PS 1001:03 Lecture 15: shoulder complex
Understand the mechanics of the glenohumeral articular surfaces,
fibrous capsule and ligaments
Synovial spheroidal multi-axial joint
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Articular surfaces - head of humerus and glenoid cavity/fossa of scapula, contact area
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Glenoid labrum
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Articular capsule
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Ligaments
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Glenohumeral joint
Superior facet (supraspinatus)
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Middle (infraspinatus)
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Inferior (teresminor)
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3 rotator cuff muscles attach to these (use SIT acronym to remember)
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3 large smooth facets for muscle attachment
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Greater tubercle is lateral in physician
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Has smooth impression for subscapularis (rotator cuff muscle) to attach to
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Lesser tubercle - more anterior
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Anatomical neck
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Important due to axillary nerve and posterior circumflex hemalartery
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Weaker area
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More commonly fractures in this area -> nerve damage
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Surgical neck
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2 necks
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Bony points and articular surfaces proximal third of humerus
Screen clipping taken: 3/04/2018 12:09 AM
L2- shoulder complex
Tuesday, 3 April 2018
12:03 AM
wk 7 Page 1
Supraspinous fossa - attach to supraspinous muscle
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Infraspinous fossa - attach to infraspinous muscle
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Coracoid process anterior
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Acromion articulates with clavicle
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Infraglenoid tubercle
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Attachment of biceps tendons
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Supraglenoid tubercle
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Bony points and articular surfaces of scapula
Screen clipping taken: 5/04/2018 5:32 PM
Theoretical position, look at it in relationship to thoracic spine
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Spine of scapula -T2
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Inferior angle - T7
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Medial border - parallel to spinous process and 2 inches/5cm away from spine
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Scapular neutral
Multiaxial joint
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Head of humerus articulates with glenoid cavity of scapula
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Relatively unstable
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Maybe due to weak ligaments, weak cuff muscles
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Rely on ligaments and muscles for stability -> prone to dislocation
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Articular surfaces glenohumeral joint
wk 7 Page 2
Screen clipping taken: 5/04/2018 5:33 PM
Increase stability
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Triangular cross section
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Margins of glenoid cavity attaches to base of triangle -> makes glenoid caivty deeper
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Relatively shallow depression of glenoid cavity made deeper by fibrocartilage around edge -
called glenoid labrum
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Tendon of longheaded biceps brachii and triceps blend with glenoid labrum -> reinforces
capsular ligaments from anterior and posterior aspects
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Articular capsule - attached to margin of glenoid cavity and to anatomical neck of humerus
(towards the top)
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Relaxed
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Inferior part
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Strengthened by anterior glenoidhumeral ligaments
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Anterior part
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Strengthened by coracohumeral ligament
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Superior part
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Tendons help blend with capsule, attachments act as dynamic stabilisers of the joint
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Glenoid labrum and glenohumeral capsule
Screen clipping taken: 5/04/2018 5:33 PM
Intrinsic - part of fibrous capsule
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Help strengthen anterior aspect of capsule
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Superior glenohumeral - point just above lesser tubercle of humerus
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Middle - points on lower part of lesser tubercle
Anterior part of capsule 3 bands
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Glenohumeral ligaments
wk 7 Page 3
Document Summary
Understand the mechanics of the glenohumeral articular surfaces, fibrous capsule and ligaments. Articular surfaces - head of humerus and glenoid cavity/fossa of scapula, contact area. Bony points and articular surfaces proximal third of humerus. 3 rotator cuff muscles attach to these (use sit acronym to remember) Has smooth impression for subscapularis (rotator cuff muscle) to attach to. Important due to axillary nerve and posterior circumflex hemalartery. More commonly fractures in this area -> nerve damage. Screen clipping taken: 3/04/2018 12:09 am wk 7 page 1. Theoretical position, look at it in relationship to thoracic spine. Medial border - parallel to spinous process and 2 inches/5cm away from spine. Head of humerus articulates with glenoid cavity of scapula. Rely on ligaments and muscles for stability -> prone to dislocation. Maybe due to weak ligaments, weak cuff muscles wk 7 page 2. Relatively shallow depression of glenoid cavity made deeper by fibrocartilage around edge - called glenoid labrum.
