Session 1 - General organisation of Head and Neck Flashcards
What supplies the muscles of mastication?
- Muscles of mastication – supplied by the mandibular division of the trigeminal nerve (branch of CN 5)
What does the facial nerve supply? What CN is the facial nerve?
Facial nerve (CN 7) supplies the superficial muscles of the neck and chin, muscles of facial expression, buccinators, muscles of the ear, and the occipitofrontalis muscle.
What is the most common non trauma cause of facial paralysis? Where does it occur? What happens?
- Most common non trauma cause is inflammation of the facial nerve near its exit from the cranium at the stylomastoid foramen:
- Inflammation causes edema which compresses the nerve at the intracranial facial canal.
- Results in affected area sagging
What structure does the facial nerve pass through? Why is this clinically relevant? Where can disease of this structure refer to?
- Nerve passes through the parotid gland and therefore vulnerable to injury during surgery on the gland or disease of the gland:
- Parotid gland disease can cause pain in the temporal region and auricle of the ear.
Where can the facial artery be palpated?
Inferior border of the mandible
What does the facial vein drain into?
Internal jugular
What structures drain into the external jugular vein?
Superficial temporal, maxillary
Where do the jugular veins drain into?
Subclavian vein
What determines where an infection in the neck can spread?
Fascial planes
What are the green, orange, purple and red fascia in the pic?
Green - investing layer
Purple - Pretracheal layer
Orange - Prevertebral layer
Red - Carotid sheath
What is the superficial cervical fascia?
Layer of fatty connective tissue that lies between the dermis of the skin and the layer of deep cervical fascia.
What is the platysma? Where is it found and what supplies it? What is its function?
- Broad thin sheet of muscle in the superficial cervical fascia.
- Supplied by the facial nerve
- Depresses the mandible and draws the corners of the mouth inferiorly.
What is the 3 functions of the deep cervical fascia?
- Supports the viscera, muscles, vessels, and lymph nodes
- Limit the spread of abscesses due to infection
- Reduce friction with regards to swallowing and turning the head and neck.
What does the muscular layer of the pretracheal layer enclose?
Infrahyoid muscle
What does the visceral layer of the pretracheal layer enclose?
Thyroid gland, trachea, oesophagus
Up to Where does the pretracheal layer extend inferiorly?
to the thorax where it blends with the fibrous pericardium
From where to where does the prevertebral layer extend to superiorly? Where does it extend to laterally
Extends from base of the cranium to the 3rd thoracic vertebra
Extends laterally as the axillary sheath that surrounds the axillary vessels and the brachial plexus.
What CN is the vagus nerve?
10
Where can an infection spread:
a) between investing and muscular pretracheal
b) between investing and visceral pretracheal
c) between prevertebral and investing
a) cant spread beyond manubrium (superior part of sternum)
b) can spread into thoracic cavity anterior to pericardium
c) can spread laterally in the neck, may perforate fascial layer and enter retropharyngeal space resulting in a bulge in the pharynx and difficulty swallowing and speaking (dysphasia and dysphonia).
What is the retropharyngeal space? Where does it run to?
- Potential space between prevertebral fascia and carotid sheath fascia.
- Major route of spread of infection from the neck to the thorax. Runs to the diaphragm.
What is the borders of the anterior triangle of the neck?
Superiorly – Inferior border of the mandible (jawbone)
Laterally – Medial border of the sternocleidomastoid
Medially – Imaginary sagittal line down midline of body
What 4 triangles can the anterior triangle be subdivided into? Where are they located?
4 - submandibular triangle
5 - submental triangle
6 - Carotid triangle
7 - Muscular triangle
What are the borders of the posterior triangle of the neck?
Anterior: Posterior border of the SCM.
Posterior: Anterior border of the trapezius muscle.
Inferior: Middle 1/3 of the clavicle.
What are the 2 subdivisions of the posterior triangle? Which ones are they on the diagram?
Occipital triangle - 2
Omoclavicular triangle - 3
What is contained in the occipital triangle?
- Spinal Accessory Nerve (CN XI)
- Trunks of Brachial Plexus
- Part of external jugular vein
- Posterior branches of cervical plexus
- Cervicodorsal trunk
- Cervical lymph node
What is contained in the omoclavicular triangle?
- 3rd part Subclavian Artery
- Part of Subclavian Vein
- Suprascapular artery
- Supraclavicular lymph nodes
What is the function of the hyoid muscles? What do they attach to?
Steady or move the hyoid and larynx. Attach to hyoid bones
Name the suprahyoid muscles
- Mylohyoid
- Geniohyoid
- Stylohyoid
- Digastric muscles (2 bellies - anterior and posterior)
name the superficial infrahyoid muscles
- Sternohyoid
- Omohyoid (2 bellies, superior and inferior)
SO superficial
Name the deep infrahyoid muscles
- Sternothyroid
- Thyrohyoid
What muscle might be damaged in a forceps delivery in the neonate? How would they present?
SCM
tilt of the head towards normal side, called toticollis
What is the neurocranium and the viscerocranium?
neurocranium - skull base and calvarium
Viscerocranium - Facial bones
What artery supplies the neurocranium and the viscerocranium?
neurocranium - ICA
viscercranium - ECA
