The hand, when vigorously applied in helping the fingers, again in turn needs a stable basis for its operation.
This basis is here needed at the wrist-joint, else the wrist-joint itself would give way upwards, under the stress of the reaction or recoil arising from the down-exertion of the hand and finger against the moving key. For this purpose of basis at the wrist-joint, the arm has to be employed; and it is available in six distinct ways. Succinctly stated, these are as follows:
The six ways of Arm-functioning:
The poised-arm element (balanced on the surface of the keys)
The forearm-rotation element
forearm weight
Whole arm weight
Forearm down-exertion added to the full weight and lastly
Upper arm forward-drive along with the forearm down-exertion (which is to be avoided)
Deltoid: Large shoulder muscle responsible for arm abduction.
Biceps Brachii: A two-headed muscle located on the upper arm that aids in elbow flexion.
Brachialis: A muscle beneath the biceps that assists in elbow flexion.
Brachioradialis: A forearm muscle that helps in flexing the elbow.
Flexor Carpi Radialis: A wrist flexor that helps in wrist abduction.
Extensor Carpi Radialis: Helps in extending and abducting the wrist.
Palmaris Longus: A thin muscle involved in flexing the hand.
Flexor Digitorum Superficialis: A muscle that helps in flexing the fingers.
Flexor Carpi Ulnaris: A muscle that flexes and adducts the wrist.
Flexor Pollicis Longus: A muscle that flexes the thumb.
Extensor Digiti Minimi: Extends the little finger.
Abductor Pollicis Brevis: Moves the thumb away from the hand.
Abductor Pollicis: Involved in thumb movement.
The anatomical diagram illustrates the muscles of the human arm, highlighting both the anterior and posterior views.
Anterior View (Left Side of the Image)** Posterior View (Right Side of the Image)
Deltoid: Shoulder muscle responsible for arm movement.
Triceps Brachii: A three-headed muscle on the back of the upper arm that extends the elbow.
Brachialis: Assists in elbow flexion.
Brachioradialis: Helps in forearm flexion.
Extensor Carpi Radialis Longus: Aids in wrist extension and abduction.
Anconeus: A small muscle that assists the triceps in elbow extension.
Extensor Carpi Radialis Brevis: Helps extend and abduct the wrist.
Extensor Digitorum: A muscle responsible for extending the fingers.
Extensor Carpi Ulnaris: Extends and adducts the wrist.
Abductor Pollicis Longus: Moves the thumb away from the hand.
Extensor Pollicis Brevis: Extends the thumb.
The diagram provides a clear view of the forearm and upper arm muscles, which play crucial roles in hand, wrist, and elbow movement.
The upper arm and forearm
The first two of these six ways of using the arm are invariably needed, whatever the nature of the passage they are compulsory.
Whereas the last four ways of applying the arm are needed only during the moment of key-descent.
The choice here depends on the tone required and these last four ways are therefore optional.
We will first consider the two required arm conditions which are
the poised arm which is also known as "balanced" on the surface of the keys
