Which of the erector spinae muscles is most lateral to the vertebral column?

a. Spinalis muscle

b. Iliocostalis muscle

c. Semispinalis muscle

d. Longissimus muscle

Video transcript

Hi, everyone. Let's take a look at this practice problem together. The Rector spiny muscle type located in the most medial position is called the answer. Options are a trapezius muscle, B, scaling muscles, C spinalis muscles and D Rhiza muscles. So let's review some of the facts that we should know about the Rector spin a muscle. So recall that the erect spina are one of the largest muscles of the vertebral column and they lie deep to the other muscles, they run vertically along the spine on both sides. Now, the Rector spiny muscle is actually composed of nine different muscles that are further subdivided into three different groups. And those three groups are the iliocostalis, the longissimus and the spinalis. And the function of the rector spina is to maintain posture as well as spine extension. So the Rector spin A muscle type, which one is located in the most medial position? Well, option A the trapezius muscle recall that the trapezius is a large triangular shaped muscle that is located along the back of the neck and upper to mid back. It is not an erector spinning muscle. So we can eliminate option A option B the scaling muscles recall that these muscles are located on the lateral side of the neck. They are also not erector spinae muscles. So option B is incorrect. Option D the risorius muscle, this is a facial muscle. So it is not located on the back at all and it is not the correct answer. The correct answer is option C the spinalis muscle. All right, everyone. I hope you found this helpful and I'll see you soon for the next practice problem.