Thyroid anatomy Flashcards
What forms the anterior triangle?
Anterior SCM
Midline from sternum -> mandible
Inferior border of the mandible
What forms the posterior triangle?
Posterior SCM
Descending part of trapezius
Middle 1/3 clavicle
What muscles are contained within the posterior triangle?
Levator scapulae
Scalenes
Inferior belly of omohyoid = muscle flaw
What is the function of SCM + what innervates it?
SCM: Rotate head + neck flexion
Accessory nerve
What are the infrahyoid muscles, their function + innervation?
Infrahyoid muscles:
Omohyoid: Ansa cervicalis, depress hyoid bone
Sternohyoid: AC, depress hyoid bone
Sternothyroid: AC Elevate thyroid cartilage
Thyrohydoid: Hypoglossal, Depress thyroid cartilage
What are the suprahyoid muscles, their function + innervation?
Anterior digastric + mylohyoid: Mandibular nerve, elevate and pull forward the hyoid bone
Posterior digastric + stylohoid: Facial nerve, depress and retract the hyoid bone
Describe the anatomy of the thyroid gland
Describe their anatomical relationships
Thyroid gland is made of 2 lobes attached by the isthmus, they lie either side of the larynx + trachea
They are made of inferior and superior poles
The fascia surrounding the thyroid and also the pre tracheal fascia anchor the thyroid gland to the larynx + trachea so it doesn’t move in swallowing
Lateral portions of lobes are in close contact with the carotid sheath
Close proximity to recurrent laryngeal nerves ( branches of CN 10)
Describe the anatomy of the parathyroid glands including their locations
Parathyroid glands are located posteriorly and there are 2 inferior + 2 superior
Superior - more consistent location, normally the middle lobe
Inferior - more inconsistent location, normally inferior pole
Describe the blood supply + veneous drainage of the thyroid gland
Superior thyroid artery - branch of external carotid
Inferior thyroid artery - branch of thyrocervical trunk ( subclavian)
Thyroid ima artery - branch of brachiocephalic trunk
Superior + middle thyroid veins -> internal jugular
Inferior thyroid veins -> brachiocephalic trunk
Describe the innervation + lymphatic drainage of the thyroid gland
Cervical ganglia of sympathetic trunk
Deep cervical nodes ( superficial or inferior), pre laryngeal, para tracheal, pre tracheal
What are the 2 main main fascia of the neck and what do they do?
Fascia = connective tissue that compartmentalises the structures of the neck
Superficial cervical fascia =Between skin dermis + deep cervical fascia. Contains the platysma muscle
Deep cervical fascia: Deep to the superficial cervical fascia and platysma. Made of several layers
Investing layer = most superficial, reaches the SCM + trapezius to divide into two and surround them
Pre vertebral = surrounds vertebral column+ associated muscles
Pre tracheal = Surrounds trachea, oesophagus, thyroid gland and infrahyoid muscles
Buccopharyngeal fasica : Covers the buccinator muscles + pharynx. Behind the pharynx
What is the alar fascia?
Almost double layer of fascia that separates the retropharyngeal space from the danger space
What are the 3 spaces within the neck compartments and what are their boundries?
Retropharyngeal fascia : Buccopharyngeal fascia anteriorly + pre vertebral fascia posteriorly
Danger space: Behind retropharngeal space by the alar fascia
Pre vertebral fascia: Space posterior to alar fascia and anterior to pre vertebral fascia
