opinion: Justice Stevens
  delivered the opinion of the Court.
  In the early morning of November 20, 1975, respondent Ralph Riley awoke with severe pains in his neck, shoulders, and arms, which later were attributed by physicians to an exacerbation of an arthritic condition. The United States Court of Appeals for the District of Columbia Circuit held that this “injury” was sufficient to invoke the “statutory presumption of compensability,” § 20(a) of the Longshoremen’s and Harbor Workers’ Compensation Act, 44 Stat. (part 2) 1436, 33 U. S. C. § 920(a), and vacated the administrative denial of disability benefits. We granted certiorari, 450 U. S. 979, and we now reverse.
  Contending that he was permanently and totally disabled by the arthritic condition, Riley’s retained counsel filed with the Deputy Commissioner a claim for compensation under the Act. See 33 U. S. C. § 913. On standard form LS-203, in response to the direction to “[djescribe in full how the accident occurred,” Riley wrote that on November 19, 1975, he was “[ljifting duct work with co-worker, weighing approximately 500 pounds, felt sharp pain in neck and sat down.” App. 111.
  An evidentiary hearing was convened before an Administrative Law Judge. After construing the evidence in a light most favorable to Riley and resolving all doubts in his favor, the Administrative Law Judge found “that Claimant sustained no injury within the meaning of Sec. 2(2) of the Act on November 19, 1975, as alleged, and that Claimant and Sutherland [Riley’s co-workerj gave false testimony as to the happening of the accident.” App. to Pet. for Cert. 24A.
  A divided panel of the Benefits Review Board affirmed the denial of disability benefits, holding that the Administrative Law Judge’s findings were supported by substantial evidence. In dissent, Member Miller stated:
  “The Act does not require that claimant prove an accident in order to establish a claim. To the contrary, compensation is payable under the Act if claimant is disabled because of injury which is causally related to his employment. 33 U. S. C. §§902(10), 902(2).” 9 BRBS 936, 940 (1979) (emphasis in origina:!).
  Member Miller defined an injury as “something go[ne] wrong within the human frame.” Ibid. Riley suffered such an injury when he awoke on November 20 with severe pain. Therefore, Member Miller would have remanded the case for a determination of “the real issue in this case,” which “is not whether claimant sustained an accident at work but whether claimant’s injury is causally related to his employment.” Ibid. That determination was to be made in light of the § 20(a) presumption, which “places the burden on employer to prove by substantial evidence that claimant’s injury did not arise out of or in the course of employment.” Ibid.
  On Riley’s petition for review, the Court of Appeals vacated the decision of the Benefits Review Board, agreeing with Member Miller’s position. Riley v. U. S. Industries/Federal Sheet Metal, Inc., 200 U. S. App. D. C. 402, 627 F. 2d 455 (1980). The court stated that “it can hardly be disputed that petitioner suffered an ‘injury^ when he awakened in pain on November 20, 1975.” Id., at 405, 627 F. 2d, at 458. The court then turned its “attention to the statutory presumption and the range of situations to which this Court has applied it.” Ibid. It construed its earlier cases as holding “that an injury need not have occurred during working hours” and “need not be traceable to any particular work-related incident to be compensable.” Id., at 405-406, 627 F. 2d, at 458-459.
  “The foregoing cases make clear the pervasive scope of the statutory presumption of compensability. Indeed, no decision of this Court has ever failed to apply the presumption to any facet of any claim before it. We now hold expressly that where a claimant has been injured, the Act requires that, in the absence of substantial evidence to the contrary, a claimant be given the benefit of a rebuttable presumption that the injury arose out of and in the course of the claimant’s employment.” Id., at 406, 627 F. 2d, at 459.
  The question for remand was not whether Riley’s “injury” stemmed from a “work-related incident,” but whether it was “ ‘employment-bred. ’ ” Ibid.
  The Court of Appeals erred because it overlooked (1) the statutory language that relates the § 20(a) presumption to the employee’s claim, and (2) the statutory definition of the term “injury.”
  I
  The Court of Appeals’ first error was its invocation of the § 20(a) presumption in support of a claim that was not made by Riley. Riley claimed that he suffered an injury at work on November 19 when he was lifting duct work and felt a sharp pain in his neck. The Administrative Law Judge found as a matter of fact that the accident had not occurred; this finding is no longer challenged. The Court of Appeals’ theory of recovery was that Riley suffered an injury at home in bed on November 20 and that Riley was entitled to .a presumption that this injury was “employment-bred.”
  Section 20(a), 44 Stat. (part 2) 1436, provides that “[i]n any proceeding for the enforcement of a claim for compensation under this Act it shall be presumed, in the absence of substantial evidence to the contrary . . . [t]hat the claim comes within the provisions of this Act.” The coverage of the presumption is debatable, but one thing is clear: the presumption applies to the claim. Even if a claimant has an unfettered right to amend his claim to conform to the proof, the presumption by its terms cannot apply to a claim that has never been made.
  Section 13 of the Act, 33 U. S. C. § 913, provides that a claimant must timely file a claim with the Deputy Commissioner. The content of the claim is not specified in that section. But § 12(b), 33 U. S. C. § 912(b), requires that the claimant timely give the Deputy Commissioner and his employer notice of his injury, and provides further that “[s]uch notice . . . shall contain ... a statement of the time, place, nature, and cause of the injury.” The claim, like the notice required by § 12 and like the pleadings required in any type of litigation, serves the purposes of notifying the adverse party of the allegations and of confining the issues to be tried and adjudicated.
  In Riley’s claim, he alleged that he suffered an accidental injury in the course of his employment on November 19. No claim has ever been made that the “injury” occurred at home and that it was somehow “employment-bred.” Even if such a vague claim stated a prima facie case of compensability, the statutory presumption does not require the administrative law judge to address and the employer to rebut every conceivable theory of recovery. At least when the claimant is represented by counsel, as Riley was, there is no reason to depart from the specific statutory direction that a claim be made and that the presumption, however construed, attach to the claim.
  II
  The Court of Appeals’ second error was its incorrect use of the term “injury.” The court stated that Riley’s attack of pain in the early morning of November 20 was an “injury” compensable under the Act if the employer did not disprove by substantial evidence that the “injury” was “employment-bred.” The fact that “‘something unexpectedly goes wrong with the human frame,’” 200 U. S. App. D. C., at 405, 627 F. 2d, at 458 (quoting Wheatley v. Adler, 132 U. S. App. D. C. 177, 183, 407 F. 2d 307, 313 (1968)), however, does not establish an “injury” within the meaning of the Act. The mere existence of a physical impairment is plainly insufficient to shift the burden of proof to the employer.
  Section 3(a) provides that “[c]ompensation shall be payable under this Act in respect of disability... of an employee, but only if the disability . . . results from an injury.” 44 Stat. (part 2) 1426, as amended, 33 U. S. C. § 903(a). Injury is defined as an “accidental injury . . . arising out of and in the course of employment.” 33 U. S. C. §902(2). Arising “out of” and “in the course of” employment are separate elements: the former refers to injury causation; the latter refers to the time, place, and circumstances of the injury. Not only must the injury have been caused by the employment, it also must have arisen during the employment.
  A prima facie “claim for compensation,” to which the statutory presumption refers, must at least allege an injury that arose in the course of employment as well as out of employment. The “injury” noticed by the Court of Appeals, however, arose in bed, not in the course of employment. Even if the Court of Appeals simply mislabeled the early morning attack of pain as the “injury” itself rather than as a manifestation of an earlier injury, the claim envisioned by the Court of Appeals did not allege any facts that would establish that Riley suffered an injury that arose in the course of employment. The statutory presumption is no substitute for the allegations necessary to state a prima facie case.
  Ill
  Riley’s claim stated a prima facie case of compensability; if the Administrative Law Judge had believed Riley’s allegations, he would have found that Riley’s attack of pain in the early morning of November 20 was caused by an injury suffered when Riley was lifting duct work on the job on November 19. The judge, however, disbelieved Riley’s allegations and marshaled substantial evidence to support his findings. The statutory presumption did not require him to adjudicate any claim that was not made, and the Court of Appeals erred in remanding for that purpose. Nor could the statutory presumption have aided Riley had he made the claim envisioned by the Court of Appeals — that he suffered an “injury” at home — for such a claim omits the requirement that a compen-sable injury arise in the course of employment.
  The judgment of the Court of Appeals is reversed.
  It is so ordered.
  Justice O’Connor took no part in the consideration or decision of this case.
  “Injury” and “statutory presumption of compensability” are terms employed by the Court of Appeals. See Riley v. U. S. Industries/Federal Sheet Metal, Inc., 200 U. S. App. D. C. 402, 627 F. 2d 455 (1980). As we explain below, the use of the term “injury” to describe Riley’s early morning attack of pain is incorrect. We do not decide the scope of the § 20(a) presumption, or, a fortiori, the appropriateness of the Court of Appeals’ characterization of it.
  Apparently, it is undisputed that Riley is permanently and totally disabled. Brief for Respondent Riley 5, n.
  The form continues with a further instruction:
  “Relate the events which resulted in the injury or occupational disease. Tell what the injured was doing at the time of the accident. Tell what happened and how it happened. Name any objects or substances involved and tell how they were involved. Give full details on all factors which led or contributed to the accident. If more space is needed, continue on reverse.” App. 111.
  The cases cited by the Court of Appeals do not support this proposition. In Butler v. District Parking Management Co., 124 U. S. App. D. C. 195, 363 F. 2d 682 (1966), the claimant became ill at work and the illness was diagnosed as a schizophrenic reaction. In Wheatley v. Adler, 132 U. S. App. D. C. 177, 407 F. 2d 307 (1968), the employee collapsed from a heart attack at work. In Mitchell v. Woodworth, 146 U. S. App. D. C. 21, 449 F. 2d 1097 (1971), the employee died of a cerebral vascular accident shortly after collapsing at work.
  We need not resolve that debate in this case. It seems fair to assume, however, that the § 20(a) presumption is of the same nature as the presumption created by § 20(d) of the Act, 33 U. S. C. § 920(d), as construed in Del Vecchio v. Bowers, 296 U. S. 280, 285-287, and the presumption defined in Rule 301 of the Federal Rules of Evidence. See also Texas Dept. of Community Affairs v. Burdine, 450 U. S. 248.
  “This statement must be more than a mere declaration that the employee has received an injury or is suffering from an illness that is related to his employment; it must contain enough details about the nature and extent of the injury or disease to allow the employer to conduct a prompt and complete investigation of the claim so that no prejudice will ensue.” 1A E. Jhirad, A. Sann, N. Golden, & B. Chase, Benedict on Admiralty § 71, p. 4-5 (7th ed. 1981).
  See generally F. James & G. Hazard, Civil Procedure §2.1 (2d ed. 1977). Of course, the workmen’s compensation process is much more simplified than modem civil litigation. Indeed, this is one of the hallmarks of the system:
  “The adjective law of workmen’s compensation, like the substantive, takes its tone from the beneficent and remedial character of the legislation. Procedure is generally summary and informal. . . . The whole idea is to get away from the cumbersome procedures and technicalities of pleading, and to reach a right decision by the shortest and quickest possible route. ... On the other hand, as every lawyer knows, there is a point beyond which the sweeping-aside of ‘technicalities' cannot go, since evidentiary and procedural rules usually have an irreducible hard core of necessary function that cannot be dispensed with in any orderly investigation of the merits of a case.” 3 A. Larson, The Law of Workmen’s Compensation §78.10, p. 15-2(1976).
  Professor Larson writes that an informal substitute for a claim may be acceptable if it “identif[ies] the claimant, indicate[s] that a compensable injury has occurred, and convey[s] the idea that compensation is expected,” id., § 78.11, p. 15-9; that “considerable liberality is usually shown in allowing amendment of pleadings to correct. . . defects,” unless the “effect is one of undue surprise or prejudice to the opposing party,” id., at 15-11; and that “wide latitude is allowed” as to variance between pleading and proof, “[b]ut if the variance is so great that the defendant is prejudiced by having to deal at the hearing with an injury entirely different from the one pleaded, the variance may be held fatal,” id., at 15 — 13—15-14. Riley had the benefit of these liberal pleading rules; nonetheless, the Court of Appeals applied the statutory presumption to a claim that was not fairly supported by the existing claim or by the evidentiary record. As Professor Larson warns, “[n]o amount of informality can alter the elementary requirement that the claimant allege and prove the substance of all essential elements in his case.” Id., at 15-12.
  “If the employer or carrier declines to pay any compensation on or before the thirtieth day after receiving written notice of a claim for compensation having been filed from the deputy commissioner, on the ground that there is no liability for compensation within the provisions of this chapter and the person seeking benefits shall thereafter have utilized the services of an attorney at law in the successful prosecution of his claim, there shall be awarded, in addition to the award of compensation, in a compensation order, a reasonable attorney’s fee against the employer or carrier in an amount approved by the deputy commissioner, Board, or court, as the case may be. which shall be paid directly by the employer or carrier to the attorney for the claimant in a lump sum after the compensation order becomes final.” 33 U. S. C. § 928(a).
  See, e. g., Ward & Gow v. Krinsky, 259 U. S. 503; Thom v. Sinclair, [1917] A. C. 127; 1A Benedict on Admiralty, supra, §43; 1 A. Larson, supra, § 6.10, at 3-2 — 3-3 (1978).
  The Act was enacted to create a federal workmen’s compensation statute for maritime employments after this Court held that state workmen’s compensation statutes constitutionally could not apply to injured maritime workers. See generally Nogueira v. New York, N. H. & H. R. Co., 281 U. S. 128. Workmen’s compensation legislation has never been intended to provide life or disability insurance for covered employees. The required connection between the death or disability and employment distinguishes the workmen’s compensation program from such an insurance program, and the separate requirements that the injury arise out of and in the course of employment are the means for assuring, to the extent possible, that the work connection is proved. See W. Dodd, Administration of Workmen’s Compensation 681 (1936); see generally Cudahy Packing Co. v. Parramore, 263 U. S. 418, 422-424.