If you say “abs”, most people think of six-packs, the diet Coke man and sit-ups.
Image courtesy of imagerymajestic / FreeDigitalPhotos.net
In fact your abs are made up of a group of 4 muscles which wrap around your abdominal area like duct tape around a parcel: front to back, diagonally in a cross, and vertically.
Together they perform a whole range of functions:
Let's take a look at each of these 4 muscles.
The outermost layer of muscle, closest to the skin, are the external obliques.
Your external obliques run diagonally downwards and inwards (imagine putting your hands in the pockets of a pair of jeans - the direction of the muscle fibres runs in the same direction as your hands).
They start from the bottom of your lower 8 ribs and run diagonally down towards your pubis. Most of the muscle fibres of the external obliques attach at the aponeurosis running down the length of the strap-like rectus abdominis, though the lower fibres attach to the pubis itself.In fact they run from along the entire length of those ribs - so it’s like a large sheet starting from near your spine going all the way to your mid-line then running downwards and inwards.
The external obliques have a number of functions:
Directly underneath (that is, deep to) the external obliques are the internal obliques.
Like the external obliques which lie on top of (or superficially to) the internal obliques, these are a sheet of muscles which wrap around the body from front to back, running diagonally. Unlike the external obliques, the internal obliques run downwards and outwards, so that they take the shape of a roof on a house when looked at from the front.
They start along the ridge of your hip bone (called the iliac crest) and run upwards and inwards towards the aponeurosis of the rectus abdominis, with the outer fibres (technically, the lateral fibres) attaching to the front of the last 4 ribs).
The actions of the internal obliques are similar to, but subtly different from the external obliques:
If you’re familiar with Pilates then you’ll know about the transverse abdominis.
These are the deepest layer of abdominal muscles laying deep to the internal intercostals.
They start from the lumbar area of the back and wrap all the way around the body horizontally to join the aponeurosis of the rectus abdominis. Effectively, they’re a natural corset.
Because they wrap around the abdomen, the transverse abdominis are important postural muscles. They’re responsible for a number of different functions:
The most common abdominal muscle to get damaged - either through overtraining or straining (such as sneezing or coughing excessively) is the rectus abdominis, but it’s not rare for others like the transverse abdominis to be affected.
Some people with certain posture types are more prone to muscle strains there than others. Your remedial massage therapist needs to understand this, and also that your abs go all the way round to your back!
In a later blog post, I’ll get more geeky and talk briefly about how all of these muscles connect together at the aponeurosis.
As always, if you think I can help, give me a call.