The Shoulder Complex Notes

The Shoulder

  • High mobility, compromised stability at GH joint.
  • Susceptible to repetitive and overuse injuries.

Muscles Acting on the Humerus

  • Pectoralis Major:
    • Action: Flexes, adducts, and internally rotates the humerus.
    • Innervation: Medial and lateral pectoral nerve (C5-C8, T1).
  • Latissimus Dorsi:
    • Action: Extends, adducts, medially rotates the humerus; pulls the shoulder inferiorly.
    • Innervation: Thoracodorsal (C6-C8).
  • Deltoid:
    • Action: Abducts the humerus; anterior fibers flex and internally rotate; posterior fibers extend and externally rotate.
    • Innervation: Axillary (C5, C6).
  • Supraspinatus:
    • Action: Abducts the humerus; slight external rotation.
    • Innervation: Suprascapular (C5, C6).
  • Infraspinatus:
    • Action: Externally rotates the humerus; slightly adducts.
    • Innervation: Suprascapular (C5, C6).
  • Subscapularis:
    • Action: Internally rotates the humerus.
    • Innervation: Subscapular (C5, C6).
  • Teres Major:
    • Action: Adducts, extends, and medially rotates the arm.
    • Innervation: Subscapular (C5, C6).
  • Teres Minor:
    • Action: Externally rotates the humerus.
    • Innervation: Axillary (C5, C6).
  • Coracobrachialis:
    • Action: Flexes and adducts the humerus.
    • Innervation: Musculocutaneous (C5, C6).

Muscles Acting on the Scapula

  • Trapezius:
    • Action: Elevates, depresses, rotates, adducts, and stabilizes the scapula.
    • Innervation: Spinal accessory Cranial nerve IX
  • Rhomboideus Major:
    • Action: Adduct, stabilize and rotate the scapula, lowering its lateral angle
    • Innervation: Dorsal Scapular C5
  • Rhomboideus Minor:
    • Action: Adduct, stabilize and rotate the scapula, lowering its lateral angle
    • Innervation: Dorsal Scapular C5
  • Levator Scapulae:
    • Action: Elevates scapula and laterally flexes the neck when the scapula is fixed.
    • Innervation: Dorsal scapular C5
  • Pectoralis Minor:
    • Action: Draws the scapula anteriorly and inferiorly.
    • Innervation: Medial pectoral C8, T1
  • Serratus Anterior:
    • Action: Stabilizes, abducts and rotates the scapula.
    • Innervation: Long thoracic C5-C7

Functional Anatomy

  • Stability:
    • Round humeral head articulates with flat glenoid.
    • Rotator cuff and long head of biceps provide dynamic stability.
    • Supraspinatus compresses the head, while other rotator cuff muscles depress the humeral head during overhead motion.
    • Muscle contractions dynamically control the capsule.
  • Scapular Stabilizing Muscles:
    • Act as a stabilizing platform for Glenohumeral motion.
    • Strong scapular muscles are imperative for efficient joint mechanics and function.
  • Scapulohumeral Rhythm:
    • Movement of scapula relative to the humerus.
    • Initial 30° of Glenohumeral (GH) abduction does not incorporate scapular motion (setting phase).
    • After the initial 30° of abduction there is a 2:1 ratio between GH and Scapulothoracic (ST) motion.

Prevention of Shoulder Injuries

  • Proper physical conditioning and warm-up are key.
  • Strengthen through full ROM.

Assessment of the Shoulder Complex

  • History, Functional Assessment, Inspection/Observation, Palpation.
  • Joint and Muscle Function Assessment:
    • Goniometry, AROM, MMT, PROM.
  • Joint Stability (Mobility) Tests & Joint Play Assessment.
  • Neurological & Vascular Examination.
  • Distal Pulses & Capillary Refill.

History Questions

  • Cause of pain, mechanism of injury, previous history.
  • Location, duration, and intensity of pain.
  • Crepitus, numbness, distortion in temperature.
  • Weakness or fatigue; what provides relief?

Observation

  • Anterior:
    • Level of the shoulders, position of the head and arm, contour of clavicles.
    • Symmetry of the deltoid muscle group, Anterior humerus and biceps brachii muscle group
  • Posterior:
    • Alignment of the vertebral column, position of the scapula.
    • Muscle development, position of the humerus. Sprengel deformity—congenitally undescended scapula

Palpation

  • Bony:
    • Sternoclavicular joint, clavicular shaft, Acromioclavicular joint, coracoid process, acromion process, Humeral head, Greater and lesser tuberosity, Bicipital groove, Spine of scapula, Vertebral border of scapula, Lateral border of scapula, Superior angle of scapula, Inferior angle of scapula
  • Soft Tissue:
    • Sternoclavicular, acromioclavicular and coracoclavicular ligaments, Rotator cuff muscles and tendons, Subacromial bursa, Sternocleidomastoid, Biceps and tendon, Coracoacromial ligament, Glenohumeral joint capsule, Deltoid muscles, Rhomboids, Latissimus dorsi, Serratus anterior, Levator scapulae, Trapezius, Supraspinatus, Infraspinatus, Teres major and minor

Joint & Muscle Function Assessment

  • Active and Passive ROM:
    • GH: Flexion/Extension, Abduction/Adduction, Internal/External Rotation, Horizontal Abduction/Adduction.
    • Shoulder Girdle: Elevation, Depression, Adduction (retraction), Abduction (protraction), Upward and Downward Rotation, Forward and backward tilt.
  • Muscle Testing: Muscles of the shoulder and those that serve as scapular stabilizers.
  • PROM

Range of Motion

  • Test AROM first then PROM
  • GH motion, Scapular motion, Combined movements (Apley’s scratch test)

Joint Mobility Assessment

  • GH Joint Mobility:
    • Loose-packed position - 55° of flexion and 20-30° of horizontal abduction
    • Assess Distraction, Caudal (inferior) glide, Posterior glide, Anterior glide
  • Scapulothoracic Joint Mobility:
    • Assess Inferior, Superior, Lateral, Medial

Special Tests

  • Test for SC Joint Instability, apply pressure to the SC joint anteriorly, superiorly and inferiorly to determine stability and/or pain with a joint sprain
  • Test for AC Joint Instability, Palpate for displacement of acromion and distal head of clavicle. Apply pressure in all 4 directions to determine stability

Shoulder Instability

  • Glenohumeral instability: Anterior, Posterior, Inferior, Multidirectional instability.
  • Can be caused from a fall with subsequent dislocation or subluxation. Additionally, instability can be caused by a labral tear

Shoulder Instability Clusters

  • Anterior instability: Apprehension test and anterior release test
  • Anterior labral tear: Apprehension test, anterior load and shift, and sulcus sign
  • Posterior instability: Jerk test and Kim test (modification of Jerk test)

Special Tests for GH Instability

  • GH Translation – anterior and posterior instability (Load & shift)
  • Anterior and posterior drawer tests
  • Sulcus Test
  • Clunk Test
  • Apprehension & Relocation (Crank Test)
    *

Subacromial Impingement Syndrome

  • Irregularly shaped acromion, Spur formation on acromion, Os acromiale
  • Loss of humeral head depression or stabilization, Poor posture, Repetitive overhead movement, Scapular dyskinesis, GH instability, Supraspinatus hypertrophy
  • Glenohumeral internal rotation deficit (GIRD)

Tests for Impingement

  • Neer’s Test and Hawkins-Kennedy test for impingement

Rotator Cuff Pathology

  • Impingement syndrome
  • Rotator cuff tendinopathy or tear
  • Subacromial bursitis

Rotator Cuff Tendinopathy Cluster

  • Hawkins-Kennedy test, infraspinatus muscle test, painful arc sign

Tests for Supraspinatus Muscle Weakness

  • Drop Arm Test, Empty Can Test

Tests for Infraspinatus Weakness

  • Infraspinatus Strength Test, External Rotation Lag Sign

Biceps Pathology and SLAP Tears

  • Bicipital tendinopathy
  • Superior labrum anterior to posterior lesions (SLAP lesions)

Biceps Tendon Pathology Cluster

  • Yergason’s test, Speed’s test, Gilcrest palm-up test

Tests for Biceps Irritation

  • Yergason’s test, Speed’s testLudington’s test

SLAP Lesions

  • Superior Labrum Types I-IV, Anterior to Posterior
  • LHBT = long head of the biceps tendon
  • SLAP = superior labrum anterior to posterior

SLAP Lesion Cluster

  • Biceps load test I and II
  • O’Brien test (Active Compression Test)

Thoracic Outlet Syndrome Causes

  • Physical trauma from a car accident
  • Repetitive injuries from job- or sports- related activities
  • Certain anatomical defects (such as having an extra rib)
  • Pregnancy

Tests for Thoracic Outlet Syndrome

  • Anterior scalene syndrome (Adson’s test)
  • Hyperabduction syndrome test (Allen’s test)
  • Military brace position test
  • Costoclavicular Syndrome Test (Roo’s Test)

Key On Field Examination of Shoulder Injuries

  • Palpation under the shoulder pads

On Field History Notes

  • Location of pain – Upper shoulder (AC sprain, Trapezius, Brachial plexus injury)
  • MOI – Internal or external rotation (with abduction) (GH joint dislocation or subluxation), FOOSH (Clavicular fracture, AC sprain, SC sprain)
  • Arm posture, Gross deformity

Injuries and Management

  • Scapular Fracture: Sling and X-ray follow-up.
  • Clavicular Fracture: Sling, figure 8 brace, may require surgery.
  • Fractures of the Humerus: Splint, treat for shock, refer.
  • Sternoclavicular Sprain: RICES, immobilize, reconditioning.
  • Acromioclavicular Sprain: Ice, stabilization, referral; potential surgery.
  • Glenohumeral (GH) Joint Sprain: RICES, rehab for ROM and strength.
  • Acute Subluxations & Dislocations: RICES, reduction by physician, immobilization.
  • Chronic Recurrent Instabilities: Strengthening, bracing, potential surgery.
  • Impingement Syndrome: Address mechanical compression and GH instability.
  • Rotator Cuff Tear: Analgesics, electrical stimulation, NSAIDs, US; potential surgery.
  • Scapular Dyskinesis: Strengthen stabilizers, stretch capsule and muscles.
  • Shoulder Bursitis: Cold, US, NSAIDs, ROM maintenance.
  • Adhesive Capsulitis: Mobilizations, stretching, electric stimulation, US.
  • Thoracic Outlet Syndrome: Correct anatomical condition, stretch, strengthen; possible surgery.
  • Biceps Brachii Rupture: Ice, sling, refer; potential surgery.
  • Bicipital Tenosynovitis: Rest, ice, US, NSAIDs, strengthening/stretching.
  • Contusion of Upper Arm: RICE, protection, ROM maintenance.
  • Peripheral Nerve Injuries: RICE, referral if muscle wasting occurs.