Posterior Triangle Flashcards
What are the borders of the posterior triangle?
the anterior border of the trapezius, the posterior border of the sternocleidomastoid (SCM), and the middle one-third of the clavicle
What is the roof of the posterior triangle?
the investing fascia
What is the floor of the posterior triangle composed of?
the anterior, middle and posterior scalene muscles,
the levator scapulae and
the splenius capitis
What are the cutaneous nerves of the nerve point of the neck (aka the punctum nervosum)?
the lesser occipital, the great auricular, the transverse cervical, and the supra scapular (the medial, intermediate, and lateral)
The path of the omohyoid demarcates a lower subdivision of the posterior triangle called what?
the omoclavicular triangle
Is the external jugular vein inside or outside of the investing fascia?
outside, BUT it penetrates this fascial layer inferiorly to join the subclavian vein directly behind the SCM near where it attaches to the manubrium and the medial clavicle
the anterior, middle and posterior scalene muscles originate from what?
cervical transverse processes
Where do the anterior and middle scalene muscles insert?
on the first rib
The borders of the anterior and middle abalone muscles form what structure?
the scalene triangle
Where does the posterior scalene muscle insert?
on the second rib
What structures pass through the scalene triangle?
the trunks of the brachial plexus and the subclavian artery
Does the subclavian vein pass through the scalene triangle?
No, it passes just anterior to the anterior scalene
What two muscles does the subclavian vein pass between in the neck?
the anterior scalene and the SCM
Does the subclavian artery pass anterior or posterior to the omohyoid (near its attachment to the scapula)?
anterior
What are the nerve roots of the phrenic nerve?
C3, C4, C5.
What muscle does the phrenic nerve descend on?
the anterior scalene
What is the sole motor innervation to the diaphragm?
the phrenic nerve
Is the phrenic nerve considered to be inside the scalene triangle?
No, it is on the anterior surface of the anterior scalene
Where does the subclavian join the internal jugular vein?
just posterior to the sternoclavicular joint
Where does the brachiocephalic trunk branch into the right common carotid artery and right subclavian artery?
just posterior to the sternoclavicular joint, sightly medial and posterior to the junction of the subclavian vein and the internal jugular vein
remember that the subclavian artery is posterior to the posterior vein and course laterally through two different spaces (artery in the scalene triangle, vein is anterior to the anterior scalene and posterior to the SCM)
What are the important branches of the common carotid artery?
There are none, other than the birfurcation to the internal and external carotid
The anterior scalene muscle divides the subclavian artery into three parts. Where are they?
The first part is medial to the anterior scalene, the second part is posterior to the anterior scalene and the third part is lateral to the anterior scalene
Where does the subclavian artery become the axillary artery?
At the lateral edge of the first rib