let’s take stock of … the lower limb !

Hello everybody! Since the number of daily readers (and followers) of my blog is (surprisingly) increasing day after day (Thank you everybody!), I thought it could be useful to take stock of some important posts I wrote about the lower limb. Let’s start from the top -the hip- and go down to the bottom -the ankle-, with 9 posts that got many views and some funny comments ūüôā

Obviously, since my PhD project is about a knee prosthesis, most of the posts (5 out of 9) are about the knee joint.¬†But in general I tried to give an overall view of some interesting topics related to the biomechanics of the lower limb. Enjoy! ūüôā

leg skeletal anatomythe Hip Joint: some hints

hammers, screws and Intramedullary nails

the Knee Bursae: some hints

the Meniscus: some hints

the Patella: some hints

Knee Alignment Conditions

Patellar Reflex

How many limbs do you actually perceive?

the Ankle Joint: some hints

the Knee Bursae: some hints

The bursae of the knee can be defined in a very simple way: they are fluid sacs, or synovial pockets. This second definition comes from the sinovial fluid that fills them.

Synovial fluid is¬†made of hyaluronic acid and lubricin, proteinases and collagenases. Its main functions are¬†reducing friction by lubricating the joint, absorbing shocks and properly “feeding” joint cartilage. In the case of the knee, the Knee Capsule encloses the Knee Cavity which is filled with synovial fluid.¬†Knee Bursae surround and sometimes communicate with the Knee Cavity, as we can see in the picture.

Usually Knee Bursae are thin-walled and represent the weak point of the joint. At the same time, their presence is really important since they enlarge the joint space. They can be grouped according to:

  • their characterization as¬†communicating¬†and¬†non-communicating¬†bursae. A communicating bursa is when a bursa is located adjacent to a joint, thus having the synovial membrane in communication with the joint itself.
  • their location (frontal, lateral, medial).

In pathological conditions, such as excessive local friction, infection, arthritides or direct trauma, fluid and debris collect within the bursa or fluid extends into the bursa from the adjacent joint. As a consequence, the walls of the bursa thicken as the bursal inflammation becomes longstanding. The term bursitis refers to pathological enlargement of the bursa. Clinically, bursitis mimics several peripheral joint and muscle abnormalities.


<–prepatellar bursitis

¬† ¬† ¬† ¬† ¬† elbow bursitis–>



sources: Wikipedia and this website