extrinsic back muscles Flashcards
How many layers of extrinsic back muscles are there
3
Trapezius O, I, A (upper, middle, lower, combo), In
O- Medial 1/3 sup nuchal line, ex. occipital protuberance, nuchal ligament, SPs c7-12, Supraspinous lig c7-t12
I- Lat 1/3 of clavicle, acromion, sup lip of spine of scapula
A:
Upper- elevates shoulder + retract scap
Middle- Retract scap
Lower- depress + retract scap
Up+low- rotate lat angle of scap sup
Stabalized- w/ scap stabalized it extends head, neck
-unilateral contraction of upper contralaterally rotates head
In- Spinal accessory nerve (motor), C2,3,4 spinal nerves
Latissiumus Dorsi- O, I, A, IN
O- SPs of lower 6 T vertebrae, superficial thoracolumber fascia, median sacral crest, iliac crest,lumbar vertebrea, lower 4 ribs
I- Floor of the intertubercular groove of humerus
A- Extends, adducts, and medially rotates humerus
In- Thoracodorsal nerve (C6,7,8)
Levator Scapulae- O, I, A, In
O- Post tubercles of TVP C1-4
I- Medial border of scapula sup to root of spine of scap
A- Elevates scap, rot lat angle of scap inf, with scap stabalized extends neck, unilaterally it lat flexes the neck and ipsilaterally rotates the neck
In- C3,4 spinal nerves, Dorsal scap nerve (c4,5)
Rhomboid Minor O, I, A, In
O- Nuchal lig, SPs of c7-T1
I- Medial border of scap at lvl of the root of spine of scap
A- retracts scap and rotates the lat angle inf
In- Doral scap nerve (c4,5)
Rhomboid Major O, I, A, In
O- SPs T2-5
I- Medial border of scap inf to root of spine of scap
A- Retracts scap, rotates inf angle of scap
In- Dorsal scap nerve (C4,5)
Serratus post sup O, I, A, In
O- nuchal lig, SPs of c7-t3
I- Sup borders of 2nd to 5th ribs
A- elevates upper ribs (largely proprioceptive)
In- 2nd- 5th intercostal nerves
Serratus post in O, I, A, In
O- Sps of t11-L2
I- Inf borders of 8th-12th ribs
A- Depresses lower ribs (largely proprioceptive)
In- Lower 3 intercostal nerves and subcostal nerve
