This is a medical malpractice case. Venice E. Hart, as plaintiff, sought by this suit against Dr. I. L. Van Zandt, the defendant, to recover damages for various permanent physical injuries such as sensory losses to his leg and foot and malfunction of elimination organs allegedly resulting from an operation performed on his lower back by defendant and from various acts and omissions on the part of defendant in connection with the post-operative care and treatment of plaintiff. At the conclusion of plaintiff’s evidence, defendant filed a motion for peremptory instruction. Upon sustaining this motion the trial court instructed the jury to return a verdict for the defendant and the court entered judgment that plaintiff take nothing. From this judgment the plaintiff appealed to the Court of Civil Appeals where the trial court’s judgment was affirmed. 383 S.W.2d 627. Mr. Hart is the petitioner.
The numerous points of error in this appeal resolve themselves into two basic questions, to-wit:
(a) Whether the record contains any evidence which would support a jury finding or findings that Dr. Van Zandt was guilty of actionable negligence in his operation upon, care and treatment of Mr. Hart; and
(b) Whether the record contains any evidence which would support a jury finding or findings that any one or more of such alleged acts of negligence was a proximate cause of Mr. Hart’s injuries.
In determining negligence in a case such as this, which concerns the highly specialized art of treating disease, the court and jury must be dependent on expert testimony. There can be no other guide, and where want of skill and attention is not thus shown by expert evidence applied to the facts, there is no evidence of it proper to be submitted to the jury. The burden of proof is on the plaintiff to show that the injury was negligently caused by the defendant and it is not enough to show the injury together with the expert opinion that it might have occurred from the doctor’s negligence and from other causes not the fault of the doctor. Such evidence has no tendency to show that negligence did cause the injury. Ewing v. Goode, 78 F. 442, 444 (C.C.Ohio, 1897) ; Bowles v. Bourdon, 148 Tex. 1, 219 S.W.2d 779 (1949); Porter v. Puryear, 153 Tex. 82, 262 S.W.2d 933 (1954).
In determining the question of proximate cause, the general rule is “that proof *793of causation must be beyond a showing of a possibility that the injuries arose from the defendant’s negligence or lack of skill, since the jury will not be permitted to speculate as to the cause of the injury. Thus where the evidence most favorably to the plaintiff develops more than one equally probable cause, for one or more of which defendant is not responsible, the plaintiff has failed to sustain his burden of proof.” 13 A.L.R. 2d 22. But, as stated by this Court in Porter v. Puryear, supra, “[t]he vital inquiry in any case involving proximate cause is whether the negligent act set in motion a natural and unbroken chain of events that led directly and proximately to a reasonably foreseeable injury or result.” (262 S.W.2d 933, 936.)
In order that we may determine whether the plaintiff has discharged this burden with respect to the question of negligence and proximate cause, we must view and interpret the evidence in the light most favorable to the plaintiff, disregarding all evidence and the inferences therefrom favorable to the defendant. Cartwright v. Canode, 106 Tex. 502, 171 S.W. 696 (1914); White v. White, 141 Tex. 328, 172 S.W.2d 295 (1943); Ford v. Panhandle & Santa Fe Ry. Co., 151 Tex. 538, 252 S.W.2d 561 (1952).
Mr. Hart first became a patient of Dr. Van Zandt in 1951, when Dr. Van Zandt diagnosed and treated Mr. Hart for a ruptured disc at the L5 SI level in a sub-acute condition. Mr. Hart responded to conservative treatment at this time and thereafter did not have much trouble with his back until September, 1959.
By way of explanation, the human spine consists of various segments of bone. In between the vertebral bones is cartilaginous material, commonly referred to as discs, which take part in the movement of the spine and perform the function of a shock absorber. Starting from the top of the spine downward, the first seven vertebrae are called cervical vertebrae; the next twelve, thoracic (or dorsal); the next five lumbar, followed by the sacrum, and then the coccyx — commonly called the tail bone. The medical profession has assigned numbers to these various vertebrae, and those of the lumbar region from top to bottom are numbered LI, L2, L3, L4 and L5. The segments of the sacrum are also numbered, and the first segment is SI, followed by S2 and S3. When reference is made, for instance, to the L4 L5 interspace, this means the space between the fourth and fifth lumbar segments. Likewise, the L5 SI intervertebral space refers to the space between the fifth lumbar and the first sacral segments which is occupied by the L5 SI disc.
On September 15th or 16th, 1959, Mr. Hart, while getting out of his car at his place of work, reached back into his car with a “sort of twisting motion” and a pain struck him in the lower back region like some one “had stuck a knife in” his back. Mr. Hart went to Dr. Van Zandt the same day about this condition and reported to him the symptoms. On examination the doctor observed that the movements of Mr. Hart’s lower back were markedly restricted and painful. On the same day, Dr. Van Zandt requested that Mr. Hart be admitted to Harris Hospital. At this time Mr. Hart was given conservative treatment which consisted of applying traction to his legs to relieve the pressure on the sacral nerves. Throughout this treatment it was apparent that Mr. Hart was having a revert pain down his left sciatic nerve (this nerve goes down into the hip and back of the left leg), which was caused by “involvement of the nerve roots” in Mr. Hart’s lower back. Other than the pain going down his left leg, Mr. Hart had no motor or sensory losses to any part of his body. X-rays taken at this time indicated a narrowing of the intervertebral disc space at the L5 SI level. Mr. Hart remained in Harris Hospital for eight to ten days at which time he was released but continued to receive treatment from the physical therapist at the doctor’s office. He appeared to be losing ground, and after an office visit on October 7, Dr. Van Zandt recommended that he re-enter *794Harris Hospital for tests and probable surgery.
Mr. Hart was re-admitted to the hospital on October 11, 1959. During the period from the date of his previous release from the hospital until the date of re-admission, Dr. Van Zandt had made two additional findings with regard to Mr. Hart’s condition: (1) The patient developed a tenderness at the lumbo-sacral area of his back (this is the point where the lumbar and sacral segments of the spine join, i. e., the L5 SI interspace), and (2) he developed a numbness on the top of his left foot with accompanying loss of motor power to the toe. At this time Mr. Hart was fifty-four (54) years old. Dr. Van Zandt testified that the nerve which feeds the muscles which control the toes could come from the L5 SI area of the spine.
Dr. Van Zandt’s first admitting diagnosis was “possible lumbro-sacral instability.” On October 12, Dr. Van Zandt’s progress report on Mr. Hart stated:
“ * * * myelogram unsuccessful this A.M. Dr. O’Bannon got a large hematome. Discogram at L4 L5 showed a good disc here. For disc and fusion at L5 SI levels tomorrow.”
The anaesthesia report of October 13, stated:
“ * * * Diagnosis, Pre-Operative. Probable ruptured disc L5 SI. Probable Lumbar-sacral instability.”
The operating room nurse’s report on October 13 stated:
“Pre-Operative Diagnosis. Probable ruptured disc lower back. Lumbosac-ral instability.”
Dr. O’Bannon, who was the radiologist consulted by Dr. Van Zandt in connection with the operation on Mr. Hart, testified that he examined and interpreted various x-rays of Mr. Hart’s back prior to the operation and the only thing of diagnostic significance which Dr. O’Bannon noted was the narrowing of the disc at the L5 SI level. Dr. O’Bannon could detect no abnormality whatever at the L4 L5 level. This finding was consistent with Dr. Van Zandt’s preoperative diagnosis of a ruptured disc at the L5 SI level.
With the pre-operative diagnosis pointing to trouble at the L5 SI level, Dr. Van Zandt, on October 13 proceeded to operate on Mr. Hart by making a five-inch lateral, or “traverse,” incision at the L4 L5 level of the ■lower back. During the course of a four-hour operation Dr. Van Zandt did not even examine the intervertebral space at the L5 SI level. At the L4 L5 interspace, Dr. Van Zandt removed the posterior section of the annulus fibrosis; the anterior section of the annulus fibrosis and the left and right walls of the disc were left in place. The doctor then attempted a bone fusion by taking three pieces of bone from the superior iliac crest and spine and placing them between the vertebral bodies between the L4 and L5 in-terspace. Immediately following surgery, Mr. Hart developed the following symptoms : (1) an inability to empty the bladder, and (2) numbness over the right side of the perinium (this is the crotch area), scrotum and penis. In other words, Mr. Hart had a lack of natural feeling in and around the above described areas.
The sensory feeling in the area wherein Mr. Hart is numb is supplied by sacral nerves. Beginning at approximately the first lumbar vertebra, the sacral nerves pass through the spinal column in what is called the cauda equina. At each lumbar vertebra the cauda equina is found to be located between the lamina of the vertebra and the intervertebral disc (the posterior section of the intervertebral disc would, therefore, be nearest to the cauda equina). The first, second, third, fourth and fifth sacral nerves pass through the spinal column in the cauda equina at the L4 L5 and the L5 SI level. At each intervertebral space following the first lumbar vertebra, a nerve root extends from the cauda equina to the right and left of the intervertebral disc.
*795A rupture of an intervertebral disc produces pressure against the nerve structure; either against the cauda equina or against the nerve roots that extend from the cauda equina at each vertebra interspace, i. e., the pressure may be against the nerve roots going out at each level or the pressure may be directly against the nerve roots which are still present inside the cauda equina. The pressure resulting from the ruptured disc is called “extra dura pressure” (“dura” is the outer covering of the nerve tissues).
Each intervertebral disc is composed of two parts: (1) the outer part, known as the annulus fibrosis, is a cartilaginious material that holds the disc in place, and (2) the inner part, known as the nucleus pul-posus, which is a soft substance that protrudes through the annulus fibrosis when the disc is ruptured. Extra dura pressure may be caused by the nucleus pulposus extruding through the annulus fibrosis and pressing against either the cauda equina or the nerve roots.
After leaving the hospital following Dr. Van Zandt’s operation, Mr. Hart had frequent office visits with the doctor. He was unable to void his bladder or bowels and had areas of numbness and lack of feeling. For the bladder condition Dr. Van Zandt referred Mr. Hart to Dr. Compere, a reputable urologist who performed a prostate operation in January, 1960, and relieved Mr. Hart’s bladder involvement to the point that Mr. Hart no longer wore a catheter for bladder relief. Dr. Van Zandt did not recommend additional surgery nor did he perform any additional myelograms or other diagnostic studies following the surgery other than to make x-ray pictures.
During December, 1959, Dr. Van Zandt sent Mr. Hart to a neurological specialist, Dr. William W. McKinney. On December 15 Dr. McKinney examined Mr. Hart and found that “the patient has some anesthesia over the right side of the perinium, the scrotum and the penis.” Dr. McKinney’s diagnosis was that the patient has suffered injury to the nerves which resulted in the patient’s condition; “it is my impression that this patient has had some trauma to the lower sacral nerves which has resulted in his bladder dysfunction.” Dr. Van Zandt directed Mr. Hart to Dr. McKinney without telling him that he had not operated at the L5 SI interspace — an omission which Dr. McKinney testified would have changed his procedure and treatment of Mr. Hart. He testified that if he had not been under the false impression that Dr. Van Zandt had removed a disc at the L5 SI level, he would have considered nerve root compression at the L5 SI level to be a strong possibility in this case. Dr. McKinney stated that a fusion, or protusion, at either the L4 L5 or L5 SI interspace could cause pressure to be exerted on the nerve roots with resulting damage thereto. He further stated that if a central extrusion of the disc over the L5 SI interspace is allowed to exert continuing pressure on the cauda equina and nerve roots and is not removed within a relatively short period, permanent and irreparable injury will result; and that nerve root involvement was responsible for Mr. Hart’s condition with regard to the numbness of certain areas of his body. Dr. McKinney testified that as soon as the diagnosis of the ruptured disc at L5 SI was made, the disc should have been removed. He further testified that it was not his regular procedure to allow a centrally extruded disc to remain with the symptoms that were existing in Mr. Hart’s case.
In May of 1960, Mr. Hart decided to leave Dr. Van Zandt and go to another doctor to try to obtain some relief. He went to Dr. Frederick C. Rehfeldt, a specialist in neurological surgery. On May 10, 1960, Dr. Rehfeldt began treating Mr. Hart. Hospital records were put in evidence showing the findings of a myelogram study requested by Dr. Rehfeldt on June 12,1960. The conclusions of the myelogram tests were:
“1. Large irregular obstructing space occupying lesion predominantly to the right of the level of the intervertebral disc between L4 L5 as shown by myelo-gram.
*7962. No demonstrable abnormality of the lumbar spinal canal above the level of L4.
3. Slight residual iodized oil in the spinal canal distally from previous mye-logram.
4. Post-operative changes involving L4 L5 as noted above.
5. Narrowing of discs between L4 L5 and L5 SI.”
The records of Dr. Rehfeldt further showed that the numbness and lack of natural feeling suffered by Mr. Hart were due to nerve root compression. On June 27, 1960, Dr. Rehfeldt performed surgery on Mr. Hart. During the course of the operation Dr. Rehfeldt found that the nerve roots were compressed at the L4 LS level. He also found that the intervertebral disc at the L5 SI level was ruptured and was compressing the dura sac. Dr. Rehfeldt then removed the discs at L4 L5 and at L5 SI which effected “decompression of L4 LS bilaterally and LS SI bilaterally.” A bar of matter was found extruding at L4 LS, pressing against the nerve root that comes off at this interspace. Dr. Rehfeldt said that if nerve root pressure was allowed to exist for a year or two, even though subsequent surgery removed the pressure on the nerve roots, there could be substantial damage to the nerves which would not heal; and although Mr. Hart showed some signs of improvement following the decompression of the nerves at L4 L5 and L5 SI, the doctor could not detect any differences in Mr. Hart’s sensory losses. Dr. Rehfeldt testified that both the L4 LS and L5 SI areas should be looked at when a patient has the symptoms of Mr. Hart, and that if he had a patient with a previous history of trouble at the L5 SI level, he would under normal procedure expose the LS SI area for review during surgery. He further stated that if a man is unsuccessfully operated on and there is nerve root pressure, following the operation which is allowed to exist for a year or two, there could be substantial damage done to the nerve roots which a subsequent operation would not cure. Essentially, Mr. Hart’s condition has remained unchanged since the date of Dr. Van Zandt’s operation up until the trial of this case.
Dr. Charles M. Hawes, a Doctor of Osteopathy (whose qualifications as a medical witness will be subsequently examined in this opinion), testified by deposition that in his opinion a doctor in the exercise of ordinary skill and care as employed by others in the medical profession in the Dallas-Fort Worth area, would have made an incision so as to expose the LS SI interspace during the course of an operation such as was performed by Dr. Van Zandt. He further testified that it was customary to explore both the L4 LS and the L5 SI interspace. The post-operative conditions of Mr. Hart were also outlined to Dr. Hawes, and in answer to hypothetical questions he stated that in his opinion, a doctor in the exercise of ordinary care and skill, when confronted with the symptoms of Mr. Hart immediately following the operation should have done exactly what was later done, viz.: to perform a myelogram and surgery. He further testified that, assuming an operation at the L4 L5 level but a diagnosis of a ruptured disc at the L5 SI level, it would not be in the exercise of ordinary skill and care in the Dallas-Fort Worth area to fail to go in and remove the disc at the LS SI level. To the same effect he testified that under the facts of Mr. Hart’s case a laminectomy should have been performed on the patient for the removal of the L5 SI disc at the time of Dr. Van Zandt’s operation.
It was Dr. Hawes’ opinion that Mr. Hart had a permanent involvement of the sacral nerves, and, based on reasonable medical probability, a delay in further surgery on a patient suffering from Mr. Hart’s symptoms immediately following the October, 1959 operation would cause or result in permanent damage to the sacral nerves. He further stated that Mr. Hart’s condition following the October, 1959 operation was caused by extra dural pressure at the L4 L5 and at the L5 SI levels.
*797The petitioner, in his Fourth Amended Original Petition, has alleged that twelve various acts and omissions on the part of Dr. Van Zandt constituted actionable negligence proximately causing his injuries. Included therein are the following allegations :
******
“(g) In failing to explore other vertebral bodies and intervertebral discs during surgery at the L-4, L-5 level.
(h) In failing to perform surgery on and remove a herniated, ruptured, or otherwise diseased interverte-bral disc at the L-5, S-l level.
s}c ifc ‡ ‡ # *
(j) In failing to perform additional surgery after the first operation to decompress the pressure which was then being exerted to the nerves and/or nerve roots in Plaintiffs back.”
Although the writer of this opinion, after a detailed study of the record, would affirm the Court of Civil Appeals’ judgment, the Court has directed the cause be written that fact issues of negligence and proximate cause are raised with regard to the above quoted allegations.
The Court is of the opinion that it would be unrealistic to hold that the above described testimony does not present a question of fact upon which reasonable minds could differ. It is not for this Court to decide whether or not Dr. Van Zandt’s failure to explore other vertebral bodies during his operation, failure to perform surgery at the L5 SI level, or his failure to perform additional surgery after the initial operation was in fact negligence proximately causing Mr. Hart’s injuries. Rather it is for this Court to decide whether or not the evidence in the record presents facts which must be passed upon by the jury. We hold that issues of negligence and causation have been raised that can only be resolved by the trier of fact, and that it was error for the courts below to sustain respondent’s motion for peremptory instruction.
Since this case is to be remanded for a new trial, it is necessary to pass on additional matters properly before the Court.
Respondent’s motion for peremptory instruction contained twenty-six numbered paragraphs. In sustaining this motion, the trial court held it “to be good in all its features.” Except for paragraphs 10, 11 and 19 the entire motion resolved into the questions of negligence and proximate cause heretofore decided. Paragraphs 10, 11 and 19 allege that petitioner failed to prove the essential elements of his cause of action “by a doctor of the same school of practice as defendant.” All of the doctors who testified, with the exception of Dr. Charles M. Hawes, who is an osteopath, hold M. D. degrees, so it is apparent that the objections in paragraphs 10, 11 and 19 are leveled at the testimony of Dr. Hawes.
In Bowles v. Bourdon, supra, 219 S. W.2d, at page 782, this Court announced the general rule with respect to the type of evidence necessary to establish a cause of action in a medical malpractice case in the following language:
“It is definitely settled with us that a patient has no cause of action against his doctor for malpractice, either in diagnosis or recognized treatment, unless he proves by a doctor of the same school of practice as the defendant: (1) that the diagnosis or treatment complained of was such as to constitute negligence and (2) that it was a proximate cause of the patient’s injuries.” (Emphasis added.)
In Porter v. Puryear, supra, 262 S.W.2d at page 936, this Court recognized that where the particular subject of inquiry is common to and equally recognized and developed in all fields of practice, a qualified surgeon of any recognized school of medicine may give evidence on the matter under inquiry.
*798Dr. L. B. Hart, who was qualified as a medical doctor and as an osteopathic doctor, testified that the subject of a laminectomy for back exploration and removal of a ruptured disc was equally recognized in both schools of medicine, and that it was equally developed in both schools of practice, because both schools use the same text books, have available the same information and read the same literature on the subject of surgical laminectomy. We therefore hold that as to the subject of inquiry in this case, the testimony of Dr. Hawes was properly admitted into evidence by the trial court.
By Points of Error Ten and Eleven, petitioner assigns error to the trial court in excluding the deposition testimony of Michael Scott, M. D. For purposes of his bill of exceptions the petitioner obtained the trial court’s ruling that the respondent’s objections to this evidence were sustained to each question and answer, severally considered.
Dr. Scott holds an M. D. degree and is licensed to practice neurosurgery in the State of Pennsylvania. It is apparent that both Dr. Scott and Dr. Van Zandt are of the same school of practice, that is, they are both licensed to practice medicine with an M. D. degree. Mr. Hart, in December of 1960, went to see Dr. Scott in an effort to obtain some relief from his condition. At that time Dr. Scott was given a history of Mr. Hart’s case and made an examination of the patient. Dr. Scott also had some correspondence with Dr. Rehfeldt and Dr. Van Zandt with regard to Mr. Hart’s case history. In Dr. Scott’s opinion, “the involvement of the nerve roots, the impairment of sensation, the Impairment in the function of involvement of the bladder was secondary to some involvement of the nerve roots which occurred during or immediately following the operation of October 13, 1959.”
We are of the opinion that Dr. Scott was in a position to render an expert opinion with regard to the cause or causes of Mr. Hart’s condition. We therefore hold that it was error for the trial court to exclude the deposition of Dr. Scott.
The judgments of the Court of Civil Appeals and the trial court are reversed and the case is remanded for new trial in accordance with this opinion.