POWER OF ATTORNEY

Know all by these presents, that the undersigned hereby constitutes and
appoints each of LAURA A. FRANCIS, MICHAEL A. PISETSKY,
MATTHEW B. HEMINGTON and JOHN T. MCKENNA, signin
individually, the undersigned's true and lawful attorneys-in fact
and agents to:

(1)	execute for and on behalf of the undersigned,
in the undersigned's capacity as an officer, director
or beneficial owner of more than 10% of a registered
class of securities of SI-BONE, INC. (the "Company"),
Forms 3, 4 and 5 (including any amendments thereto)
in accordance with Section 16(a) of the Securities
Exchange Act of 1934, as amended (the "Exchange Act")
and the rules thereunder and a Form ID, Uniform Application
for Access Codes to File on EDGAR;
(2) do and perform any and all acts for and on behalf of
the undersigned that may be necessary or desirable to execute
such Forms 3, 4 or 5 or Form ID (including any amendments thereto)
and timely file such forms with the United States Securities and
Exchange Commission and any stock exchange or similar authority;
and
(3) take any other action of any nature whatsoever in connection
with the foregoing which, in the opinion of such attorney-in-fact,
may be of benefit, in the best interest of, or legally required by,
the undersigned, it being understood that the documents executed by
such attorney-in-fact on behalf of the undersigned pursuant to this
Power of Attorney shall be in such form and shall contain such terms
and conditions as such attorney-in-fact may approve in such
attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact full
power and authority to do and perform any and every act and thing
whatsoever requisite, necessary or proper to be done in the
exercise of any of the rights and powers herein granted,
as fully to all intents and purposes as the undersigned might
or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming
all that such attorney-in-fact, or such attorney-in-fact's
substitute or substitutes, shall lawfully do or cause to be
done by virtue of this power of attorney and the rights and
powers herein granted. The undersigned acknowledges that the
foregoing attorneys-in-fact, in serving in such capacity at
the request of the undersigned, are not assuming, nor is the
Company assuming, any of the undersigned's responsibilities to
comply with Section 16 of the Exchange Act.

This Power of Attorney shall remain in full force and effect
until the earliest to occur of (a) the undersigned is no longer
required to file Forms 3, 4 and 5 with respect to the
undersigned's holdings of and transactions in securities issued
by the Company, (b) revocation by the undersigned in a signed
writing delivered to the foregoing attorneys-in-fact or (c)
as to any attorney-in-fact individually, until such
attorney-in-fact is no longer employed by the Company
or Cooley LLP.

IN WITNESS WHEREOF, the undersigned has caused this
Power of Attorney to be executed as of August 13, 2019.

SKYLINE VENTURE PARTNERS V, L.P.
By: Skyline Venture Management V, LLC
Its: General Partner
By: /s/John G. Freund-Managing Director


SKYLINE VENTURE MANAGEMENT V, LLC
By:/s/John G. Freund-Managing Member