Issue link: https://www.massageandbodyworkdigital.com/i/365665
I t p a y s t o b e A B M P C e r t i f i e d : w w w. a b m p . c o m / g o / c e r t i f i e d c e n t r a l 49 FUNCTIONAL ANATOMY education Longissimus By Christy Cael The longissimus is one of several muscles on the back that run parallel to the spine. It is one of three muscles that form the erector spinae group. The iliocostalis and spinalis are also part of this group, which spans the entire posterior trunk from the sacrum to the base of the skull. The longissimus lies between the medially oriented spinalis and laterally oriented iliocostalis and is the largest and longest of the three erector spinae muscles, connecting the sacrum to the skull. The erector spinae group lies deep to the trapezius, latissimus dorsi, rhomboid major and minor, serratus posterior superior and inferior, and splenius capitis and cervicis. The longissimus muscle is divided into three overlapping segments. The largest of the three segments, the longissimus thoracis, originates at the base of the spine, blends with the thoracolumbar fascia, then extends upward and laterally to the thoracic transverse processes and posterior surfaces of the lower nine ribs. Moving superiorly, the longissimus cervicis begins slightly medial to the insertion of the longissimus thoracis, at the transverse processes of T1–5, and extends to the transverse processes of C2–6. The third segment, the longissimus capitis, lies superficial to the longissimus cervicis. It begins at the transverse processes of T1–5 and articular processes of C4–7 and inserts on the mastoid process of the temporal bone, deep to the splenius capitis and sternocleidomastoid. As a group, the erector spinae muscles connect, stabilize, and allow for broad movements of the vertebral column. They work synergistically with the deeper transversospinalis group to maintain upright posture against gravity. The smaller, more diagonally oriented rotatores and multifidi muscles of the transversospinalis group maintain alignment and position individual vertebra while the larger, more vertically oriented erector spinae LONGISSIMUS Attachments • Origin: Posterior sacrum, medial iliac crest, transverse processes of L1–5 and T1–5, and articular processes of C4–7 • Insertion: Transverse processes of T1–12 and C2–6, posterior surface of ribs 3–12, and mastoid process of the temporal bone Actions • Extends the vertebral column (bilateral action) • Laterally flexes the vertebral column (unilateral action) • Rotates the head and neck toward same side (unilateral action of cervical portion) Innervation • Dorsal rami of spinal nerves Longissimus