The term origin is used here as equivalent to proximal attachment. The proximal attachment of the plantaris muscle represents a distinct anatomical domain from tendon course and distal attachment / insertion.
This page summarizes published anatomical descriptions and classification systems of plantaris proximal attachment / origin in adult cadaveric material [1-5].
Anatomical Basis of Proximal Attachment
The proximal attachment is an important domain of plantaris variability. Reported attachment sites and relationships include the lateral supracondylar region and lateral femoral condyle, popliteal surface of the femur, knee joint capsule, lateral head of gastrocnemius and, in selected variants, structures such as the iliotibial band, fibular collateral ligament or patellar region [2-5].
Because these structures occupy different anatomical planes of the posterolateral knee and popliteal fossa, proximal attachment should be described separately from the distal course and terminal attachment of the plantaris tendon.
Classification Scope
Published studies describe plantaris proximal attachment using both descriptive anatomical observations and formal classification systems. These approaches differ in anatomical criteria, methodology and classification structure and should therefore be interpreted within the terminology of the individual study.
Relevant adult studies include the large anatomical series of Daseler and Anson [1], the descriptive observations of Freeman et al. [2], the three-type classification reported by Nayak et al. [3], the six-type classification proposed by Olewnik et al. [4], and the three-type classification proposed by Lee et al. [5].
Published Studies and Classification Systems
Table 1. Published anatomical studies and classification systems relevant to plantaris proximal attachment / origin.
| Author / study | Study / system type | Classification structure | Anatomical focus | Morphological scope |
|---|---|---|---|---|
| Daseler and Anson [1] | Large historical anatomical series | No dedicated numbered proximal-origin classification | General morphology, prevalence and anatomical variability of the plantaris muscle in 750 lower extremities | Historical population-based anatomical context |
| Freeman et al. [2] | Descriptive anatomical study | No formal numbered origin classification | Plantaris morphology and relationships with the lateral head of gastrocnemius and patellar region | Descriptive assessment of gastrocnemius interdigitations and fibrous patellar extensions |
| Nayak et al. [3] | Formal three-type classification | Three origin types | Combinations of the lateral supracondylar ridge, knee joint capsule, lateral head of gastrocnemius and fibular collateral ligament | Classification based on combinations of proximal attachment structures |
| Olewnik et al. [4] | Formal six-type classification | Six principal types; Type I subdivided into IA and IB | Femoral, capsular, gastrocnemius-related and iliotibial-band-related proximal attachments | Classification based on combinations of structures forming the proximal attachment |
| Lee et al. [5] | Formal three-type classification | Three origin types | Proximal attachment sites and anatomical relationship with the lateral head of gastrocnemius | Classification emphasizing attachment to and blending with the lateral head of gastrocnemius |
Nayak et al. Three-Type Proximal Attachment Classification
Table 2. Nayak et al. three-type proximal attachment classification.
| Nayak type | Proximal attachment pattern | n / 52 lower limbs | Reported frequency |
|---|---|---|---|
| Type I | Lateral supracondylar ridge + knee joint capsule + lateral head of gastrocnemius | 38/52 | 73.07% |
| Type II | Knee joint capsule + lateral head of gastrocnemius | 3/52 | 5.76% |
| Type III | Lateral supracondylar ridge + knee joint capsule + lateral head of gastrocnemius + fibular collateral ligament | 7/52 | 13.46% |
| Absent plantaris | Plantaris muscle absent | 4/52 | 7.69% |
Nayak et al. [3] reported frequencies using all 52 dissected lower limbs as the denominator. The absence row is included for denominator transparency and does not represent an origin type.
Olewnik et al. Proximal Attachment Classification
Table 3. Olewnik et al. proximal attachment classification of the plantaris muscle.
| Olewnik proximal type | Proximal attachment pattern | n / 128 present plantaris muscles | Frequency |
|---|---|---|---|
| Type IA | Lateral head of gastrocnemius + lateral femoral condyle + knee joint capsule | 51/128 | 39.8% |
| Type IB | Lateral head of gastrocnemius + lateral femoral condyle + knee joint capsule + popliteal surface of the femur | 11/128 | 8.6% |
| Type II | Knee joint capsule, with indirect attachment to the lateral head of gastrocnemius through the lateral femoral condyle | 32/128 | 25.0% |
| Type III | Lateral femoral condyle + knee joint capsule | 13/128 | 10.15% |
| Type IV | Lateral femoral condyle + knee joint capsule + iliotibial band | 8/128 | 6.25% |
| Type V | Lateral femoral condyle only | 11/128 | 8.6% |
| Type VI | Rare cases | 2/128 | 1.6% |
Frequencies refer to the 128 lower limbs in which the plantaris muscle was present, not to the total dissected material of 142 lower limbs. [4]
Lee et al. Three-Type Proximal Attachment Classification
Table 4. Lee et al. three-type proximal attachment classification of the plantaris muscle.
| Lee origin type | Proximal attachment pattern | Relationship with lateral head of gastrocnemius | n | Published frequency among 154 evaluable lower limbs | Calculated frequency among 140 classifiable origins |
|---|---|---|---|---|---|
| Type 1 | Lateral supracondylar ridge + lateral femoral condyle + knee joint capsule | Attachment to the lateral head of gastrocnemius; plantaris muscle fibres blend with its tendon | 105 | 68.18% | 75.00% |
| Type 2 | Knee joint capsule + popliteal surface + lateral femoral condyle | Attachment to the lateral head of gastrocnemius without blending with its tendon | 27 | 17.53% | 19.29% |
| Type 3 | Popliteal surface immediately superior to the lateral femoral condyle + knee joint capsule | No attachment or connection to the lateral head of gastrocnemius | 8 | 5.19% | 5.71% |
Lee et al. [5] examined 160 lower limbs. The plantaris muscle was present in 146 limbs (91.25%) and absent in 14 limbs (8.75%). Six plantaris origins were damaged during dissection, leaving 154 evaluable lower limbs for the published frequency analysis and 140 present, classifiable plantaris origins.
The published frequencies for Types 1-3 were calculated using 154 evaluable lower limbs as the denominator. The additional frequencies shown in the final column were calculated by VARIANTIS using the 140 present and classifiable plantaris origins as the denominator.
The article reports Type 3 as 5.19% in the Abstract and Results, whereas Table 3 lists 5.16%. Based on the reported count of 8 cases among 154 evaluable lower limbs, the calculated value is 5.19%.
Boundary with Rare Proximal Configurations
Rare multibelly and accessory-head configurations represent a different morphological dimension from population-based classifications of proximal attachment and are documented separately in the Rare and Case-Based Variants section.
Where a rare configuration has a clearly identifiable proximal attachment pattern, that attachment may be described using an applicable published classification, while the multibelly or accessory-head morphology itself should be recorded separately.
Key Classification Points
- Origin and proximal attachment are used as equivalent anatomical terms on this page and represent a different anatomical domain from tendon course and distal attachment / insertion.
- Daseler and Anson [1] provide historical population-level anatomical context, while Freeman et al. [2] provide descriptive observations of plantaris variation without establishing formally numbered proximal-origin classifications.
- Nayak et al. [3], Olewnik et al. [4] and Lee et al. [5] proposed formal adult classifications of plantaris origin using different anatomical criteria and classification structures.
- Type labels are specific to the classification system in which they were defined and should therefore be interpreted together with the cited author and system.
- Rare multibelly and accessory-head configurations should be documented separately from population-based proximal attachment classifications.
References
1. Daseler EH, Anson BJ. The plantaris muscle: an anatomical study of 750 specimens. J Bone Joint Surg Am. 1943;25:822-827.
2. Freeman AJ, Jacobson NA, Fogg QA. Anatomical variations of the plantaris muscle and a potential role in patellofemoral pain syndrome. Clin Anat. 2008;21(2):178-181. doi:10.1002/ca.20594.
3. Nayak SR, Krishnamurthy A, Ramanathan L, Ranade AV, Prabhu LV, Jiji PJ, Rai R, Chettiar GK, Potu BK. Anatomy of plantaris muscle: a study in adult Indians. Clin Ter. 2010;161(3):249-252. PMID:20589356.
4. Olewnik L, Kurtys K, Gonera B, Podgorski M, Sibinski M, Polguj M. Proposal for a new classification of plantaris muscle origin and its potential effect on the knee joint. Ann Anat. 2020;231:151506. doi:10.1016/j.aanat.2020.151506.
5. Lee H, Heo Y, Kim D, Hwang SJ. Morphological classification of the plantaris muscle origin: a cadaveric study. Sci Rep. 2025;15:38527. doi:10.1038/s41598-025-18762-9.
VARIANTIS. Plantaris muscle: proximal attachment classification. In: VARIANTIS Encyclopedia of Human Anatomical Variation [Internet]. 2026 [cited 2026 Aug 27]. Available from: View entry URL
VARIANTIS (2026) ‘Plantaris muscle: proximal attachment classification’. VARIANTIS Encyclopedia of Human Anatomical Variation. Available at: View entry URL (Accessed: 27 August 2026).
VARIANTIS, ‘Plantaris muscle: proximal attachment classification’, VARIANTIS Encyclopedia of Human Anatomical Variation (2026), View entry URL [accessed 27 August 2026].