Understanding Hand Exercise & Grip Strength – (Part 2) The 9 Muscles That Open The Hand

Hello again. It’s Dr. Terry Zachary here. And I am the developer of Handmaster Plus.

In order to understand the proper process of exercising the hands and strengthening the grip, we must take a closer look at the location, structure, and function of all of the hand muscles. Nowhere else in the body is the function of ‘like’ muscles so misunderstood… and so neglected.

The performance of grip is a basic vital skill throughout many facets of life including sports, music, the workplace, and hobby. It cannot be overlooked.

Later in this series, we will show the reader that proper hand exercise may also be vital even in relation to your entire health and wellness. That may sound absurd now, but please read on… Our dismissive beliefs of hand exercise are deeply ingrained.

For those readers who prefer NOT to get into the details of the layout of the hand muscles, rest assured, they are rather simple:
There are 18.
9 muscles open the hand.
9 muscles close the hand.
The muscles that open the hand are generally on the ‘back’ of the hand, wrist, carpal tunnel, forearm, and elbow.
The muscles that close the hand are generally on the ‘front’ of the hand, wrist, carpal tunnel, forearm, and elbow.
If that’s all you remember, that’s enough. You’ll never train grip or hand muscles wrong again.

In Part 1 of this educational series ‘Understanding Hand Exercise & Grip’, we looked at the ‘9 Muscles That Close the Hand.’

In a similar fashion (and a similar pattern) we will now explore the lesser celebrated ‘9 Muscles That Open the Hand.’ These 9, in essence, have been neglected in most hand training protocols for over 5 decades, a fact that may contribute to more finger, thumb, hand, wrist, carpal tunnel, forearm and elbow problems than any other single underlying ingredient of cause.

The health and fitness effects due to improper (or of poorly delivered) hand training cannot be overstated. Hand muscles attach at the front AND back and therefore affect the: 1) fingers, 2) thumb, 3) hand, 4) wrist, 5) carpal tunnel, 6) forearm & 7) elbow.

In an effort to illustrate the organization and wide reach of the pattern of muscles that control your hands, let me very basically review ‘The 9 Muscles That Open the Hand,’ and compare them to ‘The 9 Muscles That Close the Hand.’ This way the reader can understand for himself or herself the potential ‘effects’ of hand muscle imbalance, especially when hand muscle imbalance becomes chronic.

By nature, the intricacy and organization of hand muscles and their movements are miraculous. When we train them, we must respect what we learn if we expect to be at and perform at our best.

Without further adieu, the ‘9 Muscles That Open the Hand’ (and their attachment points):

finger grip extensor muscles

finger & thumb extensor muscles for grip

1. Dorsal interosseous – Originate at the metacarpals (hand), insert at the base of the proximal phalanges 2,3,4 (fingers).
2. Abductor pollicus longus – Originates at the radius, ulna and interosseous membrane (forearm), inserts at the distal phalanx of the thumb.
3. Extensor pollicus longus – Originates at the ulna and interosseous membrane (forearm), inserts at the distal phalanx of the thumb.
4. Extensor pollicus brevis– Originates at the radius and interosseous membrane (forearm), inserts at the proximal phalanx of the thumb.
5. Extensor digitorum – Originates at the lateral epicondyle of the humerus via the common extensor tendon (elbow), inserts into the middle phalanges of the 4 fingers.
6. Extensor digiti minimi – Originates at the lateral epicondyle of the humerus via the common extensor tendon (elbow), inserts into the extensor expansion of the little finger.
7. Extensor indicis – Originates at the ulna and interosseous membrane (forearm), inserts at the extensor expansion of the index finger.
8. Abductor digiti minimi– Originates at the pisiform bone (wrist/carpal tunnel), inserts at the proximal phalanx of the pinky finger.
9. Abductor pollicis brevis – Originates at the transverse carpal ligament (carpal tunnel), inserts into the proximal phalanx of the thumb.

hand opening muscles

some of the intrinsic muscles that open the hand

Notice again, mirroring the path of the 9 muscles that close the hand, that the 9 muscles that open the hand attach at the fingers, thumb, hand, wrist, carpal tunnel, forearm, and elbow and will, therefore, have some effect on each of these joints or structures.to

How often do you close your hand during your daily work, hobby, music or sports pursuits? How often do you open? Repetitive gripping (or repetitive flexion) is a fact of life. It’s not a fair fight. The muscles that close the hand are at great risk of becoming dominant over the muscles that open the hands.

If you remember only 1 concept from Parts 1 & 2 of this educational series on hand strengthening and grip, let it be this:
‘9 muscles open the hand.
9 muscles close the hand.’

In later posts in this series, we will show how this chronic imbalance of the 18 hand muscles leads to joint and structure instability throughout the entire distal upper extremity, as well as circulation and lymphatic drainage concerns.

For our next post in this series, I’d like to explain something that is not well known to many: The Kinetic Chain of Grip. In other words, we’ll show you what muscles combine to allow you to grip and use your fingers. Once you understand this, the whole games changes.

Dr. Terry Zachary is an advocate for proper and complete hand exercise & grip strength training in sports, music, the workplace, modern computer, electronics/gaming/esports, therapy/rehab/wellness, and hobby. Dr. Zachary discovered that repetitive gripping imbalances have gone under the radar as a cause of muscle imbalance, weakness, poor blood flow, and poor lymph drainage for over 5 decades. He developed Handmaster Plus to provide the world with fast, easy and complete hand training to create maximum strength, balance, performance, and overall health. The result is healthy, stable fingers, thumbs, wrists, carpal tunnels, forearms, and elbows… and healthier lives.

Dr. Zachary can be reached at terry@doczac.com. For information on Handmaster Plus, visit www.handmasterplus.com