SPINALIS

GENERAL INFORMATION

The spinalis is an integral component of the erector spinal muscle group, which is pivotal in maintaining posture and enabling various back movements, including extension, lateral flexion, and spinal rotation. Significantly, these muscle groups are segmented into three distinct portions: spinalis thoracis, spinalis cervicis, and spinalis capitis.

ORIGIN

• Spinalis Thoracis: This segment originates from the spinous processes of the upper thoracic vertebrae, the two lower thoracic vertebrae, and the upper lumbar vertebrae.

• Spinalis Cervicis: Similarly, it stems from the spinous processes of the upper thoracic vertebrae. Furthermore, the origins of spinalis cervicis and capitis exhibit some anatomical variations, making them less defined.

• Spinalis Lumborum: This portion arises from the spinous processes of the lumbar vertebrae.

INSERTION POINT

• Spinalis Thoracis: This muscle inserts on the spinous processes of the cervical vertebrae C2-C6 and the upper thoracic vertebrae.

• Spinalis Cervicis: It notably inserts on the spinous processes of cervical vertebrae C2-C6 and the axis (the second cervical vertebra).

• Spinalis Lumborum: Insertion occurs at the spinous processes of the lower thoracic vertebrae T11-T12 and the lumbar vertebrae L1-L5.

• Spinalis Capitis: When present, it connects to the occipital bone.

MAJOR ARTERIES

Importantly, these muscles receive their blood supply primarily from the posterior branches of the segmental arteries and the posterior intercostal artery.

NEURAL INNERVATION

These muscles are innervated by the dorsal rami of the spinal nerves, which are crucial for their functioning.

TRIGGER POINT

Located within the muscle belly along the spine, trigger points for this muscle can be effectively targeted through manual pressure or massage to alleviate tension or discomfort. A trigger point in the spinalis often causes pain and tightness in the lower back and upper thigh.

CONCENTRIC FUNCTION

These muscles play a vital role in extending the vertebral column, which allows for movements such as bending backwards. During these actions, the spinalis works concentrically to extend and rotate the spine while also maintaining proper posture.

ECCENTRIC FUNCTION

Additionally, these muscles control the speed and direction of the vertebral column’s flexion, such as when bending forward or to the side. Eccentrically, the spinalis helps control the movement of the spine during activities like deadlifts and good mornings.

ISOMETRIC FUNCTION

Particularly when maintaining an upright posture or carrying a heavy load, these muscles work isometrically to stabilise the spine. This isometric function is essential for maintaining proper posture while sitting or standing.

RELATED MUSCLES OF THE SPINALIS (SCIENTIFIC NAMES)

• Longissimus: A key muscle of the erector spinae group, it assists in extending and rotating the spine.

• Iliocostalis: Helps extend and laterally flex the vertebral column, part of the erector spinae.

• Multifidus: Provides stability to the vertebrae during movement located along the spine.

• Quadratus Lumborum: Helps with lateral flexion and extension of the lumbar spine.

• Latissimus Dorsi: A large muscle in the back that extends, adducts, and medially rotates the arm.

• Transversospinalis: These deep muscles of the back assist in stabilising and rotating the vertebral column.

ANTAGONIST MUSCLES

• Rectus Abdominis: Flexes the spine and stabilises the core.

• Obliques (Internal and External): Rotate and laterally flex the spine and stabilise the trunk.

• Psoas Major: Assists in trunk flexion and stabilisation, as well as a deep hip flexor.

• Transversus Abdominis: Compresses abdominal contents and stabilises the trunk.

COMMON INJURIES OF SPINALIS MUSCLE

• Strains and sprains: Often due to improper lifting techniques or overuse, causing muscle fibre or ligament damage.

• Muscle spasms: Typically result from sudden movements or strains, causing sudden, involuntary contractions.

• Herniated or bulging discs: Discs pressing on nearby nerves, causing pain and potential nerve damage.

• Lower back pain and sciatica: Prevalent issues that can be caused by various factors impacting the spinalis muscle.

EXERCISE

• Back extensions: Perform on a stability ball or Roman chair to strengthen the erector spinae muscles.

• Deadlifts: Use proper form to engage the spinalis and other back muscles, improving strength and stability.

• Superman training: Lie face down and lift arms and legs off the ground simultaneously to strengthen the lower back.

• Prone back extensions: Lie face down and lift your chest off the ground to target the lower back muscles.

• Good mornings: Bend at the hips with a straight back to target the lower back and hamstrings.

STRETCHES FOR SPINALIS

• Child’s pose: Sit back on your heels with arms extended forward, stretching the back muscles.

• Cat-Camel stretch: Alternate between arching and rounding your back to improve flexibility and reduce tension.

• Lumbar rotation stretch: Lie on your back with knees bent and rotate them to each side to stretch the lower back.

• Standing or seated forward bends: Bend forward at the hips to stretch the back and hamstrings.

• Seated spinal stretch: Sit with one leg extended and the other bent, twisting the torso to stretch the spine.