Linea Alba – the aponeurosis of the ventral muscles

Today, we will have a closer look on another interesting structure of the body: Linea Alba.

There was an article about the linea alba on social media the other day, and I want to take a closer look at it:

Linea Alba, also called the white line that goes below the abdominal midline of the horse, is a ligamentous strand that begins at the sternum at the back of the sternum about 2 cm thick and passes to about 3 cm thick around the umbilicus (the umbilical cord of the horse) and ends at the prepubic tendon in the groin of the horse. This tendon attachment comes from two interesting muscles on the inside of the horse’s thighs and these are called Adductor and Pectineus. This means that Linea Alba can affect the hind leg step. If you have a horse that is short in the right rear, for example, you should check if there is tension in this ligament. How-to? Well you gently roll your fingertips along the tape and feel for knots or connective tissue.

You do small finger frictions to stretch the band then you can also back the horse afterwards. If you pull gently along your spine with your fingers so that the horse lowers your back, a stretch also occurs. Good luck” (translated from Swedish original)

To begin with the start and ending of the linea alba, which starts at the processus xiphoideus, at the bottom of the rib cage and ends at the symphysis pubica. It is part of an important stabilization system: the upper stabilization system which consists of the back of the neck and the neck plate, and the lower stabilization system consisting of the abdominal wall between the sternum and the pubic border with the linea alba.

The fibrous linea alba connects the aponeuroses of the right and left abdominal muscles in the midventral line. It begins at the sternum, where it is about 2 cm wide, encloses the umbilicus widening slightly (3 cm), and caudal to this is very narrow. It ends on the prepubic tendon.

The linea alba is not a ligament, and even if it would be, a ligament cannot have tensions, since it is lacking contractile elements such as skeletal muscles have.

The linea alba is an aponeurosis of the ventral muscles and plays a bigger role for the rectus sheath.  

I wonder also how a slight rubbing with two fingers across this ligament would help to resolve “knots” and “tensions” as the author postulates. The linea alba is 2-3 cm thick and I doubt that a thick layer of collagen-fiber-enriched tissue would show tensions and that a slight massage with two fingers would change anything.

I do not think either that a bending of the horse’s back downwards, forced by gliding along the spinal cord with your finger will stretch the linea alba in any way. This reaction of the horse is more a clear sign of uncomfortableness and maybe even pain. This method may be applied to understand if there are any tensions in the back muscles. But a stretching of the linea alba? Rather not. I therefore don’t recommend copying this maneuver.

You can though give a slight and careful massage to the transition from Linea Alba to the ventral muscles for releasing the tensions in this muscle group, if there are any.

The Linea Alba together with the neckband and the ligamentum superficialis dorsi can be seen as the stabilizer dorsal and ventral from the horse. You can consider the linea alba as the most ventral point of the equine body where all digestion organs rest on. This structure, you want fairly to be stable and not smooth and soft, right? A certain “tension” is natural and beneficial for the stability of the horse. 

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