Back Muscles: Attachments, Innervation

Front 1

Teres Minor

Back 1

Origin: superior lateral border of scapula
Insertion: inferior facet on the great tuberosicty of the humerus
Innervation: axillary nerve
Blood supply: subscapular and circumflex scapular arteries
ACTION - laterally rotates shoulder and stabilizes glenohumeral joint

Front 2

Teres Major

Back 2

Origin: Dorsal surface of the inferior angle of the scapula
Insertion: medial lip of the intertubercal groove of the humerus
Innervation: lower subscapular nerve
blood supply: subscapular and circumflex scapular arteries
ACTION - humeral adduction and MEDIAL rotation

Front 3

Spinalis

Back 3

Innervated by respective dorsal rami.
O:tendon from posterior aspect of illiac, supraspinous lig., med. post. sacrum
I: mid-thoracic/cervical spinous processes and skull
blood - lateral sacral artery
ACTION - extends vertebral column

Front 4

Longissimus

Back 4

Innervated by respective dorsal rami.
O:tendon from posterior aspect of illiac, supraspinous lig., med. post. sacrum
I: ribs, thoracic and cervical transverse processes, temporal bone.
Blood - lateral sacral artery
ACTION - laterally: flex head and neck to same side. bilaterally:extend vertebral column

Front 5

Iliocostalis

Back 5

Innervated by respective dorsal rami
O: tendon from post. aspect of illiac, supraspinous lig., med. post. sacrum.
I: lower ribs, cervical transverse processes

Front 6

Supraspinatus

Back 6

Innervated by Suprascapular nerve C5, C6
O: supraspinous fossa of the scapula
I: superior facet of the greater humeral tuberosicity.
blood - suprascapular artery
ACTION - initiates abduction

Front 7

Infraspinatus

Back 7

innervated by suprascapular nerve C5 C6
O:Infraspinous fossa of the scapula
I: medial facet of the greater humeral tuberosicity
blood - suprascapular and circumflex scapular arteries
ACTION - lateral rotation of humerus and stabilization of glenohumeral joint

Front 8

Subscapularis

Back 8

innervated by upper and lower subscapular nerves
O: subscapular fossa of the scapula
I: lesser tuberosicity of the humerus
blood - subscapular artery, transverse cervical artery
ACTION - stabilizes glenohumeral joint, medially rotates and adducts humerus

Front 9

trapezius

Back 9

Innervated by spinal accessory nerve (motor) and C3-5 (sensory)
O: occipital bone
I: along vertebrae, spine of scapula
blood - transverse cervical artery
ACTION - scapular elevation, depression, retraction and superior rotation of lateral angle

Front 10

rhomboid minor

Back 10

Innervated by dorsal scapular nerve (C4 C5)
O: spinous processes of C7-T1
I: medial border of scapula
blood - dorsal scapular artery
ACTION - scapular retraction and inferior rotation of lateral angle

Front 11

Rhomboid Major

Back 11

Innervated by Dorsal Scapular never C4 C5
O: Spinous processes of T2-T5
I: medial border of scapula
blood - Dorsal Scapular
ACTION - retraction of scapula, inferior rotation of lateral angle

Front 12

Latissimus Dorsi

Back 12

Innervated by thoracodorsal nerve.
O: thoracolumbar fascia, inferior thoracic vertebrae, inferior ribs?
I: floor of intertubercal groove of humerus
blood - thoracodorsal artery
ACTION - humeral adduction, EXTENSION and medial rotation.

Front 13

Erector Spinae

Back 13

Innervation: dorsal rami of respective spinal nerves in each region
Blood Supply: Lateral Sacral Artery
ACTION - extends vertebral column, flexes laterally

Front 14

Teres Major

Back 14

Innervation: lower subscapular nerve
O:inferior angle of scapula
I: medial lip of intertubercular sulcus of humerus.
blood supply: subscapular and circumflex scapular arteries
ACTION - humeral adduction and medial rotation.

Front 15

Teres Minor

Back 15

Innervation: axillary nerve C5 C6
O: lateral border of scapula
I: greater tubercle of humerus
Blood supply: subscapular and circumflex scapular arteries
ACTION - stabilizes glenohumeral joint and laterally rotates humerus