ICD-10-CM · Spine

M40.04

Excessive posterior curvature of the thoracic spine caused by habitual poor posture rather than structural deformity, vertebral pathology, or an underlying systemic condition.

Verified May 8, 2026 · 5 sources ↓

Status: Billable
Chapter: 13
Related CPT: 10
Region: Spine

Drawn from CDCICD10DataAAPCIcdcodesCdek

Documentation tips

What should appear in the chart to support M40.04.

Source · Editorial brief grounded in 5 cited references ↓

Record the Cobb angle from a standing lateral thoracic spine radiograph and note the apex vertebral level to confirm the deformity is within the thoracic region.
Explicitly state 'postural kyphosis' in the assessment — terms like 'rounded back' or 'thoracic kyphosis' alone do not establish postural etiology and may force a fallback to M40.14 or M40.209.
Document that the curve is flexible or reducible with positioning or active extension, which distinguishes postural from structural (Scheuermann's) kyphosis.
Note absence of vertebral end-plate irregularities, Schmorl's nodes, or wedging on imaging; their presence redirects coding to M42 (osteochondrosis of spine).
If an underlying condition such as osteoporosis is present, document whether it is causally contributing to the kyphosis — if so, code M40.14 and follow the 'code first underlying disease' instruction at M40.
For adolescent patients, record age and growth stage; postural kyphosis in adolescence is a recognized clinical entity that supports M40.04 without requiring additional modifiers.

Related CPT procedures

Procedure codes commonly billed with M40.04. Linking the right diagnosis to the right procedure is what establishes medical necessity.

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

72080 $35.07

Radiologic examination of the thoracolumbar junction (where the thoracic and lumbar spine meet), requiring a minimum of two views.

72070 $33.07

Two-view radiologic examination of the thoracic spine, including AP and lateral projections of the 12 thoracic vertebrae.

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.

99215 $192.39

Highest-level office or outpatient E/M visit for an established patient, qualifying via high-complexity medical decision making or 40–54 minutes of total provider time on the date of service.

72040 $39.75

Radiologic examination of the cervical spine capturing two or three views (e.g., AP, lateral, oblique).

72074 View procedure details

97530 View procedure details

97010 View procedure details

Common coding pitfalls

The recurring mistakes coders make with M40.04 and adjacent codes.

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

Assigning M40.04 when osteochondrosis of the spine (Scheuermann's disease) is documented — M42 is the correct code and M40.0 carries an Excludes1 note for M42.
Using M40.04 for kyphosis secondary to osteoporosis or another underlying disease — those cases require M40.14 with 'code first' sequencing for the underlying condition.
Defaulting to M40.00 (site unspecified) when the thoracic region is clearly documented in the note, losing specificity that payers increasingly require.
Confusing M40.04 with M40.05 (thoracolumbar region) when the apex of the curve sits at or near T12–L1 — confirm apex level from the radiograph before selecting the code.
Coding M40.04 alongside M41 codes for kyphoscoliosis — M40 carries an Excludes1 for kyphoscoliosis; if both a scoliotic and kyphotic component exist with rotation, M41 is the correct category.
Omitting the 'code first underlying disease' step when M40.04 is used in a patient with a concurrent systemic condition that may be driving the deformity — if causally linked, reroute to M40.14.

Clinical context

Source · Editorial summary grounded in 5 cited references ↓

M40.04 applies when documented thoracic kyphosis is postural in origin — meaning the curve is flexible, corrects partially with positional change or active extension, and is not attributable to an underlying disease such as osteoporosis, Scheuermann's osteochondrosis, or a prior surgical procedure. It is most commonly assigned for adolescent round-back deformity or adult hyperkyphosis driven by habitual slouching. The Cobb angle on standing lateral radiograph typically exceeds 40–45 degrees, and the provider must explicitly characterize the kyphosis as postural rather than structural.

Do not use M40.04 if the kyphosis results from vertebral osteochondrosis — that routes to M42. If an underlying condition such as osteoporosis drives the deformity, use M40.14 (other secondary kyphosis, thoracic region) and code first the underlying disease per the M40 category instruction. Congenital kyphosis maps to Q76.4, and postprocedural kyphosis to M96, both Excludes1 at the M40 category level. Kyphoscoliosis (M41) is also excluded from M40 — if a rotational scoliotic component is documented alongside the kyphosis, M41 takes priority.

Within the M40.0 subcategory, region specificity is required for billing: M40.00 (site unspecified), M40.03 (cervicothoracic), M40.04 (thoracic), M40.05 (thoracolumbar). Use M40.04 only when the apex of curvature falls within the thoracic spine (T1–T12). If the curve spans the thoracolumbar junction, M40.05 may be more accurate depending on apex documentation.

Sibling codes

Other billable codes under M40.0 (laterality / anatomic variants).

M40.03

Postural kyphosis, cervicothoracic region

M40.05

Postural kyphosis, thoracolumbar region

M40.00

Postural kyphosis, site unspecified

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01What distinguishes M40.04 from M40.14?

M40.04 is postural kyphosis — no underlying structural or systemic cause. M40.14 (other secondary kyphosis, thoracic region) applies when an underlying condition such as osteoporosis, neuromuscular disease, or metabolic disorder drives the deformity. M40.14 also requires 'code first' sequencing for the underlying disease.

02Can M40.04 be used for Scheuermann's disease?

No. M40.0 (the parent of M40.04) carries an Excludes1 for osteochondrosis of the spine (M42). Scheuermann's kyphosis with vertebral wedging and end-plate changes codes to M42.00–M42.09, not M40.04.

03Is a Cobb angle measurement required to bill M40.04?

ICD-10-CM does not mandate a specific Cobb angle threshold, but documenting the angle from a standing lateral radiograph is best practice. Without it, payers auditing medical necessity for physical therapy or bracing lack objective support, and the postural diagnosis is harder to defend.

04When should M40.05 (thoracolumbar) be used instead of M40.04?

Use M40.05 when the apex of the kyphotic curve falls at the thoracolumbar junction (approximately T12–L1). If the apex is clearly within T1–T12, M40.04 is correct. Confirm apex level from the radiograph report before selecting between these two codes.

05Can M40.04 and a scoliosis code (M41) be reported together?

No. Category M40 carries an Excludes1 for kyphoscoliosis (M41). If the patient has both kyphosis and scoliosis with a rotational component, M41 is the appropriate category. Excludes1 means M40 and M41 codes cannot be used together for the same condition at the same site.

06Does M40.04 require a 7th-character extension?

No. M40.04 is a 5-character code and is complete as coded. Seventh-character extensions apply to injury codes (S-codes), not M-code musculoskeletal diagnoses.

07What CPT codes are commonly paired with M40.04?

Standing lateral thoracic spine X-rays (72070, 72074, 72080) are the primary imaging codes. Physical therapy services (97110, 97530) are the most frequent therapeutic pairings. Orthopedic or spine office visits (99213–99215) also commonly carry this diagnosis code.

Sources & references

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

Mira AI Scribe

Mira's AI scribe captures the clinician's characterization of kyphosis as postural versus structural, the Cobb angle and apex vertebral level from imaging, flexibility of the curve on physical exam, and the absence of vertebral pathology such as end-plate irregularities or wedging. This documentation prevents downcoding to M40.00 (site unspecified), blocks misrouting to M42 or M40.14, and supports medical necessity for physical therapy or orthotic referrals tied to M40.04.

See how Mira captures M40.04 documentation