Anatomy of the Iliotibial Band
The iliotibial band is merely a lateral expansion of the fascia lata and made up of three layers: superficial, middle and deep.
Superficial and middle layer: encloses the tensor fascia lata anchoring it to the iliac crest. These layers unite at the distal end of the tensor fascia lata to form a tendon for the muscle. These two united layers receives fibers from the gluteus maximus and runs down the lateral thigh. As it courses down the lateral thigh Fairclough et al (2006) found the Iliotibial band continuous with the strong lateral intermuscular septum, which was firmly anchored to the linea aspera of the femur. Evans (1979) found fibers from the lateral intermuscular septum form the horizontal fibers of the iliotibial band.
Distally, after coursing through the Biceps Femoris and Vastus Lateralis Godin et al (2017) found the distal attachments of the Iliotibial band to be:
- Proximal bundle: runs nearly transversely from the superficial Iliotibial band to the distal femur. Inserts on the proximal ridge of the distal femoral body, distal to the lateral intermuscular septum 53.6 mm proximal to the lateral epicondyle.
- Distal bundle: runs from the superficial Iliotibial band from a proximal and lateral to distal and medial direction inserting on to the supracondylar flare. This could be Kaplan fibers mentioned below under 'lateral femoral condyle and epicondyle'.
- Lateral femoral condyle and epicondyle: Herbst et al (2017) found transverse fibers from the deep layer of the ITB (Kaplan fibers) connect the superficial ITB to the distal femoral metaphysis and condyle. These authors also found accessory insertions of the deep iliotibial band located proximal and anterior to the lateral femoral epicondyle.Fairclough et al (2006) described the attachment of the ITB to the region of, or directly to, the lateral epicondyle as strong fibrous ‘tendonous’ strands and then more ‘ligamentous’ strands between the lateral epicondyle of the femur and Gerdy's tubercle on the tibia. Variable and indinstinct insertions from the capsulo-osseous layer are also attached to the lateral epicondyle.
- Capsulo-osseous layer: a distinct fascial portion of the deep Iliotibial band. Runs from just proximal to the lateral gastrocnemius tubercle to the lateral tibial tubercle*. Herbst et al (2017) found variable and indistinct attachments from this layer around the lateral femoral epicondyle. The capsulo-osseous layer is intimately related to the lateral knee capsule and the fascia surrounding the lateral gastrocnemius tendon and biceps femoris (Herbst et al 2017). Evans (1979) found additional attachments to the lateral meniscus.
- Gerdy tubercle: the superficial Iliotibial band attaches on to a wide area from Gerdy tubercle anteriorly to the anterolateral and lateral tibia posteriorly. Deep fibers of the Iliotibial band attach slightly posterior to Gerdy tubercle (Herbst et al 2017).
- Iliopatellar Band: attaches to the lateral aspect of the patella and patellar tendon. The distal edge of this portion forms the lateral patellotibial ligament, part of the lateral retinaculum. Merican et al (2009) found these fibers resist knee flexion and medial patella deviation.
*: The lateral tibial tubercle is located on the anterolateral aspect of the proximal tibia, between the Gerdy tubercle and the fibular head (Godin et al 2017).
Herbst et al (2017) failed to the find the anterior lateral ligament on dissection. These authors found the capsulo-osseous layer of the ITB and the mid-third capsular ligament both occupied anatomic locations that are similar to that of the anterior lateral ligament. This ligament is documented as resisting internal rotation of the tibia.
Fairclough et al (2006) found conversely to popular belief no bursa was found between the tendonous fibrous bands of the Iliotibial band and femur just adipose tissue.
Wilke et al (2016) found more distally the Iliotibial band connected strongly to the crural fascia which in itself was hardly seperable from the peroneal longus fascia.
Deep layer: The deep layer of the iliotibial band emerges where the superficial and middle layers fuse distal to the tensor fascia lata (Putzer et al 2017). From here it runs deep attaching to the vastus lateralis and rectus femoris fascia. Coursing deeper still it follows the iliofemoral ligament to attach to the supraacetabular fossa between the tendon of the reflected head of the rectus femoris and the hip joint capsule. It resists hip extension.
Williams (1879) gives a description of the attachment of the deep layer of the iliotibial band to the rectus femoris. He describes at a short distance below the insertion of the tensor fascia lata into the deep layer of the iliotibial band a strong process of fascia lata arises from the iliotibial band passing obliquely upwards and inwards to join the tendon of the rectus femoris at the junction of its two heads. It also spreads backwards over the outer surface enclosing the reflected head of the rectus femoris, to which it is very firmly adherent, being fixed above to the inferior gluteal line, anterior inferior iliac spine and below blending with the capsule of the joint. This band of fascia binds down the tendon of the reflected head of the rectus femoris and connects the two heads.
Additional muscular attachments to the Iliotibial band include:
· Vastus Lateralis (Becker et al 2010).
· Biceps Femoris.
· Tensor Fascia Lata.
· Gluteus Maximus.
Anatomy of the Tensor Fascia Lata
The Tensor Fascia Lata arises from the anterior part of the outer lip of the iliac crest; from the outer surface of the anterior superior iliac spine, and part of the outer border of the notch below it, between the gluteus medius and sartorius; and from the deep surface of the fascia lata.
It is inserted between the two layers of the iliotibial band at about the junction of the middle and upper third of the thigh.
Actions of the Tensor fascia Lata
Traditionally the Tensor Fascia Lata along with the more vertical anterior and middle fibers of the Gluteus Medius are involved in hip abduction holding the pelvis horizontal during the stance phase of the gait:
Heel strike: anterior fibers of the Gluteus Medius initiates initial abduction during the heel strike keeping the pelvis horizontal.
Mid-stance: Tensor Fascia Lata keeps the pelvis horizontal. Anterior rotation of the pelvis is achieved from the anterior fibers of the Gluteus Medius.
The hip joint is stabilised with the posterior fibers of the Gluteus Medius from heel strike to mid-stance and from the Gluteus Minimus from mid-stance to back stride (Gottschalk et al 1989).
The other actions of the Tensor Fascia Lata include very weak internal rotation and knee extension (Umehara et al 2015).
Stretching of the Iliotibial band
Fredericson et al (2002) found a hip adduction stretch with the subjects arms reaching over head (i.e full shoulder abduction and extension) increased the stretch on the Iliotibial Band. Wilhelm et al (2017) found that a similar stretch to this (without using the added leverage of the shoulder position) didn’t uniformly increase the stretch throughout the iliotibial band but did so most prominently in the proximal portion.
Evans (1979) found the deep layer of the iliotibial band resisted hip extension.
Kaplan and Emanuel (1958) suggested the tensor fasciae latae pulls the ITB anteriorly in [hip] flexion; the gluteus maximus pulls the ITB posteriorly in [hip] extension. These authors suggested the anchorage of the ilitobial band to the lateral intermuscular septum restricts this A-P movement.
Fairclough et al (2006) noted the tension of the distal part of the Iliotibial Band altered at different degrees of knee flexion:
Initial knee flexion: during initial knee flexion bands of the Iliotibial Band that attach to the patella come under tension as the patella rotates laterally.
Further knee flexion: as the knee is further flexed tension shifts from the anterior to posterior bundles of the Iliotibial Band possibly due to the attachments of the Biceps Femoris.
As the tibia moves posteriorly the capsulo-osseous layer of the iliotibial band comes under tension. Fairclough et al (2006) gave the impression this posterior movement was on progressive knee flexion not a posterior shunt of the tibia from knee extension.
Femoral attachments anchoring the Iliotibial band to the distal femur contributes to restraining tibial internal rotation (Godin et al 2017). Kittl et al (2016) reported that the distal Iliotibial band is the primary restraint to internal rotation between 30 and 90 of knee flexion. Herbst et al (2017) concurred with these findings determining the ITB is under greatest stretch resisting internal tibial rotation at 60 degs knee flexion.
Stretching of the Tensor Fascia Lata
Traditionally the Tensor Fascia Lata has been stretched using hip adduction/extension/external rotation.
Umehara et al (2015) found that hip adduction/extension with added knee flexion at >90 degs stretched the Tensor Facsia Lata more than adding hip external rotation. This was because the Tensor Fascia Lata very minimally if not at all was used for hip internal rotation.
This may explain why using knee flexion reduced the range of motion in hip adduction when performing Ober’s test (Gajdosik 2003)
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