S42.21 – Unspecified fracture of surgical neck of humerus

ICD-10-CM 2027 diagnosis code · Injuries to the shoulder and upper arm

Non-billable header

ICD-10-CM code S42.21

Code: S42.21 (claims format: S4221)
Description: Unspecified fracture of surgical neck of humerus
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: S40-S49 Injuries to the shoulder and upper arm
Parent codes: S42 › S42.2

Billable codes under S42.21

S42.21 is a header code and cannot be used on claims. Choose the most specific code:

S42.211 – Unspecified displaced fracture of surgical neck of right humerusHeader (more codes below)
S42.212 – Unspecified displaced fracture of surgical neck of left humerusHeader (more codes below)
S42.213 – Unspecified displaced fracture of surgical neck of unspecified humerusHeader (more codes below)
S42.214 – Unspecified nondisplaced fracture of surgical neck of right humerusHeader (more codes below)
S42.215 – Unspecified nondisplaced fracture of surgical neck of left humerusHeader (more codes below)
S42.216 – Unspecified nondisplaced fracture of surgical neck of unspecified humerusHeader (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 for closed fracture
`B`	initial encounter for open fracture
`D`	subsequent encounter for fracture with routine healing
`G`	subsequent encounter for fracture with delayed healing
`K`	subsequent encounter for fracture with nonunion
`P`	subsequent encounter for fracture with malunion
`S`	sequela

Notes for S42.21

Applicable to:

Fracture of neck of humerus NOS

Notes inherited from parent codes

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

S42 – Fracture of shoulder and upper arm

Excludes1 (not coded here):

traumatic amputation of shoulder and upper arm (S48.-)

Excludes2 (not included here):

periprosthetic fracture around internal prosthetic shoulder joint (M97.3)

Notes:

A fracture not indicated as displaced or nondisplaced should be coded to displaced
A fracture not indicated as open or closed should be coded to closed

7th character note:

The appropriate 7th character is to be added to all codes from category S42

S42.2 – Fracture of upper end of humerus

Applicable to:

Fracture of proximal end of humerus

Excludes2 (not included here):

fracture of shaft of humerus (S42.3-)
physeal fracture of upper end of humerus (S49.0-)

Block S40-S49

Includes:

injuries of axilla
injuries of scapular region

Excludes2 (not included here):

burns and corrosions (T20-T32)
frostbite (T33-T34)
injuries of elbow (S50-S59)
insect bite or sting, venomous (T63.4)

Index terms for S42.21

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

Related codes in S42.2

Frequently asked questions

What is ICD-10 code S42.21?

S42.21 is the ICD-10-CM code for unspecified fracture of surgical neck of humerus, in the block S40-S49 (Injuries to the shoulder and upper arm).

Is S42.21 a billable code?

No. S42.21 is a header code with more specific child codes; report one of the billable codes listed above.

What category does S42.21 belong to?

It belongs to category S42 – Fracture of shoulder and upper arm.

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.