Fat Pad

A fat pad is a mass of closely packed fat cells surrounded by fibrous tissue septa. They may be extensively supplied with capillaries and nerve endings.

Examples are:

• Intraarticular fat pads. These are also covered by a layer of synovial cells. A fat pad sign is an elevation of the anterior and posterior fat pads of the elbow joint, and suggests the presence of an occult fracture.
• Buccal fat pad. It can be seen in nursing babies.
• The fat pad of the labia majora, which can be used as a graft, often as a so called "Martius labial fat pad graft", which can be used, for example, in urethrolysis.

Fat pad syndrome

This is a condition that we don't see too often, it's not specific to runners, triathletes, or training in general, but because it is often mis-diagnosed by doctors I thought it deserved a page of its own. It is basically a sore heel - the pain is concentrated over the centre of the heel and it feels like a deep bruise. Many doctors who don't see a lot of athletic injuries have never heard of Fat Pad Syndrome and, when confronted with pain in the heel region of the foot, will fall back on the diagnosis of 'plantar fascitis'. I have even seen patients who said their doctor never even looked at or touched their foot, they just wrote a prescription for orthotics and said they have a problem with 'heel spurs'.

The Anatomy

We were designed to function barefoot. While running shoes have added a lot of cushion and stability to our feet, we could basically run barefoot if we wanted (as evidenced by young Kenyans running in their native country or by Zola Budd who raced on the track barefoot). The natural design of the foot is incredible because not only are the bony arch and the plantar fascia created in such a way as to act as a shock absorber, but we also have about a 1 inch thick pad between our skin and the bone of the heel (the 'calcaneous') which acts as a cushion. This cushion is called a 'fat pad' because it's made up primarily of fatty tissue. The fat pad is kind of divided into sections by ligamentous 'baffles' which help keep the fat pad from spreading out and thereby aid in keeping the cushion where it belongs - under the heel. Occasionally, the heel can get injured and these baffles can become stretched and then the fat pad spreads out and we lose some of that cushion - which can make weight bearing very uncomfortable. Fortunately, it is treatable.

Signs and Symptoms

• Pain in the heel, usually on the middle of the heel. This is in direct contrast to plantar fascia pain or heel spur pain which is present at the front of the heel, not the middle.

• Pain is usually a deep, dull ache that feels like a bruise.

• Pressing with your thumb into the centre of the heel should re-create the pain.

• Condition can often be attributed to a blow to the heel - landing hard while barefoot on a hard surface, jumping in dress shoes with a hard heel, stepping on a stone while running.

• Pain is aggravated by walking barefoot on hard surfaces like ceramic tile, concrete, hardwood floors, etc.