Body system 1.00 in the SSA Blue Book covers musculoskeletal disorders for adult (Part A). SSA uses these listings at step 3 of its five-step disability evaluation. If your medical evidence meets one of the listings on this page, your claim is approved without the disability examiner moving on to past-work and labor-market analysis at steps 4 and 5.
Most claimants who do not meet a listing in this body system can still be approved at later steps based on their residual functional capacity, age, education, and past work. The medical evidence you build for a listing-match argument is the same evidence those later steps rely on, so the listing criteria are useful to read even when a claim looks like a step-5 approval candidate.
Body system code
1.00
Part A
Active listings
9
Specific impairments
Audience
Adults 18+
SSA disability evaluation
Step in evaluation
3 of 5
Listing match approves the claim
Active listings under 1.00
Every listing below has current SSA-published criteria. Codes that SSA reserved for future use or has withdrawn since 1985 are not included. Click a listing where a plain-English breakdown is available, or follow the regulation link for SSA's exact text.
Source: SSA Blue Book, body system 1.00. Last synced 2026-05-04.
How SSA describes this body system
Excerpted from SSA's regulatory introduction at the top of the body-system page. Full text and all subsection cross-references live on ssa.gov.
A. Which musculoskeletal disorders do we evaluate under these listings? 1. We evaluate disorders of the skeletal spine (vertebral column) or of the upper or lower extremities that affect musculoskeletal functioning under these listings. We use the term “skeletal” when we are referring to the structure of the bony skeleton. The skeletal spine refers to the bony structures, ligaments, and discs making up the spine. We refer to the skeletal spine in some musculoskeletal listings to differentiate it from the neurological spine (see 1.00B1 ). Musculoskeletal disorders may be congenital or acquired, and may include deformities, amputations, or other abnormalities. These disorders may involve the bones or major joints; or the tendons, ligaments, muscles, or other soft tissues. 2. We evaluate soft tissue injuries (including burns) or abnormalities that are under continuing surgical management (see 1.00O1 ). The injuries or abnormalities may affect any part of the body, including the face and skull. 3. We evaluate curvatures of the skeletal spine that affect musculoskeletal functioning under 1.15 . If a curvature of the skeletal spine is under continuing surgical management (see 1.00O1 ), we will evaluate it under 1.21 using our rules for determining medical equivalence. See §§ 404.1526 and 416.926 of this chapter. B. Which related disorders do we evaluate under other listings...
Read the full text on the SSA Blue Book 1.00 page.
What happens during a claim under 1.00
The disability examiner assigned to your claim looks for medical records that match the lettered criteria of one of the listings above. The examiner does not diagnose you and does not weigh symptoms in isolation. They line up the listing's required findings against your records and decide whether the records contain enough to satisfy the listing as written.
If your records meet a listing, the claim is approved at step 3. If not, the examiner moves on to evaluating your residual functional capacity (RFC) at steps 4 and 5. RFC is a description of what work activity you can still do despite your impairments. The listings inform the RFC because the same medical evidence the listings ask for is the evidence the examiner uses to write the RFC. The disability overview walks through the full five-step evaluation in plain English.
Work activity, SGA, and the SSDI gate
A claim under any Blue Book listing is denied at step 1 if you are working at or above the substantial gainful activity threshold. SGA is the monthly earnings test SSA applies before any medical evaluation. Earning above SGA in countable work activity means SSA never reaches the listings on this page. Earning below SGA, or being out of work entirely, lets the medical evaluation proceed.
Once you are approved and receiving SSDI, the trial work period and extended period of eligibility apply differently than at the initial-application stage. Both are explained on the SGA amount page with year-by-year thresholds since 1975.
Children's listings for the same body system
SSA publishes a parallel body system at 101.00 for the children's (under 18) side of the same conditions. Many listings cross over with tighter functional thresholds for the children's version. The Musculoskeletal disorders (children) page covers the 10 active listings on that side.