The TuneUp Program

Movement of the spine is controlled by muscles that span individual vertebrae and those that control larger sections of the spine. The smaller muscles that cross from one vertebrae to another immediately adjacent, while being active during movement, cannot compete with the larger back muscles and functionally there main role is to stabilise individual vertebral units, in a similar way to the spinal ligaments. The larger muscles will be discussed here.

The muscles of the back

Because of the central role of the spine and it's connection to other skeletal structures, not all muscles that move the spine are connected to it. The rectus abdominal muscle for example runs from the pubic bone at the front of the pelvis up onto the ribs but is the main muscle responsible for flexing the trunk. When you're crouching over your guitar it pulls the ribs down toward the pelvis the spine has only one way to go. A number of other muscles in the back also control the movement of the spine

The parvertebral muscles

Also called the erector spinae group, even occasionally by their individual names, these muscles attach to the spine and span a number of vertebral units. They all do essentially the same thing and are only distinguishable by their individual attachments, some control just the lower back, others the thoracic, others the neck. Their fibres run upward obliquely from lateral to medial and control flexion, rotation and extension of the spine. The large rows of muscles that you can palpate either side of your spine are the paravertebrals.

Quadratus Lumborum

This muscle doesn't attach to the spine itself but runs from the posterior crest of the pelvis up onto the last rib. It tends to fatigue when you've been standing for too long, especially if your pushing your pelvis forward when upper body weight is directed more posteriorly and when standing on one leg the QL on the other side has to work to stabilise the position of the pelvis. It's main function is to bend the back to one side or, when they both act together, to extend the lower back.

The Abdominal Obliques

There are two abdominal oblique muscles, named for the direction of their fibres. The external oblique originates at the linea alba a vertical connective tissue cord in the middle of the abdomen and runs upward laterally to wrap around and attach onto the rib cage. The internal oblique originates on the anterior pelvis and the fascia of the lower back and runs up onto the line alba. This arrangement makes the fibres of the external and internal oblique muscles cross each other and also means that as they cross the centre line one muscle appears to continue on to the other.