- See: Iliotibial Band Syndrome

- General Anatomy:
    - origin:
         - anterior iliac crest outer lip, anterior border of the ilium, outer surface of anterior superior iliac spine;
    - insertion:
         - iliotibial band of fascia lata on lateroanterior aspect of thigh, about 1/3 of the way down;
         - inserts proximally into the lateral epicondyle of the femur then passes in its broad expansion between lateral aspect of patella;
         - inserts distally on gerdy's tubercle: on the lateral aspect of tibia tubercle;
    - action:
         - thigh flexion at the hip, abduction, and medial rotation;
         - stabilizes the knee laterally;
         - iliotibial band moves forward in extension and backward in flexion but is tense in both positions;
         - during flexion iliotibial band,  popliteus  tendon, and LCL cross each other, whereas iliotibial band and biceps tendon remain
                   parallel to each other as  in extension, all serving to enhance lateral stability;
         - in addition to lateral ligaments and lateral capsular structures, stability is significantly dependent on iliotibial band, biceps
                  tendon, and the popliteus tendon;
                  - w/ flexion of iliotibial band, the popliteus tendon, & LCL cross each other, therby greatly enhancing lateral stability;
                 - it thus acts as a supplement ligament across lateral aspect of joint
    - synergists: medius, minimus, & upper fibers of maximus;
    - nerve supply:
         - TFL is innervated by superior gluteal nerve (L4, L5, S1), which enters muscle just slightly superior to the transverse br of  LFCA;
         - sensation to the overlying skin is provided by two sources;
                - predominate supply is from the lateral femoral cutaneous nerve;
                - superior portion of the skin cephalad to the greataer trochanter is innervated by the lateral cut br of T12;
    - arterial supply:
         - ascending branch of LFCA  & superior gluteal artery;
         - arterial supply to the TFL is thru the transverse branch of lateral femoral circumflex artery, which is usually a single branch
                  coming from profunda femoris system;
         - artery enters substance of the muscle belly proximally, ordinarily at point 6 to 10 cm below the anterior sup iliac spine;
         - TFL is drained by one or two venae comitates accompanying proximal arterial blood supply; 

- External Snapping Syndrome of the Hip: (external coxa saltans) (as opposed to internal snapping hip)
    - usually caused by the thickened posterior border of iliotibial band or anterior border of maximus muscle near its insertion;
    - band is posterior to greater trochanter (w/ hip extended) and skips anteriorly over greater trochanter with hip flexion;
    - tense fasical band catches as it slides over superior margins of greater troch as hip is flexed, adducted, or internally rotated;
    - snapping may also occur from iliopsoas tendon over bony prominence at the lesser trochanter;
    - initial treatment: IT band stretching 
    - references:
           - The Surgical Treatment of External Coxa Saltans (the Snapping Hip) by Z-plasty of the Iliotibial Band.
           - Snapping iliotibial band. Report of ten cases and review of the literature.    
           - The snapping hip. Treatment by Z-plasty.
           - Surgical technique: endoscopic gluteus maximus tendon release for external snapping hip syndrome.
           - Endoscopic iliotibial band release in snapping hip. 
           - Arthroscopic bursectomy with concomitant iliotibial band release for the treatment of recalcitrant trochanteric bursitis.
           - Focus on Hip Arthroscopy for Treatment of Periarticular disorders

- Contracture of the IT Band:
    - contracture of the IT band is common in CP and polio;
    - patients demonstrate flexion, abduction, and external rotation of the hip;
    - diff dx: abduction contracture;
    - exam:
           - Ober test:
                  - detects contracture of the iliotibial band;
                  - have pt lie on normal hip, with affect hip and knee flexed;
                  - hip is abducted and extended inorder to center the iliotibial band on the greater trochanter;
                  - then attempt to adduct the hip, which will be limited w/ contracture;
    - reference:
           - A new test for estimating iliotibial band contracture. 

- Tensor Fascia Lata Flap:
     - tensor fascia lata is an excellent choice for free tissue transfer since it is completely expendable and there other muscles that can
             serve for hip function;
             - flap may be innervated by taking lateral femoral cutaneous nerve
             - motor function is supplied by the superior gluteal motor branch;
     - cutaneous boundry of the TFL free flap is established by a line from ASIS to the lateral femoral condyle at the knee;
     - posterior border follows a line from the greater trochaner of the femur to the lateral femor condyle;
     - superiorly this flap can be taken of the iliac crest;
     - inferiorly it should stop within 5 to 8 cm of the joint;
     - TFL flap is elevated beginning distally and proceeding proximally

Functional differentiation within the tensor fasciae latae. A telemetered electromyographic analysis of its locomotor roles.

Long-term functional results in patients with anterolateral rotatory instability treated by iliotibial band transfer.

The iliotibial band friction syndrome. 

Upper extremity salvage using the tensor fascia lata flap: report of two cases.  

An Anatomic Study of the Iliotibial Tract.