Posterior Triangle

Question 1

boundaries of Posterior Triangle

Answer 1

SCM
upper trapezius
clavicle

Question 2

what is the scalene triangle and what passes through here?

Answer 2

space between the anterior and middle scalene
brachial plexus and subclavian artery pass through here
compression here causes thoracic outlet syndrome

Question 3

Anterior Scalene attachments

Answer 3

• origin: transverse processes of C3-C6

- insertion: first rib

Question 4

Middle Scalene attachments

Answer 4

• origin: transverse processes of C2-C7

- insertion: first rib

Question 5

Posterior Scalene attachments

Answer 5

• origin: transverse processes of C5-C7

- insertion: second rib

Question 6

Scalenes action

Answer 6

• when cervical vertebrae are stabilized, scalenes help with forced inhalation (pull on upper ribs)
• when ribs are stabilized, help with side bending the neck

Question 7

what travels anterior of anterior scalene?

Answer 7

subclavian vein
phrenic nerve (C3, C4, C5)