Cause, not site guide you to the right code. You can expect ICD-10 to bring lots of changes to the way you'll report myositis and other musculoskeletal system and connective tissue disorders, including muscle diastasis. When ICD-10 is enforced, you'll need to confirm the underlying diastasis cause to ensure you are applying the right code. See our expert advice on code selection below. Confirm Trauma for Diastasis The ICD-9 code for muscle separation 728.84 (Diastasis of muscle) specifies 'diastasis.' This is a muscle separation. For example, diastasis recti implies the separation of the rectus abdominis into two halves, the right and the left halves still joined at the linea alba. "The rectus abdominis is normally separated at two halves, joined at the linea alba. A diastasis describes a separation of the muscles that is abnormal. The normal rectus two halves are not abnormal. You can have a rectus disastasis if the muscles parts are separated more than they normally are," says Bill Mallon, MD, medical director, Triangle Orthopedic Associates, Durham, N.C. The corresponding ICD-10 code M62.00 (Separation of muscle [nontraumatic], unspecified site) describes the term 'separation of muscle' and specifies 'nontraumatic.' This is a better description for a condition like diastasis recti, which occurs in conditions other than trauma. This condition occurs in premature infants in whom the muscle is not mature enough to remain fused in the midline and in multiparous women in whom the muscle falls apart in the midline due to repeated stretching during multiple pregnancies. "ICD-10 has brought more specificity to the code choice by listing as 'non-traumatic,'" says Kristi Stumpf, MCS-P, CPC, COSC, ACS-OR, owner, Precision Auditing and Coding, senior orthopedic coder & auditor, The Coding Network, Washington.