What are the boundaries of the posterior triangle?

What may be damaged by stab wounds in the posterior triangle?
The apex of the lung and the brachial plexus
Would would be the consequence of a brachial plexus injury via a stab wound in the posterior triangle?
Erb’s Palsy as this is an upper trunk injury
What muscles are paralysed in Erb’s palsy?
Complete paralysis:
Partial paralysis:
What is the deformity associated with Erb’s palsy?
Arm:
Forearm:
This is due to injury of the C5 and C6 nerve roots
The accessory nerve runs posteroinferiorly through the posterior triangle.
Which muscles are supplied by this nerve?
sternocleidomastoid and deltoid
What are the boundaries of the anterior triangle?

Label the features of the larynx


What is the suprasternal notch?
A large visible dip between the neck and the two collarbones

What is shown by the letters on this image?

RL and LL - right lobe and left lobe
S - isthmus of thyroid gland
H - hyoid bone
T - thyroid cartilage
C - cricoid cartilage
What is the passage of the external jugular vein in the neck like?
What are the surface markings of this vessel?
it descends through the subcutaneous tissue of the neck on the surface of the sternocleidomastoid muscle
surface marking is a line from the angle of the mandible to the middle of the clavicle

Where are the infrahyoid muscles found?
What is their important function?
They lie distal to the hyoid bone
They depress the hyoid bone during swallowing
What are the 4 infrahyoid muscles and how can they be divided into 2 groups?
Superficial plane
Deep plane:
Label the infrahyoid muscles


What is the innervation of the infrahyoid muscles?
Thyrohyoid muscle:
All others:
What components of the larynx can be identified in the gap between the left and right infrahyoid muscles?
What is a cricothyroidotomy?
Under what circumstances would this be performed?
An incision made through the skin and cricothyroid membrane
It is used to establish a patent airway during life-threatening situations such as airway obstruction by a foreign body, angiodema or massive facial trauma
What is a tracheostomy?
Under what circumstances is this performed?
This involves creating an opening in the neck so that a pipe can be placed within the trachea temporarily or permanently
tracheostomy is performed because of airway obstruction, problems with secretions, and inefficient oxygen delivery
What is the role of the suprahyoid muscles?
they lie above the hyoid bone and have attachments to it
they form the floor of the mouth and have an important function in moving the hyoid bone during swallowing
What are the 4 suprahyoid muscles?
Label the suprahyoid muscles


What are the attachments of the two bellies of diagastric?
The anterior belly arises from the digastric fossa of the mandible
The posterior belly arises from the mastoid process of the temporal bone
They insert onto a common tendon which attaches to the hyoid bone via a fibrous sling
What is the function of diagastric muscle?
It depresses the mandible and elevates the hyoid bone
What is the carotid sheath?
a thick layer of fascia that binds together the common carotid artery, internal jugular vein and the vagus nerve in the neck
in the upper part of the neck it contains the internal carotid artery, internal jugular vein and last four cranial nerves