S1 - Organisation Of The Head And Neck

Question 1

What are some muscles of the neck ?

Answer 1

Trapezius
Sternocleidomastoid
Platysma
Infrahyoid and Suprahyoid Muscles

Question 2

What does trapezius and SCM innervated by ?

Answer 2

Accessory nerve

Question 3

What does the platysma do and what is innervated by ?

Answer 3

Draw corners of mouth and skin superiority

Facial nerve

Question 4

What are some facial expression muscles ?

Answer 4

Occpitofrontalis , orbicularis Oris and oculi
Buccinator
Zygomaticus
Levator palpebrae superioris

Question 5

What does the buccinator do ?

Answer 5

Pulls cheek inwards against teeth

Question 6

What does the zygomaticus do ?

Answer 6

Raises corner of mouth superiorly and posteriorly to allow smiling

Question 7

What does the LPS do and what is it innervated by ?

Answer 7

Elevates eyelid

Oculomotor nerve

Question 8

What are the mastication muscles innervated by ?

Answer 8

CN 5

Question 9

What are the mastication muscles and what do they do ?

Answer 9

Medial pterygoid - elevates mandible to close mouth
Lateral pterygoid - unilateral produces side to side movement of jaw
Masseter- elevates mandible to close mouth
Temporalis - elevates mandible to close mouth

Question 10

Where does omohyoid arise from ?

Answer 10

From hyoid to the shoulder and disappears behind the sternum, runs into the posterior triangle

Question 11

Where does the digastric muscle arise from ?

Answer 11

Suprahyoid, just below the chin

Attaches from mandible to hyoid (anterior) to mastoid (posterior)

Question 12

What are the five extra cranial branches of the facial nerve ?

Answer 12

To Zanzibar by motor car 
Temporal
Zygomaticus
Buccal
Mandibular
Cervical

Question 13

What are the three key branches of the trigeminal nerve ?

Answer 13

Va - ophthalmic division
Vb- maxillary division
Vc- mandibular division
Main sensory nerve of face and scalp

Question 14

What is the function of fascial planes ?

Answer 14

Ease of movement between structures

Contain spread of infection

Question 15

What are the fascial planes (Superficial to Deep)?

Answer 15

Superficial cervical fascia

Deep cervical fascia - investing layer, pre- tracheal, pre - vertebral

Question 16

What structures are seen in the superficial cervical fascia ?

Answer 16

EJV
Cutaneous nerves
Superficial lymph nodes
Platysma

Question 17

Describe the investing layer

Answer 17

Surrounds whole neck
Splits to enclose trapezius, SCM and salivary glands (submandibular and parotid glands)
Superior attachments are lower border of mandible and mastoid process and posteriorly attached to spinous process

Question 18

Describe the pre-tracheal layer

Answer 18

Muscular layer encloses infrahyoid muscles, visceral layer encloses thyroid, oesaphagus and trachea.

Question 19

What is the clinical relevance of the pre-tracheal layer ?

Answer 19

Goitre can extend retrosternally as the lower limit of pre-tracheal fascia goes into the thorax - compress other structures in root of neck such as trachea (breathlessness, stridor) or veins ( facial oedema due to obstruction). Buccopharyngeal fascia posteriorly

Question 20

Describe the pre- vertebral layer

Answer 20

Surrounds axillary vessels and brachial plexus

Question 21

How is the carotid sheath formed and what does it contain ?

Answer 21

Formed by the 3 deep fascial layers, from base of cranium to aortic arch, contains carotid artery, IJV and CN X

Question 22

What is the retropharyngeal space and what is its clinical relevance ?

Answer 22

Between pre-vertebral layer and the fascia surrounding the pharynx
Allows pharynx expansion when swallowing but in young children , there are lymph nodes which an infection can develop in after a sore throat and this can spread into the posterior mediastinum causing mediastinitis

Question 23

What is the main arterial supply of the Head and Neck ?

Answer 23

Common carotid artery via its terminal branches
Internal carotid artery
External carotid artery (its facial artery branch supplies face)

Question 24

What is the main venous drainage of the head and neck structures ?

Answer 24

Internal jugular vein
Receives venous drainage from the face (facial vein)
External jugular vein also receives drainage from scalp and face and runs much more superficially than the IJV

Question 25

What is the scalp ?

Answer 25

Scalp cover neurocranium from superior nuchal lines on occipital bones to supra- orbital margins of frontal bone and laterally extends over temporal fascia to zygomatic arches

Question 26

What does the scalp comprise of ?

Answer 26

S- skin - abundant arterial blood supply, good venous and lymphatic drainage
C - connective tissue dense - cutaneous nerves and highly vascularised
A -Aponeurosis (epicranial) attachment for muscle bellies supplied by CN VII
L - loose areolar tissue - allows free movement of scalp proper ( S C and A)
P - pericranium - dense CT, forms external periosteum of the neurocranium

Question 27

How do facial lacerations present ?

Answer 27

Tend to part widely as no distinct deep fascia and subcutaneous tissue is loose

Question 28

How do scalp injuries present ?

Answer 28

No necrosis of Calvaria since supplied by middle meninges arteries and not scalp arteries, arteries at sides protected by dense CT so may heal well, superficial wounds don’t gape due to the strength of aponeurosis, deep wounds gape widely when aponeurosis lacerated in coronal plane due to opposite pull of frontal and occipital bellies of occipitofrontalis

Question 29

How do scalp infections present ?

Answer 29

Loose CT layer is the danger area as pus/blood spreads easily and can pass into cranial cavity through small emissary veins. Can enter eyelids/root of nose as OF inserts into subcutaneous tissue

Question 30

How do black eyes come about ?

Answer 30

Blow to periorbital region