Intrinsic Back Muscles: Origin, insertion, action, innervation, blood supply.

Trapezius

orgin: external occipital protuberance, spinous process of C1-T12 Insertion: spine of scapula, acromion process and lateral 1/3 of posterior clavicle Action: elevation, upward and downward rotation and adduction of the scapula. Innervation: Accessory , C2-C4 Blood Supply: superficial branch of the transverse cervical artery

Rectus Capitis posterior minor

origin:posterior tubercle of C1 Insertion: occipital bone Action: extends the head Innervation: Suboccipital Nerve Blood supply: occipital artery

Vertebral Artery

Branches from the subclavian artery. Passes superiorly through the transverse foramina of the cervical vertebrae. As it reaches C1 it passes through the atlantoocciptal ligament and through the foramen magnum.

Greater occipital nerve

Emerges below the sub occipital triangle between C1 and C2

Sub occipital Nerve

Leaves the spinal cord between the atlas and occipital bone. Emerges between the posterior arch of C1 and the vertebral artery

Splenius Capitis

Orgin: Nuchal ligament, spinous process of C7-T3 Insertion: Mastoid process and occipital bone. Action: Rotates and flexes the neck and head toward the ipsilateral side. Acting together they extend the head and neck. Innervation: C2-C6 Blood Supply: Deep cervical artery, posterior intercostal arteries.

Serratus posterior Superior

Orgin: Spinous process of T1-T3, and nuchal ligament Insertion: Ribs 2-5 Action: Elevate the ribs during forced inspiration Innervation: 2nd-5th intercostal nerves Blood Supply: Posterior intercostal arteries

Splenius Cervicis

Orgin: T3-T6 Insertion: C1-C3 Action: Rotates and flexes the neck and head toward the ipsilateral side. Acting together they extend the head and neck. Innervation: C2-C6 Blood Supply: Deep Cervical artery and posterior intercostal arteries

Levator Scapulae

Orgin: Transverse process of C1-C4 Insertion: Superior angle the medial border of the scapula Action: Elevate scapula medially and flexes cervical spine laterally Innervation: Dorsal Scapular Nerve, C3,C4 Blood Supply: Dorsal Scapular Artery

Longissimus

Orgin: illiac crest, posterior sacrum, lumbar spinous processes, supraspinous ligament. Insertion: Ribs 2-12, costal process of lumbar vertebrae, transverse process of thoracic vertebrae Action: extension, lateral flextion of the trunk and neck. Action: extends and laterally bends the trunk and neck. Innervation: spinal nerves C1-S1 Blood supply: Deep cervical arteries, posterior intercostal arteries, subcostal arteries, lumbar arteries.

Iliocostalis

Orgin: illiac crest, posterior sacrum, lumbar spinous processes, supraspinous ligament. Insertion:Transverse processes of lumbar, ribs 6th-12th ribs, upper angle of ribs 1-6 Action: Extenstion, abduction and rotation of the spine. Innervation: C4-S5 Blood: deep cervical artery, posterior intercostal arteries, subcostal arteries and lumbar arteries

Rhomboid Major

Orgin: spinous process of T2-T5 Insertion: Medial border of the scapula inferior to the spine of the scapula Action: retraction, elevation of the scapula Innervation: Dorsal Scapular nerve Blood supply: Dorsal Scapular Artery

Latissiumus Dorsi

Orgin: spinous process of T6-12, all lumbar vertebrae, posterior 1/3 of the illiac crest, lower 3 ribs. Insertion:Intertubercular groove of the humerus Action: Extension, internal rotation and adduction of the glenohumeral joint, shoulder depression innervation: Thoracodorsal Nerve Blood: Thoracodorsal artery

Multifidus

Origin: Sacrum, transverse process of C3-L5 Insertion: Spinous process 2-4 vetebral levels superior to their origin Action: Extend and laterally bend the trunk neck, rotation to the opposite side. Blood Supply: Deep cervical arteries, posterior intercostal arteries, subcostal arteries, lumbar arteries.

Spinalis

Origin: Spinous process at inferior vertebral levels T10-L3. Insertion: Spinous process at superior vertebral levels T2-T8 and base of the skull Action: extend and laterally flex the spine. Innervation: spinal nerves C2-L3. Blood supply: Deep cervical arteries, posterior intercostal arteries, subcostal arteries, lumbar arteries.

Serratus posterior inferior

Origin: Spinous process of T11-L2 into thoracolumbar fascia Insertion: Lateral margins of Ribs 9-12 Action: Depress the Ribs Innervation: Intercostal nerves T9-T11, subcostal T12 Blood Supply: Posterior intercostal artery, subcostal artery and lumbar artery.

Semispinalis capitis

Origin: Transverse process of C3-T6. Insertion: Spinous process of C2. Action: Extension and lateral flexion of the cervical and thoracic spine and head. Innervation: C1-T12 Blood supply: Posterior intercostal arteries, deep cervical arteries.

Rectus capitis posterior Major

Origin: spinous process of C2 Insertion: occipital bone Action: extends the head Innervation Sub occipital nerve Blood supply: occipital artery.

Obliquus capitis inferior

Origin: spinous process of C2. Insertion: transverse process of C1 Action: rotates head to the same side Innervation: suboccipital nerve Blood supply: occipital artery

obliquus capitis superior

Origin: transverse process of C1 Insertion: occipital bone between the superior and inferior nuchal lines Action: Extends the head and rotates it to the same side. Innervation: suboccipital Nerve Blood supply Occipital Artery

Semispinalis Cervicis

Origin: transverse process of T1-T6 Insertion: Spinous process of C2-C5. Action: extension and rotation of the spinal column and head to the contralateral side Innervation: C1-T12 Blood supply: Deep cervical arteries, posterior costal arteries, subcostal arteries

Rotatores

Origin: transverse processes Insertion: long- spinous process of 2 vertebrea higher than their origin. Short- spinous process of 1 vertebrae higher than their origin. Action: rotates the vertebral column to the opposite side. Innervation: C1-L5. Blood Supply: deep cervical arteries, posterior intercostal arteries, subcostal arteries and lumbar arteries.

Rhomboid Minor

Spinous process of C7-T1 and inferior nuchal ligament Insertion: Medial border of the scapula inferior to the spine of the scapula Action: retraction and elevation of the scapula Innervation: Dorsal Scapular Nerve Blood Supply: Dorsal Scapular Artery