the aponeurosis (frontal and occipital) pull which creates tension and causes the wound to gape Since the blood supply to the scalp is so rich (comes from internal and external carotids), sutures can often be removed much sooner than sutures elsewhere in the body

Question 86

Why is it that following a blow to the head, bleeding as a result of injury can pass forward into the orbital region (causing a black eye) but not into the subtemporal or occipital region?

Answer 86

This is because trauma to the head does not only cause bleeding in the dense vascular CT above the aponeurosis, but in the (smaller vessels of) loose CT UNDER the aponeurosis as well. Fluid or blood can track freely within the loose CT underneath the aponeurotic layer, but can only go as far as the margins of the aponeurosis and its associated muscles; which relate to where it inserts into bone. So, blood cannot track into the subtemporal region or occipital region because... Laterally the aponeurosis is continuous with the temporalis fascia (which inserts into the zygomatic arch) Posteriorly the occipital muscle attaches to the occipital bone and mastoid process But, blood can track into the orbital region (including eyelids and root of nose) because... The frontal is muscle inserts anteriorly by merging with the skin and subcutaneous tissue (NOT bone)