What OSHA Treats as an MSD
OSHA does not maintain a closed list of musculoskeletal disorders. The agency uses a working definition that captures disorders of the muscles, nerves, tendons, ligaments, joints, cartilage, or spinal discs caused or aggravated by work-related activity. Common diagnoses in the recordkeeping context include:
- Carpal tunnel syndrome and other compressive neuropathies
- Lateral and medial epicondylitis
- Rotator cuff tendinopathy and impingement
- Low back strain, lumbar disc herniation
- De Quervain tenosynovitis, trigger finger
- Cervical strain and cervical radiculopathy
- Patellofemoral pain syndrome from kneeling work
- Hand-arm vibration syndrome
The MSD column note: 29 CFR 1904.12 has been reserved since the original MSD column rule was withdrawn. There is no separate MSD column on the OSHA 300 Log. MSDs are recorded under the standard injury or illness columns based on the case, the same as any other case meeting the 1904.7 criteria.
Acute Event vs. Cumulative Trauma
The first determination is whether the MSD arose from a single identifiable event or from cumulative exposure. The classification drives both the column on the 300 Log and the work-relatedness analysis.
Acute Event
A worker lifts a 50-lb box and feels immediate low back pain. The case is recorded as an injury. Work-relatedness is generally straightforward — a defined event in the work environment.
Cumulative Trauma
A data-entry worker develops bilateral wrist pain over months. The case is recorded as an illness under “all other illnesses.” Work-relatedness requires showing that workplace activities caused, contributed to, or significantly aggravated the condition.
Cases that begin as cumulative complaints sometimes have an acute precipitating event during a work shift. When that occurs, the date of injury is the date of the event, and the case is recorded as an injury. The cumulative history is documented but does not change the classification.
Work-Relatedness for Cumulative MSDs
Under 29 CFR 1904.5(a), an injury or illness is presumed work-related if an event or exposure in the work environment either caused, contributed to, or significantly aggravated the condition. The contribution standard is low. If workplace ergonomics played a meaningful role in producing or worsening symptoms, the case is work-related, even if non-occupational factors are also present.
In clinical practice, the questions to work through with the treating provider and the employee are:
- Are the work tasks consistent with known biomechanical risk factors for the diagnosis (forceful exertion, repetition, awkward posture, sustained loading, vibration, cold)?
- Did symptoms begin or worsen in temporal proximity to a change in job duties, production rate, equipment, or schedule?
- Is there a non-occupational activity (sport, hobby, second job, recent surgery) that could plausibly account for the same presentation?
- Does the laterality, distribution, and progression match the work pattern (e.g., dominant-hand symptoms in a repetitive-motion job)?
If a workplace contribution is plausible based on the exposure profile, the case is work-related and recordable if it meets one of the 1904.7 thresholds.
The Pre-Existing Condition Trap
More MSD recording errors come from mishandling pre-existing conditions than from any other source. The rule at 29 CFR 1904.5(b)(4) is that an injury or illness is work-related if the work environment significantly aggravated a pre-existing condition. Significant aggravation means the work caused:
- Death
- Loss of consciousness
- One or more days away from work, restricted work, or transfer
- Medical treatment beyond the level the employee would have received absent the workplace exposure
A worker with chronic, mild, well-controlled lateral epicondylitis who returns to a repetitive-grip job and now requires a corticosteroid injection has experienced significant aggravation. The case is recordable as the injection is medical treatment beyond first aid that exceeds prior care. A worker with the same diagnosis whose symptoms remain stable on a routine OTC regimen has not experienced significant aggravation.
Documentation matters. The threshold for significant aggravation is the level of treatment or impairment the employee would have experienced without the workplace exposure. That requires a clear baseline — pre-employment medical history, prior workers' comp claims, and the employee's own description of pre-injury function.
Recording Mechanics for Common MSDs
| Diagnosis | Typical Trigger for Recordability | Column |
|---|---|---|
| Carpal tunnel syndrome | Wrist splint at night, NSAIDs at prescription strength, injection, surgery, or restrictions | All other illness |
| Lateral epicondylitis | Counterforce brace beyond elastic wrap, PT, injection, restrictions | All other illness |
| Rotator cuff tendinopathy | PT, prescription medication, injection, surgery, restrictions | All other illness |
| Acute lumbar strain (lifting event) | Days away, restriction, prescription muscle relaxant, PT | Injury |
| De Quervain tenosynovitis | Thumb spica beyond elastic wrap, injection, surgery, restrictions | All other illness |
PT in the table means a course of treatment, not an evaluation. A single PT visit that produces home exercise recommendations only is observation under 1904.7, not medical treatment. A second PT visit with hands-on treatment establishes medical treatment.
Common Mistakes
Counting OTC NSAIDs as medical treatment. OTC ibuprofen at OTC strength is first aid. A prescription-strength dose is medical treatment. Document the dose given and prescribed, not the brand.
Treating a wrist cock-up splint as first aid because it has elastic. A rigid stay or thermoplastic shell is medical treatment. Only fully non-rigid supports qualify as first aid.
Concluding “not work-related” from a personal sport. A weekend tennis hobby does not by itself defeat the work-relatedness presumption for an office worker with lateral epicondylitis. Workplace contribution must be actively ruled out, not assumed away.
Using cumulative onset as a reason not to record. Cumulative MSDs are recordable when they meet the 1904.7 thresholds. The lack of an identifiable event does not excuse recording.
Recording before significant aggravation is established. A pre-existing MSD that is unchanged on a workplace re-evaluation is not recordable. Document the prior baseline and the current status before classifying the case.