Spinalis

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton  

Introduction

Musculus spinalis thoracis

The spinalis muscle group are part of the the erector spinae (ES) group (the intermediate layer of the intrinsic back muscles). The ES is made of three subgroups, with the group divisions occurring by location.

1. Spinalis subgroup, most medial
2. Longissimus subgroup, between spinalis and iliocostalis
3. Iliocostalis subgroup, most lateral

The erector spinae muscles, which spinalis belong to, are the most powerful extensors of the spine.

Anatomy

The spinalis thoracis is the major spinalis muscle, arising from the bones of the lower thoracic and upper lumbar vertebral spine and inserted into the bones of the upper thoracic vertebral spine.

The spinalis capitis and spinalis cervicis are variably developed and variably present.

The spinalis is innervated by the lateral branches of the posterior rami of the spinal nerves.

It receives blood supply via the dorsal branches of the posterior intercostal arteries, the deep cervical artery, and the muscular branches of the vertebral artery.

Function

Spinalis Capitis marked

Spinalis works synergistically with the other members of the erector spinae group. Erector spinae muscle group have 3 major functions.

1. Unilateral contraction of erector spinae results in lateral flexion (ipsilateral) and rotation of the cervical, thoracic spine and lumbar spines.
2. Bilateral contraction of erector spinae causes extension of the head, neck and cervical, thoracic and lumbar vertebrae.
3. Helps to stabilize the pelvis while balancing on one leg. During this activity, the contralateral muscle group contracts and prevents the pelvis from dipping.