Back Muscles Anatomy

Introduction

The area of the body between the neck and the gluteal regions is called the back. It consists of the extrinsic and intrinsic back muscle compartments as well as the vertebral column, or spine. The back serves a variety of purposes, including protecting and housing the spinal cord, keeping the head and body straight, and regulating the motions of the upper and lower limbs.

By the way, are you familiar with the tale of Sisyphus, a man who is compelled to roll a massive boulder up a hill for all eternity, only to have it roll down as it gets closer to the top? Many would liken his struggle to learning anatomy. However, we at Kenhub take a different tack; thus, we’ve understandably covered the back anatomy for you on this site.

Anatomy

What’s the composition of the back muscles?

Your lower back, which is situated just above your hips, is reached by your back muscles, which start just behind your skull, cross your shoulders, and run the whole length of your spine.

They cling to bones throughout your body, including your:

• The bones that comprise your spinal column are called vertebrae.
• Ribs.
• Shoulder blades, or scapulae.

What are back muscles made of?

Your muscles are made up of thousands of microscopic strands that are braided together. Your body can move when you squeeze a muscle because these fibers stretch and push together. Your back muscles form a quilt-like structure that covers your back. They cooperate to move you and your

Back muscles

• There are numerous muscles in your back. Some provide support for your trunk (your torso or midsection) and spine. Others assist you in moving, standing, and maintaining your posture. Some even facilitate breathing.
• It should come as no surprise that your back muscles are among the most frequently damaged because they support a large portion of your weight and enable you to do a variety of tasks. Problems with the back muscles are among the most common causes of back pain.
• Problems with the back muscles are among the most common causes of lower back pain.
• Anatomically, the back muscles are divided into deep (intrinsic) and superficial (extrinsic) layers. Although they are found in the back, the extrinsic back muscles help in breathing and cause shoulder motions. The thoracolumbar fascia divides the intrinsic back muscles from the extrinsic muscles, which are located deeper. They only affect the vertebral column’s joints.
• Our rock-rolling Sisyphus must have developed amazing back muscles. To understand why they are so significant, let’s examine their anatomy.

Your back muscles are divided into three groups or layers by medical professionals:

• Superficial (extrinsic) back muscles.
• Intermediate back muscles.
• Intrinsic (deep) back muscles.

Superficial back muscles

Superficial back muscles are those in your back that are nearest to the skin’s surface. They make shoulder mobility easier. When individuals imagine their back muscles, these are often the ones that come to mind. Your superficial muscles consist of:

• Latissimus dorsi: This term is typically abbreviated as “lats.” The biggest muscles in your upper torso are your lat muscles. They begin beneath your shoulder blades and reach your lower back and spine.
• Levator scapulae: Smaller muscles called levator scapulae stretch from the side of your neck to your shoulder blades.
• Rhomboids: The rhomboid muscles connect your spine and shoulder blades as well.
• Trapezius: The most often used term for the trapezius muscles is “traps.” Starting in your neck, your traps form a V shape that spans your shoulders and ends at your lower back.
• Serratus anterior: The serratus anterior muscles cover the top of your rib cage and are situated directly behind your armpits.

Intermediate back muscles

Your middle back’s muscles are situated directly above and below your ribs. hey facilitate the movement of your ribcage, even when breathing. Two intermediate back muscles are present in you:

• Serratus posterior superior: The muscle located between your shoulder blades in the shoulder girdle, situated just beneath the rhomboids.
• Serratus posterior inferior: The muscle located at the base of your ribs is called the serratus posterior inferior. It’s beneath your lats.

Intrinsic back muscles

Intrinsic muscles deep layer of the back muscles. They are closest to your spine, beneath the other two layers. Intrinsic back muscles are separated into superficial, middle, and deep subgroups by medical professionals.

They all belong to the intrinsic group despite using the same names. The repeated subgroup names allude to their relative locations. For instance, your intermediate intrinsic muscles are further from the skin’s surface than your

The Superficial Back Muscles

The trapezius, latissimus dorsi, levator scapulae, and rhomboids are the muscles that make up this group. The most superficial muscles are the latissimus dorsi and the trapezius, which cover the levator scapulae and rhomboids.

Trapezius

The trapezius is a broad, flat, triangle-shaped muscle. The muscles on either side form a trapezoid shape. It is the most superficial muscle of the back.

• Attachments: Derives from the spinous processes of C7–T12, the ligamentum nuchae, and the skull. The clavicle, acromion, and scapular spine are where the fibers are attached.
• Innervation: The accessory nerve provides motor innervation. Additionally, the C3 and C4 spinal nerves provide proprioceptor fibers to it.
• Actions: When the arm is abducted, the top fibers of the trapezius raise and rotate the scapula. The scapula is pulled inferiorly by the lower fibers and retracted by the intermediate fibers.

Latissimus Dorsi

The latissimus dorsi is a broad muscle that originates in the lower back.

• Attachments: Has a wide origin, originating from the inferior three ribs, iliac crest, thoracolumbar fascia, and the spinous processes of T6–T12. The fibers come together to form a tendon that connects to the humerus’ intertubercular sulcus.
• Innervation: Thoracodorsal nerve
• Action: The upper limb is turned medially, extended, and adducted.

Levator Scapulae

The levator scapulae is a small muscle that resembles a strap. It attaches to the scapula after starting in the neck.

• Attachments: Attaches to the medial margin of the scapula after emerging from the transverse processes of the C1–C4 vertebrae.
• Innervation: Dorsal scapular nerve
• Action: The scapula is raised.

Rhomboids

The major and minor rhomboid muscles are the two types. The major is positioned below the rhomboid minor.

Rhomboid Major

• Attachments: Derives from the T2–T5 vertebrae’s spinous processes. Connects to the scapula’s medial border, which is between the inferior angle and the scapular spine.
• Innervation: Dorsal scapular nerve innervation.
• Actions: The scapula rotates and retracts.

Rhomboid Minor

• Attachments: The spinous processes of the C7–T1 vertebrae are the source of the Rhomboid Minor Attachments. Connects to the scapula’s medial border at the level of the scapula’s spine.
• Innervation: Dorsal scapular nerve
• Actions: The scapula rotates and retracts.

The Intermediate Back Muscles

The serratus posterior superior and inferior are the two muscles that make up the intermediate group. These muscles help raise and lower the ribs and extend from the spinal column to the ribcage. It is believed that they play a minor respiratory role.

Serratus Posterior Superior

The muscle known as the serratus posterior superior is slender and rectangular in form. It is located deep within the upper back’s rhomboid muscles.

• Attachments: Comes from the cervical and thoracic spines (often C7–T3), as well as the lower portion of the ligamentum nuchae. The fibers connect to ribs 2–5 after passing inferolaterally.
• Actions: Raises ribs 2–5.
• Innervation: Intercostal nerves provide innervation

Serratus Posterior Inferior

The posterior inferior serratus is robust and wide. It is located beneath the latissimus dorsi.

• Attachments: Usually originates from the lumbar and thoracic spines (T11–L3). The fibers join to ribs 9–12 after passing superolaterally.
• Actions: Ribs 9–12 are depressed.
• Innervation: Intercostal nerves

The Intrinsic back muscles

There are three categories of back muscles: superficial, intermediate, and intrinsic.

• Superficial: connected to shoulder motions.
• Intermediate: connected to thoracic cage motions.
• Deep: connected to spinal column motions.

• The deep muscles are referred to as intrinsic muscles because they form in the back during embryonic development. The superficial and intermediate muscles are categorized as extrinsic muscles as they do not develop in the back.
• Together, the well-developed deep back muscles stretch from the sacrum to the base of the head. They are connected to the vertebral column’s motions and posture regulation.
• Deep fascia, which covers the muscles themselves, is essential to their organization.
• The deep back muscles are classified anatomically into three layers: superficial, middle, and deep.

Superficial muscles

Spinotransversales is another term for the superficial muscles. This group consists of two muscles: the splenius capitis and the splenius cervicis. They are both related to movements of the head and neck. They are located on the posterolateral side of the neck and cover the deeper neck muscles.

Splenius Capitis

• Attachments: originates from the lower portion of the ligamentum nuchae and the spinous processes of the C7–T3/4 vertebrae. The fibers are affixed to the mastoid process and occipital bone of the skull.
• Innervation: C3 and C4 spinal nerve posterior rami.
• Action: Head rotation to the same side.

Splenius Cervicis

• Attachments: Derives from the T3–T6 vertebrae’s spinous processes. The fibers are attached to the C1-3/4 transverse processes.
• Innervation: Lower cervical spinal nerves’ posterior rami.
• Action: Head rotation to the same side.

Intermediate muscles

The three intermediate intrinsic back muscles are the spinalis, longissimus, and iliocostalis. Together, these muscles form the erector spinae, a column.

The erector spinae is situated posterolaterally to the spinal column, between the costal angle of the ribs and the vertebral spinous processes.

The lumborum, thoracic, cervicis, and capitis are the superior attachments of each of the three muscles. They also all have a tendinous origin, which is caused by:

• Lumbar and lower thoracic vertebrae
• Sacrum.
• Iliac crest’s posterior side.
• Supraspinous and sacroiliac ligaments.

Iliocostalis

The iliocostalis muscle is located laterally in the erector spinae. It is divided into the thoracis, cervicis, and lumborum and is attached to the ribs.

• Attachments: joins the cervical transverse processes and the costal angle of the ribs from the same tendinous origin.
• Innervation: The spinal nerves’ posterior rami.
• Actions: acts unilaterally to flex the spinal column laterally. Extends the spinal column and head on both sides.

Longissimus

The longissimus muscle divides the spinalis and the iliocostalis. It’s the largest of the three columns. Its three parts are the cervicis, capitis, and thoracic.

• Attachments: Comes from a shared tendinous origin and joins the mastoid process of the skull, the transverse processes of C2 through T12, and the lower ribs.
• Innervation: The posterior rami of the spinal nerves.
• Actions: Acts unilaterally to flex the spinal column laterally. Extends the spinal column and head on both sides.

Spinalis muscles

Inside the erector spinae, the spinalis muscle is situated medially. Among the three muscular columns, it is the smallest. It is separated into the thoracic, cervicis, and capitis (but some people lack the cervicis portion).

• Attachments: Derives from the same tendinous origin and attaches to the occipital bone of the skull as well as the spinous processes of C2, T1, and T8.
• Innervation: The spinal nerves’ posterior rami.
• Actions: Flexes the spinal column laterally by acting unilaterally. Extends the head and spinal column on both sides.

Deep

The deep intrinsic muscles located beneath the erector spinae are collectively referred to as transversospinales. They are a collection of small muscles connected to the vertebral column’s spinous and transverse processes.

• This group consists of three main muscles:
  • Rotatores
  • Multifidus
  • Semispinalis.

The Semispinalis

The semispinalis is the shallowest of the deep intrinsic muscles. It can be separated into thoracic, cervicis, and capitis by its superior attachments, just like the intermediate muscles.

• Attachments: Derives from the transverse processes of C4-T10. The fibers adhere to the occipital bone of the skull and the spinous processes of C2-T4 after ascending four to six spinal segments.
• Innervation: The spinal nerves’ posterior rami.
• Action: The head and spinal column are extended and rotated contralaterally.

Multifidus

Beneath the semispinalis muscle is the multifidus. The lumbar region is where it is most developed.

• Attachments: Has a wide range of origins, including the sacrum, posterior iliac spine, common tendinous origin of the erector spinae, lumbar vertebral mammillary processes, transverse processes of T1–T3, and articular processes of C4–C7. The fibers adhere to the vertebral spinous processes after ascending two to four spinal segments.
• Innervation: The spinal nerves’ posterior rami.
• Actions: Maintains the spinal column’s stability.

Rotators

The rotatores are the deepest muscles in the transversospinales group. They are mainly prominent in the thoracic region.

• Attachments: Derive from the transverse processes of the vertebrae. The fibers climb and join the spinous processes and lamina of the vertebrae above.
• Actions: Aids in the spinal column’s rotation and extension. Also has a proprioceptive role and stabilizes the vertebrae.
• Innervation: The spinal nerves’ posterior rami.

Small Deep Intrinsic Muscles:

• Interspinales: Spans between neighboring spinous processes are known as interspinales. Helps to keep the spinal column stable.
• Intertransversarii: Spans between neighboring transverse processes are known as intertransversarii. Helps to keep the spinal column stable.
• Levatores costarum: This structure joins to the rib directly below and arises from the transverse processes of C7-T11. Raises the ribs.

Function

Your back muscles enable you to move and support your body. They serve as your trunk’s primary structural support. Whether you’re sitting stationary or moving, they keep you steady and assist you in maintaining your posture.

Your back muscles work together to keep your torso upright. If you choose to change positions, your back muscles move both your torso and your back. Your back muscles are always keeping you in position, even when you cannot be doing it. It’s like having a complete safety system for your posture.

Your back muscles facilitate the movement of other body components, such as your:

• Head
• Neck
• Shoulders
• Arms
• Legs

You can bend over, twist, move your head, and stretch your back thanks to the cooperation of your back muscles. Additionally, they facilitate breathing by causing your chest to expand and collapse during inhalation and exhalation. This is an involuntary activity, meaning your body acts on its own initiative without your conscious awareness.

Exercise

Lumbar extension

• Put your hands on your lower back with your fingers pointed down while standing with your feet apart. With your knees straight and your hands supporting your trunk, bend your body backward at the waist.
• Improvement: To provide support, perform the stretch with your back against a countertop.
• Hold: 5 to 10 seconds
• Repetition: Perform 5 to 10 repetitions.

Bridging

• Lie flat on your back with your feet placed firmly on the ground, knees bent, and arms relaxed alongside your body. Keeping your back straight, slowly lift your hips upward while engaging your glutes and abdominal muscles. Then, gradually lower your hips and buttocks back down to the floor.
• Improvement: Place a pillow or bolster in the space behind your knees. Perform the push-up while supporting yourself on your knees instead of your feet. According to Garreau, this limits range of motion and somewhat lessens the difficulty of the exercise.
• Hold: 5 to 10 seconds
• Repetition: Perform 5 to 10 repetitions.

Quadruped spinal flexion (cat) and extension (camel)

• Assume a quadruped (four-point kneeling) position with the knees positioned slightly posterior to the hips and the hands directly beneath the shoulders. Slowly flex the cervical spine by bringing the chin toward the chest while simultaneously rounding the thoracic and lumbar spine toward the ceiling. Hold the position for a few seconds, then gently retract and depress the shoulders, allowing the back to relax. Return to a neutral spinal position with the back slightly extended while maintaining a forward gaze. Repeat for 10 repetitions.
• Improvement: To finish the workout, plant your feet on the ground and bend forward over a surface that is the height of a bed or couch.
• Hold: 5 to 10 seconds
• Repetition: Perform 5 to 10 repetitions.

Double knee-to-chest [DKCT]

• Assume a supine position with both knees flexed and the feet placed firmly on the supporting surface. Gradually bring both knees toward the chest and gently hold them with the arms. Maintain the lumbar spine in a relaxed, supported position against the treatment surface and hold the stretch for 20–30 seconds.Gradually lower the knees and return to the initial position. Repeat the movement for several repetitions, according to the patient’s tolerance.
• Improvement: Pull in one knee at a time for a less taxing stretch that works the same muscles. If lifting your knee fully is difficult, use a towel or small strap placed behind your knee to gently pull it toward you.
• Hold: 5 to 10 seconds
• Repetition: Perform 5 to 10 repetitions.

Supine Twist  

• Position the patient in supine lying with the knees flexed and feet supported on the floor. Keep both knees together while maintaining the shoulders in contact with the treatment surface. Slowly move the knees toward the right side, ensuring controlled trunk and pelvic stability throughout the movement. Hold the position for approximately 5 seconds, then return to the neutral starting position. Repeat the movement toward the left side, maintaining the position for 5 seconds before returning to neutral. Perform several repetitions, alternating between both sides.
• Improvement : Try lowering your knees halfway to the floor rather than all the way.
• Hold: 5 to 10 seconds
• Repetition: Perform 5 to 10 repetitions.

Care

How can I maintain my back muscles?

The best techniques to avoid muscular injuries are to warm up and stretch before engaging in physical activity. Improving your general range of motion will also shield your muscles from harm. Greater flexibility allows your muscle fibers to stretch further before tearing.

Gradually increase your level of exercise. Don’t start working out much more frequently than you typically do or abruptly increase the intensity of your workout.

When should I see a healthcare provider?

Get emergency medical help right away if you notice any of these signs:

• Fever.
• Your legs may feel weak, tingly, or numb.
• Severe discomfort, weakness, or spasms in the muscles.
• Unexpected weight reduction that happens suddenly.
• Issues with bowel or bladder control.

Conditions and Disorders

What are common back muscle injuries?

Strains represent the most frequently occurring injuries to the musculature of the back. Overuse of a muscle or improper lifting can result in muscular strains, often known as pulled muscles. Muscle fiber strands are torn apart when they are stretched too much. If you’ve ever attempted to secure something with an old bungee cord, you’ve witnessed this.

Back muscle injury symptoms?

Common signs of a back muscle injury are:

• Muscle pain.
• Muscle tightness.
• Muscle weakness.
• Stiffness.
• Back spasms.
• Swelling.
• Bruising or skin discoloration.

How do providers treat back muscle injuries?

Depending on the kind of damage you have and how severe it is, a medical professional may recommend the following treatments:

• Rest: Avoid doing the thing that caused you pain. Avoid doing anything physically demanding while your back heals. Your provider will decide how long you should take a break from strenuous labor, exercise, or training.
• Heat and/or ice: Apply heat or cold therapy to the affected back region for 15-minute intervals, multiple times daily. Your provider could recommend switching between ice and heat. To keep heating pads and ice packs away from your skin, wrap them in a towel or thin linen.
• Medication: NSAIDs and acetaminophen are examples of over-the-counter drugs that help decrease swelling and relieve pain. The kind of medicine you should take and how frequently it is safe to take it will be determined by your healthcare professional. Avoid using painkillers for longer than ten days in a row without first consulting your doctor.
• Physical therapy (PT): A physical therapist will prescribe a targeted regimen of therapeutic exercises and dynamic movements to enhance muscular strength and flexibility. Additionally, PT can help you avoid further injuries, enhance your posture, and reduce discomfort.

FAQs

References

• TeachMeAnatomy. (2025, October 26). Back Anatomy | Spine, Muscles and ligaments – TeachMeAnatomy. https://teachmeanatomy.info/back/
• Professional, C. C. M. (2025, December 29). Back muscles. Cleveland Clinic. https://my.clevelandclinic.org/health/body/21632-back-muscles