Soft Tissue of the Back Innervation As a general rule muscles associated with the back are innervated by the dorsal rami of the spinal nerves They are innervated segmentally and near their origin Only a couple of exceptions Innervation Innervation The Exceptions Serratus Posterior Superior Lig Nuchae and spinous processes of C7 T3 to 2nd to 5th ribs Serratus Posterior Inferior Spinous Proceses of T11 L2 to inferior borders of last 4 ribs Elevate or depress ribs accessory respiratory muscles Innervated by ventral rami Serratus Post Major Groups of Back Muscles Those that arise from the mid line and run superiorly and laterally The Splenius Muscles Bandage Those that arise from near the mid line or slightly laterally and run almost longitudinally with no marked inward or outward slant called the Erector Spinae Major Groups The third group are those that arise laterally and run towards the mid line as they travel up Called the Transversospinalis group Last small muscles that run from one spinous process to another or one transverse process to another interspinales and intertransvesus Splenius Muscles Splenius Capitis Splenius Cervicis Lig Nuchae and Spinous Process of C7 T4 to sup Nuchal line and mastoid process Spinous processes of T3 T6 to Transvers process of C2 C4 Both extend head and neck and can laterally flex side bend the head Also support and can contribute to rotation of cervical spine and thus the head Dorsal rami of spinal nerves nearest their respective origins Splenius Erector Spinae Long Muscles with multiple overlapping origins Three sub groups iliocostalis longissimus spinalis Common origin of the entire group is a muscle mass located on the posterior sacrum iliac crest and spinous process of lumbar vertebrae Beyond that specific muscles have various attachments Erector Spinae E Spinae E Spinae The three groups are broken down into sub subgroups based upon where they are located E G in the lumbar region called lumborum in thoracic region called thoracis in cervical region called cervicis and if they reach anywhere on the skull they are called capitis E G Iliocostalis lumborum E Spinae Overlap or multiple attachments Despite the common origin of the group most muscles have various and multiple origins and insertions These tend to overlap so that the group can traverse a large length of the back Some components will attach as an insertion while new fibers will originate from the same region E Spinae For example the iliocostalis lumborum muscles will attach to the lower six ribs while the iliocostalis thoracis will originate from the lower six ribs and insert on the upper six ribs Likewise the iliocostalis cervicis will originate from the upper six ribs and insert on the transverse process of C4 thru C6 All are innervated by the dorsal rami of the nerves nearest their origin e g iliocostalis thoracis will be innervated by the lower thoracic nerves T6T12 Longissimus Generally run from the transverse processes of one level of v column up several levels to attach to another transverse process The longissimus capitis originates on t processes of T1 T4 and attach to the skull at the mastoid process hence the name capitis Is the only E Spinae to attach to skull Spinalis E Spinae nearest the mid line hence the name spinalis The spinalis group run from spines of one group of vetebrae to spines of v several segments up Most prominent in thoracic spine but also located in cervical and lumbar spine General Collective Function of E Spinae To support spine anti gravity To extend spine To laterally flex spine side bend To rotate the spine They work together Transversospinalis Group Arise laterally and run more or less to the mid line Semispinalis Capitis Transverse Process C7 T6 to Occipital bone near mid line Extend head rotate to same side Semispinalis Cervicis Transverse process T1 T6 to Spines of C2 C6 Extend head Cervical Spine and side bend Semispinalis Semispinalis Transversospinalis Group Multifidi From the sacrum and transverse process of L T and lower C vertebrae to Spinous Process of Lumbar thoracic and cervical vetebrae 2 or 3 levels up Very large and obvious in lumbar region Support V column May contribute to minor motions lat flex rot ext Rotatores Transverse processes of 2nd cervical to sacrum to lamina on vertebrae above origin one segment Same function as multifidi Interspinous and Intertransversus Run between spinous processes or transverse processes Blend with ligaments of same name Perform same function Stability Small Muscles Muscles mostly associated with the head Sub Occipital Posterior Triangle very small support head on v column minor motions Rectus Capitis Post Major Spinous process of C2 to Lateral aspect of nuchal line Dorsal ramus of suboccipital nerve Rectus capitis Post Minor Post Arch of atlas C1 to med aspect of inferior nuchal line Dorsal ramus of suboccipital nerve Sub Occ Triangle Obliqus Capitis Superior Transverse process Atlas to a point between sup and inf Nuchal line Obliqus Capitis Inferior Spinous Process Axis to transverse process atlas Suboccipital Triangle Anterior Muscles all innervated by Ventral Rami Sterno Cleido Mastoid Manubrium S and Medial clavicle to mastoid process Together head flexion unilaterally side bending same side rotation opposite side CN XI and ventral rami of C2 C3 SCM SCM Anterior Scaleni AKA Pre Vertebral Scalaneus Anterior Ant tubercle of transverse process of C2 C6 Scalene tubercle of anterior surface of 1st rib Flex and rotate spine Reverse action accessory respiratory muscle by raising 1st rib ventral rami C2 C6 Pre Vertebrals Scaleni Scaleneus Medius from post tubercle of transverse processes C2 C7 to sup surface of 1st rib behind subclavian groove Scaleneus Posterior from post tubercles of transverse processes C4 C6 to lateral superior surface of 2nd rib Flex rotate elevate rib Pre Vertebral Longus Coli Bodies of C5 T3 to bodies of C2 C4 Bilaterally flexes cervical v unilaterally rotates rotate and side bend C2 C8 innervation Longus Capitis Ant Tubercles of transverse processes of C3 C6 To inferior surface of basilar portion of occipital bone Flex c v and head rotate and flex c v Anterior Small Muscles Rectus Capitis Anterior Rectus Capitis Lateralis Ant Surface of lateral mass of the atlas to inf Surface of occipital bone anterior to foramen magnum C1 C2 Sup surface of transverse process of atlas to inferior surface of jugular process occipital bone C1 C2 Both support skull Anterior Sub Occipital Muscles