This document provides information on the anatomy and biomechanics of the shoulder joint. It describes the sternoclavicular joint, acromioclavicular joint, scapulothoracic joint, and glenohumeral joint. It discusses the tissues that stabilize each joint and their range of motion. Common injuries in overhead athletes like throwers and swimmers are described. Rehabilitation protocols focus on reducing pain, regaining range of motion, strengthening the rotator cuff and scapular muscles, and integrating the kinetic chain.

1. Center for Physiotherapy and Rehabilitation Sciences.
Jamia Millia Islamia
New Delhi

2. Sternoclavicular
Joint
Plane synovial joint.
Articular surfaces
Medial end of clavicle
Clavicular facet on sternum
Sup. Border of the cartilage of
first rib.

3. Tissues that stabilizes the SC joint :
1. Anterior and Posterior
Sternoclavicular ligament
2. Interclavicular ligament
3. Costoclavicular ligament
4. Articular Disc
5. SCM , Sternohyoid,
sternothyroid and
subclavius muscles.

4. Sternoclavicular Disk
• The articular disc at the SC joint
separates the joint into distinct
medial and lateral joint cavities
• The disc is flattened piece of
fibro-cartilage that attaches
inferiorly near the lateral edge of
clavicular facet and superiorly at
the head of clavicle and
interclavicular ligament

5. Kinematics of SC joint:
• Osteokinematics of SC joint includes:
1) Elevation(45 deg) and Depression (10
deg):
Plane - frontal
Axis – AP axis
2) Protraction and Retraction (15-30 deg
each)
plane-horizontal
axis –superior -inferior axis
3) Axial rotation of the clavicle (post.
Rotation 20-35 deg during sh.
Abduction /flexion)
axis – clavicle’s longitudinal axis

6. 2) Acromioclavicular Joint
A. Anterior View B. Posterior View

7. Structures that Stabilizes the AC joint
• 1. Superior and Inferior AC
joint capsule
• 2. Deltoid and Upper
• Trapezius
• 3. Coracoclavicular
• ligament
• 4. Articular disc

8. Osteokinematics of AC joint :

9. 3) Scapulothoracic Joint
• The ST joint is a typical joint which lacks all the traditional characteristics
of a joint except one that is motion
• The primary role of this joint is to amplify the motion of GH joint
• ANATOMIC POSITION OF SCAPULA :
Between 2nd and 7th ribs,
 Medial border located about 6cm lateral to spine ,
 10deg ant. Tilt ,5-10 deg. Upward rotation, 35deg internal rotation—
plane of scapula
ST Joint is composed of ac joint and SC joint

10. Movements at the scapulothoracic joint
• Elevation and depression
• Protraction and retraction
• Upward and downward rotation

11. GLENOHUMERAL JOINT
•Articular surface
•Large complex head of
humerus
•Shallow concavity of glenoid
fossa

12. The “Loose-Fit” of GH joint
• Glenoid fossa covers only one-third
of articular surface of humeral
head.
• In typical adult, the longitudinal
diameter of humeral head is about
1.9 times larger and transverse
diameter is 2.3 times larger than
the same diameter of the glenoid
fossa.

13. Tissues that Stabilizes the GH joint
•GH joint capsule
•Ligaments
•Rotator cuff muscles
•Glenoid labrum

15. Rotator cuff
Rotator cuff muscle
•S- Supraspinatous muscle
•I- Infraspinatous muscle
•T-Teres major muscle
•S-Sub scapularis muscle

16. Rotator cuff muscles
• Subscapularis lies anterior to capsule
• Supraspinatus, Infraspinatus and Teres
minor lie superior and posterior to
capsule
They all provide major stability during
active motion.

17. Coracoacromial Arch

18. Kinematics of GH joint
•The GH joint has three degrees of freedom
•Osteokinematics of the GH joint includes
1. Abduction and Adduction
2. Flexion and Extension
3. Internal and External rotation

19. Line of
action of
Deltoid

20. Line of
action of
Rotator
Cuff

21. Line of
Action of
“ITS”

22. Major kinematic event during shoulder
abduction

25. Conditions in and around the Shoulder
joint:
Dislocations
• Anterior
• Posterior
• Inferior
Instability
• Anterior
• Posterior
• Multi-
directional
Rotator cuff
Injuries
• Tear/sprai
n
• Tendinitis
• Tendinopa
thy
Labrum injuries
• SLAP
Lesion
• Non-
SLAP
lesion
Fractures
• Clavicle
• Humerus
• Acromio-
clavicular
joint
Less common
causes of shoulder
pain
• Biceps
tendinopathy
• Rupture of long
head of the
biceps
• Pectoralis major
tears
• Subscapularis
muscle tears
• Levator scapulae
syndrome
• Nerve
entrapments

26. BIOMECHANICS
OF THROWING

27. Four phases of Throwing
• Preparation / Wind- up
• Cocking
• Acceleration
• Deceleration/ Follow-through

28. Phases of Throwing :- Wind- up
• Wind-up / Preparation
• This establishes the rhythm of the throw
• The body rotates, hip and shoulder are at
90° to target
• Major forces arise in the lower half of the
body developing a forward-moving
controlled fall.
• The hip flexion of lead leg raises the
center of gravity.
• This phase lasts for 500-1000 milliseconds
• Muscles of the shoulder are relatively in
active.

29. Phases of Throwing :-
cocking
• In this posting all body segments are positioned in a way to
generate enough force to propel the ball forward.
• Shoulder: Abduction -> horizontal extension -> Maximum
external rotation.
• Shoulder is loaded in this position
• Anterior capsule is coiled tightly and storing elastic energy.
• Internal rotators are stretched.
• End of cocking : Lead leg is planted, body positioned for
maximum energy transfer.
• Lateral trunk flexion determines the degree of abduction
• Periscapular muscles are more active than the shoulder
muscles.
• Force couple of Upper trapezius and serratus anterior initiate
acromial elevation
• Lower trapezius maintain elevation at abduction angle greater
than 65°

30. Phases of Throwing :- Acceleration
• Acceleration is extremely explosive
• Rapid release of two forces :
• Tightly bound fibrous tissue of capsule
• Forceful internal rotators
• Subscapularis
• Pectoralis major
• Latissmus dorsi
• Teres major
• Here the rotator cuff muscles are highly activated to
keep the humeral head enlocated in the glenoid
• Acceleration is the shortest phase of throwing. It lasts
only 50 milliseconds

31. Phases of Throwing :-
Deceleration
• In this phase, very high forces pull
forward on the GHJ following ball
release.
• This places large stresses on the
posterior joint capsule.
• Both intrinsic and extrinsic muscles
fire at significant percentages of their
maximum, developing about 500N to
slow down the arm.
• This phase lasts approx. 350
millisecond which is approx. 18% of
the total time.

37. Adaptation in thrower’s
• At the shoulder, long-term throwing athletes have increased range of external rotation
• The combination of increased shoulder external rotation range of motion and breakdown of
the static stabilizers may lead to anterior instability of the shoulder and secondary
impingement.
• The normal strength ratio of internal rotators to external rotators is approximately 3:2 but in
throwers this imbalance is exaggerated and, over time, lack of external rotation strength
may increase vulnerability to injury.
• Throwing also produces structural changes at the elbow. Due to the valgus stress applied
in the throwing action there is a breakdown of the medial stabilizing structures (medial
collateral ligament, joint capsule, flexor muscles). This leads to the development of an
increased carrying angle at the elbow
• Less frequently, the eccentric overload on elbow structures causes anterior capsular
strains, forearm flexor strains and, subsequently, a fixed flexion deformity.

39. Throwing injuries :-
• Microtrauma injuries
• related to throwing occur due to the combination of excessive ROM, high compressive and
translator forces. Rapid acceleration/deceleration and ballistic movements.
• Tensile injuries
• Failure of muscles to stabilize the GHJ in presence of increased laxity.
• Initially, there maybe inflammation of the tendons, repetitive tensile stresses leads to tendon failure or labral
pathology.
• Bennett’s lesion : exostosis of posterior inferior border of glenoid labrum due to increased tensile stresses on
posterior band of IGHL. This occurs during deceleration. This can cause tears of Labrum or posterior RC.
• SLAP lesion : excessive pulling at the insertion on the labrum by the biceps tendon due to increased tensile
stresses.
• Rotator Cuff Pathology : this develops due to compressive forces by primary impingement or
secondary impingement due to instability.
• Throwing athletes usually have hyperlaxity of GHJ therefore impingement mostly has an element of instability.
• Inflammation from impingement causes fraying of the tendon and eventually leading to RC tears.
• Mostly internal impingement is observed.

40. Swimmer’s Shoulder: Let’s know the
basics

41. Swimmer’s shoulder : Biomechanics of
strokes
Backstroke :
• Recovery: elbow is extended during.
• Entry: shoulder is fully abducted, externally rotated
with scapular retraction which places stress on
anterior capsule.
Freestyle :
• Recovery :Combined motion of scapular retraction
and elevation , humeral abduction, external rotation
during.
• Pull- through: scapula is protracted, humerus
adducted.
• Trunk : rotated away from the side of pull.

42. Swimmer’s shoulder : Biomechanics of
strokes
Butterfly:
Both arms are moved through the same motion
simultaneously rather than alternative.
No trunk rotation occurs, so demand on medial scapular
stabilizers and retractors is increased.
Humeral head moves into impingement position during
recovery
Breaststroke:
• Arms are moved simultaneously. Starts in full forward
flexion, internal rotation.
• Pull- through : Elbow remain flexed, humerus is fully
adducted and brought into horizontal adduction with
forearm touching each other.
• Better than other strokes as stress on RC is less.

43. Etiology of Swimmer’s shoulder.
• Multifactorial etiology –
Subacromial impingement
involving the RC tendon, bicipital
tendon or subacromial bursa.
• May occur :-
• tight posterior capsule that
causes the humeral head to
migrate anteriorly or abnormal
acromial morphology.
• Also, presence of GH hyperlaxity
and instability.
Mechanism
Increased ROM in external
rotation causing anterior
laxity and instability
Wringing out
phenomenon
Muscle Fatigue
Faulty Mechanics

44. 3.Tennis and other racket sports.
Basic strokes in tennis:-
Primary movement patterns : Forehand,
Backhand and serve.
Forehand and backhand comprise of three
phases :
Backswing
Contact
Follow-through
These strokes may vary as some players use
a two-handed backhand or forehand.

45. 3.Tennis and other racket sports.
This may also vary in
mechanics according
to the adaptation of
the player.
But this also consists
of the basic four
phases :-
Wind-up
Cocking
Acceleration
Follow-through
Tennis serve

46. Etiology of
tennis injuries
• Anterior pain : associated with serve or overhead
smash.
• Impingement : due to the position of adduction
and internal rotation in backhand and forehand the
shoulder is predisposed to develop impingement.
Also, faulty mechanics, weak RC, poor flexibility,
poor scapular stability and decreased joint mobility
can all be contributing factors.
• Causes of injuries :
• Explosive overhead strokes
• Imbalance of external and internal rotators
• Faulty mechanics and inadequate racket
selection
• Breakdown of kinetic chain :- failing to use the
muscles of trunk, hips and lower extremity to
generate force
• Playing ‘All-arm strokes’ which puts tremendous
stress on the upper limb.

48. ACCURATE
DIAGNOSIS
EARLY PAIN
REDUCTION
INTEGRATION
OF KINETIC
CHAIN
SCAPULAR
STABILIZATION
EARLY
ACHIEVEMENT
OF 90° OF
ABDUCTION
AND GH
CLOSED CHAIN
REHABILITATION
PLYOMETRIC
EXERCISES
ROTATOR CUFF
EXERCISES

49. Specific Rehabilitation protocol:
• This is a basic protocol
• Deviation from this protocol depends on the individual’s progress and needs.
• Protocol Assumption :
• Post-surgical cases
• Stable repairs of labrum/ capsule/ rotator cuff
• Ability to achieve 90° of abduction without impingement.
• Time frame depends on
• Severity of injury
• Extent of surgical procedure
• Rehabilitation goals :
• Progress post-operative labral repairs, shoulder reconstructions and acromioplasties to 90° of
passive or active assisted abduction by four to six weeks.

50. Goals :
• Tissue healing
• Reduction of pain and inflammation
• Re-establishment of non-painful ROM
• Below 90° of abduction
• Retardation of muscle atrophy
• Scapular control
• Maintenance of fitness in other components
of kinetic chain

51. Tissue Healing
• Rest
• Short- term immobilization
• Modalities
• Surgery
Reduce pain and
inflammation
• Medications : NSAIDs,
Corticosteroid
• Ultrasound : 2 per week for
2 weeks
• Cold compression devices
Re-establishing
ROM
• Initially pain-free below 90°
abduction : passive/active-
assisted
• Pendulum exercises
• Manual capsular stretching
and cross fiber massage
• T- bar / ropes and pulleys.
Retard muscle
atrophy
• Isometric exercises : arm
below 90° both abduction
and flexion (not for RC tear
pts)

52. Scapular control
• Isometric scapular pinches and scapular elevation
• Low row
• Closed chain weight shifts
• Tilt board or circular board weight shifts
• Shoulder flexed at 60° and abducted less than 45°
Maintain fitness in rest of the kinetic chain
• Aerobic exercise : running, bicycling, stepping.
• Anaerobic agility drills
• Lower extremity strengthening: machines, squat exercises,
open chain leg lifts.
• Elbow and wrist strengthening : isometrics, resistance bands
• Flexibility exercises
• Integration of kinetic chain by leg and trunk stabilization on a
ball, employing rotational and oblique patterns of contraction.

53. Kinetic chain exercises

54. Criteria for moving out of acute phase
Progression of tissue healing : sufficiently healed for active movements
Passive ROM : 66-75% of opposite side
Minimal pain
MMT in non-pathological areas of 4+/5
Kinetic chain function and integration.

55. Recovery PhaseGoals Normal active and passive
shoulder and GH ROM
Improved scapular control
Normal upper extremity
strength and strength balance
Normal shoulder
arthrokinematics in single as
well as multiple plane of
Normal kinetic chain and
generation patterns.

56. • Normal Range of motion
• Active-assisted motion above 90° of abduction
with wand
• Active-assisted then active motion in internal and
external rotation with scapula stabilized so that
rotation is normalized without substitution
movements from scapula.
• Scapular control
• Scapular PNF patterns
• Closed-chain exercises at 90° of flexion, 90°
abduction, scapular retraction/protraction and
elevation/depression
• Modified push-ups
• Regular push-ups
• Ball catch and push exercises
• Dips
• Clock
• Low row
• Lawn mower

57. • Upper extremity strength and strength
balance
• GH PNF
• Closed chain exercises at 90° of flexion then 90°
abduction, using GH depressors and GH
internal/external rotators
• Forearm curls
• Isolated RC exercises
• Machine or weights : light bench presses, military
presses and pull –downs
• Resistance should be light initially and progressed as
strength improves.
• Focus should be on proper mechanics

58. • Normal shoulder arthrokinematics
• ROM exercises – 90° of abduction (since this is the functional
position for most throwing activities)
• Muscle activity at 90° of abduction (to establish normal muscle firing
patterns and force generation patterns) combined with PNF and
closed chain exercises.
• Open chain exercises : mild plyometrics.
• Normal kinetic chain and force generation
• Normalization of all inflexibilities throughout the kinetic chain.
• Normal agonist-antagonist force couple in leg using squat,
depth jumps, lunges, and hip extensions.
• Trunk rotation exercises with medicine ball or tubing
• Integrated exercises with leg and trunk stabilization, rotation,
patterns from hip to shoulder, medicine ball throws
• Rotator cuff strength of 4+/5 or higher
• Normal kinetic chain functions.

60. Functional phase
• To increase muscle power and endurance in the
upper extremity
• To increase normal multiple plane neuromuscular
control – locally, regionally and in the entire
chain
• Instruction in rehabilitation activities
• Sport-specific activities
Goals

61. • Power and endurance in upper
extremity:
• Position : 90° of abduction of shoulder, trunk
rotation, and diagonal arm motions, rapid
external/internal rotation
• Diagonal and multiplanar motions with rubber tubing,
light weights, small medicine balls, or if available
isokinetic machines
• Plyometrics :
• Wall push-ups
• Corner push-ups
• Weighted ball throws with tubing
• Tubing exercises mimicking throwing or serving
• Medicine ball exercises
• Increase multiplanar neuromuscular
control
• Force dependent motor- firing patterns should be re-
established.
• Special care must be taken to integrate all of the
components of the kinetic chain completely to
generate and funnel the proper forces to and through
the shoulder.

62. • Rehabilitation
• Flexibility : general body for sport-specific problems
• Strength : appropriate amount and location of strength for
force generation, trunk rotation for sports specific activities
• Power : rapid movements in appropriate planes with light
weights.
• Endurance : mainly anaerobic exercises.
• Sports-specific activities:
• Functional progression of throwing or serving must be
complete before full completion is allowed.
• Very few deviation from the normal parameters of arm
motion, arm position, force generation, etc. should be
allowed
• The athlete may move through the progression as rapidly as
possible.

64. The thrower’s 10 protocol

74. Criteria for return to play.
Normal clinical presentation
Normal shoulder arthrokinematics
Normal kinetic chain integration
Completed progressions
• As with any sports-related injury, decisions on return-to-competition following injury to the rotator
cuff should be made collaboratively with the team physician, rehabilitation staff, and the athlete.
• The decision should be predicated on physical exam findings consistent with pre-injury levels of
pain, range of motion, stability, strength, and overall shoulder function.
• The athlete should demonstrate adequate power and muscular endurance and be able to
satisfactorily perform all that is required based on the demands of their sport.
• It is recommended that the return to team-related activities and training should be step-wise and
titrated accordingly.
• Upon return-to-competition, the athlete should be carefully monitored to avoid a repeat injury