Cross-section Of The Neck Flashcards
Which cervical vertebrae are typical and atypical?
Typical - C3-C6
Atypical - C1-2, C7
Features of the typical cervical vertebrae?
Large and triangular vertebral foramen
Transverse processes have transverse foramen
Spinous processes are short and bifid
Features of the atypical vertebrae?
C1 - no spinous process or body
C2 - peg-like dens projecting superiorly from its body
C7 - long spinous process, not bifid. Large transverse processes with small transverse foramen
Where does the hyoid bone lie?
At the level of C3
Between the mandible and thyroid cartilage
Muscles which suspend the hyoid bone connect to where?
Mandible Styloid process Thyroid cartilage Manubrium of sternum Scapulae
What is the purpose of the hyoid bone?
Attachment for anterior neck muscles
Prop to keep airway open
Name the suprahyoid muscles and their innervation
Stylohyoid: facial nerve
Digastric
- anterior belly: trigeminal
- posterior belly: facial
Mylohyoid
-trigeminal
Geniohyoid
-C1 roots
Overall action of the suprahyoid muscles?
Elevate the hyoid bone, which initiates swallowing
Which suprahyoid muscle forms the floor of the mouth?
Mylohyoid
Name the infrahyoids and their innervation
Sternohyoid
-anterior rami of C1-3
Omohyoid
-anterior rami of C1
Sternothyroid
-ant rami of C1-3
Thyrohyoid
-ant ramus of C1-3
Attachments of the sternocleidomastoid?
Medial head from manubrium of sternum
Lateral head from medial third of clavicle
Mastoid process of temporal bone
Innervation of the sternocleidomastoid?
Accessory nerve - C2-3
Attachments of the trapezius?
Skull and spinous process of C7-T12
Attaches to clavicle, acromion and spine of scapula
Actions of the trapezius?
Elevates scapula and rotates it during abduction
Middle fibres retract the scapula
Lower fibres pull it inferiorly
Borders of the anterior triangle in the neck?
Superior - inferior border of mandible
Lateral - medial border of SCM
Medial - sagittal line down body
Structures in the anterior triangle?
Common carotid artery which bifurcates here Internal jugular vein Cranial nerves -facial -glossopharyngeal -vagus -accessory -hypoglossal
What are the subdivisions of the anterior triangle?
Carotid triangle
Submental triangle
Submandibular triangle
Muscular triangle
Contents of the carotid triangle?
Carotid artery which bifurcates
Internal jugular vein
Hypoglossal and vagus nerves
Clinical relevance of the carotid triangle?
Structures in the triangle are easily accessible here for surgery as they are more superficial
Carotid sinus is here which contains baroreceptors - carotid rub
Which nerve feeds info from the carotid triangle to the brain about blood pressure?
Glossopharyngeal nerve
What does the submental triangle contain?
Submental lymph nodes which filter from floor of mouth and tongue
What does the submandibular triangle contain?
Submandibular gland
Lymph nodes
Facial artery and vein
What does the muscular triangle contain?
Infrahyoid muscles
Pharynx
Thyroid gland
Parathyroid gland
Borders of the posterior triangle?
Anterior - posterior border of SCM Posterior - anterior border of trapezius Inferior - Middle third of clavicle Roof -investing layer of fascia Floor - prevertebral fascia
Contents of the posterior triangle?
Muscles
- omohyoid
- splenius captitis
- levator scapulae
- anterior, middle and posterior scalene
Vasculature
- external jugular vein which drains into the subclavian vein here
- transverse cervical artery
- subclavian artery and vein
Nerves
- accessory nerve
- cervical plexus
- trunks of brachial plexus
What are the subdivisions of the posterior triangle?
Occipital triangle superiorly
Subclavian triangle inferiorly
Split by omohyoid muscle
What injury can happen in the posterior triangle?
Severance of the external jugular vein
Fascia maintains the lumen - air is drawn in - froth in right atrium and ventricle - cyanosis
Therefore pressure needs to be applied
What numbing thing can happen in the posterior triangle?
Cervical plexus nerve block - injected along posterior border of the SCM
Not carried out on patients with pulmonary or cardiac problems because it can damage the phrenic nerve
What structures does the carotid sheath contain?
Internal jugular vein
Common carotid artery
Vagus nerve
Deep cervical lymph nodes
What does the pre-vertebral fascia contain?
Muscles surrounding the vertebrae
Base of skull to T2/3
What does the pre-tracheal fascia contain?
Thyroid
Trachea
Oesophagus
What are the two main layers which surround the whole neck called?
Superficial cervical fascia
Deep investing fascia
If there is an infection posterior to the pre-vertebral fascia, what can happen?
Erode through the pre-vertebrae fascia and drain into the retropharyngeal space
Where can infection spread if it begins between the investing fascia and visceral part of the pre-tracheal fascia?
Can spread inferiorly into the chest and cause an infection of the anterior mediastinum
What structures does the superficial cervical fascia contain?
Neurovascular supply to the skin Superficial veins eg external jugular vein Superficial lymph nodes Fat Playtysma muscle
Innervation of the platysma muscle?
Facial nerve
Importance of fascia in the neck?
Allows structures to slide over one another
Puts them into compartments
Helps us to determine where infection and cancer can spread
Name the three layers of the deep cervical fascia
Deep investing
Pretracheal
Prevertebral
Function of the deep cervical fascia?
Supports viscera, muscles, vessels and deep lymph nodes
Limits the spread of abscesses resulting from infection
Allows structures in the neck to pass over each other during breathing and turning the head and neck
Which structures does the investing layer of fascia enclose?
SCM
Trapezius
Submandibular and parotid salivary glands
Structures in the occipital triangle?
Spinal accessory nerve Trunks of brachial plexus Parts of external jugular vein Posterior branches of the cervical plexus Cervicodorsal trunk Cervical lymph node
Contents of the omoclavicular/subclavian triangle?
Subclavian artery
Part of subclavian vein
Suprascapular artery
Supraclavicular lymph nodes
