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== Introduction<br>  ==
== Introduction<br>  ==


Soleus is a powerfull lower limb muscle which along with gastronemius and plantaris forms the CALF muscle or TRICEPS SURAE.It runs from back of knee to the ankle. Its name is derived from the Latin word, "solea," meaning "sandal."It is located in superficial posterior compartment of the leg.<br>
[[Image:Soleus 3.jpg|thumb|right]] Located in superficial posterior compartment of the leg '''Soleus''' is a powerful lower limb muscle, which is situated deep to the gastronemius muscle.  Together with gastronemius and plantaris, it forms the calf muscle or triceps surae. It runs from back of the knee to the ankle and is multipennate.  


Soleus muscle is not present in all mammal and it differ in shape in various mammals.In humans the soleus muscle is multipennate but in some mammals it is unipennate.<ref>Botta G, Piccinetti A, Giontella M, Mancini S (2001). "Il potenziamento dell’attività di pompa venosa del tricipite surale in ortopedia e traumatologia mediante l’utilizzo di una nuova apparecchiatura di ginnastica vascolare" [Strengthening of venous pump activity of the sural tricipital in orthopaedics and traumatology by means of a new equipment for vascular exercise]. Giornale Italiano di Ortopedia e Traumatologia (in Italian) 27: 84–8.</ref><ref>Ariano MA, Armstrong RB, Edgerton VR (January 1973). "Hindlimb muscle fiber populations of five mammals". The Journal of Histochemistry and Cytochemistry 21 (1): 51–5.</ref> Soleus is absent in dogs and vestiginal in horses.<ref>Meyers, Ron A.; Hermanson, John W. (2006). "Horse Soleus Muscle: Postural Sensor or Vestigial Structure?". The Anatomical Record Part a 288A 288 (10): 1068–1076.</ref>
The soleus has the greatest physiological cross sectional area (CSA) of the calf muscles and is thought to provide up to 80% of triceps surae force<ref>Fukunaga T, Roy RR, Shellock FG, Hodgson JA, Day MK, Lee PL, et al. Physiological cross-sectional area of human leg muscles based on magnetic resonance imaging. J Orthop Res. 1992;10(6):928–34.</ref>.
{| class="wikitable"
|+
|Muscle
|Physiological CSA (cm²)
|%
|-
|Soleus
|230
|71
|-
|Medial Gastrocnemius
|68
|22
|-
|Lateral Gastrocnemius
|28
|7
|}


&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [[Image:Soleus 1.png]] &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;[[Image:Soleus 3.jpg]] &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;[[Image:Soleus 2.jpeg]] &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>
== Anatomy  ==


. <br>
=== Origin ===


== Anatomy<ref>Gray's anatomy.Student edition.</ref><ref>Duke's orthopaedics.Wheeless' Textbook of Orthopaedics</ref> ==
*Posterior surface of the head and upper 1/3 of the shaft of the fibula;
*Middle 1/3 of the medial border of the tibia, tendinous arch between tibia and fibula.<br>


'''ORIGIN'''<br>
=== Insertion ===


*posterior surface of the head and upper 1/3 of the shaft of the fibula;
* Posterior surface of the calcaneus via the Achilles tendon
*middle 1/3 of the medial border of the tibia, tendinous arch between tibia and fibula.<br>


'''INSERTION'''<br>
=== Action ===


Into calcaneus with gastrocnemius by way of achilles tendon<br>
*Plantar flexion of the foot at the ankle;
 
*Reversed origin insertion action: when standing, the calcaneus becomes the fixed origin of the muscle;
'''ACTION'''<br>
*Soleus muscle stabilizes the tibia on the calcaneus limiting forward sway.


*Plantar flexion of the foot at the ankle;
=== Nerve supply ===
*Reversed origin insertion action: when standing, the calcanius becomes the fixed origin of the muscle;
*Soleus muslce stabilizes the tibia on the calcaneus limiting forward sway.<br>


'''NERVE SUPPLY'''<br>
Tibial nerve, L4, L5, S1 , S2


Tibial nerve, L4, L5, S1 , S2<br>
No sensory supply to the intramuscular aponeurosis.


'''SYNERGISTS'''<br>
=== Synergists ===


Gastrocnemius, Plantaris, Tibialis posterior, Peroneus longus and Brevis, FHL and FDL.<br>
[[Gastrocnemius|Gastrocnemius]], Plantaris, Tibialis posterior, Peroneus longus and Brevis, FHL and FDL.  


'''ANTAGONIST'''
=== Antagonists ===


Tibialis anterior  
Tibialis anterior  


'''BLOOD SUPPLY'''<br>
=== Blood supply ===


*Blood supply of the soleus muscle is from peroneal artery proximally and the posterior tibial artery distally;  
*Blood supply of the soleus muscle is from peroneal artery proximally and the posterior tibial artery distally;  
*Muscle has a mixed blood supply;  
*Muscle has a mixed blood supply;  
*Vascular supply of the soleus is from popliteal, posterior tibial, &amp; peroneal vascular pedicles to the proximal muscle, peroneal pedicles to distal lateral belly, and segmental posterior tibial pedicles to distal medial belly;  
*Vascular supply of the soleus is from popliteal, posterior tibial, &amp; peroneal vascular pedicles to the proximal muscle, peroneal pedicles to distal lateral belly, and segmental posterior tibial pedicles to distal medial belly;  
*w/ distal pedicles from the posterior tibial artery ligated &amp; based on proximal pedicles from the posterior tibial and peroneal arteries, muscle can be transposed medially or laterally to cover defects in middle third of the leg;  
*With distal pedicles from the posterior tibial artery ligated &amp; based on proximal pedicles from the posterior tibial and peroneal arteries, muscle can be transposed medially or laterally to cover defects in middle third of the leg;  
*Proximal vasculature arises directly from the popliteal vessels and can reliably carry all but the distal 4 to 5 cm of the muscle;  
*Proximal vasculature arises directly from the popliteal vessels and can reliably carry all but the distal 4 to 5 cm of the muscle;  
*Intramuscularly, vasculature of the soleus divides into a bipenniform segmental pattern;  
*Intramuscularly, vasculature of the soleus divides into a bipenniform segmental pattern;  
*w/ this vascular pattern, either half of the soleus muscle can be used, leaving a functional hemisoleus muscle intact
*With this vascular pattern, either half of the soleus muscle can be used, leaving a functional hemisoleus muscle intact


== Function  ==
== Function  ==


It have 2 major functions<br>
Soleus has two major functions:<br>  
 
*'''To act as skeletal muscle:''' Along with other calf muscle it is powerfull plantarflexor and&nbsp; have major contribution&nbsp; in running,walking and dancing.In the seated calf raise (knees flexed approximately 90º), the gastrocnemius are virtually inactive while the load is borne almost entirely by the soleus.In moderate force, the soleus is preferentially activated in the concentric phase, whereas the gastrocnemius is preferentially activated in the eccentric phase <ref>A Nardone, C Romanò,M Schieppati.Selective recruitment of high-threshold human motor units during voluntary isotonic lengthening of active muscles.J Physiol. 1989 February; 409: 451–471.</ref>.Human soleus muscle have majority of slow twitch fibers.Human soleus fiber composition is quite variable, containing between 60 and 100% slow fibers.<ref>Ariano MA, Armstrong RB, Edgerton VR (January 1973). "Hindlimb muscle fiber populations of five mammals". The Journal of Histochemistry and Cytochemistry 21 (1): 51–5.</ref><ref>Burke RE, Levine DN, Salcman M, Tsairis P (May 1974). "Motor units in cat soleus muscle: physiological, histochemical and morphological characteristics". The Journal of Physiology 238 (3): 503–14.</ref><ref>Gollnick PD, Sjödin B, Karlsson J, Jansson E, Saltin B (April 1974). "Human soleus muscle: a comparison of fiber composition and enzyme activities with other leg muscles". Pflügers Archiv 348 (3): 247–55</ref>.<br>  
*'''To act as muscle pump:''' along with other calf muscles it is known as peripheral heart as in uprite posture it enhance pumping the venous blood back into heart from periphery


<br>  
*'''To act as skeletal muscle:'''
**Along with other calf muscles it is powerful plantarflexor and&nbsp;has a major contribution&nbsp; in running, walking and dancing.
**It is also a major postural muscle designed to stop the body from falling forwards at the ankle during stance.
**In the seated calf raise (knees flexed approximately 90º), the gastrocnemius is virtually inactive while the load is borne almost entirely by the soleus.
**In moderate force, the soleus is preferentially activated in the concentric phase, whereas the gastrocnemius is preferentially activated in the eccentric phase <ref>Nardone A, Romanò C, Schieppati M. Selective recruitment of high-threshold human motor units during voluntary isotonic lengthening of active muscles. J Physiol. 1989;409(1):451–71.</ref>.
**Human soleus muscle tissue consists predominantly of slow twitch fibers, though the composition can range between 60 and 100% slow fibers.<ref>Ariano MA, Armstrong RB, Edgerton VR. Hindlimb muscle fiber populations of five mammals. J Histochem Cytochem. 1973;21(1):51–5.</ref><ref>Burke RE, Levine DN, Salcman M, Tsairis P. Motor units in cat soleus muscle: physiological, histochemical and morphological characteristics. J Physiol. 1974;238(3):503–14.</ref><ref>Gollnick PD, Sjödin B, Karlsson J, Jansson E, Saltin B. Human soleus muscle: a comparison of fiber composition and enzyme activities with other leg muscles. Pflugers Arch. 1974;348(3):247–55.</ref>.


<br>  
*'''To act as muscle pump:'''
**The soleal pump assists with venous return from the periphery to the heart when upright as the venous circulatory system passes through the muscle tissue.<br>


== Palpation  ==
== Palpation  ==


&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; {{#ev:youtube|ZUxv-s6Xyho}}  
{{#ev:youtube | BKQLeO0HZrE | 400}}When palpating the Soleus, plantarflex the ankle with the knee flexed to 90 degrees to ensure that gastrocnemius remains relaxed.  The lateral and medial aspects of the muscle can then be palpated from the lateral and medial sides of the Achilles tendon. The muscle is palpable for most of the distance from distal to proximal though the proximal attachments will become more difficult to palpate if the heads of gastrocnemius are large.
 
<br>


== Accessory soleus muscle (ASM)<br>  ==
== Accessory soleus muscle (ASM)<br>  ==


It is present in 0.7 to 5.5% of humans.<ref>Sookur PA, Naraghi AM, Bleakney RR, Jalan R, Chan O, White LM. Accessorymuscles: anatomy, symptoms and radiology evaluation. Radiographics. 2008;28(2):481-99.</ref>It is usually observed during the second or third decade of life and is more commonly seen in females than males at a ratio of 2:1. It is mostly unilateral.<ref>Crespo E, Minguez MF, Gascó J, Silvestre A, Jolín T, et al. Músculo sóleo accesorio como diagnóstico diferencial de un tumor de partes blandas del tobillo. Acta Ortop Castellano-Manch. 2004;(5):37-41.</ref><ref>Romanus B, Lindahl S, Sterner B. Accessory soleus muscle. A clinical and radiographic presentation of eleven cases. J Bone Joint Surg Am. 1986; 68(5):731-4.</ref><ref>Salomão O, Carvalho Junior AE, Fernandes TD, Romano D, Adachi PP, Sampaio Neto R. Músculo solear acessório: aspectos clínicos e achados cirúrgicos. Rev Bras Ortop. 1994;29(4):251-5.</ref><ref>Leswick DA, Chow V, Stoneham GW. Resident's corner. Can Assoc Radiol J. 2003;54(5):313-5.</ref><ref>Featherstone T. MRI diagnosis of accessory soleus muscle strain. Br J Sports Med. 1995;29(4):277-8.</ref><ref>Doda N, Peh WC, Chawla A. Symptomatic accessory soleus muscle: diagnosis and follow-up on magnetic resonance imaging. Br J Radiol. 2006;79(946):e129-32.</ref>. This supernumerary muscle is located under the gastrocnemius muscle, in the posterior upper third of the fibula, in the oblique soleus line, between the fibular head and the posterior part of the tibia. From its origin, the ASM runs anteriorly and medially until it reaches the Achilles tendon.<ref>Flavio Belmont Del Nero; Cristiane Regina Ruiz; Roberto Aliaga Junior.The presence of accessory soleous muscle in humans.Einstein (São Paulo) vol.10 no.1 São Paulo Jan./Mar. 2012.</ref><br>  
It is present in 0.7 to 5.5% of humans.<ref>Sookur PA, Naraghi AM, Bleakney RR, Jalan R, Chan O, White LM. Accessory muscles: anatomy, symptoms and radiology evaluation. Radiographics. 2008;28(2):481-99.</ref>It is usually observed during the second or third decade of life and is more commonly seen in females than males at a ratio of 2:1. It is mostly unilateral.<ref name=":1">Romanus B, Lindahl S, Sterner B. Accessory soleus muscle. A clinical and radiographic presentation of eleven cases. J Bone Joint Surg Am. 1986; 68(5):731-4.</ref><ref>Salomão O, Carvalho Junior AE, Fernandes TD, Romano D, Adachi PP, Sampaio Neto R. Músculo solear acessório: aspectos clínicos e achados cirúrgicos. Rev Bras Ortop. 1994;29(4):251-5.</ref><ref>Leswick DA, Chow V, Stoneham GW. Resident's corner. Can Assoc Radiol J. 2003;54(5):313-5.</ref><ref>Featherstone T. MRI diagnosis of accessory soleus muscle strain. Br J Sports Med. 1995;29(4):277-8.</ref><ref>Doda N, Peh WC, Chawla A. Symptomatic accessory soleus muscle: diagnosis and follow-up on magnetic resonance imaging. Br J Radiol. 2006;79(946):e129-32.</ref>. This supernumerary muscle is located under the gastrocnemius muscle, in the posterior upper third of the fibula, in the oblique soleus line, between the fibular head and the posterior part of the tibia. From its origin, the ASM runs anteriorly and medially until it reaches the Achilles tendon.<ref name=":0">Del Nero FB, Ruiz CR, Aliaga Junior R. The presence of accessory soleous muscle in humans. Einstein (Sao Paulo). 2012;10(1):79–81.</ref><br>  


&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; [[Image:ASM.jpg]] &nbsp; &nbsp; &nbsp;&nbsp;[[Image:ASM2.jpg]] &nbsp; &nbsp; &nbsp; <br>  
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; [[Image:ASM.jpg]] &nbsp; &nbsp; &nbsp;&nbsp;[[Image:ASM2.jpg]] &nbsp; &nbsp; &nbsp; <br>  


'''TYPES:'''<br>  
<span style="line-height: 1.5em;">Depending upon its insertion it is of 5 types, or in other words it can origininate from 5 sites</span>
 
Depending upon its insertion it is of 5 types, or in other words it can origninate from 5 sites<br>  


*Achilles tendon<br>  
*Achilles tendon<br>  
Line 82: Line 101:
*Medial part of the calcaneus<br>
*Medial part of the calcaneus<br>


Sometimes it is impossible to precisely identify the ASM origin and insertion, since the MRI fails to show details, depending on the slices.<ref>Flavio Belmont Del Nero; Cristiane Regina Ruiz; Roberto Aliaga Junior.The presence of accessory soleous muscle in humans.Einstein (São Paulo) vol.10 no.1 São Paulo Jan./Mar. 2012.</ref>Itmay cause pain on exercise. One may suspect a soft-tissue tumor, such as lipoma, hemangioma, and even sarcoma, but the anomalous muscle has a typical appearance on plain radiographs, and the appearance on computed tomography is diagnostic. If the patient is asymptomatic, no therapy is required, but if pain or other discomfort is provoked by exercise, exploration with fasciotomy or excision of the accessory muscle is recommended, as was done in six of our eleven patients who were seen between 1968 and 1985.<ref>Romanus B, Lindahl S, Stener B.Accessory soleus muscle. A clinical and radiographic presentation of eleven cases.J Bone Joint Surg Am. 1986 Jun;68(5):731-4.</ref><br>  
Sometimes it is impossible to precisely identify the ASM origin and insertion, since the MRI fails to show details, depending on the slices<ref name=":0" />. It may cause pain on exercise. One may suspect a soft-tissue tumor, such as lipoma, hemangioma, and even sarcoma, but the anomalous muscle has a typical appearance on plain radiographs, and the appearance on computed tomography is diagnostic. If the patient is asymptomatic, no therapy is required, but if pain or other discomfort is provoked by exercise, exploration with fasciotomy or excision of the accessory muscle is recommended, as was done in six of our eleven patients who were seen between 1968 and 1985<ref name=":1" />.
 
== Pathology ==


== Sprain and rupture  ==
=== Strain/Rupture ===


Full or partial rupture of the soleus muscle usually occurs when the calf muscle becomes stretched while it is contracting (eccentric contraction). Partial ruptures represent the majority of the ruptures. The rupture occurs in many instances at the point of attachment of the soleus muscle to the Achilles tendon, which will often trigger an inflammation of the Achilles tendon as a result of the soleus rupture.  
A muscle strain occurs when muscle fibers are damaged by the loads placed on them by activity. A gradual onset of pain is commonly reported during soleus strain and often with no specific mechanism of injury (MOI). This may be due to the limited sensory innervation to the intramuscular aponeurosis.  In cases where a specific MOI is identified, steady-state running appears to be the commonest cause of injury<ref>Pizzari T. The risks, epidemiology and return to play of calf muscle strain injuries [Internet]. 2021 Mar. Available from: <nowiki>https://www.youtube.com/watch?v=OvC5bn5aGXk</nowiki></ref>.  


Symptoms: Pain when activating the calf muscle (running and jumping), when applying pressure on the Achilles tendon approx. 4 cm. above the anchor point on the heel bone or higher up in the calf muscle, and when stretching the tendon. Walking on tip-toe will aggravate the pain.<br>In all cases when there is a sense of a "crack", or sudden shooting pains in the Achilles tendon, medical attention should be sought as soon as possible. Ultrasound scanning or MRI examination is used to advantage when making the diagnosis, as even full ruptures can easily be overlooked by normal clinical examination. <ref>citated from (sportnetdoc.com/foot-achilles/rupture-of-the-soleus-muscle) citated on august 31,2013.</ref><br>
Symptoms:


Further, about the soleus and calf strain can be read [http://www.physio-pedia.com/Calf_Strain here ]
* Pain with active or resisted plantar flexion
* Pain during walking, running, jumping or hopping
* Tenderness on palpation of the injury site


Whenever there occurs calf strain and the soleus is the muscle affected then there occur usually the medial or lateral pain i.e along the soleus fibres. And when the pain is in the bulk of the calf muscle then the gastrocnemius is the muscle affected,but, mostly both the muscles are affected together.<br>


'''SOLEUS SYNDROM:'''<br>
Investigations:


Another cause of medial pain (posteriomedial aspect of ankle) just above the medial malleous is the '''soleus syndrome.'''<ref>Michael RH, Holder LE: The soleus syndrome. Am J Sports Med  1985; 13:87.</ref> It occurs because of abnormal sliping of soleus muscle from its normal origin site and is similar to exertional campartment syndrome and commaly seen in dancers and athlets. Respond well to conservative treatment and if not then rarely fasciotomy of the soleus insertion may be required.<ref>David A.Porter,Lew C.Schow.Baxter's Foot and Ankle in Sports.2nd Edition.Mosby Publication.</ref><br><br>
Diagnostic ultrasound or MRI can be advantageous to confirm an injury diagnosis and ensure that injuries accurately assessed as full ruptures can be overlooked with clinical exam on occasion. <ref>urtehave_com. Rupture of the soleus muscle - Sportnetdoc [Internet]. Sportnetdoc.com. 2011 [cited 2013 Aug 31]. Available from: <nowiki>http://sportnetdoc.com/foot-achilles/rupture-of-the-soleus-muscle</nowiki></ref><br>


<br>
Further information about soleus and calf strains is available [http://www.physio-pedia.com/Calf_Strain here]


== References  ==
== References  ==
Line 104: Line 126:
<references />  
<references />  


[[Category:Anatomy]]
[[Category:Anatomy]] [[Category:Muscles]] [[Category:Ankle]] [[Category:Musculoskeletal/Orthopaedics]]
[[Category:Ankle - Anatomy]]  [[Category:Ankle - Muscles]]

Latest revision as of 17:44, 27 November 2021


Original Editor ­ Aarti Sareen

Top Contributors - Aarti Sareen, Laura Chimimba, Kim Jackson, Admin, Evan Thomas, Vanessa Rhule and Richard Benes

Introduction
[edit | edit source]

Soleus 3.jpg

Located in superficial posterior compartment of the leg Soleus is a powerful lower limb muscle, which is situated deep to the gastronemius muscle.  Together with gastronemius and plantaris, it forms the calf muscle or triceps surae. It runs from back of the knee to the ankle and is multipennate.

The soleus has the greatest physiological cross sectional area (CSA) of the calf muscles and is thought to provide up to 80% of triceps surae force[1].

Muscle Physiological CSA (cm²) %
Soleus 230 71
Medial Gastrocnemius 68 22
Lateral Gastrocnemius 28 7

Anatomy[edit | edit source]

Origin[edit | edit source]

  • Posterior surface of the head and upper 1/3 of the shaft of the fibula;
  • Middle 1/3 of the medial border of the tibia, tendinous arch between tibia and fibula.

Insertion[edit | edit source]

  • Posterior surface of the calcaneus via the Achilles tendon

Action[edit | edit source]

  • Plantar flexion of the foot at the ankle;
  • Reversed origin insertion action: when standing, the calcaneus becomes the fixed origin of the muscle;
  • Soleus muscle stabilizes the tibia on the calcaneus limiting forward sway.

Nerve supply[edit | edit source]

Tibial nerve, L4, L5, S1 , S2

No sensory supply to the intramuscular aponeurosis.

Synergists[edit | edit source]

Gastrocnemius, Plantaris, Tibialis posterior, Peroneus longus and Brevis, FHL and FDL.

Antagonists[edit | edit source]

Tibialis anterior

Blood supply[edit | edit source]

  • Blood supply of the soleus muscle is from peroneal artery proximally and the posterior tibial artery distally;
  • Muscle has a mixed blood supply;
  • Vascular supply of the soleus is from popliteal, posterior tibial, & peroneal vascular pedicles to the proximal muscle, peroneal pedicles to distal lateral belly, and segmental posterior tibial pedicles to distal medial belly;
  • With distal pedicles from the posterior tibial artery ligated & based on proximal pedicles from the posterior tibial and peroneal arteries, muscle can be transposed medially or laterally to cover defects in middle third of the leg;
  • Proximal vasculature arises directly from the popliteal vessels and can reliably carry all but the distal 4 to 5 cm of the muscle;
  • Intramuscularly, vasculature of the soleus divides into a bipenniform segmental pattern;
  • With this vascular pattern, either half of the soleus muscle can be used, leaving a functional hemisoleus muscle intact

Function[edit | edit source]

Soleus has two major functions:

  • To act as skeletal muscle:
    • Along with other calf muscles it is powerful plantarflexor and has a major contribution  in running, walking and dancing.
    • It is also a major postural muscle designed to stop the body from falling forwards at the ankle during stance.
    • In the seated calf raise (knees flexed approximately 90º), the gastrocnemius is virtually inactive while the load is borne almost entirely by the soleus.
    • In moderate force, the soleus is preferentially activated in the concentric phase, whereas the gastrocnemius is preferentially activated in the eccentric phase [2].
    • Human soleus muscle tissue consists predominantly of slow twitch fibers, though the composition can range between 60 and 100% slow fibers.[3][4][5].
  • To act as muscle pump:
    • The soleal pump assists with venous return from the periphery to the heart when upright as the venous circulatory system passes through the muscle tissue.

Palpation[edit | edit source]

When palpating the Soleus, plantarflex the ankle with the knee flexed to 90 degrees to ensure that gastrocnemius remains relaxed.  The lateral and medial aspects of the muscle can then be palpated from the lateral and medial sides of the Achilles tendon. The muscle is palpable for most of the distance from distal to proximal though the proximal attachments will become more difficult to palpate if the heads of gastrocnemius are large.

Accessory soleus muscle (ASM)
[edit | edit source]

It is present in 0.7 to 5.5% of humans.[6]It is usually observed during the second or third decade of life and is more commonly seen in females than males at a ratio of 2:1. It is mostly unilateral.[7][8][9][10][11]. This supernumerary muscle is located under the gastrocnemius muscle, in the posterior upper third of the fibula, in the oblique soleus line, between the fibular head and the posterior part of the tibia. From its origin, the ASM runs anteriorly and medially until it reaches the Achilles tendon.[12]

            ASM.jpg       ASM2.jpg      

Depending upon its insertion it is of 5 types, or in other words it can origininate from 5 sites

  • Achilles tendon
  • Upper calcaneus region
  • Insertion in the upper calcaneus,
  • Medial calcaneus region,
  • Medial part of the calcaneus

Sometimes it is impossible to precisely identify the ASM origin and insertion, since the MRI fails to show details, depending on the slices[12]. It may cause pain on exercise. One may suspect a soft-tissue tumor, such as lipoma, hemangioma, and even sarcoma, but the anomalous muscle has a typical appearance on plain radiographs, and the appearance on computed tomography is diagnostic. If the patient is asymptomatic, no therapy is required, but if pain or other discomfort is provoked by exercise, exploration with fasciotomy or excision of the accessory muscle is recommended, as was done in six of our eleven patients who were seen between 1968 and 1985[7].

Pathology[edit | edit source]

Strain/Rupture[edit | edit source]

A muscle strain occurs when muscle fibers are damaged by the loads placed on them by activity. A gradual onset of pain is commonly reported during soleus strain and often with no specific mechanism of injury (MOI). This may be due to the limited sensory innervation to the intramuscular aponeurosis.  In cases where a specific MOI is identified, steady-state running appears to be the commonest cause of injury[13].

Symptoms:

  • Pain with active or resisted plantar flexion
  • Pain during walking, running, jumping or hopping
  • Tenderness on palpation of the injury site


Investigations:

Diagnostic ultrasound or MRI can be advantageous to confirm an injury diagnosis and ensure that injuries accurately assessed as full ruptures can be overlooked with clinical exam on occasion. [14]

Further information about soleus and calf strains is available here

References[edit | edit source]

  1. ↑ Fukunaga T, Roy RR, Shellock FG, Hodgson JA, Day MK, Lee PL, et al. Physiological cross-sectional area of human leg muscles based on magnetic resonance imaging. J Orthop Res. 1992;10(6):928–34.
  2. ↑ Nardone A, Romanò C, Schieppati M. Selective recruitment of high-threshold human motor units during voluntary isotonic lengthening of active muscles. J Physiol. 1989;409(1):451–71.
  3. ↑ Ariano MA, Armstrong RB, Edgerton VR. Hindlimb muscle fiber populations of five mammals. J Histochem Cytochem. 1973;21(1):51–5.
  4. ↑ Burke RE, Levine DN, Salcman M, Tsairis P. Motor units in cat soleus muscle: physiological, histochemical and morphological characteristics. J Physiol. 1974;238(3):503–14.
  5. ↑ Gollnick PD, Sjödin B, Karlsson J, Jansson E, Saltin B. Human soleus muscle: a comparison of fiber composition and enzyme activities with other leg muscles. Pflugers Arch. 1974;348(3):247–55.
  6. ↑ Sookur PA, Naraghi AM, Bleakney RR, Jalan R, Chan O, White LM. Accessory muscles: anatomy, symptoms and radiology evaluation. Radiographics. 2008;28(2):481-99.
  7. ↑ 7.0 7.1 Romanus B, Lindahl S, Sterner B. Accessory soleus muscle. A clinical and radiographic presentation of eleven cases. J Bone Joint Surg Am. 1986; 68(5):731-4.
  8. ↑ Salomão O, Carvalho Junior AE, Fernandes TD, Romano D, Adachi PP, Sampaio Neto R. Músculo solear acessório: aspectos clínicos e achados cirúrgicos. Rev Bras Ortop. 1994;29(4):251-5.
  9. ↑ Leswick DA, Chow V, Stoneham GW. Resident's corner. Can Assoc Radiol J. 2003;54(5):313-5.
  10. ↑ Featherstone T. MRI diagnosis of accessory soleus muscle strain. Br J Sports Med. 1995;29(4):277-8.
  11. ↑ Doda N, Peh WC, Chawla A. Symptomatic accessory soleus muscle: diagnosis and follow-up on magnetic resonance imaging. Br J Radiol. 2006;79(946):e129-32.
  12. ↑ 12.0 12.1 Del Nero FB, Ruiz CR, Aliaga Junior R. The presence of accessory soleous muscle in humans. Einstein (Sao Paulo). 2012;10(1):79–81.
  13. ↑ Pizzari T. The risks, epidemiology and return to play of calf muscle strain injuries [Internet]. 2021 Mar. Available from: https://www.youtube.com/watch?v=OvC5bn5aGXk
  14. ↑ urtehave_com. Rupture of the soleus muscle - Sportnetdoc [Internet]. Sportnetdoc.com. 2011 [cited 2013 Aug 31]. Available from: http://sportnetdoc.com/foot-achilles/rupture-of-the-soleus-muscle
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