This case involves the interpretation of the filing and notice provisions in RCW 51.52.110 which impact superior court appellate jurisdiction in workers' compensation cases. We affirm.
On April 10, 1982, Am-Fac employee, Jose Vasquez, injured his ankle at work when a grate covering a gutter collapsed under him, catching his foot. However, Mr. Vasquez did not report the incident to the supervisor on duty. While drinking with friends the following evening, Mr. Vasquez fell outside his truck. The next day, Mr. Vasquez was examined by a physician who diagnosed a bimaleolar fracture of the right ankle.
Mr. Vasquez filed an industrial insurance claim which the Department of Labor and Industries (DLI) allowed. Am-Fac, the self-insured employer, appealed and the Board of Industrial Insurance Appeals reversed DLI on September 22,1983, finding Mr. Vasquez did not sustain an industrial injury. Mr. Vasquez received notice of the Board's denial of his petition for review. He filed a notice of appeal with the Superior Court and mailed copies of the appeal to DLI, the Board, and Am-Fac's attorney.
Am-Fac's motion to dismiss for lack of subject matter jurisdiction was denied May 7, 1984. Following trial, the jury returned a verdict in favor of Mr. Vasquez reversing the Board's decision and awarding Mr. Vasquez attorney fees under RCW 51.52.130.
Am-Fac claims the Superior Court lacked subject matter jurisdiction because Mr. Vasquez failed to follow the filing and notice requirements in RCW 51.52.110. RCW 51.52.110 *381provides in part:
Within thirty days after a decision of the board to deny the petition . . . for review . . . has been communicated to such worker, . . . such worker . . . may appeal to the superior court. If such worker . . . fails to file with the superior court its appeal as provided in this section within said thirty days, the decision of the board to deny the petition ... for review or the final decision and order of the board shall become final.
. . . Such appeal shall be perfected by filing with the clerk of the court a notice of appeal and by serving a copy thereof by mail, or personally, on the director and on the board. If the case is one involving a self-insurer, a copy of the notice of appeal shall also be served by mail, or personally, on such self-insurer. ... If the case is one involving a self-insurer, such self-insurer shall, within twenty days after receipt of such notice of appeal, serve and file its notice of appearance and such appeal shall thereupon be deemed to be at issue.
(Italics ours.) Filing an appeal in superior court and serving notice on the specified parties are both required to perfect an appeal under this statute. Smith v. Department of Labor & Indus., 23 Wn. App. 516, 518, 596 P.2d 296 (1979). The statute is mandatory and jurisdictional. Spokane v. Department of Labor & Indus., 34 Wn. App. 581, 584, 663 P.2d 843, review denied, 100 Wn.2d 1007 (1983). Am-Fac first contends Mr. Vasquez' appeal is defective in three respects: (1) he filed the appeal beyond the 30-day period; (2) he served notice to DLI and the Board beyond the 30-day period; and (3) he notified the self-insured employer's attorney rather than Am-Fac.
1. Whether Mr. Vasquez timely filed the appeal in superior court.
The facts are uncontroverted that the Board notified Mr. Vasquez in a letter dated November 2, 1983, that his petition for review was denied. Mr. Vasquez actually received this notice on November 4, 1983, and filed a notice of appeal in superior court on December 5, 1983. If the 30-day period commences when the Board mailed the notice, *382then the latest Mr. Vasquez could have filed a timely notice of appeal was Friday, December 2; if it commences when Mr. Vasquez received the notice, then Mr. Vasquez timely filed notice on the 30th day.1 The Supreme Court has construed "communicated" in the context of former RCW 51.52.0602 to mean "only that a copy of the order be received by the workman". Rodriguez v. Department of Labor & Indus., 85 Wn.2d 949, 953, 540 P.2d 1359 (1975). See also Nafus v. Department of Labor & Indus., 142 Wash. 48, 52, 251 P. 877, 255 P. 148 (1927). Consequently, although we note this rule in some instances will pose difficult proof problems, we hold the 30-day period commenced upon Mr. Vasquez' receipt of the notice, and his filing of the appeal in superior court was timely.
2. Whether Mr. Vasquez timely served notice.
RCW 51.52.110 limits an aggrieved party to 30 days in which to file and serve a notice of appeal. Smith, at 518. Mr. Vasquez argues all parties were timely served when he deposited notice in the mail on the 30th day, while Am-Fac contends service was defective because notice was received beyond the specified time period. RCW 51.52.110 states an appeal "shall be perfected by . . . serving a copy [of the notice] by mail, or personally" on the director, the Board, and the self-insurer. "Service" is not defined in RCW 51.52, nor does RCW 51.52.110 specify when service by mail is deemed to be complete.
*383Rule 5(b) of the Federal Rules of Civil Procedure provides that "[s]ervice hy mail is complete upon mailing", 2 J. Moore, Federal Practice, at 5-2 (1983), and a commonsense interpretation of RCW 51.52.110, "serving . . . by mail", is consistent with that rule. In contrast, Washington's Superior Court Civil Rule 5(b)(2)(A) states:
If service is made by mail, the papers shall be deposited in the post office addressed to the person on whom they are being served, with the postage prepaid. The service shall be deemed complete upon the third day following the day upon which they are placed in the mail. . .
(Italics ours.) Superior court civil rules are procedural rules, however, applicable only after the commencement of an action, and thus do not purport to extend subject matter jurisdiction of the court. Reeves v. Department of Gen. Admin., 35 Wn. App. 533, 537, 667 P.2d 1133, review denied, 100 Wn.2d 1030 (1983); Tarabochia v. Gig Harbor, 28 Wn. App. 119, 123, 622 P.2d 1283 (1981).
Moreover, the civil rules are clearly intended to apply only to civil actions invoking the general jurisdiction of the superior courts. In contrast, an administrative appeal invokes appellate, not general or original superior court jurisdiction.3 Reeves, at 537. See also Olson v. Civil Serv. Comm'n, 43 Wn. App. 812, 719 P.2d 1343 (1986) (CR 6(a) not applicable where time set forth in administrative regulations). Because "'delay and even the loss of lawsuits [should not be] occasioned by unnecessarily complex and vagrant procedural technicalities'", substantial compliance with procedural rules is sufficient to invoke the general as well as the RCW 51.52.110 appellate jurisdiction of the superior court. In re Saltis, 94 Wn.2d 889, 896, 621 P.2d 716 (1980) (quoting Curtis Lumber Co. v. Sortor, 83 Wn.2d *384764, 767, 522 P.2d 822 (1974)). Here, we hold Mr. Vasquez timely complied with RCW 51.52.110 service requirements when he mailed notice within 30 days of his receipt of the Board's denial of review.
3. Whether Am-Fac was properly served.
RCW 51.52.110 provides that " [i]f the case is one involving a self-insurer, a copy of the notice of appeal shall also be served by mail, or personally, on such self-insurer". Here, the record reveals that Mr. Vasquez served Am-Fac's attorney rather than Am-Fac, itself, on December 6 or 7, 1983.
The RCW 51.52.110 requirement of notice is a practical one meant to insure interested parties receive actual notice of appeals of Board decisions and is satisfied upon: (1) receipt of actual notice of appeal to the superior court, or (2) service of the notice of appeal in a manner reasonably calculated to give notice. In re Saltis, at 896. Here, Mr. Vasquez did in fact serve Am-Fac's attorney by mail, which we conclude to be a manner reasonably calculated to give notice to the employer.
Am-Fac next contends the evidence is not legally sufficient to support the verdict. Following the denial of its motion to dismiss, Am-Fac proceeded to present its case to the jury. Generally, this constitutes a waiver of a defendant's challenge to the sufficiency of the evidence. Heinz v. Blagen Timber Co., 71 Wn.2d 728, 730, 431 P.2d 173 (1967); accord, Goodman v. Bethel Sch. Dist. 403, 84 Wn.2d 120, 524 P.2d 918 (1974). Although Am-Fac cites CR 41(b)(3) for the contrary result, that rule applies to bench trials only. Here, the case was tried to a jury; thus, Am-Fac has waived this issue.
If Am-Fac had not waived this issue, the result would be the same. A jury's verdict should not be disturbed if there is substantial evidence to support it. Bennett v. Department of Labor & Indus., 95 Wn.2d 531, 534, 627 P.2d 104 (1981). Where the injured worker prevails before the jury, the evidence must be viewed in the light most *385favorable to him. Bennett, at 534. Here, Am-Fac's challenge goes to the medical testimony of Dr. Starkweather who used the word "possible" at one point to describe the connection between the workplace accident and Mr. Vasquez' injury. Although the causal connection between a claimant's physical condition and his employment must be established by medical testimony, such testimony is not always necessary to prove every element of causation. Bennett, at 533. Thus, the evidence is sufficient if a reasonable person can infer from all the facts and circumstances that the causal connection exists. Bennett, at 533. Moreover, it is generally held that:
The distinction between probability and possibility should not follow too slavishly the witnesses' choice of words, as sometimes happens in respect to medical testimony. A doctor's use of such words as "might," "could," "likely," "possible" and "may have," particularly when coupled with other credible evidence of a non-medical character, such as a sequence of symptoms or events corroborating the opinion, is . . . sufficient to sustain an award.
2 A. Larson, Workmen's Compensation § 80.30, at 15-86 to 15-87 (1986). Here, there is sufficient corroborating evidence in Mr. Vasquez' testimony and that of co-workers and friends to support the jury verdict.
Finally, we examine whether attorney fees were properly awarded to Mr. Vasquez. RCW 51.52.130 provides in part:
If, on appeal to the court from the decision and order of the board, said decision and order is reversed or modified and additional relief is granted to a worker . . ., a reasonable fee for the services of the worker's . . . attorney shall be fixed by the court.
Since the Board's decision was reversed and additional relief granted, the award of attorney fees and costs was proper. Johnson v. Tradewell Stores, Inc., 95 Wn.2d 739, 630 P.2d 441 (1981).
Affirmed.
Green, C.J., concurs.
WAC 263-12-175, authorized by RCW 51.52.020, provides that time "shall be computed by excluding the first day and including the last, unless the last day is a Saturday, Sunday, or legal state holiday, and then it is excluded and the next succeeding business day included". Since the 30th day fell on Sunday, Mr. Vasquez gained an additional day in which to file his notice of appeal.
Former RCW 51.52.060 provided:
"Any workman . . . aggrieved by an order, decision, or award of the [Department of Labor and Industries] must, before he appeals to the courts, file with the [Board of Industrial Insurance Appeals] and the director, by mail or personally, within sixty days from the day on which such copy of such order, decision, or award was communicated to such person, a notice of appeal to the board." Rodriguez v. Department of Labor & Indus., 85 Wn.2d 949, 951, 540 P.2d 1359 (1975).
Because of the superior court's appellate jurisdiction in this area, we note by analogy RAP 18.6(b) which provides:
"(b) Service by Mail. Except as otherwise provided in rule 17.4, if the time period in question applies to a party serving a paper by mail, the paper is timely served if mailed within the time permitted for service. If the time period in question applies to the party upon whom service is made, the time begins to run 3 days after the paper is mailed to the party." (Italics ours.)