Achilles Watershed Area
What is a watershed
A watershed is not a garden water feature despite its name!
It is defined in the merriam-webster dictionary as “a crucial dividing point, line, or factor”.
The Achilles watershed area is the area where there is a decrease in blood supply in the tendon
between 3 and 6 cm up from the attachment to the calcaneum.
The blood supply is meant to come down from the musclotendinous junction at the top,
and up from the bony attachment to the heel at the bottom.
This is represented in the diagram opposite by the blue arrows.
The area in the middle (pink) has a lower supply – the Achilles watershed area – where most ruptures take place.
This was first described in 1959 by Lagergren & Lindholm who examined the blood vessels supplying the Achilles Tendon.
This was taken on a stage further by Carr and Norris in 1989 who injected a dye into the vessels of cadavers. They concluded “there was a reduction in both the number and mean relative area of vessels in the mid-section of the tendon.”
In 2000 Stein, Laprell, Tinnemeyer and Petersen used radioisotopes to measure the intra-vascular volume of the human Achilles tendon and concluded “When the tendon was divided into three regions, we found the lowest intravascular volume in the middle region (3–6 cm above the tendon insertion).”
All of these studies used cadavers and the average age of the cadavers was early 70′s!
There is a decrease in blood supply to the Achilles Tendon with increasing age so perhaps these subjects
are not the best for the projection of results onto a fit and healthy population of athletes.
Blood flow in chronic Achilles tendinopathy disputes Achilles Watershed Area
Aström in 1994 measured blood flow and reported a significantly lower tendon blood flow at the insertion (bottom end), but otherwise even vascular distribution – no Achilles watershed area in symptom-free individuals.
More recently in 2008 an article by Knobloch stated “we found that in symptomatic tendinopathy neovascularisation is associated with a significantly increased capillary blood flow in the Achilles tendon at the point of pain” This means that there is an increase in blood flow at the mid-portion area of the Achilles tendon when painful.
This entry was posted on Friday, November 19th, 2010 at 8:01 pm and is filed under Achilles Tendon / Calf, Achilles Tendon Injury - Achilles Tendonitis Injury, Pain and Repair. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.