Unit 3 - Thorax, Abdomen, Pelvis, and Perineum: Muscles of the Thoracic Wall (Ex. III) Flashcards
middle scalene
O: transverse processes of C1 and C2; P tubercles of transverse processes of C3-C7
I: rib 1 P to groove for subclavian a.
Inn: direct branches from C and B plexuses (C3-C8)
A: w/ ribs mobile - raises upper ribs (inspiration); w/ ribs fixed - ipsilaterally laterally flexes C spine and bilaterally flexes neck
P scalene
O: P tubercles of transverse processes of C5-C7
I: outer surface of rib 2
Inn: direct branches from C and B plexuses (C3-C8)
A: w/ ribs mobile - raises upper ribs (inspiration); w/ ribs fixed - ipsilaterally laterally flexes C spine and bilaterally flexes neck
external intercostals
O: lower margin of rib
I: upper margin of next lower rib
course obliquely forward and downward from costal tubercle to chondro-osseous junction
Inn: 1st-11th intercostal nn.
A: raise ribs (inspiration); support intercostal spaces; stabilize chest wall
internal intercostals
O: lower margin of rib
I: upper margin of next lower rib
course obliquely forward and upward from costal angle to sternum
Inn: 1st-11th intercostal nn.
A: lower ribs (expiration); support intercostal spaces; stabilize chest wall
innermost intercostals
O: lower margin of rib
I: upper margin of next lower rib
course obliquely forward and upward from costal angle to sternum
Inn: 1st-11th intercostal nn.
A: lower ribs (expiration); support intercostal spaces; stabilize chest wall
transversus thoracis
O: sternum and xiphoid process (inner surface)
I: costal cartilage, inner surface of ribs 2-6
Inn: 2nd-6th intercostal nn.
A: weakly lowers ribs (expiration)
A scalene
O: A tubercles of transverse processes of C3-C6
I: scalene tubercle of rib 1
Inn: direct branches from C and B plexuses (C3-C8)
A: w/ ribs mobile - raises upper ribs (inspiration); w/ ribs fixed - ipsilaterally laterally flexes C spine and bilaterally flexes neck
