Download The Shoulder - Acceleration ESP

The Shoulder
Continuing Education
Anatomy and Kinesiology
•
•
1.
2.
3.
4.
Composed of four distinct
articulations.
Each joint works interdependently and
in concert.
Sternoclavicular (SC)
Acromioclavicular (AC)
Scapulothoracic (ST)
Glenohumeral (GH)
Sternoclavicular Joint (SC)
Acromioclavicular Joint (AC)
http://www.leadingmd.com/
Scapulothoracic Joint
(ST)
Glenohumeral Joint
(GH)
http://www.medicalook.com
The glenohumeral and
scapulothoracic muscles serve as
accelerators, decelerators, and
stabilizers and are essential for
arm stability because the only
bony attachment of the upper
extremity to the sternum is the
clavicle.
http://www.anatomy.tv/
Optimal function depends upon
appropriate muscle strength,
muscle tone, and synchronous
motion.
This synchronous movement is
referred to as ‘scapulohumeral
rhythm’
http://www.anatomy.tv/
Brukner & Khan (2007) Clinical Sports Medicine (Chptr 17)
Scapulohumeral rhythm
•First 30 degrees of shoulder
elevation involves a "setting
phase":
–The movement is largely
glenohumeral.
–Scapulothoracic movement is small
and inconsistent.
• 30-90° of shoulder elevation:
– The glenohumeral and
scapulothoracic joints move
simultaneously at a 2:1 ratio of
glenohumeral to scapulothoracic
movement.
• 90-180° of shoulder elevation:
– The glenohumeral and
scapulothoracic joints move
simultaneously at a 1:1 ratio of
glenohumeral to scapulothoracic
movement.
Clarnette, R. G. & Miniaci, A. Clinical exam of the shoulder. Med Sci Sports Exerc 30, S1-6 (1998).
Scapulohumeral rhythm serves
at least two purposes:
1.It preserves the length-tension
relationships of the glenohumeral
muscles;∴ ↑ force production
through ROM.
2.It prevents impingement between
the humerus and the acromion;
∴ ↓ arthrokinematic movement
between the two bones.
Lack of Scapular Rotation
During Arm Elevation
• The glenohumeral relationship similar to
a seal balancing a ball on its nose or a
golf ball on a tee.
• Shoulder stability is provided by
static constraints - the glenohumeral
ligaments, glenoid labrum and capsule
dynamic constraints - predominantly
the rotator cuff muscles
Rotator Cuff
•Subscapularis
•Supraspinatus
•Infraspinatus
•Teres minor
Tendons of these four muscles blend
closely with each other and the shoulder
joint capsule. Their primary function is to
centralize the humeral head, limiting
superior translation during abduction.
Brukner & Khan (2007) Clinical Sports Medicine (Chptr 17)
Anatomy
Overview
?
Infraspinatus
Origin: Infraspinous fossa
Insertion: Greater Tubercule
Actions: Sh ER, Ext, Horiext
Innervation: Suprascapular
?
Latissimus Dorsi
Origin: Spinous processes T7-Lx,
lower 3 ribs, illiac crest, inf angle
of scapula
Insertion: Bicipital Groove
Actions: Sh Ext, IR, Add, Lx lat flex
& Scap dep
Innervation: Thoracodorsal
?
Rhomboid Major
Origin: C7-T5
Insertion: Medial border scap
Actions: Scap add, elev
Innervation: Dorsal scapular
?
Subscapularis
Origin: Subscapular fossa
Insertion: Lesser Tub
Actions: Sh IR, stab
Innervation: Subscapular
?
Serratus Anterior
Origin: Ribs 1-9
Insertion: Medial Border Scap
Actions: Scap abd/pro, lat rot, stab
Innervation: Long Thoracic
Important Force
Couples
Rotator Cuff - Deltoid
•Deltoid functions to elevate the arm and
produces superior translation of humeral
head.
•Inferior and medial forces of rotator cuff
offset superior translation of deltoid
(specifically the INF, TM, subscap).
•RC also assists in limiting
anterior/posterior translation of humeral
head.
Traps – Serratus Ant
• Rotation of
scapula is
provided by
trapezius force
couple (upper,
mid, lower) and
and serratus
anterior.
Integrated RC – Deltoid and
Scapular Force Couples
• Scapular rotation during arm elevation adds to
total ROM.
• Lack of scapular rotation = impingement.
• Scapular rotation is necessary to keep
acromion moving away from deltoid insertion.
• Lack of scapular rotation = Head of humerus
translates superiorly.
• Failure of scapular retraction = Head of
humerus translates anteriorly.
Stability Series
Time to have a go!
Questions/Comments?