Superficial Anatomy of the Back and Core

The muscles of your back and core (trunk), like all others, are described in layers. Superficial muscles are those that are more external than others. In other words, they are closer to the surface of the body.

The superficial anatomy of your back and core is involved in moving your upper body, maintaining good posture, coughing, and even having a bowel movement. And like all muscles, they can be injured.

This article explains what makes up the superficial structures in your back and core, their roles, and what conditions can affect them.

Superficial Back Anatomy

Something doesn't need to be on the very outside of the body to be superficial. It only needs to be closer to the body's surface than another body part.

The most external layer of back muscles is a group of four called the extrinsic back muscles.

They include:

• Trapezius
• Latissimus dorsi
• Levator scapula
• Rhomboid (major and minor) 
  

The trapezius muscle is the most superficial of all back muscles. The latissimus dorsi is next.

Because each of the extrinsic muscles is large, it's easy to find them. And because they are superficial back muscles located just under your skin, you can touch them if you know where they are.

Of course, back muscles and other structures don't stop at the superficial layer. Several more layers of back muscles live beneath the extrinsic group.

Superficial Core Anatomy

Your core muscles are your abdominals—the essential muscles that protect your back.

The rectus abdominus is the most superficial ab muscle. You got an external view of this muscle if you've ever seen a fitness buff with a sculpted six-pack.

Underneath the rectus abdominus lie five other ab muscles. They are:

• Two external obliques
• Two internal obliques
• One transverse abdominus

The rectus abdominus is superficial to the external obliques. The external obliques are superficial to the internal obliques.

How These Muscles Function

Your superficial back muscles control how you move your shoulders and neck.

• The trapezius muscles enable you to correct your posture, move your upper body, and lift and lower your arms.
• The latissimus dorsi helps you extend, twist, and rotate your arm.
• The levator scapula helps you raise and lower your shoulder blade.
• The rhomboids allow you to pull your shoulder blade toward your spine and release it.

Your rectus abdominus muscle helps you tuck under your pelvis. It also allows you to contract or pull down on your upper body and ribs. It's the muscle you feel when you do a crunch or sit-up.

You also use this muscle when you cough or have a bowel movement. And as you might expect, it plays a significant role in childbirth.

Conditions That Affect These Muscles

The superficial muscles in your back and core can be injured suddenly or over time. The most common injuries to superficial muscles are strains and tears.

Strains

If you lift something heavy or overuse a muscle in your back or core, it can stretch too far. Symptoms of a muscle strain include:

• Pain that gets worse when you move
• Tense, tight, or stiff feeling
• Cramping or spasms
• Tenderness
• Swelling
• Decreased range of motion
• Bruising or color changes if severe

Mild strains often heal on their own. While the muscles recover, it's important to rest and protect them by limiting your activities until the pain goes away.

If your muscle strain is more severe, it's good to see a healthcare provider. You may need an imaging test to see the extent of the damage. You may also need to work with a physical therapist who can guide you through recovery.

Tears

It's rare for one of the muscles in your back or your core to tear. It's more common among athletes who exert tremendous force on the muscle. For example, a professional baseball pitcher has a higher risk of tearing the latissimus dorsi.

Strenuous exercise can also cause a tear in the rectus abdominus. Tears are more common in vulnerable spots. An example is a spot where the muscle and tendon join.

In addition, the rectus abdominus muscle can also tear down the middle, separating the left and right sides. This is called diastasis recti. This injury most commonly occurs in pregnancy due to the increased tension on the abdominal wall. However, it is also common in newborns. This tear can heal on its own or after giving birth. It rarely requires surgical repair.

Tears can be mild or severe. You may need an imaging test, such as magnetic resonance imaging (MRI), to determine how severe a tear is.

What Recovery Can Look Like

Recovering from a muscle strain or tear takes time. However, you can reduce pain, swelling, and scar tissue buildup with the PRICE approach:

• Protection or Rest: Rest the injured area and limit its use. However, total bed rest isn't the best plan. It can lead to loss of muscle tone. Instead, keep moving, but don't pick up heavy objects.
• Ice: Use cold packs early in your recovery. Cold limits swelling and can reduce pain.
• Compression: Use a stretchy bandage to put pressure on the area, if possible. Compression can reduce pain and swelling.
• Elevation: When you're resting, prop yourself up on pillows.

For pain, some healthcare providers recommend non-steroidal anti-inflammatory drugs (NSAIDs) such as Advil (ibuprofen).

Many people work with a physical therapist to rebuild strength with a customized program of exercises.

If you have a severe tear or rupture, you may need surgery to repair the injury.

Summary

Superficial muscles of your back and core are located just beneath your skin. That includes the latissimus dorsi, trapezius, rhomboid, and levator scapula muscles in your back. In your core, the outermost muscle is the rectus abdominus.

You can injure these muscles through overuse or sudden traumas. A mild muscle strain will cause pain and swelling. More severe injuries could cause bruising or limit your ability to move.