This is prohibition.
On August 31, 1980, John Reynolds suffered an eye injury in Barry County, Missouri, while working on a haybine mower conditioner alleged to have been manufactured by Sperry. He was taken to Springfield, Missouri, where he was treated by B.G. Prater, M.D., of E.E.N.T. Clinic, at Lester E. Cox Medical Center.
A petition for damages was filed in the Circuit Court of the City of St. Louis. Theories of strict liability, negligence and breach of warranty were asserted against Sperry. Negligent treatment was asserted against Prater, E.E.N.T. and Cox.
Plaintiffs are residents of Barry County. Sperry is a foreign corporation with a registered agent, C.T. Corporation, in the City of St. Louis. Sperry has an office for the transaction of its usual and customary business in St. Louis County. We were informed on oral argument that Sperry has an office for the transaction of its usual and customary business in Greene County. Prater is a resident of Greene County. E.E. N.T. and Cox are corporations with offices for the transaction of their usual and customary business in Greene County.
Sperry, Prater, E.E.N.T. and Cox filed motions to dismiss in which they questioned jurisdiction and venue in the Circuit Court of the City of St. Louis. Respondent Judge Corcoran overruled the motions. Re-lators sought prohibition in the Eastern District of the Court of Appeals. Prohibition was denied. Relators then sought prohibition in this Court. In January 1983, provisional rules in prohibition were ordered to issue. The causes are consolidated for disposition in this opinion. Prohibition will lie where venue is improper and the trial court is without jurisdiction. State ex rel. Allen v. Barker, 581 S.W.2d 818, 824 (Mo. banc 1979).
It is well settled that where three corporations are sued with one individual, as here, venue is determined according to § 508.010, RSMo 1978. State ex rel. Baker v. Goodman, 364 Mo. 1202, 274 S.W.2d 293 (banc 1954). Section 508.010 reads in part as follows:
“Suits instituted by summons shall, except as otherwise provided by law, be brought:
*621“(1) When the defendant is a resident of the state, either in the county within which the defendant resides, or in the county within which the plaintiff resides, and the defendant may be found;
“(2) When there are several defendants, and they reside in different counties, the suit may be brought in any such county;
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“(6) In all tort actions the suit may be brought in the county where the cause of action accrued regardless of the residence of the parties, and process therein shall be issued by the court of such county and may be served in any county within the state; * * *.”
We make the following observations:
(1) If the assertions of liability made in plaintiffs’ petition against the four defendants (Sperry, Prater, E.E.N.T. and Cox) amount to one cause of action, venue in the City of St. Louis is proper because Sperry had a registered agent, C.T. Corporation, in the City of St. Louis. State ex rel. Whiteman v. James, 364 Mo. 589, 265 S.W.2d 298 (banc 1954).
[2] If the assertions of liability made in plaintiffs’ petition against the four defendants amount to a cause of action against Sperry and a separate cause of action against Prater, E.E.N.T. and Cox, venue in the City of St. Louis is improper because the joinder of two or more separate causes of action in a single petition does not create venue as to both causes in the City of St. Louis. State ex rel. Turnbough v. Gaertner, 589 S.W.2d 290 (Mo. banc 1979).
(3) Prater, E.E.N.T. and Cox cannot be held liable for the original harm alleged to have been inflicted by Sperry in Barry County, but only for the additional harm alleged to have been caused by their treatment of the eye in Greene County. State ex rel. Baldwin v. Gaertner, 613 S.W.2d 638 (Mo. banc 1981).
(4) Sperry can be held liable for damages arising from the original harm alleged to have been inflicted by Sperry in Barry County and from the subsequent harm alleged to have been caused by the treatment in Greene County. Boehmer v. Boggiano, 412 S.W.2d 103, 108 (Mo.1967).
(5) If recovery is had against Sperry for all damages arising from the original harm and the subsequent harm, Sperry is afforded “a separate cause of action” against Prater, E.E.N.T. and Cox for the proportionate amount of liability based on their relative fault. Safeway Stores, Inc. v. City of Raytown, 633 S.W.2d 727, 732 (Mo. banc 1982).
We reach the following conclusions: this case is controlled by Turnbough, supra, and, because plaintiffs have a separate cause of action against Sperry and a separate cause of action against Prater, E.E. N.T. and Cox, venue in the City of St. Louis is improper.
However, plaintiffs are not without a forum. They may sue Sperry alone in St. Louis County or in Greene County (where Sperry has offices for the transaction of its usual and customary business) for all damages suffered. § 508.040, RSMo 1978. Plaintiffs may not sue Sperry alone in the City of St. Louis. State ex rel. Whaley v. Gaertner, 605 S.W.2d 506 (Mo.App.1980).
The provisional rules in prohibition are made absolute.
RENDLEN, C.J., HIGGINS, GUNN and BILLINGS, JJ., and MORGAN, Senior Judge, concur. BLACKMAR, J., dissents in separate opinion filed. WELLIVER, J., not sitting.