Gluteus Medius-The Neglected One-MRI

53 yr old  lady with chronic pain right hip region with no  trauma, shows  ill-defined ,irregular , edematous foci  in the  tendon insertion region of greater  tuberosity, with possible fatty degeneration of muscle belly and no avulsion fracture. Gluteus minimus also shows similar features suggesting strain of glutei possibly responsible.

Teaching points by Dr MGK Murthy.

1. Gluteus medius originates from outer surface of ilium and gluteal aponeurosis and inserts on to oblique  ridge  on the  lateral surface  of greater trochanter. A bursa separates  the tendon from the surface of the trochanter, over which it glides  for various functions. When the leg is straight it  abducts , when the hip is flexed internally rotates, when the hip is extended externally rotates, all functions aided by minimus .
2. Dysfunction  of medius is best identified by positive Trendelenburg  test. Common cause( up to 46% in some series) of chronic backache, buttock pain  radiating to thigh
3. Muscle strain versus  tendinopathy versus  partial or complete tears  are a spectrum that needs to be analyzed on imaging. X- ray may play role in identifying the bony abnormalities including spurring and chips or calcifications. USG is helpful particularly  in cases of  bursal evaluation and  as  initial assessor  of the dysfunction. MRI is the gold standard for evaluating both medius and minimus , with regards to size of belly, musculotendinous junction, tendinous insertion, marrow abnormality of trochanter, soft tissue abnormality, associated findings in hip joint .