title: MRI of the tibioastragalus anticus of Gruber muscle: a rare accessory muscle and normal anatomical variant.
abstract: We present the case of a 31-year-old man who sustained a hyperplantar flexion injury of his right ankle, and was evaluated using computed tomography and MRI to assess for osseous and ligamentous injury. The MRI and CT studies demonstrated a tibioastragalus anticus of Gruber (TAAG) muscle in the lower limb's anterior compartment. To our knowledge, the imaging of this muscle has not been previously described. The TAAG muscle arises from the lower third of the anterolateral tibia and the interosseous membrane. Its tendon passes laterally, deep to the tibialis anterior and extensor hallucis longus tendons, and inserts onto the anterior superolateral neck of the talus in a fan-like manner. Knowledge and recognition of this tendon are important for both diagnostic accuracy and surgical planning, and could potentially be used as a tendon transfer or graft in the appropriate clinical setting. The presence of this accessory muscle should not be confused with a pathological condition.
authors.affiliation: Imperial College Healthcare NHS Trust, London, UK. yberkowitz@nhs.net.|Imaging Department, 3rd Floor, QEQM, St Mary's Hospital, Praed Street, London, W2 1NY, UK. yberkowitz@nhs.net.
authors.forename: Yaron
authors.identifier: http://orcid.org/0000-0003-4195-169X
authors.initials: Y
authors.lastname: Berkowitz
authors.affiliation: Imperial College Healthcare NHS Trust, London, UK.
authors.forename: Nadeem
authors.initials: N
authors.lastname: Mushtaq
authors.affiliation: Imperial College Healthcare NHS Trust, London, UK.|Imaging Department, 3rd Floor, QEQM, St Mary's Hospital, Praed Street, London, W2 1NY, UK.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Amiras
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D033162:Incidental Findings; D008279:Magnetic Resonance Imaging; D008297:Male; D018482:Muscle, Skeletal / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D012016:Reference Values
keywords: Accessory muscle; Anterior compartment; Lower limb; Normal variant; Tibioastragalus anticus of Gruber; Tibioastragalus of Gruber