Citation Nr: 9922763 Decision Date: 08/12/99 Archive Date: 08/24/99 DOCKET NO. 94-06 421 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in Des Moines, Iowa THE ISSUES 1. Entitlement to service connection for a low back disorder as secondary to residuals of a gunshot wound of the left thigh. 2. Entitlement to an increased rating for residuals of a left thigh gunshot wound, currently evaluated as 30 percent disabling. REPRESENTATION Appellant represented by: Disabled American Veterans WITNESS AT HEARING ON APPEAL The veteran ATTORNEY FOR THE BOARD J.R. Bryant, Associate Counsel INTRODUCTION The veteran served on active duty from March 1969 to October 1971. This matter comes before the Board of Veterans' Appeals (Board) of the Department of Veterans Affairs (VA) on appeal from an October 1993 rating determination by the Des Moines, Iowa, Regional Office (RO) which denied service connection for a low back disorder as secondary to residuals of a gunshot of the left thigh. This case was previously before the Board in March 1996 and remanded for additional development and adjudication. In January 1999 the Board determined that it was necessary to obtain an opinion from a medical expert with the Veterans Health Administration (VHA). The opinion has been rendered and the veteran's representative was provided a copy of that opinion and given the opportunity to respond. FINDINGS OF FACT 1. There is no etiological relationship between the veteran's low back disorder and his service-connected left thigh gunshot wound residuals. 2. The veteran's residuals of a left thigh gunshot wound are manifested by a mild limp on the left and some inhibition on muscle strength testing; the muscle injury is no more than moderately severe, but there is associated nerve damage best characterized as mild incomplete paralysis . CONCLUSIONS OF LAW 1. A low back disorder is not proximately due to or the result of the veteran's service-connected left thigh gunshot wound residuals. 38 U.S.C.A. §§ 1110, 5107 (West 1991 & Supp. 1998); 38 C.F.R. § 3.310(a) (1998). 2. A 40 percent combined rating for residuals of a left thigh gunshot wound, based on a 10 percent rating for sciatic nerve injury in addition to the 30 percent rating for Muscle Group (MG) XIV injury, is warranted. 38 U.S.C.A. §§ 1155, 5107 (West 1991); 38 C.F.R. §§ 4.25, 4.55, 4.56, 4.71a, Code 5314, 4.124a, Code 8520 (1998). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS Factual Background Service medical records show that on May 13, 1971 the veteran sustained a gunshot wound to the left thigh. Examination revealed a through-and through missile wound of the left thigh extending from the lateral aspect to the medial aspect across the lower third. The wound was debrided and the veteran was released from the hospital on May 21. He had a partial foot drop and diminished sensation in the left peroneal distribution. An electromyography showed sciatic nerve damage. X-ray examination revealed no bony injury or retained fragments. The veteran underwent physical therapy, muscle stimulation and muscle strengthening exercises on a daily basis and subsequently recovered full function of his left foot, walked with a normal gait and stance and had only minimal weakness on dorsiflexion with some minimal sensory loss over the lateral aspect of the foot. Service connection has been established for left thigh gunshot wound residuals, including knee and sciatic nerve pathology. Postservice VA examinations in February 1973 and February 1977, were negative for back complaints. An August 1993 statement from the veteran's private chiropractor indicates the veteran was initially evaluated in May 1993 for complaints of low back pain. On examination he was found to have a herniated lumbar disc as well as a chronic left leg partial paralysis consistent with his past history of a left leg gunshot wound and resultant nerve damage. Subsequently the paralysis had substantially altered the veteran's gait and biomechanical function of the lumbar spine, which increased the joint degeneration and surrounding joint soft tissue degeneration to the lumbosacral spine. The examiner concluded that it was probable that the degeneration suffered to the lumbar spine disc was a result of the chronic ramification of the left leg. An August 1993 statement from W.N. Peterson, D.C. indicated the veteran had been a patient since December 1973 with initial complaints of left brachial neuritis and low back syndrome. Dr. Peterson noted the veteran's history was significant for a left leg gunshot wound with resulting soft tissue and nerve damage which produced a partial paralysis of the left leg, and that the paralysis had altered the veteran's gait to the point of causing degenerative joint disease which had altered disc tissue to the point of disc herniation. It was Dr. Peterson's opinion that the disc herniation, damaged nerve tissue and soft tissue would result in a progressive worsening of the biomechanical function of his lumbar and lumbo-pelvic structures. On VA examination in September 1993 the veteran gave a history of gunshot wound to the left proximal thigh and that since that time he has walked with an abnormal gait resulting in low back pain. He reported that 6-12 months prior he had an exquisite increase in his lower back and left lower extremity pain. He was evaluated by an orthopedic surgeon who diagnosed an L5-S1 herniated disc. The veteran had a partial discectomy. Since that time, he had partial resolution of his symptoms to the baseline low back pain with a decrease in the more acute exacerbation. He denied any lower extremity weakness or bowel or bladder incontinence. On examination, it was noted that the veteran was obese and walked with a left-sided antalgic gait. Lumbar motion was limited and painful. Manual motor testing revealed break- away weakness throughout the left lower extremity which was graded at 3-5/5 intermittently. He had intact light touch sensation in both lower extremities. Deep tendon reflexes were 2+ and more brisk on the right than the left to both the knees and the ankles. He had a negative Patrick's test. X- rays showed changes consistent with degenerative disc disease at L5-S1. There was partial sacralization of L5. There were post-operative changes of a left-sided L4-5 laminotomy. The clinical impression was status L5-S1 partial discectomy with continued low back pain. The examiner concluded that the veteran's claim that his low back problem was secondary to his abnormal gait was not inconceivable, however it was difficult to confirm. It was noted that the veteran had several other risk factors for low back pain, including obesity, sedentary lifestyle and history of smoking. Examination of the left hip revealed full range of motion from 0 to 140 degrees with a 60-degree arch of rotation. He had pain with any type of motion of the hip. Manual testing revealed break-away weakness of all muscle groups in the left lower extremity which was intermittently grade 3 to grade 5/5. He had intact light touch sensation throughout the left lower extremity. X-rays showed no evidence of any abnormality. The clinical impression was status post gun shot wound to the left proximal thigh with resultant pain and antalgic gait. The veteran complained that he had nerve damage as a result of the gunshot wound, however manual motor testing did not reveal any specific motor group weakness. He instead had diffuse breakaway weakness of the left lower extremity. Although he was noted to have an exquisite amount of pain with the left hip motion, there were no degenerative changes noted in the joint on X-rays. The examiner concluded that he most likely had painful symptoms resulting from the soft tissue injury. There was no evidence of neurologic damage. At a hearing before a traveling Member of the Board in April 1994, the veteran testified that after service discharge he began seeing a chiropractor for left leg pain and was told that his back was degenerating at a rapid rate because of the way he walked. He testified that he was told that he would swing his left leg when walking because of his foot drop resulting in pressure and causing him to throw his lower back out. He testified that his leg occasionally gave out and that he had pain with prolonged sitting or standing. The veteran testified that he could only walk a block and a half and then had to rest. September 1990 to May 1995 records from the University of Iowa Hospital show ongoing treatment for low back and left leg pain. In May 1993 the veteran was evaluated for a four- week history of pain in the low back, left buttock, posterior thigh and calf. His history was significant for chronic low back pain and longstanding numbness in the left lower extremity. Magnetic resonance imaging showed left lateral disc herniation at L4-5. The veteran underwent a left L4-L5 laminotomy and partial discectomy in June 1993. On follow-up examination in August 1993 it was noted that he was doing well following his L4-5 discectomy and had returned to his normal level of activities, but his chronic symptoms of left foot drop and numbness were still present. In November 1993 the veteran was evaluated for an acute onset of low back pain. He was evaluated in May 1994 for complaints of activity-related low back pain that limited his ability to walk to less than 100 yards. He also experienced weakness of both legs with prolonged ambulation. On examination the veteran was noted to be morbidly obese with a history of smoking. Reflexes were absent at both knees and at the left ankle. He had 5/5 motor strength in manual motor testing throughout in the lower extremities, although he did demonstrate breakaway weakness in all motor groups on the left. Sensation was intact to light touch. The veteran was evaluated in May 1995 for an increase in pain and weakness. He could ambulate independently and heel-toe walk. He had difficulty squatting, but could return upright with associated increase of back pain symptoms. Neurologic evaluation revealed knee jerk reflex was 2+ and symmetrical. Ankle jerk was absent on the left and 2+ on the right. There were no tension signs in sitting or supine. Sensory and motor examinations of the lower extremities were grossly intact. A June 1996 letter from chiropractor, D.C. Dornbier, shows the veteran was treated periodically for lumbosacral intervertebral disc syndrome with resultant muscle spasm. VA medical records show treatment of low back pain beginning in June 1996. Private treatment records show evaluation for lumbar spasms beginning in 1988. On VA examination in February 1997, it was noted that at the time of the injury in service the veteran had no particular complications with wound healing other than a contusion of the sciatic nerve with some partial foot drop. There was no evidence of severed nerves and the foot drop symptoms subsequently improved. The examiner noted there was no history in the service medical records that the veteran had any injury or symptoms relative to the low back or spine. The veteran had chiropractic treatment on a fairly regular basis beginning shortly after discharge in the early 1970s and the examiner's review of these records revealed that treatment was initially for neck and upper extremity problems and then, later, the low back, in 1988. At that time he began having low back pain with some radiation into the left leg, which became particularly troublesome in 1993. Subsequent evaluation revealed a large disc rupture at the L4-5 level on the left and the veteran underwent laminectomy with good relief of left sciatica symptoms. He continued to have symptoms of low back pain and some residual tingling and pins-and-needles in the foot in a spotty distribution which may be a residual of the old sciatica nerve palsy or perhaps was left sciatica related to disc rupture. In any event, the veteran did not have significant foot drop or steppage gait problems. Since his left sciatica symptoms, he had walked with a mild limp. On examination the veteran walked with a mild limp on the left leg. This was not consistent with a foot drop type of gait, and did not appear particularly antalgic with a quick step. His standing posture was symmetric. He was able to heel-toe walk, although initially denying the ability to do so. He had well-developed muscles in the thigh and calf. Thigh and calf circumference measurements showed no asymmetry, suggesting no particular atrophy of muscles of the thigh or calf. Muscle testing for strength shows some inhibition of dorsiflexion, plantar flexion, ankle inversion, ankle eversion, great and common toe extension and flexion on the left ranging about 4+ on a five point scale in all groups. The examiner was not sure that this represented true weakness, but rather reflex inhibition or learned behavior. There was no pain with full knee extension while seated. He had full painless hip and knee motions. Deep tendon reflexes of the knee were present and symmetric. Deep tendon reflexes at the heel cord were present, but diminished on the left side. The clinical impression was history of gunshot wound, left thigh, with partial sciatic nerve palsy with near full recovery; developmental abnormalities of the low back with sacralized L5 segment and spina bifida, L5 level and degenerative disc disease with history of disc herniation, post-laminectomy status. The examiner concluded that the nature of the veteran's mild sciatic nerve palsy residuals and mild gait abnormality would not have a major effect on the production of degenerative changes in the lumbar spine, which did not become symptomatic until 17 years later. The examiner could not clearly relate the condition of the veteran's low back to the left thigh injures he sustained in 1971. A statement from E.M. Found, Jr., M.D. dated in February 1998 indicates that in all likelihood the veteran's left lower extremity gunshot injury altered his gait pattern and his low back mechanics, which may have contributed to the development of his low back condition. In January 1999, the Board requested that VHA review the veteran's file and provide advisory medical opinions on the following questions: a) "Is it as least as likely as not that the veteran's low back disability was caused by an altered gait due to his service-connected left thigh gunshot wound or is otherwise due to his gunshot wound?" and b) "If the answer to (a) is no, did an altered gait or other pathology associated with the veteran's left thigh gunshot wound cause or contribute to cause an increase in low back disability?". In a memorandum received in March 1999, a VA orthopedic specialist provided a detailed summary of the record and concluded: In regard to the questions posed in the letter of 29 January, 1999 it can be stated that the subject veteran had a partial injury to the peroneal division of the left sciatic nerve in May of 1971 from which he recovered almost completely without surgical intervention. He was noted on several occasions to have a normal gait. Only when specifically tested for weakness was intermittent weakness of the foot noted. He was not walking with a drop foot, never required a brace to support the foot, and was found fit for all sea duty by the specialists who examined him. He was found to have no appreciable impairment of the left lower extremity at the time of his discharge from U.S.N.H San Diego and on separation from the Navy. He later appeared to have marked weakness of the quadriceps muscle on one occasion. This could not have resulted from the bullet wound which he sustained. He had marked variability of his symptoms at different times. It was only much later when he developed a back problem with a herniated disc that he described a disabling foot drop and gait abnormalities which affected the back. There is no logical relation of the most minimal impairment of the lower extremity due to the GSW to the later development of a herniated intervertebral disc after 20 years. Certain conditions of the lower extremity can produce stress to the back. A hip fusion or ankylosis can cause back trouble. Contracture of the ilio-tibial band with restricted extension of the hip has been thought to lead to back trouble. The claimant veteran had neither of these disorders. Paralysis of the hip abductor muscles can produce an abnormal trunk lurch with late back difficulties. A paralytic trunk lurch, when present, is treated by a cane. Mr. [redacted] was never found to need a cane. He always had full mobility of the hip and knee. There is no record of a disorder of the knee joint. There was no quadriceps atrophy and no physical basis for the occasional weakness of the thigh which he has manifested. Thus in response to question A: There was no appreciable gait disturbance until he developed sciatica in 1993 and that also apparently recovered following surgery. B: There was no altered gait which would have produced, caused, or contributed to a low back disorder many years after a minimal nerve injury in the leg. He never required the simple solution for weak dorsiflexors of the foot and ankle - a plastic foot drop orthosis. I can find no relation of the wound of 1971 to his later back disorder. Analysis I. Service Connection The Board finds that the veteran's claim for service connection for low back disability secondary to gunshot wound residuals of the left thigh is well grounded within the meaning of 38 U.S.C.A. § 5107(a) (West 1991) in that it is a "plausible claim, one which is meritorious on its own or capable of substantiation." Murphy v. Derwinski, 1 Vet.App. 78, 81 (1990). The Board further finds that the statutory duty to assist has been satisfied. The law permits the grant of service connection for a disability which results from disease or injury incurred in or aggravated by active military service. 38 U.S.C.A. § 1110. To grant service connection on a secondary basis, 38 C.F.R. § 3.310(a) provides that the injury or disease must be proximately due to or the result of the service-connected disease or injury. Also, when a service-connected disability aggravates, but is not the proximate cause of, a non-service- connected disability, service connection may be established for the increment of the nonservice-connected disability attributable to the service-connected disability. Allen v. Brown, 7 Vet. App. 439 (1995). The veteran contends that an altered gait due to nerve damage from his left thigh gunshot wound produced additional stress and strain on his low back and resulted in degenerative arthritis of the lumbar spine. Treatment reports from private chiropractors indicated that paralysis had substantially altered the veteran's gait and biomechanical function to the lumbar spine, which in turn increased the joint and soft tissue degeneration to the lumbosacral spine. A VA examiner in September 1993 concluded that the veteran's claim that his low back problem was secondary to his abnormal gait was not inconceivable, but that it was difficult to confirm. Other risk factors for low back pain, including obesity, sedentary lifestyle and history of smoking were noted. A VA examiner in February 1997 noted that the nature of the veteran's mild sciatic nerve palsy residuals and mild gait abnormality would not have a major effect on the production of degenerative changes in the lumbar spine, which did not become symptomatic until 17 years later. A subsequent statement from E.M. Found, Jr., M.D. indicated that in all likelihood the previous gunshot injury to the veteran's left lower extremity altered his gait pattern and mechanics to his low back and may have been a contribution to the development of his low back condition. The conflicting medical opinions prompted the Board to obtain a VHA advisory opinion. The reviewing VHA specialist concluded that there was no logical relation of the most minimal impairment of the lower extremity due to the gunshot wound to the later development of a herniated intervertebral disc after 20 years. The VHA opinion noted that there was no appreciable gait disturbance until the veteran developed sciatica in 1993, which apparently recovered following surgery. There was no altered gait which would have produced, caused, or contributed to, a low back disorder many years after a minimal nerve injury in the leg. Furthermore the veteran did not have any of the conditions thought to lead to back trouble such as hip fusion/ankylosis, contracture of the ilio-tibial band with restricted extension of the hip or paralysis of the hip abductor muscles. In addition he never required the simple solution for weak dorsiflexors of the foot and ankle - a plastic foot drop orthosis. The VHA opinion is a detailed reasoned response based on a review and analysis of the entire record, and the reviewing orthopedic specialist refers to specific events and medical history to support his conclusions. The opinions offered by the veteran's private doctors do not refer to the information they relied upon in forming their opinions. No clinical foundation for the opinions was given. Accordingly, the Board concludes that of the opinions offered, greater weight is to be accorded to the VHA opinion. See Hayes v. Brown, 5 Vet. App. 60, 69-70 (1993) ("It is the responsibility of the BVA to assess the credibility and weight to be given the evidence") (citing Wood v. Derwinski, 1 Vet. App. 190, 192-93 (1992)). See also Guerrieri v. Brown, 4 Vet.App. 467, 470-471 (1993) (the probative value of medical evidence is based on the physician's knowledge and skill in analyzing the data, and the medical conclusion the physician reaches; as is true of any evidence, the credibility and weight to be attached to medical opinions are within the province of the Board). In light of the foregoing, the Board finds that the preponderance of the evidence is against a holding that the veteran's claimed low back disorder and service-connected gunshot wound residuals are etiologically or causally associated. The preponderance of the evidence, including particularly the VHA advisory opinion, is likewise against a grant of service connection for low back disability under Allen. , The competent evidence of record does not show that the gunshot wound residuals caused aggravation of the low back condition. While the veteran's testimony and allegations of entitlement have been considered, his statements are not competent evidence of causality. As a layperson, he is not competent to give a medical opinion on diagnosis or etiology of a disorder. LeShore v. Brown, 8 Vet.App. 406 (1995); Dean v. Brown, 8 Vet.App. 449 (1995). II. Increased Rating The veteran's claim for an increased rating is well grounded within the meaning of 38 U.S.C.A. § 5107(a). Proscelle v. Derwinski, 2 Vet.App. 269 (1992). The Board is also satisfied that all relevant facts have been properly developed, and that no further assistance to the veteran is required in order to comply with 38 U.S.C.A. § 5107(a). The veteran has received recent VA examinations that have addressed his medical history and complaints, and have included detailed clinical findings relative to the service connected gunshot wound. Disability evaluations are determined by the application of a schedule of ratings which is based on average impairment of earning capacity. 38 U.S.C.A. § 1155; 38 C.F.R., Part 4. Separate diagnostic codes identify the various disabilities. In evaluating the veteran's request for an increased rating, the Board considers the medical evidence of record. The medical findings are then compared to the criteria set forth in the VA's Schedule for Rating Disabilities. An evaluation of the level of disability present must include consideration of the functional impairment of the veteran's ability to engage in ordinary activities, including employment, and the effect of pain on the functional abilities. 38 C.F.R. §§ 4.10, 4.40, 4.59. Furthermore, the Court has held that the VA must consider the applicability of regulations relating to pain. Quarles v. Derwinski, 3 Vet.App. 129, 139 (1992); Schafrath v. Derwinski, 1 Vet.App. 589, 593 (1993); Hatlestad v. Derwinski, 1 Vet.App. 164, 167 (1991). Under the regulations, the "functional loss due to pain is to be rated at the same level as the functional loss when flexion is impeded." Schafrath at 592. Where there is a question as to which of two evaluations shall be applied, the higher evaluation will be assigned if the disability picture more nearly approximates the criteria required for that rating. Otherwise, the lower rating will be assigned. 38 C.F.R. § 4.7. Moderate disability of the muscles may result from through and through or deep penetrating wounds of relatively short track by a single bullet or small shell or shrapnel fragment, without the explosive effect of a high velocity missile, residuals of debridement, or prolonged infection. The history of the disability should be considered, including service department records or other evidence of in service treatment of the wound. Consistent complaints of one or more of the cardinal symptoms of muscle disability, particularly lowered threshold of fatigue after average use affecting the particular functions controlled by the injured muscles. Evidence of entrance and (if present) exit scars which are linear or relatively small and so situated as to indicate relatively short track of missile through muscle tissue, some loss of deep fascia or muscle substance or impairment of muscle tonus, and loss of definite power or lowered threshold of fatigue when compared to the sound side. 38 C.F.R. § 4.56(d)(2). Moderately severe disability of the muscles is characterized by evidence of a through and through or deep penetrating wound by a high velocity missile of small size or a large missile of low velocity, with debridement or with prolonged infection, or with sloughing of soft parts, and intermuscular cicatrization. Service department records or other sufficient evidence showing hospitalization for a prolonged period for treatment of a wound should be considered. Records in the file of consistent complaints of cardinal symptoms of muscle wounds should also be noted. Evidence of an inability to keep up with work requirements may be considered. Objective findings should include entrance and (if present) exit scars so situated as to indicate the track of a missile through important muscle groups. Indications on palpation of loss of deep fascia, or loss of muscle substance or moderate loss of normal firm resistance of muscles compared with the sound side may be considered. Tests of strength and endurance of the muscle groups involved should demonstrate positive evidence of impairment. 38 C.F.R. § 4.56 (d)(3). Severe disability of the muscles is characterized by evidence of through and through or deep penetrating wound due to a high velocity missile, or large or multiple low velocity missiles, or shattering bone fracture or an open comminuted fracture with extensive debridement or prolonged infection and sloughing of soft parts, intermuscular binding and cicatrization. Service department records or other sufficient evidence showing hospitalization for a prolonged period in service for treatment of a wound should be considered. Records in the file of consistent complaints of cardinal symptoms of muscle wounds should also be noted. Evidence of an inability to keep up with work requirements may be considered. Objective evidence of severe disability includes ragged, depressed, and adherent scars of skin so situated as to indicate wide damage to muscle groups in the track of a missile. X-ray may show minute multiple scattered foreign bodies indicating spread of intermuscular trauma and explosive effect of a missile. Palpation shows loss of deep fascia or of muscle substance or soft or flabby muscles in wound area. Muscles do not swell and harden normally in contraction. Tests of strength or endurance or coordinated movements compared with the sound side indicate severe impairment of function. Diminished muscle excitability to pulsed electrical current compared with the sound side may be present. Visible or measured atrophy may or may not be present. Adaptive contraction of an opposing group of muscles, if present, indicates severity. Adhesion of a scar to one of the long bones, scapula, pelvic bones, sacrum or vertebrae, with epithelial sealing over the bone rather than true skin covering, in area where bone is normally protected by muscle, indicates the severe type. Atrophy of muscle groups not included in the track of the missile, particularly of the trapezius and serratus in wounds in the shoulder girdle, and induration or atrophy of an entire muscle following simple piercing by a projectile also indicates severe disability. 38 C.F.R. § 4.56(d)(4). The cardinal signs and symptoms of muscle disability are loss of power, weakness, lowered threshold of fatigue, fatigue- pain, impairment of coordination and uncertainty of movement. 38 C.F.R. § 4.56(c) (1998). VA has a duty to acknowledge and consider all regulations which are potentially applicable through the assertions and issues raised in the record. Schafrath v. Derwinski, 1 Vet. App. 589 (1991). Effective July 3, 1997, the Schedule for rating muscle injuries was amended. The United States Court of Veterans Appeals (now the United States Court of Appeals for Veterans Claims) (Court) has held that where laws or regulations change after a claim has been filed or reopened but before the administrative or judicial appeal process is completed, unless Congress provides otherwise, the version of the law most favorable to the appellant will apply. Karnas v. Derwinski, 1 Vet. App. 308 (1990). Although the criteria for rating muscle injuries were amended on July 3, 1997, the basic criteria for Muscle Group ( MG ) XIV are unchanged and the veteran's disability has been evaluated by the RO under the old and new criteria. Diagnostic Code 5314 provides the criteria for rating injuries to MG XIV, the anterior thigh group. The Rating Schedule provides that a moderately severe muscle injury involving M G XIV warrants a 30 percent evaluation and a severe muscle injury warrants a 40 percent evaluation. The anterior thigh group muscle functions include extension of the knee, simultaneous flexion of hip and flexion of knee, tension of fascia lata and iliotibial, and, acting with other muscle groups, postural support of body and synchronizing hip and knee. 38 C.F.R. § 4.73. The rating for the disability at issue has been in effect for over 20 years and, accordingly, is protected and may not be reduced regardless of the current manifestations of disability shown. See 38 U.S.C.A. § 110. The veteran's gunshot wound has resulted in no more than moderately severe muscle injury. Service medical records show that the original shrapnel wound was described as through-and-through, resulting in partial foot drop and sciatic nerve damage. However, there was no bony injury or retained fragments. There likewise was no indication of prolonged treatment or infection with sloughing of soft parts, or intermuscular cicatrization that would satisfy the requirements for a severe muscle injury under 38 C.F.R. § 4.56. The veteran subsequently recovered full function of the left foot and had only minimal residual weakness and sensory loss. Moreover, there is no objective medical evidence that the veteran's current disability picture is manifested by more than moderately severe muscle injury. On VA examination in September 1993, the veteran had breakaway weakness of the left lower extremity and full range of motion with evidence of pain on motion. There was no tissue loss by comparison, or tendon, bone or joint damage and no degenerative changes noted on X-ray. On VA examination in February 1997, there was no significant muscle loss noted and the physician specifically noted the veteran had well-developed muscles in the thigh and calf. There was no asymmetry, suggesting no particular atrophy of thigh or calf muscles. Muscle strength testing showed inhibition which the examiner did not believe showed true weakness, but rather reflex inhibition or learned behavior. The veteran had full, painless hip and knee motions. Knee reflexes were present and symmetric. Reflexes at the heel cord were diminished on the left side. The only objective findings of any disability were of a mild limp not considered consistent with a foot drop type gait and some inhibition on muscle strength testing. These objective findings do not reflect more than moderately severe muscle injury. Hence, a rating in excess of 30 percent under Code 5314 is not warranted. The veteran's left thigh gunshot wound injury also resulted in sciatic nerve injury. Initially, he had partial footdrop and loss of sensation. The footdrop resolved. There may have been recurrence of footdrop symptoms, but this has been related to lumbar disc herniation, not to the gunshot wound injury. Nevertheless, there was a sensory component to the sciatic nerve injury which appears to have persisted to the present. From the comments of recent examiners and reviewers to the effect that the veteran "recovered almost completely" from his sciatic nerve injury and that there was "near (emphasis added) full recovery", it may be inferred that some disturbance of sensation remains. 38 C.F.R. § 4.55(a) prohibits combining muscle injury ratings with peripheral nerve paralysis rating of the same body part unless the injuries affect entirely different functions. That is the situation in this case. The injury to MG XIV affects knee, hip, and thigh functions. The sciatic nerve injury impairment of function consists of loss of sensation in the lower leg/foot. These are entirely separate and distinct functions. Hence, separate ratings for muscle and nerve injuries are permissible in this case. Under 38 C.F.R. § 4.124a, Code 8520, moderate incomplete paralysis of the sciatic nerve warrants a 20 percent rating. Mild incomplete paralysis warrants a 10 percent rating. Under the explanation of the term "incomplete paralysis" in the note preceding Code 8510, where the involvement is wholly sensory, the rating should be for the mild, or at most, the moderate degree. Here, there is nothing in the clinical data of record to indicate there is more than mild involvement. Hence, a rating of 10 percent, but no higher, under Code 8520 is warranted. When the 30 percent rating for MG XIV is combined with the 10 percent rating for nerve injury, the resulting rating is 40 percent. 38 C.F.R. § 4.25. ORDER Service connection for a low back disorder as secondary to service-connected left thigh gunshot wound residuals is denied. A 40 percent combined rating for residuals of a left thigh gunshot wound, based on a 10 percent rating for nerve injury in addition to the 30 percent rating for MG XIV injury, is granted, subject to the regulations governing payment of monetary awards. George R. Senyk Member, Board of Veterans' Appeals