Dr. Mike Marshall's Pitching Book: Chapter Eighteen

Coaching Baseball Pitchers: Chapter Eighteen By Michael G. Marshall, Ph.D. Copyright 2007
Chapter Eighteen:   Hand and Finger Joints
Hand Joint
1. Hand Bones

     a. Metacarpal Bones

     The hand has five metacarpal bones that articulate, on their proximal end, with the carpal bones of the wrist and, on their distal end, with the proximal phalanges of the five digits (fingers). The first metacarpal bone articulates with the first digit (thumb). The second metacarpal bone articulates with the second digit (index finger). The third metacarpal bone articulates with the third digit (middle finger). The fourth metacarpal bone articulates with the fourth digit (ring finger). The fifth metacarpal bone articulates with the fifth digit (little finger).

2. Hand Joint Kinesiological Actions

     The movement of the Metacarpal bones defines the kinesiological actions of the hand. The Metacarpals move closer together and farther apart.

     a. Metacarpal Abduction: When muscles contract that move Metacarpal bones farther apart.
     b. Metacarpal Adduction: When muscles contract that move Metacarpal bones closer together.

3. Hand Muscles

     The three Palmar Interossei muscles, the four Dorsal Interossei muscles and the four Lumbrical muscles make up the intermediate muscles of the hand.

     a. Plantar Interossei

     The first Plantar Interossei muscle attaches to the ulnar side of the Metacarpal II bone and to the ulnar side of the Proximal Phalange II bone. Therefore, when the first Plantar Interossei muscle contracts, these structures move closer together. This means that the first Plantar Interossei muscle moves the index finger toward the middle finger.

     The second Plantar Interossei muscle attaches the radial side of the Metacarpal IV bone and to the radial side of the Proximal Phalange IV bone. Therefore, when the second Plantar Interossei muscle contracts, these structures move closer together. This means that the second Plantar Interossei muscle moves the ring finger toward the middle finger.

     The third Plantar Interossei muscle attaches to the radial side of the Metacarpal V bone and to the radial side of the Proximal Phalange V bone. Therefore, when the third Plantar Interossei muscle contracts, these structures move closer together. This means that the third Plantar Interossei muscle moves the little finger toward the ring finger.

     b. Dorsal Interossei

     The first Dorsal Interossei muscle attaches to the adjacent sides of the Metacarpal I and Metacarpal II bones and to the radial side of the Proximal Phalange II bone. Therefore, when the first Dorsal Interossei muscle contracts, these structures move closer together. This means that the first Dorsal Interossei muscle moves the index finger toward the thumb.

     The second Dorsal Interossei muscle attaches to the adjacent sides of the Metacarpal II and Metacarpal III bones and to the radial side of the Proximal Phalange III bone. Therefore, when the first Dorsal Interossei muscle contracts, these structures move closer together. This means that the second Dorsal Interossei muscle moves the middle finger toward the index finger.

     The third Dorsal Interossei muscle attaches to the adjacent sides of the Metacarpal III and Metacarpal IV bones and to the ulnar side of the Proximal Phalange III bone. Therefore, when the first Dorsal Interossei muscle contracts, these structures move closer together. This means that the third Dorsal Interossei muscle moves the middle finger toward the ring finger.

     The fourth Dorsal Interossei muscle attaches to the adjacent sides of the Metacarpal IV and Metacarpal V bones and to the ulnar side of the Proximal Phalange IV bone. Therefore, when the fourth Dorsal Interossei muscle contracts, these structures move closer together. This means that the fourth Dorsal Interossei muscle moves the ring finger toward the little finger.

     c. Lumbricales

     The first Lumbricales muscle attaches to the radial side of the tendon of the Flexor Digitorum Profundus muscle for second digit (index finger) and to the tendon of the Extensor Digitorum muscle at the base of the Proximal Phalange II. Therefore, when the first Lumbricales muscle contracts, these structures move closer together. This means that the first Lumbricales muscle moves the index finger toward the thumb.

     The second Lumbricales muscle attaches to the radial side of the tendon of the Flexor Digitorum Profundus muscle for third digit (middle finger) and to the tendon of the Extensor Digitorum muscle at the base of the Proximal Phalange III. Therefore, when the second Lumbricales muscle contracts, these structures move closer together. This means that the second Lumbricales muscle moves the middle finger toward the index finger.

     The third Lumbricales muscle attaches to the radial side of the tendon of the Flexor Digitorum Profundus muscle for fourth digit (ring finger) and to the tendon of the Extensor Digitorum muscle at the base of the Proximal Phalange IV. Therefore, when the third Lumbricales muscle contracts, these structures move closer together. This means that the third Lumbricales muscle moves the ring finger toward the middle finger.

     The fourth Lumbricales muscle attaches to the radial side of the tendon of the Flexor Digitorum Profundus muscle for fifth digit (little finger) and to the tendon of the Extensor Digitorum muscle at the base of the Proximal Phalange V. Therefore, when the fourth Lumbricales muscle contracts, these structures move closer together. This means that the fourth Lumbricales muscle moves the little finger toward the ring finger.

4. The Kinesiological Actions of the Hand Joint During the Marshall Baseball Pitching Motion

     To achieve high spin velocities with my Maxline True Screwball, Maxline Fastball Sinker, Maxline Pronation Curve and Torque Fastball Slider, my baseball pitchers have to squeeze the baseball tightly between their middle and index fingers. Therefore, during the acceleration phase of the Marshall baseball pitching motion, to provide the oppositional force to the middle finger, the muscles that mioanglosly abduct the ring finger must maximally contact.

     During the deceleration phase of the Marshall baseball pitching motion, to recover from their maximal contraction during the acceleration phase, the muscles that abduct must relax.

Finger Joints
1. Finger Bones

     a. Proximal, Middle and Distal Phalange Bones

     All five digits has Proximal Phalange bones that articulate with Metacarpal bones. However, only the four medial digits have Middle Phalange bones that articulate with Proximal Phalange bones. All five digits have Distal Phalange bones, but only in the four medial digits do they articulate with Middle Phalange bones. The Distal Phalange of the first digit (thumb) articulates with its Proximal Phalange bone.

2. Finger Joint Kinesiological Actions

     The movement of the Phalanges define the kinesiological actions of the fingers. The anterior and posterior surfaces of the fingers move closer to each other or away from each other.

     a. Finger Joint Extension: When muscles contract to move the anterior surfaces of the fingers move away from each other.
         2) Finger Joint Flexion: When muscles contract to move the anterior surfaces of the fingers closer to each other.

2. Finger Joint Muscles

     On one end, Finger Joint muscles attach to the Middle or Distal Phalanges.

     a. Flexor Digitorum Superficialis

     The Flexor Digitorum Superficialis muscle attaches to the lateral surfaces of the Middle Phalange II, III, IV and V bones and to the medial epicondyle of the Humerus bone, to the coronoid process of the Ulna bone and to the oblique line of the Radius bone. Therefore, when the Flexor Digitorum Superficialis muscle contracts, these structures move closer together. This means that the Flexor Digitorum Superficialis muscle flexes the Finger Joints.

     Because, during the acceleration phase of the baseball pitching motion, baseball pitchers must powerfully drive the tips of their index and middle fingers through the baseball, the Flexor Digitorum Superficialis muscle flexes Middle Phalanges II and III bones.

     b. Flexor Digitorum Profundus

     The Flexor Digitorum Profundus muscle attaches to the lateral surfaces of the Distal Phalange II, III, IV and V bones and to the medial and anterior surfaces of the Ulna bone, to the interosseus membrane and to the deep fascia of the forearm. Therefore, when the Flexor Digitorum Profundus muscle contracts, these structures move closer together. This means that the Flexor Digitorum Profundus muscle flexes the Finger Joints.

     Because, during the acceleration phase of the baseball pitching motion, baseball pitchers must powerfully drive the tips of their index and middle fingers through the baseball, the Flexor Digitorum Produndus muscle flexes Distal Phalanges II and III bones.

     c. Extensor Digitorum

     The Extensor Digitorum muscle attaches to the lateral and posterior surfaces of the Distal Phalange II, III, IV and V bones and, by a common extensor tendon, to the lateral epicondyle of the Humerus bone and to the intermuscular septa. Therefore, when the Extensor Digitorum muscle contracts, these structures move closer together. This means that the Extensor Digitorum muscle extends the Finger Joints.

     Because, during the deceleration phase of the baseball pitching motion, baseball pitchers must safely return the Distal Phalange II, III, IV and V to their normal resting position, the Extensor Digitorum muscle extends the Distal Phalanges II, III, IV and V bones.

4. The Kinesiological Actions of the Finger Jointss During the Marshall Baseball Pitching Motion

     a. Maxline Fastball

     During the acceleration phase of the Marshall baseball pitching motion for my Maxline Fastball, baseball pitchers need to powerfully mioanglosly flex their index and middle fingers.

     During the deceleration phase of the Marshall baseball pitching motion for my Maxline Fastball, to safely decelerate and stop the powerful flexion of their index and middle fingers through release, baseball pitchers need to powerfully plioanglosly extend their index and middle fingers.

     b. Maxline True Screwball

     During the acceleration phase of the Marshall baseball pitching motion for my Maxline Fastball, baseball pitchers need to powerfully mioanglosly flex their index and middle fingers horizontally through the top seam of the baseball.

     During the deceleration phase of the Marshall baseball pitching motion for my Maxline Fastball, to safely decelerate and stop the powerful index and middle finger flexion through release, baseball pitchers need to powerfully plioanglosly extend their index and middle fingers.

     c. Maxline Pronation Curve

     During the acceleration phase of the Marshall baseball pitching motion for my Maxline Fastball, baseball pitchers need to powerfully mioanglosly drive the ring finger side of their middle finger through the top seam of the baseball.

     During the deceleration phase of the Marshall baseball pitching motion for my Maxline Fastball, to safely decelerate and stop the powerful middle finger metacarpal abduction through release, baseball pitchers need to relax these abductor muscles.

     d. Torque Fastball

     During the acceleration phase of the Marshall baseball pitching motion for my Torque Fastball, to drive the index and middle fingers of their pitching hand inside of vertical through release, baseball pitchers need to powerfully mioanglosly flex their index and middle fingers.

     During the deceleration phase of the Marshall baseball pitching motion for my Torque Fastball, to safely decelerate and stop the index and middle finger flexion through release, baseball pitchers need to plioanglosly extend their index and middle fingers.

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