Week 3 - A - Thyroid gland anatomy - craig cunningham Flashcards
What is the lobe of the thyroid gland seen in approx 45% of the population?
The pyramidal lobe most commonly originates from the left lateral lobe
the thyroid gland begins its development as a midline epithelial proliferation at the junction between the anterior 2/3rds and the posterior 1/3rd of the tongue What is this junction known as in adults?
The foramen caecum
What week of development does the thyroid gland reach its final position in relevance to the trachea/oesophagus?
In the 7th week of development
What is the group of muscles located within the superficial fascia immediately deep to the skin? Belongs to a group of muscles known as the muscles of facial expression?
The platysma muscles
What nerve innervates the platysma muscles? (clue - they are the muscles of facial expression)
The facial nerve - Cranial nerve VII
The neck contains many fascial compartments What is the compartment deep to the superficial fascia that encloses all other facial compartments of the neck?
The investing (deep) fascia
What muscles does the investing fascia contain?
Contains the trapezius muscles - posterior of the fascia
Contains the sternocleidomastoid mucles - anterior of the fascia
Apart from the investing fascia of the neck, what are the other three fascial compartments of the neck?
Prevertebral fascia
Pretracheal fascia
Carotid sheaths
The prevertebral facia is located posteriorly, what does it contain?
The prevertebral fascia contains the cervical vertebra and the postural neck muscles
The pretracheal (deep) fascia deep to the investing fascia located anteriorly & encloses what? (muscle, gland, 3 other sturctures)
The pretracheal fascia enclose the -
Strap muscles (infrahyoid muscles)
Thyroid gland
Trachea and oesophagus
Recurrent laryngeal nerve
Finally there are the carotid sheaths located laterally to the pretracheal fascia WHat do the carotid sheaths contain? (4 structures)
The common carotid arteries
The vagus nerves
The internal jugular vein
Deep cervical lymph nodes
What are the attachments of the sternocleidomastoid muscle?
Sternal head attaches to the manubrium of the sternum
Clavicular head attaches to medial end of clavicle
Both heads attach superiorly to the mastoid process of the temporal bone
What nerve supplies the sternocleidomastoid muscle? What other muscle does this nerve supply?
Sternocleidomastoid muscle supplied by the spinal accesory nerve (CN XI)
CN XI also supplies the trapezius muscles
What are the three branches of the arch of the aorta? (from right to left)
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
The right vagus nerve descend through the neck in the carotid sheath giving two somatic branches to the larynx in the neck What are these branches?
The superior laryngeal nerve
The recurrent laryngeal nerve
The recurrent laryngeal nerves control all intrinsic muscles of the larynx except for which muscle? What nerve supplies this? (branch of the vagus) Which muscle causes the opening of the vocal cords?
The cricothyroid muscle
Supplied by the superior laryngeal nerve
The recurrent laryngeal supplies the only muscle to open the vocal cords - the posterior cricoarytenoid muscles (abducts the vocal cords)
The strap muscles of the neck, also known as the infrahyoid muscles either originate form or insert on the hyoid bone What are the 4 strap muscles?
Sternohyoid muscle
Sternothyroid muscle
Thyrohyoid muscle
Omohyoid muscle (omo=shoulder)
What are the attachments of the four strap muscles?
Sternohyoid - sternum to hyoid bone
Sternothyroid - sternum to thyroid cartilage
Thyrohyoid - thyroid cartilage to hyoid bone
Omohyoid - hyoid to shoulder
Which strap muscle contains an intermediate tendon attaching the superior and inferior bellies? The intermediate tendon is attached to the clavicle via a fascial sling
The omohyoid muscle
what is the type of incision made in a classical thyroidectomy which is within a natural skin crease or in the direction of langers lines?
A collar incision
Where is the collar incision made? (superior to what and through what)
Just superior to the the clavicles and the jugular notch and through skin and platymsa
what is the opening between vocal cords which prevents aspiration or helps produce a good cough?
Rima glottidis
what effect does unilateral and bilateral injury of the reucrrent laryngeal nerve have on the voice and cough?
unilateral - hoarseness and weak cough
bilateral - aphonia (inability to produce sound) and inability to close rima glottidis
What cranial nerves sensory receptors can be stimulate in sneezing? What cranial nerves sensory receptors can be stimulated in coughing?
CN V or CN IX sensory receptors stimulated in sneezing
CN IX or CN X sensory receptors stimulated in coughing
