ICD-10 Code M21.37

Foot drop (acquired)

Version 2019 Non-Billable Code

Not Valid for Submission

M21.37 is a "header" nonspecific and non-billable code code, consider using a code with a higher level of specificity for a diagnosis of foot drop (acquired). The code is NOT valid for the year 2020 for the submission of HIPAA-covered transactions.

ICD-10: M21.37
Short Description:Foot drop (acquired)
Long Description:Foot drop (acquired)

Consider the following ICD-10 codes with a higher level of specificity:

Code Classification

  • Diseases of the musculoskeletal system and connective tissue (M00–M99)
    • Other joint disorders (M20-M25)
      • Other acquired deformities of limbs (M21)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (first year ICD-10-CM implemented into the HIPAA mandated code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020

Information for Medical Professionals

Index to Diseases and Injuries

The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10 code(s). The following references for the code M21.37 are found in the index:


Information for Patients


Foot Injuries and Disorders

Each of your feet has 26 bones, 33 joints, and more than 100 tendons, muscles, and ligaments. No wonder a lot of things can go wrong. Here are a few common problems:

  • Bunions - hard, painful bumps on the big toe joint
  • Corns and calluses - thickened skin from friction or pressure
  • Plantar warts - warts on the soles of your feet
  • Fallen arches - also called flat feet

Ill-fitting shoes often cause these problems. Aging and being overweight also increase your chances of having foot problems.


[Learn More]

ICD-10 Footnotes

General Equivalence Map Definitions
The ICD-10 and ICD-9 GEMs are used to facilitate linking between the diagnosis codes in ICD-9-CM and the new ICD-10-CM code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs.

  • Approximate Flag - The approximate flag is on, indicating that the relationship between the code in the source system and the code in the target system is an approximate equivalent.
  • No Map Flag - The no map flag indicates that a code in the source system is not linked to any code in the target system.
  • Combination Flag - The combination flag indicates that more than one code in the target system is required to satisfy the full equivalent meaning of a code in the source system.