Functional Anatomy

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Functional Anatomy Biomechanics - Shoulder
Girdle

• Noel Goodstadt, MPT, OCS, CSCS
• University of Delaware

2
Shoulder Girdle Complex

• 4 Articulations
• 1. Glenohumeral Joint (Shoulder)
• 2. Acromioclavicular Joint (AC)
• 3. Sternoclavicular Joint (SC)
• 4. Scapulothoracic Joint (ST)

3
Sternoclavicular Joint

• Medial clavicle - manubrium of the sternum 1st
  costal cartilage
• 2 saddle-shaped joint surfaces with a disk in
  between
• Only articulation of UE to axial skeleton
• 3 DOF

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Degrees of Freedom

• 45º Elevation 15º Depression about A-P axis in
  frontal plane
• 15º of Protraction Retraction about S-I axis in
  trans. Plane
• 30-50º Rotation about its longitudinal axis
• Must rotate appropriately to allow normal
  scapular rotation

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Clavicle Fractures

• May restrict motion at SC / AC joints, which can
  lead to problems throughout the shoulder girdle

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Acromioclavicular Joint

• Lateral clavicle - acromion of scapula
• 3 DOF
• Another 30º of rotation
• combined with SC jt 60º
• accounts for 1/3 of the 180º of shoulder
  elevation

1st 30º is GH (setting), then 21 GHAC-SC
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AC Joint

• AC Joint sprains are fairly common
• MOI - Fall on shoulder or contact in sports
• Most can be treated with Fig.-8 strap PT
• Distal clavicle resected when necessary

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AC Joint

• Painful or degenerative AC joint can restrict /
  alter shoulder ROM
• Always a differential Dx with impingement
  conditions
• Impingement tests may be positive
• Dx. Tests
• Cross Body Adduction
• Se 77, Sp 79
• OBriens Test
• Se 41, Sp 92
• AC Resisted Extension Test
• Se 72, Sp 84

Efstathios, et al 2004
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AC Sprains

• Type I
• Sprain of AC ligaments and capsule
• No loss of joint stability
• Type II
• Same as Type I with disruption of AC ligaments
• Sprain to the CC ligaments
• Joint stability A/P compromised

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AC Sprains

• Type III
• Complete AC and CC rupture
• Joint stability compromised S/I and A/P
• Type IV - VI
• More severe variations of Type III
• displacement of the clavicle
• Consider muscle damage or compromise depending on
  displacement

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Scapulothoracic Articulation

• The articulation between the scapula and the
  thorax
• Angle of orientation
• 30-50º anterior frontal plane
• GH - Elevation in this plane is referred to as
  scaption
• Plane of the Scapula (POS)
• Least resistance

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Scapulothoracic Articulation

• Motions of the Scapula
• Protraction-Retraction
• Elevation-Depression
• Abduction-Adduction
• Upward Downward Rot
• Anterior-Posterior tilting

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Scapulothoracic Articulation

• Mobility vs. Stability
• Musculature attachment to axial skeleton
• Bony attachment through SC joint via the clavicle
• relatively unstable base

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Scapular Stabilizers

• Serratus Anterior
• Trapezius
• Rhomboids
• Levator Scapula
• Pectorals
• Latissimus Dorsi

Depresses Humeral Head
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Importance of Upward Rotation

• Upward rotation
• glenoid to remain in articulation with the
  humeral head
• promotes stability
• Maintains the muscles length-tension relationships

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3D Scapular Position Orientation

• Lukasiewicz et al. 1999
• 37 subjects normals patients with impingement
• Connected to a 3D electromechanical digitizer
• measuring position and orientation with arm at
  the side, elevated in POS to horizontal, and at
  maximum elevation
• Conclusion The chief abnormality in patients
• lack of posterior tilting and excessive superior
  translation

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Clinical Evaluation of Scapular Dysfunction

• Kibler et al., 2002
• Reliability study Compared 2 physicians and 2
  physical therapists ability to assess for
  scapular abnormalities
• 26 subjects videotaped, six normals
• 4 defined categories of scapula abnormalities
• Conclusion A moderate level of agreement and
  reliability was present for intertester
  reliability and slightly greater intratester
  reliability

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Scapulohumeral Rhythm

• Coordinated activity of all articulations of the
  shoulder complex
• Positions glenoid to articulate with humeral head
• Maintains appropriate length/tension
  relationships for dynamic stability

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Scapulohumeral Rhythm

• The scapular stabilizers provide a stable base
  for shoulder mobility
• Proximal stability promotes distal mobility
• Neuromm. Control
• key component to dynamic shoulder stability

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Glenohumeral Joint

• 6 Degrees of Freedom
• Greatest ROM of any Joint

A Balance of Mobility
Stability
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Glenohumeral ROM

• Total
• Forward Elevation 120 degrees 180
• Extension 55 degrees
• Abduction 120 degrees 180
• Internal Rotation 70 degrees 90
• External Rotation 90 degrees
• Horizontal Adduction 45 degrees
• Horizontal Abduction 35 degrees
• AAOS

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Mechanisms of Shoulder Joint Stability
Shoulder Stability
Static Factors
Dynamic Factors
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Static Factors

• Articular Bony Anatomy
• Glenoid Labrum
• Capsule Ligaments
• (-) Intra-articular Pressure
• Adhesion - Cohesion

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Bony Anatomy

• Scapular Orientation
• 30 anterior to the frontal plane
• Glenoid Version
• 7 retroversion
• 5 inclination
• Humeral Orientation
• angle of inclination 130 - 150
• angle of torsion 30 retroversion

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Size Mismatch
Humeral Head is Large
Glenoid Fossa surface area is 25-30 of
the Humeral Head surface area
Glenoid Fossa is Smaller More Shallow
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Glenoid Labrum

• Fibrous ring around the periphery of the glenoid
• Anchor point on the glenoid for the
  capsuloligamentous structures

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Glenoid Labrum

• Contributes to stability by increasing socket
  depth approximately 50 in all directions
• Howell Galinat, Clin Orthop, 1989

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Glenoid Labrum

• Stabilizing role with compression even after
  ligaments have been cut / disrupted

Must have both Labrum and Ligament Pathology to
Dislocate
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Capsuloligamentous Structures

• Rotator Cuff Interval
• Supraspinatus Subscapularis
• SGHL, CHL, MGHL
• Middle Glenohumeral Ligament
• Inferior Glenohumeral Ligament Complex
• Posterior Capsule

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Rotator Interval

• SGHL CHL limits inferior translation
• 0o to 30o Abd. (50o)
• also limits ER in this range

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Middle Glenohumeral Ligament

• Primary restraint to anterior translation in 45o
  -75o Abduction
• Limits ER in mid-abduction

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Inferior Glenohumeral Ligament Complex

• Anterior Band
• Posterior Band
• Axillary Pouch

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IGHL Complex

• At 90o Abd neutral rotation supports humeral
  head like a hammock
• ER - moves ant. forming a barrier to anterior
  dislocation
• IR - moves post. forming a barrier to posterior
  dislocation

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Negative Intra-articular Pressure

• Pressure within the joint is (-) creating a
  vacuum in the joint
• Levick, J Rheum, 1983
• Kumar et al, JBJS, 1985
• Venting of capsule increases translation
• Gibbs et al, CORR, 1991

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Adhesion - Cohesion

• Viscous Intermolecular forces from wet surfaces
  of the joint provide
• High tensile strength (difficult to pull
  apart)
• Low shear strength (slide easily)
• Matsen et al, Glenohumeral Instability, 1998

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Dynamic Factors

• Rotator Cuff Biceps
• Scapular Stabilizers
• Coordinated Scapulohumeral Rhythm
• Neuromuscular Control

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Rotator Cuff

• Supraspinatus
• Infraspinatus
• Teres Minor
• Subscapularis

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Rotator Cuff

• Rotator cuff muscles tendons function as
  Dynamic Ligaments

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Supraspinatus

• Resultant Force is towards
• Joint Compression
• Poppen et al, JBJS, 1976
• Inman et al, JBJS, 1944

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Posterior Rotator Cuff Subscapularis

• Humeral Head depressors and apply compressive
  force
• Reduce anterior strain on ligaments

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Rotator Cuff - Deltoid

• Balance of Forces / Coupled for Stability
• Cuff reduces shear force of deltoid
• Depresses the humeral head to prevent superior
  migration force of deltoid (impingement)

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Impingement Syndrome

• Pathological compression
• Supraspinatus
• Subacromial bursa
• LHB
• Compression occurs
• Coracoacromial arch
• Anterior third of the acromion
• AC joint

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Impingement Syndrome

• Irritation of the rotator cuff muscle
• Compromises its function as a depressor of the
  humeral head

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Impingement Syndrome

• A reactive progression of this syndrome is
  defined by a narrowing of the subacromial outlet
  by spur formation in the coracoacromial ligament
  and on the undersurface of the anterior third of
  the acromion.

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Impingement Syndromes

• Typical History
• Painful arc of motion with elevation
• Painful with overhead activities
• Often Painful with quick movements
• Usually cannot sleep on that shoulder
  due to pain
• ?Night Pain
• Often have Hx of repetitive activity
• Need to rule out other causes
• Differentiate primary vs. secondary impingement

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Impingement Locations
47
Impingement Classification

• Primary
• Structural Issue - Loss of Space
• Due to anatomical variations or degenerative
  spurring
• Secondary
• Due to Instability (excess translation)

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Primary Impingement

• Result of abnormal mechanical relationship
  between the rotator cuff and the coracoacromial
  arch
• Factors that increase primary impingement
• AC joint congenital anomoly degenerative
  spur
• Coracoid congenital anomoly
• abnormal shape (surgery/trauma)
• RC Calcific deposits
• tendon thickening (surgery/trauma)
• upper surface irregularities (tears)
• Humerus increased prominence of greater
  tuberosity from congenital anomolies or
  malunions

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Primary Impingement

• Acromial Morphology

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Primary Impingement

• Neers Stages of Impingment Syndrome
• Stage I Edema and Inflammation
• Stage II Fibrosis and Tendinitis
• Stage III Bone Spurs and Tendon Ruptures

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Primary Impingement

• Stage I Edema and Inflammation
• (lt 25 years)
• Reversible lesion
• Tender to palpation over greater tuberosity
• Tender to palpation over anterior ridge of
  acromion
• Painful arc 60º - 120º
• Impingement sign
• Restricted ROM with significant subacromial
• inflammation

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Primary Impingement

• Stage II Fibrosis and Tendinitis
• (25-40 years)
• Not reversible by modifying activities and time
• Greater degree of soft tissue crepitus
• Catching sensation with lowering of the arm 100º
• Limited A/PROM of the shoulder
• All the signs from Stage I

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Primary Impingement

• Stage III Bone Spurs and Tendon Ruptures (gt40
  years)
• Not reversible conservatively
• Limited shoulder ROM, which is more pronounced
  with AROM
• Infraspinatus atrophy
• Weakness of shoulder abduction and ER
• Biceps tendon involvement
• AC Tenderness
• Signs from Stage I II

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Primary Impingement

• Degenerative Spurring

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Secondary Impingement

• Associated with Instability - static/dynamic

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Secondary Impingement

• Relative Narrowing
• Result of GH or scapulothoracic joint instability
• GH instability RC dysfunction
• Overworked to stabilize
• Leads to an abnormal superior translation of the
  humeral head
• ST instability RC dysfunction
• Improper positioning of the scapula with relation
  to the humerus

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Rotator cuff weakness or fatigue
Scapulothoracic muscle weakness or fatigue
Overload of passive restraints
Functional scapulothoracic instability
Disruption of scapulohumeral rhythm
Glenohumeral instability
Relative subacromial space narrowing
Secondary subacromial impingement
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Secondary Impingement

• Usually younger
• Participate in overhead sporting activities
• Baseball
• Swimming
• Volleyball
• Tennis
• May describe a feeling of the arm going dead

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Secondary Impingement

• Joint Mobility Restrictions
• Thickening of tendons from injury or surgery
• Posterior Capsule Tightness

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Examination of Impingement

• symptoms
• pain with arm movement above the horizontal
• ?night pain
• signs
• impingement tests
• weak and painful supraspinatus mm. tests

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Neers Sign

• Forward elevation with overpressure
• Arm medially rotated
• Cuff is impinged between the greater tuberosity
  the acromion
• Pain decreases with lowering of the arm
• If positive with the arm laterally rotated check
  the AC joint

• (Magee, 4th ed.)

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Neers Impingement Test

• Diagnostic test
• Inject anesthetic agent into subacromial space
  and repeat the Neers sign. If pain is no longer
  there, the test is () for subacromial
  impingement
• ?? Noxious Stim.

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Hawkins-Kennedy Test

• Arm is IR in 90º of FE
• Can vary degrees of horizontal add/abd.
• (Magee, 4th ed.)
• Pain is indicative of cuff/biceps impingement on
  CA ligament or AC jt.

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Secondary Impingement

• () Impingement signs () signs for instability
• Also have Hx consistent with instability

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Posterior-Superior Impingement

• Also called internal impingement
• Found in overhead athletes that throw or strike
• Pain in posterior-superior shoulder in 90º/90º
  position
• Secondary to anterior laxity
• Irritation of the posterior-superior capsule and
  rc as it tries to balance for the increased
  anterior translation

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Coracoid Impingement

• Aka Cross-body adduction sign
• Horizontal Adduction with overpressure
• Pain is indicative of impingement on the bursa,
  AC pathology, or posterior cuff/capsule
• Depends on location of the pain

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Manual Muscle Testing

• Depending on the severity and duration of
  symptoms, the patient may or may not have
  weakness, but usually will have pain
• Can you accurately grade strength in presence of
  pain?
• Generally most notable in Supraspinatus, but also
  in posterior cuff
• test in various angles

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Cuff Testing

• External rotation
• _at_ 0º of abduction
• _at_ 90º of abduction
• Internal rotation
• _at_ 0º of abduction
• _at_ 90º of abduction
• Varying angles between and above

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Rotator Cuff Pathology

• Full vs. Empty Can - Isolated Supraspinatus MMT
  at 90º of elevation in POS
• Positive if weakness or pain or both occur
• Indicative of a tear of the tendon, neuropathy of
  the suprascapular nerve
• tear???

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Empty vs. Full Can

• Concluded the optimal test for the supraspinatus
  to be the full can position
• decreased infraspinatus activity.
• Kelly, 1996
• Criterion Weakness increases accuracy for dx of
  a tear.
• Itoi, et al. 1999
• Empty Can Test is more pain provocative, both
  tests were equivocal with weakness for
  sensitivity of a partial or full thickness tear.
• Kim, et al. 2006

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Rotator Cuff Pathology

• Drop Arm Test
• Abduct patients shoulder to 90º
• have patient slowly lower it to their side
• test if patient is unable to lower arm slowly
  from 90º or has severe pain
• Patients age can help in differential dx.
• (Magee 4th ed.)

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Rotator Cuff Pathology

• Subscapularis Testing
• Lift-Off Test
• Belly Press Test
• Tokish et al., 2003
• Concluded that the belly press test maximally
  activates the upper fibers, and the lift-off test
  maximally activates the lower fibers. (plt.05)
• Positive finding
• lag sign

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Rotator Cuff Pathology

• Mechanism Classifications
• Tensile vs. Compressive
• Primary vs. Secondary
• Partial vs. Full

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Tensile Cuff Failure

• Primary Tensile Cuff Disease
• Occurs in stable shoulders
• Rotator cuff begins to tear due to the loads
  it sees in decelerating the shoulder
• Secondary Tensile Cuff Disease
• Instability adds to the forces the cuff sees and
  leads to cuff tears

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Partial Thickness Cuff Tears
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Partial Thickness Cuff Tears

• Outside-in tears
• General orthopaedic population
• Neers Stage III - Middle Age to Elderly
• Wear and tear from the superior surface of the
  Supraspinatus and/or other RTC mm.
• Inside-out tears
• Younger, most likely athletes
• Wear and tear of the undersurface of the muscle
  from the humerus
• RC is challenged to center the humeral head in
  the glenoid
• Cyclic progressive failure

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Conservative Treatment

• Most impingement and partial rotator cuff tears
  can be treated non-operatively
• Most important component is protection from
  contributing factor (Relative Rest)
• NSAIDS

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Conservative Treatment

• Factors in individualizing treatment
• Age
• Stage I vs. Stage II
• Activity Level
• Impairments

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Conservative Treatment

• Ice other modalities (E-stim., Phoresis, etc.)
• Treat the tendons involved
• Stretching Strengthening in the PAINLESS ROM
• mobilization vs. manual stretch
• Joint restrictions often inferior and posterior
  capsule
• Early physiologic range stretching may be limited
  by impingement pain
• Soft Tissue tightness often subscapularis and
  pectoralis tightness
• strengthening start at 0º of abduction and
  progress up

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Conservative Treatment

• Start by emphasizing the scapular stabilizers
  (need to provide a stable base for the GH jt)
• What scapular mm. exercise can impinge the
  shoulder?
• Strengthen cuff in the painless ROM
• Use the overload principle as soon as the acute
  stage is under control
• Also work on dynamic stabilization of the GH jt.
• Shrug Sign

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Exercise principles

• Position supine to upright
• Avoid shoulder hike
• Mode passive to active assist to active
• Frequency, not intensity - submaximal
• Avoid impingement/significant discomfort
• ROM upstairs/strength downstairs
• Functional exercise - synergy

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Conservative Treatment

• Phase 1
• Maximal Protection Acute Phase
• Phase 2
• Motion Phase Subacute Phase
• Criteria for progressing into phase 2
• Decreased pain and/or sx
• Increased ROM
• Improved muscle function

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Conservative Treatment

• Phase 3 Intermediate Strengthening
• Criteria for progression to Phase 3
• Decrease in pain and sx.
• Normal AAROM
• Improved muscular strength
• Phase 4 Dynamic Advanced Strengthening
• Criteria for progression to Phase 4
• Full, non-painful ROM
• No Pain or sx.
• Greater than 70 strength of the uninvolved

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Functional Training

• When the athlete demonstrates good strength and
  appropriate control of the shoulder girdle,
  progress to functional activities
• Overhead strengthening
• Criterion no shoulder hike and no increase in
  pain
• Release to an interval program once patient is
  independent and understands the soreness rules

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Rx Should be a Team Effort

• Athlete - Therapist - Physician - Trainers -
  Coaches - Family, etc.
• Biomechanical analysis of sport skills may be
  necessary
• If progress is slow a corticosteroid injection
  may help
• Do Not let them work through pain
• Unsuccessful if no improvement after 3 months

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When conservative management fails

• Surgical intervention
• Primary impingement
• Widening the subacromial outlet by arthroscopic
  decompression acromioplasty
• Secondary impingement
• Directed toward the etiology of the symptoms
• Ex surgical treatment for anterior joint
  instability would include anterior stabilization

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Subacromial Decompression/ Partial Tear
Debridement

• Generally can move the shoulder to tolerance
  immediately passively
• Stages of Healing
• DCE (similar to Type II AC separation)
• If substitution patterns exist do not allow the
  patient to use them
• Control symptoms and promote normal motion and
  muscle activity
• Pain increase generally at 2-6 weeks post-op

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Procedure - Arthroscopic Subacromial Decompression

• Visualization
• scope minimal incision
• Fixation
• none
• Anterior Deltoid compromise

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Modification to Rehabilitation

• Primarily due to partial resection of acromion
  and its deltoid attachment
• Avoid resisted flexion, abduction, and horizontal
  adduction for 4 weeks
• Avoid passive horizontal abduction

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Mini-Open Rotator Cuff Repair

• Most common open procedure
• Deltoid is split
• Use suture anchors or suture in trough for
  fixation

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Mini-Open Rotator Cuff Repair

• Visualization
• split the deltoid
• Fixation
• in bone trough in the humerus
• sutures through the bone /or suture anchors
• greater fixation than arthroscopic
• Surgery
• always supraspinatus
• maybe infraspinatus and teres minor
• ? RC Interval is closed

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Mini-Open Rotator Cuff Repair

• Large Tears gt 5cm, retracted
• Tendons are effectively shortened, so expect some
  tightness
• Other pathology may exist
• Activity level of patient - ??

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Factors Affecting Rehabilitation

• Restrictions depend on surgeon
• (No Active ER ABD for 4 - 12 weeks)
• Usually based on size of tear and whether the
  muscle retracted
• Quality of muscle tissue will also effect
  restrictions
• Passive restrictions will also exist
• what muscles were repaired?
• avoid passive internal rotation for 2-4 weeks
• At the least supraspinatus was sick
• Other tendons might be involved

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Rehabilitation Concerns

• Rehab must allow for tissue healing constraints
• Primarily a result of tendinous repair
• Key Issues
• Fixation Strength
• Soft tissue healing to bone

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Primary Goals

• Maintain integrity of repair
• Re-establish passive mobility
• Re-establish muscular balance
• Reduce pain muscular inhibition
• Return patient to full activities

97
Continuum of Treatment

• PROM
• Dynamic Stabilization
• AROM
• RROM

98
General Surgical Principles

• visualization
• many of the precautions for therapy are a result
  of structures that are violated in order for the
  surgeons to be able to see
• fixation
• principles of mechanics and biologic healing set
  other precautions for rehabilitation procedures

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General Principles

• surgery
• the structures that were resected, repaired or
  reconstructed also affect the rehabilitation
  procedures

100
Procedure -Arthrotomy (open)

• visualization
• incision - more precautions associated with
  visualization
• fixation
• mechanical fixation is usually excellent

101
Procedure -Arthroscopy

• visualization
• fewer precautions because scope allows
  visualization and access with minimal damage to
  structures on the way in

102
Procedure -Arthroscopy

• fixation
• often technically impossible to achieve fixation
  strengths comparable to those in open procedures

103
Biologic Healing

• dependent on the structures and their inherent
  healing potential, not procedure dependent
• Surgery-Modified Rehab
• dependent on tissue blood supply

104
Summary

• all aspects of the surgical procedure
  (visualization, fixation and the repair or
  reconstruction itself) necessitate modification
  of the rehabilitation program
• modifications include alterations in timing, type
  and intensity of exercise

105
Summary

• knowledge of surgical procedure can assist the
  therapist in designing the most cost-effective
  and time-efficient rehabilitation programs for
  patients

106
Arthroscopic Repair

• Increasing number of arthroscopic RC repairs
• Visualization
• Nothing is taken down, unless combined with
  another procedure
• Fixation
• Still not proven to be better than the gold
  standard
• More difficult procedure
• Rehab
• Limitations may need to be extended by 1-2 weeks
• Less post-operative pain

107
Arthroscopic Rehabilitation Guidelines

• Diminished fixation strength compared to
  mini-open
• Slower progression
• Patient often feels better
• Need to protect healing tissue early
• Arthroscopic failed earlier earlier gapping
  with less force
• (Burra, Jablonski,Cain AOSSM 2002)

108
Return to Sports

• Upon completion of step wise progression of
  rehab.
• ROM
• Stabilization
• Strengthening
• Normalized function
• Golf 14-16 weeks
• Tennis 20 weeks
• Swimming 22 weeks

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