Understanding Hand Exercise & Grip Strength – (Part 1) The 9 Muscles That Close The Hand

My name is Dr. Terry Zachary. I’ve been involved specifically in grip and hand muscle training for over 25 years. In applications ranging from sports, music, therapy, the workplace, hobby & modern electronics, I can’t say strongly enough how important I feel properly understood hand exercise is to your health, fitness, and performance.

Over these decades, my opinion of grip and hand strength training has changed substantially. Every year, through research, our group discovers more reasons why proper, complete hand muscle training is vital. The more we test, the more details we find. Learn the hand muscles and their vast reach and you will understand my passion.

In regard to the health & fitness culture, we tend to move onto training the biceps, triceps, shoulders, back, and chest – and so on – as our vital exercise focal points. Exercises in these historically popular areas have been demonstrated over and over for good reason. Yet not much consideration has been given to proper hand exercise and overall grip muscle training.

It serves anyone involved in grip related activities to study or reflect on the detailed and diverse attachment points and effects that the hand muscles have on the various joints and components of the upper extremity. If you are a healthcare or fitness professional, it is a good idea to review grip muscles regularly. If you are like I was, hand muscle anatomy can get away on you easily!

So what is it about the diverse hand muscles that have left them to be so carelessly dismissed from all upper extremity health and training concerns? They are a vital part of the fitness story, a vital part of the kinetic chain of grip and are depended on in the training room when addressing the entire upper body. The ‘hand grip’ is often the link of the user to the training weight or resistance in upper body training. Grip happens as a known kinetic chain.

9 Muscles Close the Hand

9 Muscles Close the Hand

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

If you depend on your hands in your daily routine, this is a subject you need to have a grasp on. Grip performance may seem adequate one day and be completely gone the next. Just ask any injured athlete in golf, tennis, hockey, baseball, and gymnastics to name a few. Or ask any musician, gamer or dental hygienist. These imbalances can be debilitating and life-altering.

In an effort to illustrate the diversity of the anatomical area that controls the hand, let us now very basically review ‘The 9 Muscles That Close the Hand’ and mention their general origin and insertion points to illustrate the diverse path of each muscle. This way the reader can see for him- or herself all the potential negative and positive ‘effects’ of hand exercise.

Hand Closing Muscles

1. Palmar interosseous – Originate at the metacarpals (hand), insert at the proximal phalanges (fingers).
2. Adductor pollicus– Originates at metacarpals (hand) and carpals (wrist), inserts at the proximal phalanx of the thumb.
3. Flexor digitorum superficialis – Originates at the medial epicondyle (elbow) of the humerus, and at the ulna and radius (forearm), inserts into middle phalanges of the 4 fingers.
4. Flexor digitorum profundus – Originates at the ulna and interosseous membrane between the ulna and radius (forearm), inserts into the distal phalanges of the 4 fingers.
5. Opponens digiti minimi – Originates on the transverse carpal ligament (the roof of the carpal tunnel), inserts at the metacarpal of the pinky finger.
6. Opponens pollicus – Originates on the transverse carpal ligament (carpal tunnel), inserts at the metacarpal of the thumb.
7. Flexor pollicus brevis – Originates at the transverse carpal ligament (carpal tunnel), trapezium, trapezoid & capitate bones (wrist), inserts at the proximal phalanx of the thumb.
8. Flexor digiti minimi – Originates at the transverse carpal ligament (carpal tunnel), inserts at the proximal phalanx of the pinky finger.
9. Flexor pollicis longus – Originates at the radius and interosseous membrane (forearm), inserts into the distal phalanx of the thumb.

Please note that many may add another muscle to the muscles that close the hand:
Palmaris brevis – Originates at the transverse carpal ligament (carpal tunnel) and palmar aponeurosis, inserts at the skin of the ulnar border of the hand.

As you can see in bold, the hand muscles as a whole have many diverse attachments throughout the upper extremity. They are far from simple. Thus, they will clearly have an effect on the health, stability, and performance of a diverse group of key joints and structures. Notice the diverse hand muscle attachment sites at the fingers, thumb, hand, wrist, carpal tunnel, forearm, and elbow. They have to affect the stability of all of these areas!

If you can picture these muscle paths, try to also imagine how many areas they cross as they ‘shorten’ when in use. More than anytime in history, we are a repetitive grip culture. We must be aware. These 9 muscles are regularly being shortened. Any structure that they connect to is currently becoming shortened and imbalanced …even though you likely don’t feel the problem… yet.

How will you respond?

Hand muscles clearly have diverse attachments and should be taken very seriously. They must be studied better. They must be understood better. And they must be included in all health and training protocols.

A review of the ‘9 Muscles That Open the Hand’ is next to follow in this blog post series. It’s about to get more interesting. And more complicated. And more important.

Thanks for reading!

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