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Overview
Overview
Shoulder (glenohumeral) joint: articulation of the head of the humerus and the glenoid fossa of the scapula
Ball-in-socket joint - more mobile than stable
Movements
Movements
Flexion: ROM 0-180/extension - ROM 0-60
Sagittal plane & frontal axis
Spin
Abduction: ROM 0-180/adduction (glide/roll)
Medial: ROM 0-70/lateral rotation: ROM 0-90
Horizontal abduction/adduction (shoulder only)
Greater tubercle of the proximal humerus limits shoulder abduction & flexion ROM when the shoulder is not rotated laterally
Lateral rotation moves the tubercle posteriorly from under the acromion to avoid contact
Circumduction: a combination of all shoulder movements that describes the arc/circle of movement possible at the shoulder
Scaption: used to describe movements that occur in the plane of the scapula (30 degrees forward of the frontal plane
The glenohumeral joint in an open-packed position of 55 degrees abduction and 30 degrees horizontal adduction = greatest amount of arthrokinematic movement
Has a firm end feel
Bone Landmarks
Bone Landmarks
Scapula
Glenoid fossa: slightly concave surface at superior end of axillary border; faces slightly anteriorly, laterally, and superiorly
Infraglenoid tubercle: raised portion on the inferior lip of the glenoid fossa; attachment for long head of triceps brachii
Supraglenoid tubercle: raised portion on superior lip of glenoid fossa; attachment for long head of biceps brachii
Coracoid process: beak-shaped projection on anterior-superior surface; attachment for short head of biceps brachii, coracobrachialis, & pectoralis minor
Glenoid labrum: fibrocartilaginous ring attached to rim of glenoid fossa; deepens articular cavity
Subscapular fossa: slightly concave anterior (costal) surface of scapula; attachment for subscapularis
Infraspinous fossa: posterior aspect of scapula inferior to spine of scapula; attachment for infraspinatus
Supraspinous fossa: concave posterior aspect of scapula superior to spine of scapula; attachment for supraspinatus
Humerus
Head: convex proximal end; faces medially & slightly posteriorly; articulates with glenoid fossa
Anatomical neck: circumferential groove between head & tubercle
Greater tubercle: large projection lateral to head & lesser tubercle; attachment for supraspinatus, infraspinatus, & teres minor
Lesser tubercle: smaller projection on anterior surface; medial to greater tubercle; attachment for subscapularis
Surgical neck: slightly constricted area just below tubercles; between tubercles & shaft
Shaft (body): area between surgical neck proximally and condyles distally
Deltoid tuberosity: slight protuberance on lateral aspect; midway between surgical neck and midpoint of shaft; attachment for deltoid
Bicipital (intertubercular) groove: anterior longitudinal groove between tubercles; path for long head of biceps tendon; attachment for latissimus dorsi on floor of groove
Bicipital lips (medial/lateral ridges): medial/lateral margins of bicipital groove; attachment for teres minor (medial) & pectoralis minor (lateral)
Radius
Radial tuberosity: small protuberance on medial aspect near proximal end; attachment for biceps brachii
Ulna
Olecranon process: posterior proximal end of ulna; attachment for triceps brachii
Joints, Ligaments & Other Structures
Joints, Ligaments & Other Structures
Joints
Glenoid labrum (ring attached to glenoid fossa) increases stability of shoulder & enhances joint congruity
Subdeltoid bursa: large bursa located between deltoid and joint capsule
Subacromial bursa: bursa located between acromion & coracoacromial ligament & joint capsule
Ligaments
Joint capsule - thin-walled, attaches around the rim of glenoid fossa & neck of humerus
Inferior portion has extra folds to accommodate abduction/flexion -creates vacuum to help hold humeral head against glenoid fossa
Superior glenohumeral ligament: pleated folds of anterior capsule that attaches to supraglenoid tubercle & humerus near proximal tip of lesser tubercle
Middle glenohumeral ligament: pleated folds of anterior capsule that attaches below superior glenohumeral ligament along anterior glenoid margin & lesser tubercle; blends with tendon of subscapularis
Inferior glenohumeral ligament: pleated folds of anterior capsule that attaches to anterior/posterior aspects of glenoid fossa & to inferior/medial aspects of humeral neck; reinforces anterior capsule
Coracohumeral ligament: attaches to dorsal lateral side of coracoid process & greater/lesser tubercles of humerus; reinforces superior portion of joint capsule
Transverse humeral ligament: attaches to tubercles & lips of bicipital groove; encloses bicipital groove anteriorly; maintains tendon of long head of biceps in bicipital groove
Other structures
Rotator cuff: tendinous band formed by blending of tendinous insertions of subscapularis, supraspinatus, infraspinatus, & teres minor muscles --> forms "cuff" of muscles that surround the head of humerus
Maintains head of humerus within glenoid fossa
Thoracolumbar fascia (lumbar aponeurosis): fibrous sheet superficial to sacrospinalis; attaches to spinous process of lower thoracic and lumbar vertebrae, supraspinal ligament, posterior portion of iliac crest & sacrum; attachment for latissimus dorsi
Muscles
Muscles
Deltoid: superficial triangular-shaped muscle that covers the shoulder on three sides and gives the shoulder the rounded shape
Moves humerus within glenoid fossa - open kinetic chain
Anterior deltoid:
Origin = outer third of clavicle
Insertion = deltoid tuberosity
Action: abduction, horizontal adduction, flexion, medial rotation (of humerus); depression of shoulder girdle when humerus is stabilized
Diagonal line of pull - oblique
Middle deltoid:
Origin = acromion process (lateral side)
Insertion = deltoid tuberosity
Action: shoulder abduction, depression of shoulder girdle when humerus is stable
Diagonal line of pull - vertical
Posterior deltoid:
Origin = Spine of scapula
Insertion = deltoid tuberosity
Action: shoulder abduction, extension, lateral rotation, horizontal abduction
Diagonal line of pull - oblique
Biceps Brachii: large, fusiform muscle located superficially on the anterior aspect of the arm
Multi-joint muscle
Origin = Long head - supraglenoid tubercle of scap; short head - coracoid process
Insertion = radial tuberosity of radius
Action: shoulder flexion, elbow flexion, forearm supination
Diagonal line of pull - vertical
Coracobrachialis:
Origin = coracoid process of scap
Insertion = medial surface of humerus near midpoint
Action: shoulder flexion, adduction, stabilizes shoulder
Diagonal line of pull - vertical
Pectoralis Major: thick, fan-shaped superficial muscle
Clavicular portion:
Origin = medial third of clavicle
Insertion = lateral lip of bicipital groove of humerus (inferior to sternal portion)
Action: shoulder flexion (first 60degrees), medial rotation, adduction, horizontal adduction
Diagonal line of pull - mostly vertical (becomes horizontal when shoulder flexes)
Sternal Portion:
Origin = sternum; costal cartilage of first 6 ribs
Insertion = lateral lip of bicipital groove of humerus (superior to clavicular portion)
Action: medial rotation, adduction, horizontal adduction, shoulder extension from full flexion; elevates body when upper extremities are stabilized
Diagonal line of pull - vertical (in full flexion)
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