4 things you may not know about human anatomy

Since Flemish anatomist Andreas Vesalius died on this day in 1564, our learning of modern human anatomy remains a lifelong commitment for most surgeons, researchers and educators.

Vesalius’ observations overturned misconceptions in anatomy that had prevailed for centuries – proving there is always more to discover in the human body.

“Now, more than ever, we are experiencing an exciting time for anatomical research and shaping the way the discipline is taught through new learning resources,” says Professor Jennifer Wilkinson-Berka, head of the School of Biomedical Sciences and leading vascular biologist.

“The School is at the forefront of this teaching and research through the Melbourne Academy of Surgical Anatomy (MASA).”

Today, in honour of Vesalius, is World Anatomy Day. And it’s a perfect time to marvel at some of the things your joints, ligaments and muscles can (and can’t) do.

You can take these four tests, learn the reasoning and see how MASA clinicians and academics use this knowledge to investigate new surgical and rehabilitation techniques.

1) TRY THIS Place your palm on the table, stretch out your fingers except for your middle finger, which you flex back into your palm. Now, try lifting each of your out-stretched fingers off the table. What happens?

YOUR ANATOMY The tendons that straighten your fingers are interconnected in the back of your hand. Your index and little finger have an additional muscle and tendon each for extension.

However, the middle and ring fingers have variable interconnections, which means they are variably affected by each other’s movement.

MASA EXPLANATION The interconnectivity and duplication for the index and little fingers of the extensor tendons provides a safe and reliable source of tendons for grafting elsewhere in the body, without negatively affecting finger function.

MASA investigates new surgical techniques and improves the understanding of the human body so that tissues, like these, can be put to even greater use.

2) TRY THIS With your hand fully relaxed, try to only flex the joint at the end of any one finger. Can you do it?

YOUR ANATOMY There is only one flexor tendon that is attached to the bone at the tip of your finger. Most people can’t flex this joint by itself.

But, with great effort, some people can, which indicates they most likely have a longer or larger area for their extensor tendons to attach on the other side of the finger. This helps restrain the other finger joints.

MASA EXPLANATION Understanding the anatomical basis of finger biomechanics is essential for surgically repairing an injured finger and returning it to full function.

MASA works to improve understanding of the very fine, detailed anatomy of regions like the finger, allowing up-to-date, accurate and clinically applicable anatomy to inform teaching and clinical practice.

3) TRY THIS Place your elbow on a table and try to lift a heavy object with your hand, with your palm facing the table. Keeping your elbow on the table. Can you lift the object without it rotating?

YOUR ANATOMY Lifting with your elbow touching the table limits the elbow flexion.

With a lighter weight, your muscles that only flex your elbow can do the job. However, with a heavier weight, a bigger muscle must be recruited.

This is the biceps brachii muscle, which is a supinator (rotator) of your forearm. In order for it to help lift the object by flexing your elbow, it must rotate as well. Watch as the thumb side of your hand rotates away from the table.

MASA EXPLANATION Surgical repair of avulsion injuries – pulling a tendon out of the bone – requires excellent anatomical knowledge. The biceps brachii muscle is vulnerable to avulsion at the elbow, particularly with heavy weight lifting.

MASA explores the anatomical basis of surgical techniques, the strength of surgical repairs and aids in the training of other health care providers needed to treat, rehabilitate and prevent such injuries.

4) TRY THIS Pretend to squeeze a softball in your fingers. While squeezing hard, slightly flex your wrist in the same direction as your finger movements. Look at the skin creases just before the palm at the end of your forearm. Do you have a prominent tendon that stands out? Some will, some won’t and some might only have it on one wrist.

YOUR ANATOMY This is a classic example of anatomical variation. Here, you are testing to see if you have a palmaris longus muscle, by forcing its tendon to stand out at the wrist.

This muscle is attached into a large flat sheet of tissue in the palm of our hand. It’s a muscle thought to selectively tighten that band, improving your grip on something you’re holding by more tightly conforming the palm to that object.

MASA EXPLANATION Awareness of anatomical variation is essential for many areas of health care – and treatment plans should be altered to suit the variation.

This could be as simple as not cutting a variant blood vessel during surgery, to completely changing the rehabilitation plan for an athlete.

MASA is constantly on the lookout for clinically-relevant variants, and is building one of the world’s largest databases of anatomical variations.

Banner: Getty Images