ICD-10-CM · Spine

M46.08

Pathological changes at the ligamentous and muscular attachment sites of the spine within the sacral and sacrococcygeal region, including inflammatory or degenerative disruption at the sacrum or coccyx insertions.

Verified May 8, 2026 · 4 sources ↓

Status: Billable
Chapter: 13
Related CPT: 15
Region: Spine

Drawn from CDCICD10DataCMSAAPC

Documentation tips

What should appear in the chart to support M46.08.

Source · Editorial brief grounded in 4 cited references ↓

Explicitly name the affected region as 'sacral' or 'sacrococcygeal' — generic 'low back enthesopathy' without site specification forces a less specific code.
Distinguish sacral/sacrococcygeal enthesopathy from lumbosacral enthesopathy (M46.07); document the exact spinal level(s) involved to avoid site-coding errors.
Record the presumed etiology — inflammatory (e.g., spondyloarthropathy), mechanical overload, or repetitive strain — since this may require an additional primary diagnosis code.
Note imaging findings that support the diagnosis: MRI bone marrow edema at sacral entheses, CT erosions at sacrococcygeal ligamentous insertions, or ultrasound findings of entheseal thickening.
If conservative care has been attempted (PT, NSAIDs, injections), document it; this substantiates medical necessity for ongoing or escalating treatment tied to this code.

Related CPT procedures

Procedure codes commonly billed with M46.08. Linking the right diagnosis to the right procedure is what establishes medical necessity.

Source · CMS LCDs · AAOS specialty guidance · claims-pattern analysis

72100 $40.42

Radiologic examination of the lumbosacral spine capturing two or three views, used to evaluate the lumbar vertebrae and sacrum for injury, degeneration, or structural abnormality.

72110 $53.44

Radiologic examination of the lumbar spine (lumbosacral) with a minimum of four views, including oblique and/or bending views.

72120 $42.09

Radiologic examination of the lumbosacral spine using bending views only, minimum of four views, to assess spinal flexibility and alignment.

72170 $28.06

Radiologic examination of the pelvis capturing one or two views, used to evaluate pelvic bones, sacrum, and coccyx for fractures, arthritis, or other structural abnormalities.

72190 $43.42

Radiologic examination of the pelvis requiring a minimum of three separate views, capturing the pelvic bones, hip joints, and surrounding structures.

27096 $175.69

Injection into the sacroiliac joint with fluoroscopic or CT image guidance, including arthrography when performed.

20552 $51.77

Injection(s) into one or two muscles for single or multiple trigger points at a single session.

97110 $29.06

Therapeutic exercise billed per 15-minute unit, targeting strength, endurance, range of motion, or flexibility with direct one-on-one patient contact.

99213 $95.19

Established patient office or outpatient visit requiring 20–29 minutes of total time or low-complexity medical decision-making.

99214 $135.61

Office visit for an established patient requiring moderate-complexity medical decision making (MDM), or 30–39 minutes of total provider time on the date of service.

72220 View procedure details

72240 View procedure details

98940 View procedure details

98941 View procedure details

98942 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M46.08 and adjacent codes.

Source · Editorial brief grounded in CDC ICD-10-CM tabular guidance, AAOS coding references, and cited references ↓

Using M46.07 (lumbosacral region) when the documented site is sacral or sacrococcygeal — these are adjacent but distinct codes; check the note carefully.
Defaulting to M46.09 (multiple sites) when only the sacral/sacrococcygeal region is documented — use M46.08 when the provider specifies this single region.
Coding M46.08 as a primary diagnosis when an underlying inflammatory spondyloarthropathy (e.g., M45.x ankylosing spondylitis) is the driving condition — sequence the primary condition first.
Confusing sacral enthesopathy with sacroiliac joint dysfunction (M53.3) or coccydynia (M53.3) — enthesopathy specifically involves ligamentous/muscular attachment pathology, not joint instability or isolated coccyx pain without entheseal involvement.

Clinical context

Source · Editorial summary grounded in 4 cited references ↓

M46.08 applies when a provider documents spinal enthesopathy localized to the sacral or sacrococcygeal region — meaning disorder of the ligamentous or muscular attachments at or around the sacrum and coccyx. The condition involves pathological changes at entheses (insertion points) that may stem from mechanical overload, inflammatory spondyloarthropathy, or repetitive stress. Pain, reduced spinal stability, and local tenderness over the sacrococcygeal area are typical clinical presentations.

This code sits under the M46.0 parent (Spinal enthesopathy) and is the most caudal site-specific code in that series. It does not capture enthesopathy at the lumbosacral junction — that's M46.07. If the enthesopathy spans multiple spinal regions, use M46.09 instead. When an underlying inflammatory spondyloarthropathy (e.g., ankylosing spondylitis) drives the enthesopathy, code the primary condition first and M46.08 as an additional code if clinically relevant.

CMS explicitly recognizes M46.08 as a diagnosis that supports medical necessity for chiropractic manipulation services (CMS Article A56273). It maps to MS-DRG 551 (Medical back problems with MCC) or 552 (without MCC) under DRG v43.0, so accurate comorbidity capture affects DRG assignment.

Sibling codes

Other billable codes under M46.0 (laterality / anatomic variants).

M46.00

Spinal enthesopathy, site unspecified

M46.04

Spinal enthesopathy, thoracic region

M46.06

Spinal enthesopathy, lumbar region

M46.01

Spinal enthesopathy, occipito-atlanto-axial region

M46.05

Spinal enthesopathy, thoracolumbar region

M46.09

Spinal enthesopathy, multiple sites in spine

M46.07

Spinal enthesopathy, lumbosacral region

M46.03

Spinal enthesopathy, cervicothoracic region

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 4 cited references ↓

01What is the difference between M46.07 and M46.08?

M46.07 is spinal enthesopathy at the lumbosacral region (the junction of L5 and S1). M46.08 covers the sacral and sacrococcygeal region proper — at or below S1 down through the coccyx. The provider's documented site determines which code applies; don't assume they're interchangeable.

02Can M46.08 be used as the primary diagnosis for chiropractic billing?

Yes. CMS Article A56273 explicitly lists M46.08 among the ICD-10-CM codes that support medical necessity for chiropractic manipulation services, so it is a valid primary diagnosis in that context.

03Should M46.08 be coded alongside ankylosing spondylitis?

If the sacral enthesopathy is a manifestation of ankylosing spondylitis (M45.x), sequence the ankylosing spondylitis first. M46.08 may be added as an additional code if it provides clinically relevant specificity, but verify payer policy on secondary diagnosis reporting.

04Does M46.08 require a 7th character?

No. M46.08 is a 6-character M-code and does not use 7th-character extensions. The 7th-character encounter designations (A, D, S) apply to injury codes in the S-chapter, not to Chapter 13 musculoskeletal codes like M46.08.

05What imaging supports M46.08 for audit purposes?

MRI is most informative — bone marrow edema at sacral entheses, entheseal thickening, or periosteal reaction at sacrococcygeal ligamentous insertions. CT can show erosions or sclerosis at attachment sites. Plain radiographs may demonstrate sacrococcygeal periostitis. Document the modality, date, and relevant findings in the note.

06Is M46.08 appropriate when the coccyx alone is involved?

Yes, provided the pathology is enthesopathic in nature (ligamentous or muscular attachment disorder). If the presentation is isolated coccyx pain without documented entheseal involvement, consider M53.3 (coccydynia) instead and confirm with the provider.

07What MS-DRG does M46.08 map to?

Under MS-DRG v43.0, M46.08 groups to DRG 551 (Medical back problems with MCC) or DRG 552 (Medical back problems without MCC), depending on documented comorbidity complexity. Accurate comorbidity coding affects which DRG is assigned.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

01CDC ICD-10-CM Tabular List 2026 (effective Oct 1, 2025)
02
icd10data.com
https://www.icd10data.com/ICD10CM/Codes/M00-M99/M45-M49/M46-/M46.08
03
cms.gov
https://www.cms.gov/medicare-coverage-database/view/article.aspx?articleid=56273&ver=26 (CMS Article A56273, Billing and Coding: Chiropractic Services)
04
aapc.com
https://www.aapc.com/codes/icd-10-codes/M46.08

Mira AI Scribe

Mira AI Scribe captures the anatomic site (sacrum vs. coccyx vs. sacrococcygeal), presence or absence of inflammatory spondyloarthropathy, imaging findings supporting entheseal pathology, and any prior conservative treatment. This prevents site ambiguity that forces a drop to unspecified parent M46.0 and flags if a primary inflammatory diagnosis should be sequenced ahead of M46.08.

See how Mira captures M46.08 documentation