Monday, 2 February 2015

Vastus Intermedius : 1 of 4 QUADS

We're DONE the Adductors and we're starting a New Muscle Group! :
The QUADRICEPS FEMORIS (better know as your QUADS) and guess what? There are FOUR of them :) And Femoris is simply referring to your thigh bone - your Femur -where they live!

Let's start with the Deepest of the four: Vastus Intermedius

If you were to look at your thigh right now you wouldn't see Vastus Intermedius, not only is it hiding under Rectus Femoris (a special quad -coming soon!), it's also wedged between ("inter") and can even blend into its' Quad neighbours (Vastus Lateralis & Medialis - also coming soon!)

Muscle Attachment Points:

Origin: Anterior & Lateral surfaces of the Femur (thigh bone) AND the lateral lip of the linea aspera of the femur*.
Insertion:  tibial tuberosity via the patellar ligament**

*there is a ridge on your femur called the "linea aspera", many muscle attach on various aspects of it. When I say "lateral lip" of the linea aspera, it simply means the "outside edge" of the ridge. ((whereas Medial lip would be the INSIDE edge.))
**The tibial tuberosity is that bump just under your knee. ALL the quads actually attach HERE - via the same tendon (patellar - which refers to the Knee and of course CROSSES the knee joint.

Muscle Action:
 extension of the leg at the knee joint.
(basically straightening the leg from a knee bent position.)

As we understand muscles and their attachment points more and more, we soon realize that said muscle's ACTIONS depend largely on WHICH joints they cross.  
Vastus Intermedius crosses the knee joint only.

You'd have a hard time KICKING a ball (or kicking anything) without  knee extension

Over the next few weeks we'll continue exploring the Quads! See you next Monday!