S86.91 – Strain of unspecified muscle and tendon at lower leg level

ICD-10-CM 2027 diagnosis code · Injuries to the knee and lower leg

Non-billable header

ICD-10-CM code S86.91

Code: S86.91 (claims format: S8691)
Description: Strain of unspecified muscle and tendon at lower leg level
Billable: No – use a more specific code below
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 19. Injury, poisoning and certain other consequences of external causes (S00-T88)
Block: S80-S89 Injuries to the knee and lower leg
Parent codes: S86 › S86.9

Billable codes under S86.91

S86.91 is a header code and cannot be used on claims. Choose the most specific code:

S86.911 – Strain of unspecified muscle(s) and tendon(s) at lower leg level, right legHeader (more codes below)
S86.912 – Strain of unspecified muscle(s) and tendon(s) at lower leg level, left legHeader (more codes below)
S86.919 – Strain of unspecified muscle(s) and tendon(s) at lower leg level, unspecified legHeader (more codes below)

7th character values

Codes in this category need a 7th character to describe the encounter or episode of care (use placeholder X for empty positions).

Character	Meaning
`A`	initial encounter
`D`	subsequent encounter
`S`	sequela

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

S86 – Injury of muscle, fascia and tendon at lower leg level

Excludes2 (not included here):

injury of muscle, fascia and tendon at ankle (S96.-)
injury of patellar ligament (tendon) (S76.1-)
sprain of joints and ligaments of knee (S83.-)

Code also:

any associated open wound (S81.-)

7th character note:

The appropriate 7th character is to be added to each code from category S86

Block S80-S89

Excludes2 (not included here):

burns and corrosions (T20-T32)
frostbite (T33-T34)
injuries of ankle and foot, except fracture of ankle and malleolus (S90-S99)
insect bite or sting, venomous (T63.4)

Index terms for S86.91

Entries in the ICD-10-CM alphabetic index that lead to this code:

Injury, muscle, leg, strain

Related codes in S86.9

Frequently asked questions

What is ICD-10 code S86.91?

S86.91 is the ICD-10-CM code for strain of unspecified muscle and tendon at lower leg level, in the block S80-S89 (Injuries to the knee and lower leg).

Is S86.91 a billable code?

No. S86.91 is a header code with more specific child codes; report one of the billable codes listed above.

What category does S86.91 belong to?

It belongs to category S86 – Injury of muscle, fascia and tendon at lower leg level.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.