Superficial Back Muscles

Front 1

Trapezius

Back 1

Function: Head extension, hyperextension, lateral flexion, and rotation. Elevation, depression, outward rotation, and adduction of the scapula
Innervation: Superficial transverse cervical artery
Blood Supply: Accessory nerve (originating at C3/C4)
Insertion: Superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous process of C7-T12
Origin: 1/3 lateral part of clavicle, acromion, and spine fo the scapula

Front 2

Latissimus Dorsi

Back 2

Function: Elevation, depression, and medial rotation of the humerus
Innervation: Thoracordosal nerve (originates C6/C7/C8)
Blood Supply: Thoracordosal artery
Origin: Spinous process of T7-L5, posterior surface of sacrum, superior surface of iliac crest, lower 3/4 ribs, inferior angle of the scapula
Insertion: Intertubercular groove of the medial/anterior humerous

Front 3

Levator Scapulae

Back 3

Function: Elevation of the scapula and helps other muscles in moving the lateral side of the scapula inferiorly
Innervation: Dorsal sacral nerve (originates C4/C5) and ARN of C3
Blood Supply: Dorsal sacral artery
Origin: Spinous process of C1-C4
Insertion: Superior angle of scapula

Front 4

Rhomboid Minor

Back 4

Function: adducts and retracts the scapula
Innervation: Dorsal sacral nerve ARN
Blood Supply: Dorsal sacral artery
Origin: Spinous process of C7-T1
Insertion: Medial side of scapula from the superior angle to the spine of the scapula

Front 5

Rhomboid Major

Back 5

Function: adducts and retracts the scapula
Innervation: Dorsal sacral nerve ARN
Blood Supply: Dorsal sacral artery
Insertion: Spinous process of T2-T5
Origin: Medial side of scapula from just inferior to the RMinor to the inferior angle