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.
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.
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
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.
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 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.
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
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
Girdle Kinesiological Actions
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.
girdle muscles attach to scapulas from vertebral column, rib
and hip bones.
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.
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'
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.
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
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.
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.
Major and Minor
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.
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.
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.
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.
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
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.
Shoulder Girdle Actions
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
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.
forearm accelerations, to help forearms accelerate toward home
plates, shoulder girdle muscles accelerate, stop and snap back.
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.