Back Muscles

Lesson Overview

In this lesson, we introduce the anatomy of the back muscles.

Objective

Learn the anatomical terminology and function of superficial, intermediate and deep back muscles.

Description

Describe ways that back muscles may be categorized. Name the superficial, intermediate and deep / intrinsic back muscles, and explain what they do.

Introduction

  • Back muscles may be categorized as superficial, intermediate or deep.
  • Another common categorization is extrinsic vs. intrinsic. In this system, extrinsic muscles encompass the superficial and intermediate muscles and intrinsic refers to the deep back muscles.

Superficial Muscles

  • Muscles: Trapezius, Latissimus Dorsi, Levator Scapulae, Rhomboids
  • Description: These muscles are located just underneath the skin and superficial fascia. They originate from the spinal column and attach to shoulder bones.
  • Actions: They are associated with movements of the shoulder.

Intermediate Muscles

  • Muscles: Serratus Posterior Superior, Serratus Posterior Inferior
  • Description: These muscles run from the spinal column to the rib cage.
  • Actions: They assist with movements of the rib cage.

Deep or Intrinsic Muscles

The Deep Back Muscles as a Whole

  • Muscles: Erector Spinae, Muscles located beneath the Erector Spinae including The Multifidus
  • Description: The deep back muscles are covered by deep fascia. (The deep muscles may be further broken down into categorizations of superficial, intermediate and deep layers, which we don’t go into here). The deep back muscles are considered part of the core musculature.
  • Actions: These muscles are associated with movements of the spine and in controlling posture.

Erector Spinae (Spinal Erectors)

  • Muscles: The Erectors consist of three groups of muscles running the length of either side of the spine:
    • The Spinalis Group is most medial (closest to spine).
    • The Longissimus is the next group.
    • The Iliocostalis is the most lateral group.
  • Description: The erectors are deep, located beneath two other layers of muscles and covered by fascia. (Core Walking)
  • Actions:
    • Help to maintain erect posture.
    • Stabilize the spine during flexion.
    • Assist in side bending and spinal rotation.

[The erectors act as] powerful extensors to promote the return of the back to the erect position… primarily responsible for the extension of the back (straightening the spine) as well as more specific movements such as extension of the neck and sideward movements of the head. – Muscles Used, Erector Spinae

Multifidus Muscles

  • Description: The Multifidus muscles are a series of deep muscles that run the length of the spine.
  • Actions: They stabilize vertebrae as well as assist in spinal rotation and extension.
  • Teaching Consideration: With those who have experienced back pain, knowledge of the Multifidus muscles can help in learning to recruit the core for stabilization. See article for more information