WEEK 2: Back Muscles Layer 1, 2, 3 Flashcards
EXAM 1
2 major groups of muscles
extrinsic (surface, limb movers)
intrinsic (deep)
What spinal nerve are all intrinsic muscles innervated by
posterior rami of spinal nerve
Rami
branch of nerves
Deep fascia back muscle
Thoracolumbar fascia Posterior
Thoracolumbar fascia middle
Thoracolumbar fascia anterior
What layers are only in the upper back and neck
2 and 4
Which layers are extrinsic muscles
1,2,3
which layers are the TRUE back muscles
4,5,6
Back Muscles - Layer 1: Action & Nerve Supply
Trapezius
Latissimus Dorsi
Acts on the arm & Anterior rami
Trapezius - Origin, insertion, innervation, Action, Blood Supply
Origin (doesn’t move)
-EOP
-Medial aspect of superior nuchal ligament
-SPs C7-T12
-Nuchal ligament
Insertion (moves)
-Lateral aspect of the clavicle
-Spine of the scapula
-Acromion process
Innervation
-Spinal accessory nerve (CN 11 XI - motor)
-C3-C4 proprioception
Action
- scapulothoracic elevation, retraction depression
Blood Supply
-transverse cervical a.
—-branch of the thyrocervical trunk of the subclavian a.
Process
a projection or outgrowth of tissue from a larger bone
Proprioception
kinesthesia, is your body’s ability to sense movement, action, and location
What kind of nerve is CN 11 XI ?
spinal accessory nerve - motor nerve
Innervates
-trapezius
-sternocleidomastoid muscle
Triangle of osculation
-useful for assessment using a pulmonary auscultation and thoracic procedures
-The triangle of auscultation is bounded by the latissimus dorsi muscle (inferior), trapezius muscle (medial), scapula (lateral), and the rhomboid major, fascial sheet, 6th and 7th ribs, and intercostal space (anterior or floor)
Latissimus Dorsi - Origin, insertion, innervation, Action, Blood Supply
Origin
- SP T7-L5
-Inferior angle of the scapula
-inferior 3-4 ribs
-crest of ilium
-dorsal surface of the sacrum
-thoracolumbar fascia
Insertion
-Floor of the intertubercular groove of the Humerus
(bicipital groove OR Intertubercular sulcus)
Innervation
-thoracodorsal nerve (C6-C8)
—– ventral rami of the spinal nerves from C6-C8 spinal cord segments)
Action
-shoulder extension
-arm adduction
-medial rotation of the arm
Blood Supply
-thoracodorsal n & a. (dorsi)
What’s another work for “groove”
sulcus - a depression or groove in the cerebral cortex
Back Muscles - Layer 2: Action & Nerve Supply
Levator scapulae
Rhomboid Minor
Rhomboid Major
Acts on the arm & Anterior Rami
Nerve - Dorsal Scapula Nerve (C5 - root)
Levator Scapulae - Origin, insertion, innervation, Action, Blood Supply
Origin
- posterior tubercles
-TP C1-C4
Insertion
- Superior angle of scapula
Innervation
- dorsal scapular nerve (C5) (posterior)
-Ventral Rami C3-C4 (anterior)
Action
- scapulothoracic elevation and downward rotation
Blood Supply
-dorsal scapula a.
What does C5 mean
all the fibers from this nerve come from C5 spinal nerve
Rhomboid Minor - Origin, insertion, innervation, Action, Blood Supply
Origin
-Nuchal Ligament
-Sp C7 - T1
Insertion
- root of the spine of the scapula
Innervation
- dorsal scapula nerve (C5)
Action
- assist the major with retracting scapula and rotate to depress glenoid cavity; fix scapula to thoracic wall
Blood Supply
-dorsal scapula a.
Rhomboid Major - Origin, insertion, innervation, Action, Blood Supply
Origin
-SP T2 - T5 (4 vs)
Insertion
-medical border of the scapula (inferior to the spine of the scapula)
Innervation
- Dorsal scapula nerve (C5)
Action
- retract scapula and rotate to depress glenoid cavity; fix scapula to thoracic wall
Blood Supply
-dorsal scapular a.
glenoid cavity
forms a joint with the head of the humerus. This is a ball and socket joint that allows for triaxial motion: flexion/extension, abduction/adduction, and rotation
What type of muscles are rhomboid minor and major
Synergist
Back Muscles - Layer 3: Action & Nerve Supply
Serratus Posterior Superior
Serratus Posterior Inferior
-respiratory muscles
-proprioceptive
-BOTH innervated by intercostal nerves
proprioceptive
known as kinesthesia, is your body’s ability to sense movement, action, and location. It’s present in every muscle movement you have. Without proprioception, you wouldn’t be able to move without thinking about your next
Serratus Posterior Superior - Origin, insertion, innervation, Action, Blood Supply
“respiratory muscles”
Origin
-Nuchal Ligament
-SP C7-T3
Insertion
-Superior borders of 2-4 ribs
Innervation
- ventral rami T2-T5 (intercostal nn)
Action
- elevates ribs 2-4 (helps with deep inspiration)
Blood Supply
Serratus Posterior Inferior - Origin, insertion, innervation, Action, Blood Supply
Origin
-SP T11-L2
Insertion
- inferior border of 8-12 ribs
Innervation
- ventral rami T9-T12 (intercostal nn)
Action
- depresses ribs 8-12 (helps with forced expiration)
Blood Supply
