Transcript SHOULDER COMPLEX

SHOULDER COMPLEX
Extrinsic Shoulder Muscles

Review the following:
Pectoralis major
Pectoralis minor
Serratus anterior
Trapezius complex
Latissimus dorsi
Levator scapulae
Rhomboideus major
Rhomboideus minor
Sensory Supply to Shoulder
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Supraclavicular nerves:
From cervical plexus
C3-4
Supply skin over clavicle and over the
superior-lateral aspect of pectoralis major
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Cutaneous branches of dorsal rami:
Penetrate deep and superficial back muscles
Supply skin on either side of midline of back
Shoulder Movements
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Elevation (scapula):
Levator scapulae and rhomboids
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Depression (scapula):
Latissimus dorsi
Shoulder Movements
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Abduction (scapula):
Serratus anterior
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Abduction (shoulder):
Middle deltoid
Biceps brachii assists
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Adduction (scapula):
Middle trapezius
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Adduction (shoulder):
Pectoralis major (clav)
Latissimus dorsi
Shoulder Movements
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Upward rotation (scapula):
Serratus anterior
Upper and lower
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trapezius (force couple)
Downward rotation (scapula):
Rhomboids
Levator scapulae
Quadrilateral Space
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Boundaries:
Inferior glenohumeral
capsule.
Teres major.
Triceps longus.
Surgical neck of humerus.
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Contents:
Axillary nerve.
Posterior circumflex
humeral artery.
Shoulder Complex Joints
Sternoclavicular joint (SC)
 Acromioclavicular joint (AC)
 Glenohumeral joint (GH)
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Sternoclavicular Joint (SC)
Plane synovial joint
 Articulating surfaces:
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Sternal end of clavicle
Articular notch on manubrium
First costal cartilage
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3 degrees of freedom
SC Joint Movements
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Elevation and depression:
Occurs around AP axis
Elevation = 45 degrees
Depression = 15 degrees
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Protraction and retraction:
Occurs around vertical axis
Protraction ROM = 15 degrees
Retraction ROM = 15 degrees
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Rotation:
Occurs around transverse axis
Sternoclavicular Joint
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Joint disc
Fibrocartilage meniscus
Attached to:
Clavicle inferiorly
Manubrium and first costal cartilage inferiorly
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Ligaments:
Anterior/posterior sternoclavicular ligaments:
Check anterior/posterior movements of
clavicular head.
SC Joint Ligaments
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Costoclavicular ligament:
Axis for elevation and depression
Axis for protraction and retraction
Main check for elevation
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Interclavicular
Acromioclavicular Joint
Plane synovial joint
 3 degrees of freedom
 Articulation surfaces:
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Convex facet on lateral end of clavicle
Concave facet on acromion
AC Joint Movements
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Scapular rotation:
Occurs around AP axis.
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Winging of vertebral border of scapula:
Occurs around vertical axis.
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Tipping of inferior angle of scapula:
Occurs around coronal axis.
Acromioclavicular Joint
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Acromioclavicular
ligaments:
Superior and inferior
Reinforce joint
capsule
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Coracoclavicular:
Trapezoid (lateral)
Conoid (medial)
Glenohumeral Joint
Ball-and-socket joint
 Synovial
 Components:
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Head of humerus
Glenoid fossa of scapula
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Glenoid labrum
Fibrocartilage meniscus
Deepens articulating surface of glenoid fossa
Glenohumeral Joint
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Ligaments:
Glenohumeral
Coracohumeral
Coracoacromial
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Joint capsule:
Very lax
Up to an inch of
passive distraction
GH Joint Movements
Flexion/extension of brachium:
 Abduction/adduction of brachium:
 Lateral/medial rotation of brachium:
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Shoulder Complex Components
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Scapulothoracic joint:
Not a true anatomic joint
Represented by sliding of scapula on thoracic cage
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Coracoacromial arch:
Components:
Acromion
Coracoid process
Coracoacromial ligament
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Subacromial/subdeltoid bursae
ROTATOR CUFF
Rotator Cuff
Composed of four muscles whose tendons
of insertion form a partial “cuff” around the
head of the humerus.
 Involved in snubbing and rotating head of
humerus
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Rotator Cuff Components
Supraspinatus
 Infraspinatus
 Teres minor
 Subscapularis
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S
I
T
S
Rotator Cuff
Rotator Cuff
Scapulohumeral Rhythm
Refers to relatively uninterrupted
movement of upper extremity from
dependent position to full abduction.
 Requires simultaneous and coordinated
movements of all the previous-named
joints.
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Scapulohumeral Rhythm
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ROM:
Full abduction:
180 degrees
Contributed by glenohumeral joint:
120 degrees
Contributed by scapulothoracic movement:
60 degrees:
Sternoclavicular joint = 40 degrees
Acromioclavicular joint = 20 degrees
Ratio of GH to ST = 2:1
Steps in Arm Abduction
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Movement (searching) of scapula:
Serratus anterior clamps scapula to thoracic wall
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Snubbing of head of humerus into glenoid fossa:
Rotator cuff muscles
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First few degrees of abduction:
Supraspinatus
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External rotation of humerus:
Infraspinatus
Clinical Applications
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Deltoid paralysis:
Axillary nerve
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Serratus anterior paralysis:
Long thoracic nerve
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Tears in rotator cuff
Supraspinatus most often torn: