Lateral and Medial Gastroc – Calf Anatomy
The main bulk of your calf anatomy is made up of the Gastroc. The Gastrocs or more correctly Gastrocnemius Muscles comprise of two parts (or heads) – the medial Gastroc and the lateral Gastroc.
Carefully look at the diagram on the left.
It shows the back of the right calf.
The medial Gastroc or Medial Head of Gastrocnemius is shaded blue and is situated on the inner side of the leg.
The lateral Gastroc or Lateral Head of Gastrocnemius is shaded purple and is found on the outer side of the leg.
Both Gastroc muscles blend with the Achilles Tendon which is central and shaded red in the diagram.
The deeper muscle (Soleus) is shaded yellow and lies underneath the Gastrocs and also blends into the Achilles tendon.
The Achilles Tendon attaches to the back of the Heel Bone – Calcaneum.
In this diagram the Red Dotted Line represents the joint line of the knee.
You can see that the Hamstring Muscles (in Green) are attached below the knee joint and the Gastroc Muscles attach above the Knee Joint Line to the back lower end of the Femur Bone.
So the Gastrocs cross BOTH the Knee and Ankle Joints.
This is an important factor in a Pulled Calf Muscle.
Injured Calf / Gastroc Muscle
There are various terms used by people to describe muscle injuries.
You will hear terms like ‘calf muscle strain’, ‘overstretched calf muscle’, ‘Gastroc strain’, ‘pulled Gastroc muscle’, ‘torn calf muscle’ etc.
These terms mean different things to different people.
If you look at the diagram you can see the complex arrangement of fibres in a muscle.
The tiny muscle fibres are arranged together in groups or bundles.
These bundles (fasciculi) are then grouped together to form bigger groups of fibres.
All these bundles have connective tissue surrounding them and this allows the action of the muscles to work through the tendon and produce movements.
The phrases ‘strains’, ‘pulls’ and ‘tears’ are better classified as different GRADES of strain:
Grades of Strain
GRADE ONE STRAIN – is damage to a few of the small fibres only – less than 5%
GRADE TWO STRAIN – is damage to many more fibres but there is not a complete tear of the muscle
GRADE THREE STRAIN – is a complete rupture of the muscle
Calf / Gastroc Strain (Grade 1 Strain)
With a Grade 1 strain of the Gastroc there is a sharp pain at the time of injury. It may be possible to localise the pain – put your finger on the spot. Sometimes because only a relatively few fibres are involved it may be possible to continue with running or your sport. The next day however there is considerable tightness and pain and it may be difficult to put your heel down and definitely difficult to raise up onto your toes on one leg or hop on the affected leg. There may even be some slight bruising appear after a few days. It generally takes 7 to 14 days to recover fully from a Grade 1 strain.
Pulled Calf / Gastroc Muscle (Grade 2 Strain)
Grade 2 strains of the Gastrocnemius involve many more fibres than a Grade 1 strain and as a result it is not possible to continue with running. The pain is immediate and sharp and you pull up instantaneously! There will always be bruising with a Grade 2 strain and it is painful if not impossible to put your heel down on the affected leg. Use of crutches is advisable as is use of a heel raise on both sides. Return to fitness after a Grade 2 strain is 2 to 3 weeks generally.
Torn Calf / Gastroc Muscle (Grade 3 Strain)
A Grade 3 strain happens at the junction between the muscle and the Achilles Tendon and presents just like a torn Achilles. There is immediate severe pain at the time and you can’t use the leg – the muscle does not work. On examination the is a gap in the muscle where it joins the tendon and the “squeeze” test is positive. Generally surgery is required with these injuries and recovery takes up to 6 months.
Pain in Back of Calf / Gastroc
There are other sources of pain that affect the back of the calf.
The most common is Sciatica which comes either from irritation of a nerve root in the lower back (for example a herniated lumber disc), or from irritation of the Sciatic Nerve itself as it passes through the buttock where it is irritated by a tight Piriformis muscle.
Another common cause is Cramp – which affects the muscle when it is fatigued and it goes into spasm. Causes of cramping may include low oxygen levels in the muscle (hypoxia0, dehydration, or low blood salt. Muscle cramps may also be a symptom or complication of pregnancy, kidney disease, thyroid disease, hypokalaemia (low potassium levels), hypomagnesaemia (low magnesium levels) or hypocalcaemia (low calcium levels), restless-leg syndrome and varicose veins
Gastroc / Gastrocnemius Muscle Tear
A Gastroc muscle tear can be partial or complete – the pain is immediate and it is impossible to continue with any activity.
A complete tear takes place at the musculo-tendinous junction where the Gastroc joins to the Achilles Tendon.
A complete tear is know as a Grade 3 Strain and a partial tear as a Grade 2 Strain – See Above.
Swollen Calf / Gastroc Muscle
A swollen calf can be due to a Grade 2 or 3 Strain of the Gastrocs and is due to the damage to the muscle fibres with blood and fluid leaking out of damaged vessels.
Another common cause of swelling in the calves is not due to trauma but to a condition affecting the veins in the calf – Varicose Veins.
Inflammation of the veins in the calf can also lead to swollen calves and this is called Phlebitis.
A serious swelling in the calf can occur when you suffer a DVT or Deep Vein Thrombosis and this is due to a clot forming deep in the calf. With a DVT the vein becomes blocked and the leg swells. The danger is if a part of the clot breaks away as it can become lodged in the vessels of the lung causing significant problems there.
You know have an understanding of
- the anatomy of the calf and posterior knee
- the structure of a muscles
- the different grades of strain in the Gastroc
- common sources of pain in the calf
- other conditions than can cause the calf to swell
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This entry was posted on Tuesday, October 19th, 2010 at 4:18 pm and is filed under Gastroc and Pain in Calf Muscles. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.