FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Journal of anatomy2018; 233(1); 55-63; doi: 10.1111/joa.12818

Parameters and functional analysis of the deep epaxial muscles in the thoracic, lumbar and sacral regions of the equine spine.

Abstract: The epaxial muscles produce intervertebral rotation in the transverse, vertical and axial axes. These muscles also counteract the movements induced by gravitational and inertial forces and movements produced by antagonistic muscles and the intrinsic muscles of the pelvic limb. Their fascicles are innervated by the dorsal branch of the spinal nerve, which corresponds to the metamere of its cranial insertion in the spinous process. The structure allows the function of the muscles to be predicted: those with long and parallel fibres have a shortening function, whereas the muscles with short and oblique fibres have an antigravity action. In the horse, the multifidus muscle of the thoracolumbar region extends in multiple segments of two to eight vertebral motion segments (VMS). Functionally, the multifidus muscle is considered a spine stabiliser, maintaining VMS neutrality during spine rotations. However, there is evidence of the structural and functional heterogeneity of the equine thoracolumbar multifidus muscle, depending on the VMS considered, related to the complex control of the required neuromuscular activity. Osteoarticular lesions of the spine have been directly related to asymmetries of the multifidus muscle. The lateral (LDSM) and medial (MDSM) dorsal sacrocaudal muscles may be included in the multifidus complex, the function of which is also unclear in the lumbosacral region. The functional parameters of maximum force (F ), maximum velocity of contraction (V ) and joint moment (M) of the multifidus muscles inserted in the 4th, 9th, 12th and 17th thoracic and 3rd and 4th lumbar vertebrae of six horses were studied postmortem (for example: 4MT4 indicates the multifidus muscle that crosses four metameres with cranial insertion in the T4 vertebra). Furthermore, the structural and functional characteristics of LDSM and MDSM were determined. Data were analysed by analysis of variance (anova) in a randomised complete block design (P ≤ 0.05). For some muscles, the ordering of V values was almost opposite to that of F values, generally indicating antigravity or dynamic functions, depending on the muscle and VMS. The muscles 3MT12, 3ML3 and 4ML4 exhibited high F and low V values, indicating a stabilising action. The very long 7MT4 and 8MT4 multifidus had low F and high V values, suggesting a shortening action. However, some functional characteristics of interest did not fall within these general observations, also indicating a dual action. In summary, the results of the analysis of various structural and functional parameters confirm the structural and functional heterogeneity of the equine thoracolumbar multifidus complex, depending on the VMS, regardless of the number of metameres crossing each fascicle. To clarify the functions of the equine multifidus muscle complex, this study aimed to assess its functional parameters in thoracolumbar VMSs with different movement characteristics and in the MDSM and LDSM muscles, hypothesising that the functional parameters vary significantly when the VMS is considered.
© 2018 Anatomical Society.
Get Full Text
Publication Date: 2018-04-30 PubMed ID: 29708263PubMed Central: PMC5987835DOI: 10.1111/joa.12818Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research investigates the structure and function of deep back muscles (epaxial muscles) in horses, specifically in the thoracic, lumbar, and sacral spine regions. Exploring the functional parameters—maximum force, maximum contraction speed, and joint moment—of these muscles in different vertebras of horses, the study discovers variations that can impact how these muscles contribute to horse movement and spinal stability.

Function and Characteristic of Epaxial Muscles

  • Epaxial muscles are located along the spine and play a crucial role in vertebral rotation across different axes. These muscles help counteract gravitational and inertial forces and movements generated by opposing muscles and the innate muscles of the horse’s leg.
  • Depending on their fibre structure, these muscles can either shorten or provide anti-gravity effects. Long, parallel fibres indicate the muscles’ shortening function, while short, oblique fibres suggest an anti-gravity action.

Structural and Functional Heterogeneity in the Multifidus Muscle

  • The multifidus muscle in a horse’s thoracolumbar region plays a vital role in spinal stabilization. It extends across multiple segments each composed of two to eight Vertebral Motion Segments (VMS). Different functional and structural aspects of this muscle vary depending on the VMSs.
  • Misalignments in the multifidus muscle are related directly to spinal injuries. Other sacrocaudal muscles – the lateral dorsal sacrocaudal muscle (LDSM) and medial dorsal sacrocaudal muscle (MDSM) – encompassed in the multifidus complex have uncertain roles in the lumbar and sacral regions.

Functional Parameters Study and Findings

  • The study examined the functional parameters (maximum force, maximum contraction speed, and joint moment) of the multifidus muscles connected to specific thoracic and lumbar vertebrae in six horses. It also determined the structural and functional features of LDSM and MDSM.
  • The findings noted variations in muscle function based on the VMS. Specifically, some muscles demonstrated stabilizing actions, while others suggested a shortening action. However, there were exceptions where muscles showed a dual action.

Conclusion

  • The research confirms the multifidus muscles’ structural and functional heterogeneity, which depends on VMS, regardless of the number of metameres (segments of a creature’s body) each fascicle (bundle of muscle fibres) passes through.
  • The study highlights the need for further research to clearly establish the differing functions of the equine multifidus muscle complex across the VMSs.

Cite This Article

APA
García Liñeiro JA, Graziotti GH, Rodríguez Menéndez JM, Ríos CM, Affricano NO, Victorica CL. (2018). Parameters and functional analysis of the deep epaxial muscles in the thoracic, lumbar and sacral regions of the equine spine. J Anat, 233(1), 55-63. https://doi.org/10.1111/joa.12818

Publication

Journal of anatomy
ISSN: 1469-7580
NlmUniqueID: 0137162
Country: England
Language: English
Volume: 233
Issue: 1
Pages: 55-63

Researcher Affiliations

García Liñeiro, J A
  • Department of Health and Equine Production, School of Veterinary Sciences, Buenos Aires University, Buenos Aires, Argentina.
Graziotti, G H
  • Department of Anatomy, School of Veterinary Sciences, Buenos Aires University, Buenos Aires, Argentina.
Rodríguez Menéndez, J M
  • Department of Anatomy, School of Veterinary Sciences, Buenos Aires University, Buenos Aires, Argentina.
Ríos, C M
  • Department of Anatomy, School of Veterinary Sciences, Buenos Aires University, Buenos Aires, Argentina.
Affricano, N O
  • Department of Anatomy, School of Veterinary Sciences, Buenos Aires University, Buenos Aires, Argentina.
Victorica, C L
  • Department of Anatomy, School of Veterinary Sciences, Buenos Aires University, Buenos Aires, Argentina.

MeSH Terms

  • Animals
  • Back Muscles / anatomy & histology
  • Back Muscles / physiology
  • Horses
  • Lumbar Vertebrae / anatomy & histology
  • Lumbar Vertebrae / physiology
  • Sacrum / anatomy & histology
  • Sacrum / physiology
  • Thoracic Vertebrae / anatomy & histology
  • Thoracic Vertebrae / physiology

References

This article includes 44 references
  1. Barone R (1989) Anatomie Comparée des Mammifères Domestiques, Tome 2: Artrologie et Miologie, pp. 603–614, 683–689. Paris: Vigot.
  2. Bottinelli R, Reggiani C. Human skeletal muscle fibres: molecular and functional diversity.. Prog Biophys Mol Biol 2000;73(2-4):195-262.
    pubmed: 10958931doi: 10.1016/s0079-6107(00)00006-7google scholar: lookup
  3. Burkholder TJ, Fingado B, Baron S, Lieber RL. Relationship between muscle fiber types and sizes and muscle architectural properties in the mouse hindlimb.. J Morphol 1994 Aug;221(2):177-90.
    pubmed: 7932768doi: 10.1002/jmor.1052210207google scholar: lookup
  4. Butcher MT, Hermanson JW, Ducharme NG, Mitchell LM, Soderholm LV, Bertram JE. Contractile behavior of the forelimb digital flexors during steady-state locomotion in horses (Equus caballus): an initial test of muscle architectural hypotheses about in vivo function.. Comp Biochem Physiol A Mol Integr Physiol 2009 Jan;152(1):100-14.
    pubmed: 18835360doi: 10.1016/j.cbpa.2008.09.007google scholar: lookup
  5. Clayton HM, Kaiser LJ, Lavagnino M, Stubbs NC. Evaluation of intersegmental vertebral motion during performance of dynamic mobilization exercises in cervical lateral bending in horses.. Am J Vet Res 2012 Aug;73(8):1153-9.
    pubmed: 22849675doi: 10.2460/ajvr.73.8.1153google scholar: lookup
  6. Delp SL, Suryanarayanan S, Murray WM, Uhlir J, Triolo RJ. Architecture of the rectus abdominis, quadratus lumborum, and erector spinae.. J Biomech 2001 Mar;34(3):371-5.
    pubmed: 11182129doi: 10.1016/s0021-9290(00)00202-5google scholar: lookup
  7. Denoix JM. Spinal biomechanics and functional anatomy.. Vet Clin North Am Equine Pract 1999 Apr;15(1):27-60.
    pubmed: 10218240doi: 10.1016/s0749-0739(17)30162-1google scholar: lookup
  8. Eng CM, Smallwood LH, Rainiero MP, Lahey M, Ward SR, Lieber RL. Scaling of muscle architecture and fiber types in the rat hindlimb.. J Exp Biol 2008 Jul;211(Pt 14):2336-45.
    pubmed: 18587128doi: 10.1242/jeb.017640google scholar: lookup
  9. Evans HE (1993) Miller's Anatomy of the Dog. 3rd edn, pp. 292–318. Philadelphia: WB Saunders Company.
  10. Felder A, Ward SR, Lieber RL. Sarcomere length measurement permits high resolution normalization of muscle fiber length in architectural studies.. J Exp Biol 2005 Sep;208(Pt 17):3275-9.
    pubmed: 16109889doi: 10.1242/jeb.01763google scholar: lookup
  11. García Liñeiro JA, Graziotti GH, Rodríguez Menéndez JM, Ríos CM, Affricano NO, Victorica CL. Structural and functional characteristics of the thoracolumbar multifidus muscle in horses.. J Anat 2017 Mar;230(3):398-406.
    pmc: PMC5314397pubmed: 27861847doi: 10.1111/joa.12564google scholar: lookup
  12. Getty R, Sisson S, Grossman JD (1975) The Anatomy of the Domestic Animals, 5th edn, vol. 1, pp. 281–379. London: WB Saunders Company.
  13. Ghasemi A, Zahediasl S. Normality tests for statistical analysis: a guide for non-statisticians.. Int J Endocrinol Metab 2012 Spring;10(2):486-9.
    pmc: PMC3693611pubmed: 23843808doi: 10.5812/ijem.3505google scholar: lookup
  14. Groesel M, Zsoldos RR, Kotschwar A, Gfoehler M, Peham C. A preliminary model study of the equine back including activity of longissimus dorsi muscle.. Equine Vet J Suppl 2010 Nov;(38):401-6.
    pubmed: 21059036doi: 10.1111/j.2042-3306.2010.00282.xgoogle scholar: lookup
  15. Harrison SM, Whitton RC, King M, Haussler KK, Kawcak CE, Stover SM, Pandy MG. Forelimb muscle activity during equine locomotion.. J Exp Biol 2012 Sep 1;215(Pt 17):2980-91.
    pubmed: 22875767doi: 10.1242/jeb.065441google scholar: lookup
  16. Haussler KK. Anatomy of the thoracolumbar vertebral region.. Vet Clin North Am Equine Pract 1999 Apr;15(1):13-26, v.
    pubmed: 10218239doi: 10.1016/s0749-0739(17)30161-xgoogle scholar: lookup
  17. Hermanson JW. Architecture and the division of labor in the extensor carpi radialis muscle of horses.. Acta Anat (Basel) 1997;159(2-3):127-35.
    pubmed: 9575363doi: 10.1159/000147975google scholar: lookup
  18. Higham TE, Biewener AA. Functional and architectural complexity within and between muscles: regional variation and intermuscular force transmission.. Philos Trans R Soc Lond B Biol Sci 2011 May 27;366(1570):1477-87.
    pmc: PMC3130453pubmed: 21502119doi: 10.1098/rstb.2010.0359google scholar: lookup
  19. Hyytiäinen HK, Mykkänen AK, Hielm-Björkman AK, Stubbs NC, McGowan CM. Muscle fibre type distribution of the thoracolumbar and hindlimb regions of horses: relating fibre type and functional role.. Acta Vet Scand 2014 Jan 27;56(1):8.
    pmc: PMC3922740pubmed: 24468115doi: 10.1186/1751-0147-56-8google scholar: lookup
  20. Kaigle AM, Holm SH, Hansson TH. Experimental instability in the lumbar spine.. Spine (Phila Pa 1976) 1995 Feb 15;20(4):421-30.
    pubmed: 7747225doi: 10.1097/00007632-199502001-00004google scholar: lookup
  21. Kearns CF, McKeever KH, Abe T. Overview of horse body composition and muscle architecture: implications for performance.. Vet J 2002 Nov;164(3):224-34.
    pubmed: 12505395doi: 10.1053/tvjl.2001.0702google scholar: lookup
  22. Ker RF, Alexander MCN, Bennett MB. Why are mammalian tendons so thick?. J Zool 216, 309–324.
  23. Licka T, Frey A, Peham C. Electromyographic activity of the longissimus dorsi muscles in horses when walking on a treadmill.. Vet J 2009 Apr;180(1):71-6.
    pubmed: 18314362doi: 10.1016/j.tvjl.2007.11.001google scholar: lookup
  24. Lieber RL, Fridén J. Functional and clinical significance of skeletal muscle architecture.. Muscle Nerve 2000 Nov;23(11):1647-66.
    pubmed: 11054744doi: 10.1002/1097-4598(200011)23:11<1647::aid-mus1>3.0.co;2-mgoogle scholar: lookup
  25. Lieber RL, Ward SR. Skeletal muscle design to meet functional demands.. Philos Trans R Soc Lond B Biol Sci 2011 May 27;366(1570):1466-76.
    pmc: PMC3130443pubmed: 21502118doi: 10.1098/rstb.2010.0316google scholar: lookup
  26. Macintosh JE, Valencia F, Bogduk N, Munro RR. The morphology of the human lumbar multifidus.. Clin Biomech (Bristol, Avon) 1986 Nov;1(4):196-204.
    pubmed: 23915550doi: 10.1016/0268-0033(86)90146-4google scholar: lookup
  27. Marx JO, Olsson MC, Larsson L. Scaling of skeletal muscle shortening velocity in mammals representing a 100,000-fold difference in body size.. Pflugers Arch 2006 May;452(2):222-30.
    pubmed: 16333661doi: 10.1007/s00424-005-0017-6google scholar: lookup
  28. Mc Gowan C, Stubbs NC, Hodges P. Back Pain in Horses. pp. 9–35.
  29. Moseley GL, Hodges PW, Gandevia SC. Deep and superficial fibers of the lumbar multifidus muscle are differentially active during voluntary arm movements.. Spine (Phila Pa 1976) 2002 Jan 15;27(2):E29-36.
    pubmed: 11805677doi: 10.1097/00007632-200201150-00013google scholar: lookup
  30. Nickel R, Schummer A, Seiferle E. The Anatomy of the Domestic Animals, Volume 1: The Locomotor System of the Domestic Mammals. .
  31. Payne RC, Veenman P, Wilson AM. The role of the extrinsic thoracic limb muscles in equine locomotion.. J Anat 2005 Feb;206(2):193-204.
    pmc: PMC1571467pubmed: 15730484doi: 10.1111/j.1469-7580.2005.00353.xgoogle scholar: lookup
  32. Robert C, Audigié F, Valette JP, Pourcelot P, Denoix JM. Effects of treadmill speed on the mechanics of the back in the trotting saddlehorse.. Equine Vet J Suppl 2001 Apr;(33):154-9.
    pubmed: 11721558doi: 10.1111/j.2042-3306.2001.tb05380.xgoogle scholar: lookup
  33. Rome LC, Sosnicki AA, Goble DO. Maximum velocity of shortening of three fibre types from horse soleus muscle: implications for scaling with body size.. J Physiol 1990 Dec;431:173-85.
    pmc: PMC1181769pubmed: 2100306doi: 10.1113/jphysiol.1990.sp018325google scholar: lookup
  34. Schilling N. Metabolic profile of the perivertebral muscles in small therian mammals: implications for the evolution of the mammalian trunk musculature.. Zoology (Jena) 2009;112(4):279-304.
    pubmed: 19375292doi: 10.1016/j.zool.2008.09.007google scholar: lookup
  35. Schilling N, Carrier DR. Function of the epaxial muscles during trotting.. J Exp Biol 2009 Apr;212(Pt 7):1053-63.
    pubmed: 19282502doi: 10.1242/jeb.020248google scholar: lookup
  36. Sharir A, Milgram J, Shahar R. Structural and functional anatomy of the neck musculature of the dog (Canis familiaris).. J Anat 2006 Mar;208(3):331-51.
    pmc: PMC2100244pubmed: 16533316doi: 10.1111/j.1469-7580.2006.00533.xgoogle scholar: lookup
  37. Stubbs NC, Hodges PW, Jeffcott LB, Cowin G, Hodgson DR, McGowan CM. Functional anatomy of the caudal thoracolumbar and lumbosacral spine in the horse.. Equine Vet J Suppl 2006 Aug;(36):393-9.
    pubmed: 17402454doi: 10.1111/j.2042-3306.2006.tb05575.xgoogle scholar: lookup
  38. Stubbs NC, Kaiser LJ, Hauptman J, Clayton HM. Dynamic mobilisation exercises increase cross sectional area of musculus multifidus.. Equine Vet J 2011 Sep;43(5):522-9.
    pubmed: 21496085doi: 10.1111/j.2042-3306.2010.00322.xgoogle scholar: lookup
  39. Thompson SM, Reilly P, Emery RJ, Bull AM. An anatomical description of the pennation angles and central tendon angle of the supraspinatus both in its normal configuration and with full thickness tears.. J Shoulder Elbow Surg 2011 Sep;20(6):899-903.
    pubmed: 21454103doi: 10.1016/j.jse.2011.01.005google scholar: lookup
  40. Townsend HG, Leach DH. Relationship between intervertebral joint morphology and mobility in the equine thoracolumbar spine.. Equine Vet J 1984 Sep;16(5):461-5.
    pubmed: 6489309doi: 10.1111/j.2042-3306.1984.tb01981.xgoogle scholar: lookup
  41. van Weeren PR. Kinematics of the equine back. In: Equine Back Pathology: Diagnosis and Treatment, Chapter 5, pp. 39–59.
  42. van Weeren PR, Mc Gowan CM, Haussler KK. Developmental of a structural and functional understanding of the equine back. Equine Vet J 42(Suppl. 38), 393–400.
    pubmed: 0
  43. Williams SB, Wilson AM, Rhodes L, Andrews J, Payne RC. Functional anatomy and muscle moment arms of the pelvic limb of an elite sprinting athlete: the racing greyhound (Canis familiaris).. J Anat 2008 Oct;213(4):361-72.
    pmc: PMC2644771pubmed: 18657259doi: 10.1111/j.1469-7580.2008.00961.xgoogle scholar: lookup
  44. Zaneb H, Peham C, Stanek C. Functional anatomy and biomechanics of the equine thoracolumbar spine. A review.. Turk J Vet Anim Sci 37, 380–389.

Citations

This article has been cited 2 times.
  1. Purdoiu RC, Voiculeț IC, Aldea JA, Lăcătuș R, Patrichi T, Lucaci FD, Chan T, Kircher P, Mârza SM. Evaluation of Attenuation of Lumbar Epaxial Musculature in Dogs with Spinal Pathology. Animals (Basel) 2025 May 19;15(10).
    doi: 10.3390/ani15101468pubmed: 40427345google scholar: lookup
  2. Ogden NKE, Winderickx K, Stack JD. Computed tomography of the equine caudal spine and pelvis. Pathological findings in 56 clinical cases (2018-2023). Equine Vet J 2025 Sep;57(5):1279-1289.
    doi: 10.1111/evj.14426pubmed: 39428125google scholar: lookup
Subscribe to our newsletter
Join 99,608 horse owners like you who receive our email updates on horse health and nutrition.