Without an understanding of functional musculoskeletal system recovery, the translation of knowledge concerning neurological recovery from laboratory discoveries to bedside applications will be incomplete. Because improvements in neurological function after cell transplantation are minor and can be easily ignored, this article draws attention to the minimal improvements required to allow a spinal cord injury patient or person to live a relatively independent life. These minimal improvements include (1) the key muscle power required for trunk stability; (2) the key muscle power required to allow a paraplegic to walk; and (3) the key muscle power required for hand usefulness or functionality.

The system of muscle power grading promoted by the British Medical Research Council (MRC) is more sensitive and delicate than the ASIA Standards, as the latter only accept the full range of movement of a joint. The MRC system seems to be preferable to the ASIA Standards in clinical trials of cell transplantation, wherein minute improvements in function might result in large differences in the quality of life.

The threshold of function is a grade 3 power level. Even if all relevant muscles fail to achieve a power higher than grade 3, the patient can be minimally functional and hence relatively independent. These relevant muscles include the latissimus dorsi, hip flexors, hip abductors, shoulder abductors and flexors, elbow flexors and extensors, and wrist extensors. These muscles are innervated by the C5-7 spinal cord segments except the latissimus dorsi, for which innervation extends to C8.