BACK MUSCLE

GENERAL INFORMATION

The back muscles play a critical role in posture, as well as upper body movement and stability. Furthermore, they support the spine, assist in lifting, and allow for a wide range of motion in the arms and shoulders. The back is composed of multiple layers of muscles, from the superficial to the deep, all contributing to a range of activities, including lifting, twisting, and stabilising the body during movement.

ORIGIN

• Latissimus Dorsi: Spinous processes of the lower six thoracic vertebrae, lumbar vertebrae, iliac crest, and sacrum.
• Trapezius: Occipital bone, ligamentum nuchae, and spinous processes of C7-T12 vertebrae.
• Rhomboid Major: Spinous processes of T2-T5 vertebrae.
• Rhomboid Minor: Spinous processes of C7-T1 vertebrae.
• Erector Spinae: Posterior sacrum, iliac crest, lumbar and lower thoracic vertebrae.

INSERTION POINT

• Latissimus Dorsi: Intertubercular groove of the humerus.
• Trapezius: Lateral third of the clavicle, acromion, and spine of the scapula.
• Rhomboid Major: Medial border of the scapula below the spine.
• Rhomboid Minor: Medial border of the scapula at the spine.
• Erector Spinae: Ribs, transverse processes of thoracic and cervical vertebrae, and mastoid process.

MAJOR ARTERIES

• Dorsal Scapular Artery: Supplies the rhomboids and trapezius.
• Thoracodorsal Artery: Provides blood flow to the latissimus dorsi.
• Posterior Intercostal Arteries: Supply the erector spinae and surrounding muscles.

NEURAL INNERVATION

• Latissimus Dorsi: Thoracodorsal nerve (C6-C8).
• Trapezius: Spinal accessory nerve (CN XI) and branches of the cervical plexus (C3-C4).
• Rhomboids: Dorsal scapular nerve (C4-C5).
• Erector Spinae: Posterior branches of spinal nerves.

TRIGGER POINT

Common trigger points in the back include the upper trapezius and rhomboids, causing pain in the upper back, neck, and shoulders. These trigger points can be activated by poor posture or overuse, leading to tightness and discomfort during arm or neck movements.

CONCENTRIC FUNCTION

• The Latissimus Dorsi: is responsible for shoulder extension, adduction, and medial rotation.
• The Trapezius: elevates, retracts, and rotates the scapula.
• The Rhomboids: retract the scapula, pulling it towards the spine.
• The Erector Spinae: muscles extend the spine and maintain posture.

ECCENTRIC FUNCTION

These muscles control the lowering or opposite movement of the back, such as slowly lowering the arms or controlling spinal flexion when bending forward.

• The Latissimus Dorsi: resists excessive shoulder flexion.
• The Erector Spinae: slow down forward bending and prevent uncontrolled flexion of the spine.

ISOMETRIC FUNCTION

• Stabilises: The spine and shoulders during static positions, like maintaining an upright posture or holding the arms in a fixed position.
• The Erector Spinae: Prevents spinal flexion during heavy lifting or while holding a weight overhead.

RELATED MUSCLE – SCIENTIFIC NAMES

• Serratus Anterior: Assists in scapular movement and stabilisation.
• Levator Scapulae: Elevates the scapula and assists in neck movement.
• Infraspinatus: Aids in shoulder external rotation and stabilisation.
• Teres Major: Works with the latissimus dorsi in shoulder adduction and medial rotation.
• Subscapularis: A part of the rotator cuff aiding in internal shoulder rotation.

ANTAGONIST

• Pectoralis Major: Opposes the latissimus dorsi in shoulder adduction and extension.
• Deltoid (Anterior Fibres): Opposes shoulder extension and assists in flexion.
• Serratus Anterior: Opposes the trapezius and rhomboids by protracting the scapula.
• Rectus Abdominis: Opposes the erector spinae by promoting spinal flexion.
• External Obliques: Assist in flexing and rotating the trunk, opposing the erector spinae.

COMMON INJURIES

• Muscle Strains: Overstretching or tearing of the back muscles, common from lifting heavy objects improperly.
• Lower Back Pain: Often caused by weak or overused erector spinae muscles, leading to discomfort in daily activities.
• Scapular Dyskinesis: Poor movement of the scapula due to weak rhomboids or trapezius, resulting in shoulder pain.
• Thoracic Outlet Syndrome: Compression of nerves or blood vessels near the upper trapezius causing pain and numbness in the neck, shoulder, and arm.
• Latissimus Dorsi Tendinopathy: Overuse or inflammation of the latissimus dorsi tendon, often seen in athletes performing repetitive overhead movements.

EXERCISES

• Pull-Ups: It is a bodyweight exercise that effectively strengthens the latissimus dorsi by pulling the body up towards a bar, thereby enhancing back as well as shoulder strength.
• Bent-Over Rows: Using a barbell or dumbbell, this exercise targets the trapezius and rhomboids by pulling the weight towards the body, promoting upper back muscle growth.
• Deadlifts: A compound movement that strengthens the erector spinae and lower back by lifting a barbell from the ground, improving overall back strength and posture.
• Lat Pulldowns: When using a cable machine, this movement targets the latissimus dorsi by pulling the bar down towards the chest, thus enhancing upper back strength.
• Face Pulls: Similarly, performed with a cable machine, this exercise strengthens the rhomboids and trapezius by pulling the rope towards the face, thereby improving posture and shoulder health.

STRETCHES

• Cat-Cow Stretch: A yoga stretch in which the spine is alternately arched and rounded, thereby improving flexibility while also reducing tension in the erector spinae and lower back.
• Child’s Pose: A yoga pose that stretches the lower back and legs by sitting back on the heels and reaching the arms forward, promoting relaxation and spinal decompression.
• Thread The Needle Stretch: A stretch for the rhomboids and trapezius, where one arm is threaded under the body while on all fours, helping to relieve tension in the upper back.
• Lat Stretch: To begin, stand with arms overhead and then gently pull one arm across the body, thereby stretching the latissimus dorsi and improving flexibility in the shoulders and upper back.
• Seated Forward Bend: Sitting with legs extended, reaching towards the toes to stretch the erector spinae and hamstrings, improving lower back flexibility and relieving tension.