| Muscle |
Origin |
Insertion |
Action |
Nerve |
| Errector Spinae | Medial - Spinalis
Middle - Longissimus
Lateral - Iliocostalis | | Extension and Lateral Flexion of the spine | Spinal |
| Quadratus Lumborum | Posterior Iliac Crest | Transverse Process L1-4 and the 12th Rib | Lateral flexion to the same side | Branches of the T12-L1 |
| Trapezius | Occiput
C7-T12 Spinous Processes | Lateral 1/3 clavicle
acromion processes and spine to the root of the spine | elevation
upward rotation
retraction
depression | accessory |
| Rhomboids Minor | C7-T1 Spinous Processes | Root of the spine of the scapula | retraction of the scapula | dorsal scapula |
| Rhomboids Major | T2-5 Spinous Processes | Vertebral Border from the root of the spine to the inferior angle | retraction downward rotation of scapula | dorsal scapula |
| Latissimus Dorsi | T6 Spinous Processes to Iliac crest and lower 3 or 4 ribs | Bicipital Groove of humerus | adduction, extension, and medial rotation of humerus | thoracordorsal |
| Teres Major | inferior angle of the scapula | medial lip of the bicipital groove of the humerus | extension, medial rotation, and adduction of humerus | subscapular |
| Deltoid | Lateral 1/3 clavicle, acromion, spine of the scapula | deltiod tuberosity | abduction. flexion, extension, medial and lateral rotation of humerus | axillary |
| Supraspinatus | Supraspinous Fossa of the scapula | upper part of the greater tubercle of the humerus | abduction of humerus, draws humerus toward glenoid fossa | supra-scapular |
| Infraspinatus | Infraspinous fossa of the scapula | middle portion of the greater tubercle of the humerus | lateral rotation and horizontal abduction of humerus | supra-scapular |
| Teres Minor | Upper axillary border of the scapula | lower portion of the greater tubercle on the humerus | lateral rotation of humerus | axillary |
| Subscapularis | Subscapular fossa of the scapula | lesser tubercle of the humerus | medial rotation of humerus | subscapularis |
| Levator Scapulae | C1-C4 | Vertebral border of scapula between superior angle and spine | Bilateral-extends the head and neck Laterally- flexes head and neck and rotates head and neck | Dorsal Scapular |
