Back: Name, Origin, Insertion, Action, Innervation:

Name: Trapezius

Origin: Superior nuchal line, external occipital protuberance, medial margin of the ligamentum nuchae, spinous processes of CVII to TXII and the related supraspinous ligaments

Insertion: Superior edge of the crest of the spine of the scapula, acromion, posterior border of lateral 1/3 of clavicle

Action: Rotation of scapula. The upper fibres elevate the scapula. The lower fibres depress the scapula. The middle fibres adduct the scapula.

Innervation: Cranial nerve 11* (C3 & C4)

Arterial Supply: Transverse cervical artery, Dorsal scapular artery

Name: Latissimus Dorsi

Origin: Spinous process of T7 - L5, Sacrum, Iliac crest, ribs 9-12

Insertion: Floor of intertubercular sulcus of the humerus

Action: Extends, Adducts, Medially rotates humerus

Innervation: Thoracodorsal nerve (C6, C7, C8)

Arterial Supply: Thoracodorsal artery, Intercostal arteries

Name: Levator Scapulae

Origin: Transverse processes of C1 & C2 vertebrae , C3 & C4 vertebrae (posterior tubercles of transverse processes)

Insertion: Posterior surface of medial border of scapula

Action: Elevates scapula

Innervation: Dorsal Scapular Nerve (C5)

Arterial Supply: Dorsal scapular artery

Name: Rhomboid major

Origin: Spinous processes of T2–T5 vertebrae, Intervening supraspinous ligaments

Insertion: Posterior surface of medial border of scapula

Action: Retract & elevate scapula

Innervation: Dorsal scapular nerve (C5)

Arterial Supply: Dorsal scapular artery

Name: Rhomboid minor

Origin: Spinous processes of C7 & T1, Lower end of ligamentum nuchae

Insertion: Posterior surface of medial border of scapula

Action: Retract & elevate scapula

Innervation: Dorsal scapular nerve (C5)

Arterial Supply: Dorsal scapular artery

Name: Serratus posterior superior

Origin: Lower portion of ligamentum nuchae, spinous processes of C7 to T3, and supraspinous ligaments

Insertion: Upper border of ribs 2-5

Action: Elevates ribs 2-5

Innervation: Anterior rami T2-T5

Name: Serratus posterior inferior

Origin: Spinous processes of T11 to L3 & supraspinous ligaments

Insertion: Lower border of ribs 9-12

Action: Depresses ribs 9-12, Stabilises ribs when diaphragm contracts

Innervation: Anterior rami T9-T12

Name: Iliocostalis

Origin: Iliac crest, Sacrum, Spinous processes of lower thoracic and lumbar vertebrae

Insertion: Ribs. Lower cervical vertebrae (lumborum, thoracis)

Action: Together - Extensors of vertebral column & head. Individually - Lateral flexors of vertebral column & turn head same side.

Innervation: Dorsal rami of adjacent spinal nerves

Name: Longissimus

Origin: Iliac crest, Sacrum, Spinous processes of lower thoracic and lumbar vertebrae

Insertion: Base of skull (thoracis, cervicis, capitis)

Action: Together - Extensors of vertebral column & head. Individually - Lateral flexors of vertebral column & turn head same side.

Innervation: Dorsal rami of adjacent spinal nerves

Name: Spinalis

Origin: Iliac crest, Sacrum, Spinous processes of lower thoracic and lumbar vertebrae

Insertion: Spinous processes of adjacent vertebrae (thoracic, cervicis, capitis)

Action: Together - Extensors of vertebral column & head. Individually - Lateral flexors of vertebral column & turn head same side.

Innervation: Dorsal rami of adjacent spinal nerves

Arterial Supply: Deep cervical (cervical), Posterior intercostal (thoracic), Lumbar arteries (lumbar)