During pitching, all muscles must function properly. However, to discuss all muscles requires too much space and reader's time. Therefore, I will discuss only thirty-six muscles that attach on one end to pitching arm's clavicle, scapula or humerus bones. Further, when discussing kinesiological joint actions, I will discuss only upper arm accelerations, forearm accelerations and decelerations. Recognize that plioanglosly acting deceleration muscles become mioanglosly acting recovery muscles. Transition muscles operate at controlled uniform velocities that eliminate injury concerns.

Chapter 8: Shoulder Girdle

a. Shoulder Girdle Bones

Scapulas are shoulder girdles' bones of interest. Because clavicles solidly join scapulas, clavicles are secondary shoulder girdles' bones of interest. Sternoclavicular and costoclavicular ligaments secure clavicles to manubriums and first rib costal cartilages, respectively. Clavicle/sternum joints have articular discs. Consequently, clavicles have medial motion ranges. Laterally, clavicles attach to scapular acromion processes. Two-part coracoclavicular and acromioclavicular ligaments secure clavicles to scapulas. Clavicle/scapula joints do not have articular discs. Therefore, clavicles do NOT have motion ranges.

Clavicle maintain scapulas at fixed distances from sternums. Therefore, scapulas cannot move closer to or farther away from sternums. However, scapulas can move up and down backs and around sides of rib cages. Consequently, shoulder girdles enjoy tremendous motion ranges.

Without question, scapulas' extreme motion ranges contribute greatly to pitching. Pitchers with longer clavicles have leverage advantages. Therefore, after surgery where doctors removed his clavicle's lateral one-third, when Washington Redskin quarterback Billy Kilmer requested rehabilitation help, I did not know how well his shoulder girdle would respond. Without complete clavicles, muscle actions have to stabilize scapulas' medial/lateral movement. Therefore, I eliminated his passing arm's medial/lateral movement.

In his next season's first game, Billy passed the Redskins to victory. Without his clavicle's lateral one-third, he passed the football powerfully and accurately. Unfortunately, his battered legs could not keep pace with his passing arm and indominable spirit for the whole season.

b. Other Shoulder Girdle Bones

Shoulder girdle muscles attach at one end to either clavicles or scapulas. Shoulder girdle muscles' other ends attach to vertebral column, rib or hip bones.
Vertebral columns have three sections; cervical, thoracic and lumbar. Seven cervical vertebrae make up the neck. Twelve ribs posteriorly attach to twelve thoracic vertebrae. Five lumbar vertebrae complete vertebral columns' distal ends.

Manubriums, bodies and xiphoid processes make up sternums. First ribs attach to sternums' manubriums. Ribs' two through seven attach to sternums' bodies. Xiphoid processes are cartilaginous tips that hang from sternums' bodies. Ribs' one through seven anteriorly attach to sternums. Costal cartilages attach to ribs seven, Ribs' eight, nine and ten attach to costal cartilages. Ribs' eleven and twelve float freely.

The sacrum, two ilium bones, two ischium bones and two pubis bones form circular hip structures. Below lumbar vertebrae, five fused sacral vertebrae make up sacrums. Bi-lateral sacroiliac ligaments stabilize sacrums with two ilium bones. Ilium bones are the largest of three bones that make up hips' two halves. Three bones fuse into acetabulums. Acetabulums are joint sockets that receive femur heads. Iliac crests form hips' superior limits. Ischium bones form hips' posterior/inferior limits. Humans sit on ischial tuberosities. Pubic ligaments anteriorly attach two pubis bones together.

c. Shoulder Girdle Kinesiological Actions

Scapular movements define shoulder girdle kinesiological actions. Scapulas move up and down, tilt toward front and back, rotate upward and downward and move away from and toward vertebral columns.

1. Abductions occur when shoulder girdle muscles contract to move scapulas away from vertebral columns.

2. Adductions occur when shoulder girdle muscles contract to move scapulas toward vertebral columns.

3. Backward Tilt occurs when shoulder girdle muscles contract to backwardly tilt scapulas' coracoid processes.

4. Forward Tilt occurs when shoulder girdle muscles contract to forwardly tilt scapulas' coracoid processes.

5. Depression occurs when shoulder girdle muscles contract to downwardly move scapulas.

6. Elevation occurs when shoulder girdle muscles contract to upwardly move scapulas.

7. Downward Rotation occurs when shoulder girdle muscles contract to downwardly rotate scapulas' acromion processes.

8. Upward Rotation occurs when shoulder girdle muscles contract to upwardly rotate scapulas' acromion processes.

d. Shoulder Girdle Muscles

Shoulder girdle muscles attach to scapulas from vertebral column, rib and hip bones.

1. Pectoralis Minor

Pectoralis minor muscles attach to scapulas' coracoid processes and superior surfaces of ribs' three through five (R3-R5). When pectoralis minor muscles contract, scapulas' coracoid processes and R3-R5s' anterior surfaces move closer together. Pectoralis minor muscles forwardly tilt, depress and downwardly rotate scapulas. During upper arm accelerations, pectoralis minor muscles forwardly tilt scapulas. Because upper arm accelerations depend on scapula stability against which upper arms generate toward home plate force, pectoralis minor muscles forwardly solidify scapulas' coracoid processes.

2. Serratus Anterior

Serratus anterior muscles attach to a groove along entire vertebral borders of scapula's internal surfaces and to lateral surfaces of ribs' one through nine (R1-R9). When serratus anterior muscles contract, scapulas' vertebral borders and R1-R9s' lateral surfaces move closer together. Serratus anterior muscles abduct scapulas. During upper arm accelerations, serratus anterior muscles powerfully abduct scapulas. Because upper arm accelerations depend on scapula stability against which upper arms generate toward home plate force, serratus anterior muscles forwardly solidify scapulas' coracoid processes.

3. Subclavius

Subclavius muscles attach to clavicles' inferior surfaces and to the anterior aspects of rib ones' (R1) superior borders. When subclavius muscles contract, clavicles and R1s move closer together. Subclavius muscles indirectly forwardly tilt, depress and downwardly rotate scapulas. During upper arm accelerations, subclavius muscles forwardly tilt scapulas. Because upper arm accelerations depend on scapula stability against which upper arms generate toward home plate force, subclavius muscles forwardly solidify scapulas' coracoid processes.

4. Latissimus Dorsi II

Latissimus dorsi II muscles attach to scapulas' inferior angles, to spinous processes of thoracic vertebraes' (T7-T12) seven through twelve, to posterior/superior surfaces of ribs' nine through twelve (R9-R12) and to iliac crests' superior surfaces. When latissimus dorsi II muscles contract, scapulas' inferior angles and iliac crests, T7-T12s and R9-R12s move closer together. Scapulas' inferior angles typically rests at thoracic vertebrae eight (T8) levels. Therefore, latissimus dorsi II muscles depress, adduct, downwardly rotate and backwardly tilt scapulas. During decelerations, latissimus dorsi II muscles powerfully depress, adduct, downwardly rotate and backwardly tilt scapulas.

Without powerful latissimus dorsi II muscles to decelerate pitching arms, pitchers cannot powerfully accelerate pitches. Eight percent of the population do not have latissimus dorsi II muscle attachments to scapulas' inferior angles. To diagnose whether persons have latissimus dorsi II muscles, have them place the back of their hands on their hips and forwardly move their elbows together. If scapulas' inferior angles backwardly protrude dramatically, then they do not have this muscle.

5. Levator Scapulae

Levator scapulae muscles attach to cervical vertebraes' one through four (C1-C4) transverse processes and to scapulas' vertebral borders from medial angles to spine roots. When levator scapulae muscles contract, scapulas' superior surfaces and C1-C4 move closer together. Scapulas' medial angles typically rest T2 levels. Therefore, levator scapulae muscles elevate, adduct, forwardly tilt and downwardly rotate scapulas. During accelerations, levator scapulae muscles mildly forwardly tilt scapulas. During decelerations, levator scapulae muscles mildly adduct and downwardly rotate scapulas.

6. Rhomboid Major and Minor

Rhomboid major and minor muscles attach to cervical vertebrae seven (C7), thoracic vertebrae one through five (T1-T5) spinous processes and to scapulas' vertebral borders from spine roots to inferior angles. When rhomboid major and minor muscles contract, scapulas and C7-T5 move closer together. Scapular spine roots typically rest at T4 levels. Therefore, rhomboid major and minor muscles adduct and downwardly rotate scapulas. During decelerations, rhomboid major and minor muscles powerfully adduct, depress and downwardly rotate scapulas.

7. Trapezius I

Trapezius I muscles attach to lateral one-third of clavicles' superior surfaces, skull's occipital protuberances, superior nuchal lines and cervical vertebraes' one through three (C1-C3). When trapezius I muscles contract, clavicles, occipital protuberances and C1-C3s move closer together. Trapezius I muscles upwardly rotate and elevate scapulas. During decelerations, trapezius I muscles adduct scapulas. Secretaries complain of muscle knots where shoulders meet necks. These are trapezius I muscle knots. Unsupported hanging arms stress trapezius I muscles.

8. Trapezius II

Trapezius II muscles attach to superior surfaces of scapulas' acromion processes and to transverse processes of cervical vertebraes' one through seven (C1-C7). When trapezius II muscles contract, scapulas' superior surfaces and C1-C7 transverse processes move closer together. Trapezius II muscles upwardly rotate, elevate and adduct scapulas. During decelerations, trapezius II muscles adduct scapulas.

9. Trapezius III

Trapezius III muscles attach to superior surfaces of scapula's spine and to transverse processes of thoracic vertebraes' one through five (T1-T5). Trapezius III muscles overlay rhomboid major and minor muscles. When trapezius III muscles contract, superior surfaces of scapular spines and T1-T5 transverse processes move closer together. Trapezius III muscles adduct and downwardly rotate scapulas. During decelerations, trapezius III muscles adduct, depress and downwardly rotate scapulas.

10. Trapezius IV

Trapezius IV muscles attach to scapular spine roots and transverse processes of thoracic vertebraes' six through twelve (T6-T12). When trapezius IV muscles contract, scapular spine roots and T6-T12 transeverse processes move closer together. Trapezius IV muscles adduct, depress, downwardly rotate and backwardly tilt scapulas. During decelerations, trapezius IV muscles adduct, depress, downwardly rotate and backwardly tilt scapulas.

In conclusion, pectoralis minor and serratus anterior muscles forwardly lock scapulas with thoraxes. If scapulas cannot sustain firm bases against which pitching arms drive toward home plates, then pitching arms slip like running feet slip when running in soft beach sand. Because scapulas do not move much or rapidly, pitchers have few problems with scapula deceleration muscles.

e. Pitching Shoulder Girdle Actions

1. Transition

During transitions, shoulder girdle muscles mioanglosly adduct and backwardly tilt and isoanglosly elevate and upwardly rotate scapulas. Adductions and backward tilts stretch upper arm acceleration muscles. Adductions lengthen serratus anterior muscles and backwardly tilts lengthen pectoralis minor muscles. Elevations and upwardly rotations maintain scapulas' vertical alignments against gravity's effects.

2. Upper Arm Acceleration

During upper arm accelerations, shoulder girdle muscles mioanglosly abduct, forwardly tilt and elevate and isoanglosly upward rotate scapulas. Abductions drive scapulas to rib cages' lateral surfaces. Forward tilts drive coracoid processes toward R3-R5s' anterior surfaces. Elevation drives scapulas' superior borders upwardly. Upward rotations upwardly maintain scapulas' acromion processes.

3. Forearm Acceleration

During forearm accelerations, to help forearms accelerate toward home plates, shoulder girdle muscles accelerate, stop and snap back.

4. Deceleration

During decelerations, shoulder girdle muscles plioanglosly adduct, backwardly tilt and depress and isoanglosly upwardly rotate scapulas. Adductions stop and snap back abducting scapulas. Backward tilts stop and snap back forward tilting scapulas. Depressions stop and snap back elevating scapulas. Meanwhile, upward rotations upwardly maintain scapulas' acromion processes.

Coaching Adult Pitchers