GENERAL INFORMATION
The semispinalis thoracis is part of the semispinalis group within the transversospinales muscles. Specifically, it is a deep back muscle located in the upper back and neck. Consequently, it plays a crucial role in extending and rotating the vertebral column and helping maintain body posture.
ORIGIN OF SEMISPINALIS THORACIS
The semispinalis thoracis originates from the transverse processes of the upper five to six thoracic vertebrae and the lower three to four cervical vertebrae. Therefore, its points of origin are well-positioned to support its function in spinal movement.
INSERTION POINT
The semispinalis thoracis inserts into the spinous processes of the upper thoracic and lower cervical vertebrae, about four to six segments above the origin. Thus, semispinalis thoracis insertion points enable it to span several vertebral segments, enhancing its role in spinal stability and movement.
MAJOR ARTERIES
The semispinalis thoracis is primarily supplied by the dorsal branches of the segmental arteries. Consequently, these arteries provide the necessary blood flow to support the muscle’s function.
NEURAL INNERVATION
The posterior rami of spinal nerves innervate this muscle. Therefore, proper nerve function is essential for the activation and control of the semispinalis thoracis.
TRIGGER POINT OF SEMISPINALIS THORACIS
Trigger points for the semispinalis thoracis are generally located within the muscle belly along the spine. These can be stimulated through manual pressure or massage for relief. As a result, targeted therapy can alleviate discomfort and improve muscle function.
CONCENTRIC FUNCTION
The semispinalis thoracis helps in the extension and contralateral (opposite side) rotation of the vertebral column. Thus, it is integral to various spinal movements, ensuring effective and controlled extension and rotation.
ECCENTRIC FUNCTION
The muscle controls the speed and direction of the vertebral column’s flexion and rotation. Consequently, it plays a critical role in maintaining stability and control during these movements.
ISOMETRIC FUNCTION
The semispinalis thoracis provides stability to the vertebral column during movements and maintains the upright posture of the body. Therefore, it is essential for supporting proper posture and spinal alignment.
RELATED MUSCLES (SCIENTIFIC NAMES)
- Semispinalis Cervicis: Works with the thoracis to stabilise and move the cervical spine.
- Semispinalis Capitis: Extends and rotates the head, complementing the thoracis.
- Longissimus: Aides in extension and lateral flexion of the spine and neck.
- Multifidus: Provides segmental stabilisation of the spine.
- Rotatores: Enhances vertebral rotation and proprioceptive feedback.
ANTAGONIST MUSCLES
- Rectus Abdominis: Flexes the spine, opposing the back extension.
- Obliques (Internal and External): These aid in trunk rotation and lateral flexion and oppose back extension.
- Psoas Major: Primarily flexes the hip and lumbar spine, providing opposition to the spinal extension.
COMMON INJURIES
- Muscle strains and sprains: Common from overuse or incorrect lifting.
- Postural problems: Lead to imbalances and chronic discomfort in the upper back.
- Muscle spasms or tension: Often triggered by stress or poor ergonomic practices.
EXERCISES FOR SEMISPINALIS THORACIS
- Prone Back Extensions: Lie face down and lift the upper body to strengthen the back muscles.
- Cat-Cow Pose: Enhances spinal flexibility and strength through extension and flexion movements.
- Cobra Pose: Targets the spinal extensors, improving posture and back extension.
- Stability Ball Back Extensions: Use a ball to increase the range of motion and strengthen the back.
- Pilates for Spinal Rotation: Focus on controlled movements to enhance spinal rotation and extension.
STRETCHES
- Child’s Pose Stretch: A deep relaxation pose that stretches the back and promotes flexibility.
- Cat-Camel Stretch: Mobilizes the entire spine in a gentle flexion and extension cycle.
- Seated or Standing Forward Bend: Stretches the back and hamstrings, easing tension in the spinal extensors.
- Gentle Yoga Twists: Improve spinal mobility and alleviate stiffness through rotational stretches.
- Lying Knee Twist: Lie on your back and gently rotate your knees to one side, stretching the lower back and thoracic spine.
Regular practice of these exercises and stretches can significantly improve the function and health of the semispinalis thoracis, promoting better posture, reducing the risk of injury, and enhancing overall spinal stability.