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Lateral gastrocnemius tendon

The lateral gastrocnemius tendon is the tendinous continuation of the lateral head of the gastrocnemius muscle, part of the triceps surae group. It originates from the posterior femoral condyle and converges with the medial gastrocnemius tendon, eventually joining the soleus tendon to form the Achilles tendon, which inserts into the calcaneus.

The lateral gastrocnemius tendon contributes to powerful plantarflexion of the foot and assists in knee flexion. It is important clinically because of its frequent involvement in calf strains (“tennis leg”), tendinopathy, and tears near the myotendinous junction.

Synonyms

  • Lateral head gastrocnemius tendon

  • Lateral calf tendon

  • Part of triceps surae tendon complex

Origin and Insertion

  • Origin: Posterior aspect of the lateral femoral condyle (via lateral gastrocnemius muscle fibers)

  • Course: Forms a tendinous continuation distally, blending with the medial gastrocnemius tendon and soleus tendon

  • Insertion: Contributes to the Achilles tendon, which inserts into the posterior surface of the calcaneus

Nerve Supply

  • Supplied by the tibial nerve (S1–S2) via its motor innervation to the gastrocnemius muscle

Arterial Supply

  • Sural branches of the popliteal artery

  • Posterior tibial artery branches

  • Contributions from the peroneal artery

Venous Drainage

  • Venous blood drains via the posterior tibial veins, peroneal veins, and into the popliteal vein

Function

  • Assists in plantarflexion of the ankle via the Achilles tendon

  • Contributes to knee flexion when the foot is dorsiflexed

  • Acts as part of the propulsive mechanism during walking, running, and jumping

  • Helps stabilize the posterior knee and ankle joints

Clinical Significance

  • Frequently injured in myotendinous junction tears (often associated with medial head tears → “tennis leg”)

  • Can be affected by tendinopathy, degeneration, or partial tears

  • Involved in Achilles tendon injuries, since it contributes to the tendon complex

  • Important in surgical repair of Achilles tendon ruptures, where tendon grafts or reconstructions may involve gastrocnemius tendon tissue

MRI Appearance

T1-weighted images:

  • Tendon appears as a low-signal (dark) linear structure

  • Surrounded by bright subcutaneous and intermuscular fat that provides contrast

T2-weighted images:

  • Normal tendon remains dark (low signal)

  • Tendinopathy, partial tears, or degeneration appear as bright focal signal changes within the tendon

STIR (Short Tau Inversion Recovery):

  • Normal tendon shows very low signal

  • Strains, tears, or inflammation appear as bright hyperintense regions within or around tendon

Proton Density Fat-Saturated (PD FS):

  • Tendon is dark (low signal)

  • Pathology (strain, microtear, paratenonitis) shows bright hyperintense signal

T1 Fat-Sat Post-Contrast:

  • Normal tendon shows minimal to no enhancement

  • Inflamed or injured tendon may show focal or diffuse enhancement, particularly around tendon sheath or in paratenonitis

CT Appearance

Non-Contrast CT:

  • Tendon appears as a linear soft tissue density extending from lateral femoral condyle toward Achilles tendon

  • Calcification may be present in chronic tendinopathy

  • Acute tears may show focal swelling or loss of tendon continuity

Post-Contrast CT:

  • Normal tendon does not enhance

  • Enhancement may be seen in surrounding soft tissues in cases of inflammation, infection, or neoplastic infiltration

  • Hematoma adjacent to tendon may appear as hyperdense or rim-enhancing collections

MRI images

Lateral gastrocnemius tendon sag cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

MRI images

Lateral gastrocnemius tendon sag cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000_00001

MRI images

Lateral gastrocnemius tendon axial cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

CT image

Lateral gastrocnemius tendon axial ct image

CT image

Lateral gastrocnemius tendon ct sagittal image