ICD10BillableValid for clinical use

ICD-10 Code M21.379: Foot drop, unspecified foot

M21.379 is a billable ICD-10 diagnosis code used to classify Foot drop, unspecified foot in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the musculoskeletal system and connective tissue (M00-M99).

Reviewed by HealthAssure Clinical TeamUpdated 26 May 2026

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Diseases of the musculoskeletal system and connective tissue (M00-M99).

When is it used?

  • May be used when a clinician documents foot drop, unspecified foot in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

Code hierarchy

chapter
13Diseases of the musculoskeletal system and connective tissue (M00-M99)
block
M00-M25Arthropathies
block
M20-M25Other joint disorders
category
M21Other acquired deformities of limbs
category
M21.3Wrist or foot drop (acquired)
category
M21.37Foot drop (acquired)
currentM21.37

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

Orthopedic SpecialistRheumatologist

Coverage-related procedures and services

HCPCS G0255high
CURRENT PERCEPTION THRESHOLD/SENSORY NERVE CONDUCTION TEST, (SNCT) PER LIMB, ANY NERVE
Source: CMS coverage guidance
CPT 95873high
ELECTRICAL STIMULATION FOR GUIDANCE IN CONJUNCTION WITH CHEMODENERVATION (LIST SEPARATELY IN ADDITION TO CODE FOR PRIMARY PROCEDURE)
Source: CMS coverage guidance
CPT 95905high
MOTOR AND/OR SENSORY NERVE CONDUCTION, USING PRECONFIGURED ELECTRODE ARRAY(S), AMPLITUDE AND LATENCY/VELOCITY STUDY, EACH LIMB, INCLUDES F-WAVE STUDY WHEN PERFORMED, WITH INTERPRETATION AND REPORT
Source: CMS coverage guidance
CPT 95874high
NEEDLE ELECTROMYOGRAPHY FOR GUIDANCE IN CONJUNCTION WITH CHEMODENERVATION (LIST SEPARATELY IN ADDITION TO CODE FOR PRIMARY PROCEDURE)
Source: CMS coverage guidance
CPT 51785high
NEEDLE ELECTROMYOGRAPHY STUDIES (EMG) OF ANAL OR URETHRAL SPHINCTER, ANY TECHNIQUE
Source: CMS coverage guidance
CPT 95872high
NEEDLE ELECTROMYOGRAPHY USING SINGLE FIBER ELECTRODE, WITH QUANTITATIVE MEASUREMENT OF JITTER, BLOCKING AND/OR FIBER DENSITY, ANY/ALL SITES OF EACH MUSCLE STUDIED
Source: CMS coverage guidance

Coding guidelines

Common synonyms

Foot drop, unspecified footFoot drop

Frequently asked questions

Code details

CodeM21.379
SystemICD10
Display nameFoot drop, unspecified foot
ChapterDiseases of the musculoskeletal system and connective tissue (M00-M99)
BlockOther joint disorders

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.

ICD-10 Code M21.379 for Foot drop, unspecified foot | HealthAssure