BACK MUSCLES

Origin of trapezius

Superior nuchal line, external occipital protuberance, spinous processes of C7-T12

Insertion of trapezius

Lateral third of clavicle, acromion, spine of scapula

Nerves for trapezius

Spinal roots C3 and C4 of spinal accessory nerve

Arteries for trapezius

Descending scapular artery, transverse cervical artery

Action of superior trapezius alone

elevate scapula

Origin of Latissimus dorsi

Spinous processes of T7-T12, Iliac crest, Thoracolumbar fascia

Insertion of Latissimus dorsi

Floor of intertubercular (bicipital) groove of humerus

Nerves for Latissimus dorsi

Thoracodorsal nerve

Arteries for Latissimus dorsi

Thoracodorsal artery (main), descending (Dorsal) Scapular artery

Action of Latissimus dorsi

Extends, adducts, medially rotates humerus, raises body toward arms when climbing

Origin of Rhomboid Minor

Spinous processes C7 – T1

Origin of Rhomboid Major

Spinous processes T2 – T5

Insertion of Rhomboid Minor

Vertebral (medial) border of scapula at root of spine

Insertion of Rhomboid Major

Vertebral (medial) border of scapula from root of spine to inferior angle

Nerves for Rhomboid Major and Minor

Dorsal Scapular nerve

Arteries for Rhomboid Major and Minor

Descending (Dorsal) Scapular artery

Action of Rhomboid Major and Minor

Retract and rotate scapula, Tilts glenoid fossa inferiorly, Fixes scapula to thoracic wall, Axis of rotation

Origin of Levator Scapulae

Transverse processes of C1 – C4

Insertion of Levator Scapulae

Vertebral border of scapula between root of the spine and the superior angle

Nerves for Levator Scapulae

Dorsal Scapular nerve, cervical nerves C3 and C4

Arteries for Levator Scapulae

Descending (Dorsal) Scapular artery

Action of Levator Scapulae

Elevates scapula, Tilts glenoid fossa inferiorly, Action of Rotation

Origin of Serratus Posterior superior

Spinous processes of C7 – T3

Insertion of Serratus Posterior superior

Ribs 2-5

Nerves for Serratus Posterior superior

Intercostal nerves of ribs 2-5

Arteries for Serratus Posterior superior

Posterior intercostal artery

Action of Serratus Posterior superior

Elevates ribs, Inspiration, Proprioception

Origin of Serratus Posterior inferior

Spinous processes of T11 – L2

Insertion of Serratus Posterior inferior

Ribs 8 or 9-12

Nerves for Serratus Posterior inferior

Intercostal nerves of ribs 9-12

Arteries for Serratus Posterior inferior

Posterior intercostal artery

Action of Serratus Posterior inferior

Depresses ribs, Inspiration, Proprioception

Origin of Splenius Capitis and Cervicis

Entire muscle from the Spinous processes of C7 to T4-T5

Insertion of Splenius Capitis

Mastoid process, lateral aspect of superior nuchal line

Insertion of Splenius Cervicis

Transverse tubercles of C1 – C4

Nerves for Splenius Capitis and Cervicis

Dorsal rami of cervical spinal nerves

Arteries for Splenius Capitis and Cervicis

Occipital artery, transverse cervical artery

Action of Splenius Capitis and Cervicis

Lateral bending and rotation of head (acting alone), Extend head and neck, tilt head backward (acting together)

Origin of Erector Spinae

Broad tendon from iliac crest, sacrum, inferior spinous processes

Insertion of iliocostalis

Ribs

Insertion of longissimus

Ribs, transverse processes of cervical and thoracic vertebrae, mastoid process, occipital bone

Insertion of spinalis

Spinous processes of thoracic and cervical vertebrae and occipital bone

Nerves for Erector Spinae

Dorsal rami of spinal nerves

Arteries for Erector Spinae

Intercostal and lumbar arteries

Action of Erector Spinae

Laterally bend and rotate vertebral column and head (Acting Alone), Extend vertebral column and head, arch back (Acting Together)

Origin of Semispinalis

Transverse processes of C4 to T12

Insertion of Semispinalis

Occipital bone between superior and inferior nuchal line, spinous processes of the vertebrae above each transverse process origin.

Nerves for Semispinalis

Dorsal rami of spinal nerves

Arteries for Semispinalis

Intercostal arteries

Action of Semispinalis

Stabilizes vertebral column, Maintain posture, Extends and Laterally rotates head and vertebral column

Origin of Multifidus

Sacrum, ilium, and transverse processes of thoracic and lumbar vertebrae

Insertion of Multifidus

Spinous processes of vertebrae above origin, span 2-4 vertebrae

Nerves for Multifidus

Dorsal rami of spinal nerves

Arteries for Multifidus

Intercostal arteries

Action of Multifidus

Stabilize vertebrae, Maintain posture, Extend spine, Lateral bending of vertebral column