Anomalous lumbrical muscles in the hand: A case report Frank Durksen, M.D., Winnipeg, Manitoba, Canada
Variations in the number, location, and insertion of the lumbrical muscles in the hand are well recognized, but lumbrical tendons arising in the forearm are rare. 1-5 Latarjet 6 mentioned the possibility of a lumbrical inserting into the forearm muscles or bone. Le Double l7 alluded to a case similar to the one described here. Butler and BigleyB reported on one case where a tendon arising in the index lumbrical inserted proximally into the flexor superficialis of the index. Mehta and Gardner,9 in a study of 75 hands, reported that the lumbricals could originate in the forearm. Still and Kleinert lO found a little finger lumbrical muscle in Guyon's canal and a large lumbrical to the index arising in the carpal tunnel from an aberrant distally located flexor superficialis muscle. Schultz, Endler, and Huddleston l l reported a case where a supernumerary lumbrical to the index arose in the carpal tunnel and inserted side to side with the normal lumbrical muscle. Eriksen l2 reported a similar case on the long finger. Case report S. M., a 64-year-old railroad engineer, fell from a slowly moving train and suffered a traumatic amputation of his left upper limb at mid-arm level and a fracture dislocation of the thoracolumbar spine with partial paraplegia. He had been a healthy, robust man and never had symptoms related to his hands, wrists, or forearms. Upon examining the dissected specimen, three thin tendons were seen extending from the musculotendinous junction of the profundus muscles of the index, middle, and ring fingers (Fig. I). Those lay parallel to the flexor profundus tendons and each ended in a separate lumbrical muscle belly in the proximal palm and distal portion of the carpal tunnel. This accessory lumbrical muscle contained distally with a short flat tendon and the normally located and developed lumbrical muscles to the index, middle, and ring fingers. A From the Section of Orthopaedics, Health Sciences Centre, University of Manitoba, Winnipeg, Manitoba, Canada. Received for publication Jan. 21, 1978. Reprint requests: Frank Durksen, M.D., Section of Orthopaedics, Health Sciences Centre, University of Mannitoba, Winnipeg, Manitoba R3E OZ3, Canada.
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THE JOURNAL OF HAND SURGERY
Fig. 1. Illustration of the three anomalous lumbricals, two elevated by the hemostat. The hook is on the flexor superficialis to the little finger. normal small lumbrical muscle was present in the little finger in normal position and arose from the flexor profundus tendons of the ring and little fingers in a pennate fashion. The normal lumbricals to the ring and middle fingers had similar muscular attachments, but the abnormal lumbrical muscles were joined only to the radial side of the respective flexor profundus tendons. Small branches from the median nerve entered the abnormal lumbricals to the index and middle fingers and a small branch from the ulnar nerve passed into the abnormal lumbrical to the ring finger. The normallumbrical innervation was median nerve to first and second and ulnar nerve to third and fourth lumbricals.
0363-5023/78/060550+02$00.20/0 © 1978 American Society for Surgery of the Hand
Vol. 3, No.6 November, 1978
Anomalous lumbrical muscles
Clinical examination of his remaining hand disclosed no abnormalities. 6.
Summary An unusual anatomical variant of lumbrical muscles in a functionally normal hand has been described. Aberrant lumbricals were demonstrated to the index, middle, and ring fingers and their tendons extended to the musculotendinous junction of the profundus muscles in the forearm. REFERENCES I. Boyes JH: Bunnell's surgery of the hand, Philadelphia, 1964, JB Lippincott Co, p 485 2. Kaplan EB: Functional and surgical anatomy of the hand, ed 2, Philadelphia, 1965, 18 Lippincott Co, p 85 3. Basu SS, Hazary S: Variations of the lumbrical muscles of the hand. Anat Rec 136:501-4, 1960 4. Russel RF, Sunderland S: Abnormalities of the lumbrical muscles of the hand. J Anat 72:306-7, 1937-8 5. Touborg JA: Carpal tunnel syndrome caused by an ab-
7.
8.
9. 10.
II.
12.
551
normal distribution of the lumbrical muscles. Scand J Plast Reconstr Surg 4:72, 1970 Latarjet A: Traite d'anatomic humaine, vol. I, Paris, 1928, Gaston Doin y Cie, p 1091 LeDouble AF: Traite des variations du systeme musculaire de l'homme, Paris, 1897, Schleicher Freres, pp 183 & 203 Butler B Jr, Bigley EC: Aberrant index (first) lumbrical tendinous origin associated with carpal tunnel syndrome. J Bone Joint Surg [Am] 53:160-2, 1971. Mehta HJ, Gardner WU: Study of lumbrical muscles in the Human Hand J Anat. 109:227-238, 1961. Still JM Jr, Kleinert HE: Anomalous muscles and nerve entrapment in the wrist and hand. Plast Reconstr Surg 52:394-400, 1973 Schultz RJ, Endler PM, Huddleston HD: Anomalous median nerve and an anomalous muscle belly of the first lumbrical associated with carpal tunnel syndrome. J Bone Joint Surg [Am] 55: 1744-6, 1973 Eriksen J: A case of carpal tunnel syndrome on the basis of an abnormally long lumbrical muscle. Acta Orthop Scand44:275-7,I973
Information for Authors Most of the provisions of the Copyright Act of 1976 became effective on January 1, 1978. Therefore, all manuscripts must be accompanied by the following written statement, signed by one author: "The undersigned author transfers all copyright ownership of the manuscript (title of article) to the American Society for Surgery of the Hand in the event the work is published. The undersigned author warrants that the article is original, is not under consideration by another journal, and has not been previously published. I sign for and accept responsibility for releasing this material on behalf of any and all co-authors." Authors will be consulted, when possible, regarding republication of their material.
Variations in the number, location, and insertion of the lumbrical muscles in the hand are well recognized, but lumbrical tendons arising in the forearm are rare. 1-5 Latarjet 6 mentioned the possibility of a lumbrical inserting into the forearm muscles or bone. Le Double l7 alluded to a case similar to the one described here. Butler and BigleyB reported on one case where a tendon arising in the index lumbrical inserted proximally into the flexor superficialis of the index. Mehta and Gardner,9 in a study of 75 hands, reported that the lumbricals could originate in the forearm. Still and Kleinert lO found a little finger lumbrical muscle in Guyon's canal and a large lumbrical to the index arising in the carpal tunnel from an aberrant distally located flexor superficialis muscle. Schultz, Endler, and Huddleston l l reported a case where a supernumerary lumbrical to the index arose in the carpal tunnel and inserted side to side with the normal lumbrical muscle. Eriksen l2 reported a similar case on the long finger. Case report S. M., a 64-year-old railroad engineer, fell from a slowly moving train and suffered a traumatic amputation of his left upper limb at mid-arm level and a fracture dislocation of the thoracolumbar spine with partial paraplegia. He had been a healthy, robust man and never had symptoms related to his hands, wrists, or forearms. Upon examining the dissected specimen, three thin tendons were seen extending from the musculotendinous junction of the profundus muscles of the index, middle, and ring fingers (Fig. I). Those lay parallel to the flexor profundus tendons and each ended in a separate lumbrical muscle belly in the proximal palm and distal portion of the carpal tunnel. This accessory lumbrical muscle contained distally with a short flat tendon and the normally located and developed lumbrical muscles to the index, middle, and ring fingers. A From the Section of Orthopaedics, Health Sciences Centre, University of Manitoba, Winnipeg, Manitoba, Canada. Received for publication Jan. 21, 1978. Reprint requests: Frank Durksen, M.D., Section of Orthopaedics, Health Sciences Centre, University of Mannitoba, Winnipeg, Manitoba R3E OZ3, Canada.
550
THE JOURNAL OF HAND SURGERY
Fig. 1. Illustration of the three anomalous lumbricals, two elevated by the hemostat. The hook is on the flexor superficialis to the little finger. normal small lumbrical muscle was present in the little finger in normal position and arose from the flexor profundus tendons of the ring and little fingers in a pennate fashion. The normal lumbricals to the ring and middle fingers had similar muscular attachments, but the abnormal lumbrical muscles were joined only to the radial side of the respective flexor profundus tendons. Small branches from the median nerve entered the abnormal lumbricals to the index and middle fingers and a small branch from the ulnar nerve passed into the abnormal lumbrical to the ring finger. The normallumbrical innervation was median nerve to first and second and ulnar nerve to third and fourth lumbricals.
0363-5023/78/060550+02$00.20/0 © 1978 American Society for Surgery of the Hand
Vol. 3, No.6 November, 1978
Anomalous lumbrical muscles
Clinical examination of his remaining hand disclosed no abnormalities. 6.
Summary An unusual anatomical variant of lumbrical muscles in a functionally normal hand has been described. Aberrant lumbricals were demonstrated to the index, middle, and ring fingers and their tendons extended to the musculotendinous junction of the profundus muscles in the forearm. REFERENCES I. Boyes JH: Bunnell's surgery of the hand, Philadelphia, 1964, JB Lippincott Co, p 485 2. Kaplan EB: Functional and surgical anatomy of the hand, ed 2, Philadelphia, 1965, 18 Lippincott Co, p 85 3. Basu SS, Hazary S: Variations of the lumbrical muscles of the hand. Anat Rec 136:501-4, 1960 4. Russel RF, Sunderland S: Abnormalities of the lumbrical muscles of the hand. J Anat 72:306-7, 1937-8 5. Touborg JA: Carpal tunnel syndrome caused by an ab-
7.
8.
9. 10.
II.
12.
551
normal distribution of the lumbrical muscles. Scand J Plast Reconstr Surg 4:72, 1970 Latarjet A: Traite d'anatomic humaine, vol. I, Paris, 1928, Gaston Doin y Cie, p 1091 LeDouble AF: Traite des variations du systeme musculaire de l'homme, Paris, 1897, Schleicher Freres, pp 183 & 203 Butler B Jr, Bigley EC: Aberrant index (first) lumbrical tendinous origin associated with carpal tunnel syndrome. J Bone Joint Surg [Am] 53:160-2, 1971. Mehta HJ, Gardner WU: Study of lumbrical muscles in the Human Hand J Anat. 109:227-238, 1961. Still JM Jr, Kleinert HE: Anomalous muscles and nerve entrapment in the wrist and hand. Plast Reconstr Surg 52:394-400, 1973 Schultz RJ, Endler PM, Huddleston HD: Anomalous median nerve and an anomalous muscle belly of the first lumbrical associated with carpal tunnel syndrome. J Bone Joint Surg [Am] 55: 1744-6, 1973 Eriksen J: A case of carpal tunnel syndrome on the basis of an abnormally long lumbrical muscle. Acta Orthop Scand44:275-7,I973
Information for Authors Most of the provisions of the Copyright Act of 1976 became effective on January 1, 1978. Therefore, all manuscripts must be accompanied by the following written statement, signed by one author: "The undersigned author transfers all copyright ownership of the manuscript (title of article) to the American Society for Surgery of the Hand in the event the work is published. The undersigned author warrants that the article is original, is not under consideration by another journal, and has not been previously published. I sign for and accept responsibility for releasing this material on behalf of any and all co-authors." Authors will be consulted, when possible, regarding republication of their material.
