Andersson — Link

Reality: This depends on the type of Andersson Link dysfunction. If the patient has an anteriorly tilted pelvis (lordotic posture), the hamstrings are already long and weak. Stretching them further destroys the link. If the patient has a posteriorly tilted pelvis (flat back), the hamstrings are short and tight; stretching them restores the link.

What to do: Patient supine, hip and knee at 90°. Extend the knee. Interpretation: If knee extension is limited to less than 20 degrees from vertical, the hamstrings are pathologically short. This will pathologically pull the sacrum into counternutation via the Andersson Link. andersson link

Because the Andersson Link influences the curvature of the lumbar spine, a hypertonic (overly tight) link reduces the lumbar lordosis. A flattened lumbar spine increases intradiscal pressure on the posterior annulus fibrosus, potentially accelerating disc bulges or herniations (especially at L4-L5 or L5-S1). Reality: This depends on the type of Andersson

This is the reverse problem. In PHT, the hamstring tendon attachment at the ischial tuberosity becomes degenerative. Clinicians must address the Andersson Link here by looking at the sacrum. If the SI joint is hypomobile (stuck), it increases tension through the sacrotuberous ligament into the hamstring tendon, preventing healing. If the patient has a posteriorly tilted pelvis

Reality: While the biceps femoris attaches adjacent to the STL, some anatomists argue that the connection is via loose connective tissue and not a direct tendinous continuation. However, recent ultrasound and cadaveric studies (as of 2018-2023) have confirmed that there is significant myofascial continuity, making the "link" functionally real.

Clinically, you can test the Andersson Link with three simple steps.