Kinesiology

Lesson 7 of 16

Back and spine

The spine provides a flexible axial support system, while back muscles help extend, rotate, and control the trunk. The erector spinae group runs longitudinally and contributes to extension and postural control. Deeper segmental muscles help coordinate local stability. Respect the spinous processes and adapt pressure to the person's comfort and position.

Key points

• The vertebral column has cervical, thoracic, lumbar, sacral, and coccygeal regions.
• Erector spinae includes iliocostalis, longissimus, and spinalis columns.
• Bilateral erector spinae activity extends the spine; unilateral activity contributes to same-side lateral flexion.
• Multifidus and other deep muscles help control intervertebral motion.
• Latissimus dorsi links the trunk and pelvis functionally with the upper limb.
• Use supported positioning rather than asking a client to hold a strained spinal posture.

Key terms

Iliocostalis

O: common tendon from sacrum, iliac crest, and lumbar region; I: angles of ribs and cervical transverse processes; A: extends and ipsilaterally side-bends spine.

Longissimus

O: common erector tendon and thoracolumbar fascia; I: ribs, thoracic/cervical processes, and mastoid region; A: extends spine/head and ipsilaterally side-bends.

Spinalis

O: lower thoracic and lumbar spinous processes; I: upper thoracic and cervical spinous processes; A: extends the spine.

Multifidus

O: sacrum, posterior ilium, and vertebral processes; I: spinous processes several levels above; A: stabilizes and assists extension/contralateral rotation.

Latissimus dorsi

O: lower thoracic spinous processes, thoracolumbar fascia, iliac crest, and lower ribs; I: floor of intertubercular groove of humerus; A: extends, adducts, and medially rotates arm.