Back Muscles

Trapezius (Purposeful Activity)

Reaching overhead, rowing a kayak or canoe

Trapezius (Action)

Upper fibers: extend head/neck; Middle fibers: adduct & stabilize scapula; Lower fibers: depress scapula

Trapezius (Origin)

External occipital protuberance, nuchal ligament, spinous processes of C7-T12

Trapezius (Insertion)

Lateral 1/3 of clavicle, acromion, and spine of scapula

Trapezius (Innervation)

Spinal accessory nerve (CN XI)

Latissimus Dorsi (Purposeful Activity)

Opening a heavy door, lat pull-downs, swimming downstroke

Latissimus Dorsi (Action)

Extends, adducts, and medially rotates the humerus

Latissimus Dorsi (Origin)

Spinous processes of T7-L5, thoracolumbar fascia, sacrum, iliac crest, ribs 10-12

Latissimus Dorsi (Insertion)

Floor of the intertubercular sulcus of the humerus

Latissimus Dorsi (Innervation)

Thoracodorsal nerve

Levator Scapulae (Purposeful Activity)

Shrugging shoulders, carrying a briefcase

Levator Scapulae (Action)

Unilaterally elevates the scapula and downwardly rotates it

Levator Scapulae (Origin)

Transverse processes of 1st through 4th cervical vertebrae (C1-C4)

Levator Scapulae (Insertion)

Medial border of scapula between superior angle and spine

Levator Scapulae (Innervation)

Cervical C3 and C4, dorsal scapular C4 and C5

Rhomboid Major and Minor (Purposeful Activity)

Reaching into back pocket

Rhomboid Major and Minor (Action)

Adduct (retract) and elevate the scapula

Rhomboid Minor (Origin)

Spinous processes of C7 to T1

Rhomboid Major (Origin)

Spinous processes of T2 to T5

Rhomboid Major and Minor (Insertion)

Medial border of the scapula

Rhomboid Major and Minor (Innervation)

Dorsal scapular nerve (C4-C5)

Erector Spinae (Purposeful Activity)

Maintaining upright posture against gravity

Erector Spinae (Action)

Bilaterally extend vertebral column; unilaterally laterally flex to the SAME side

Erector Spinae (Origin)

Common tendon on posterior sacrum, iliac crest, and lumbar/lower thoracic spinous processes

Erector Spinae (Insertion)

Posterior spinous and transverse processes of thoracic/cervical vertebrae and ribs

Erector Spinae (Innervation)

Dorsal rami of lower cervical spinal nerves

Quadratus Lumborum (Purposeful Activity)

Lifting, walking

Quadratus Lumborum (Action)

Unilaterally tilt pelvis and laterally flex vertebral column to SAME side; assist extension

Quadratus Lumborum (Origin)

Posterior iliac crest

Quadratus Lumborum (Insertion)

Last rib (Rib 12) and transverse processes of first through fourth lumbar vertebrae (L1-L4)

Quadratus Lumborum (Innervation)

Lumbar plexus (T12, L1-L3)

Splenius Capitis (Purposeful Activity)

Social interaction, driving, turning the head

Splenius Capitis (Action)

Unilaterally rotate and laterally flex head and neck to the SAME side (bilaterally extend)

Splenius Capitis (Origin)

Lower half of ligamentum nuchae and spinous processes of C7 to T4

Splenius Capitis (Insertion)

Mastoid process, lateral superior nuchal line, and transverse processes of C1 to C3

Splenius Capitis (Innervation)

Dorsal rami of lower cervical spinal nerves

Multifidi and Rotatores (Transversospinalis) (Purposeful Activity)

Twisting during yoga or sports

Multifidi and Rotatores (Action)

Rotate vertebral column to the OPPOSITE side (bilaterally extend)

Multifidi and Rotatores (Origin)

Sacrum and transverse processes of lumbar through cervical vertebrae

Multifidi and Rotatores (Insertion)

Spinous processes of lumbar vertebrae up to the 2nd cervical vertebra (Axis)

Multifidi and Rotatores (Innervation)

Dorsal rami of lower cervical spinal nerves