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47 terms

Ch. 10 Shoulder Joint

Origins and Insertions, Ligaments, Muscles, Bones and Landmarks
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Shoulder Joint
a ball-and-socket joint with movement in all three planes and around all three axes; has 3 degrees of freedom; made up of the humeral head articulating with the glenoid fossa of the scapula; most movable joint in the body and least stable
Shoulder Joint Motions
-flexion/extension and hyperextension
-abduction and adduction
-medial and lateral rotation
-horizontal abduction and horizontal adduction
Scaption
motion similiar to flexion and abduction
Scapular Plane
opposed to the sagittal or frontal plane; approximately 30 degrees forward of the frontal plane; most common functions occur in this plane
Glenoid Fossa
A shallow, somewhat egg-shaped socket on the superior end, lateral side; articulates with the humerus
Glenoid Labrum
Fibrocartilaginous ring attached to the rim of the glenoid fossa, which deepens the articular cavity
Subscapular Fossa
Includes most of the area on the anterior (costal) surface, proving attachment for the subscapularis muscle
Infraspinous Fossa
Below the spine, proving attachment for the infraspinatus muscle
Supraspinous Fossa
Above the spine, providing attachment for the supraspinatus muscle
Axillary Border
Proving attachment for the teres major and teres minor muscles
Acromion Process
Broad, flat area on the superior lateral aspect, providing attachment for the middle deltoild muscle
Humerus
longest and largest bone of the upper extremity
Head of Humerus
semirounded proximal end; articulates with the scapula
Surgical Neck
Slightly constricted area just below tubercles where the head meets the body
Anatomical Neck
Circumferential groove separating the head from the tubercle
Shaft
Or "body"; the area between the surgical neck proximally and the epicondyles distally
Greater Tubercle
Large projection lateral to head and lesser tubercle; provides attachment for the supraspinatus, infraspinatus, and teres minor muscles
Lesser Tubercle
Smaller projection on the anterior surface, medial to the greater tubercle; provides attachment for the subscapularis muscle
Deltoid Tuberosity
On the lateral side near the midpoint; not usually a well-defined landmark
Bicipital Groove
"intertubercular groove"; the longitudinal groove between the tubercles, containing the tendon of the long head of the biceps
Bicipital Ridges
lateral and medial lips of the bicipital groove, or the crests of the greater and lesser tubercles, respectively; lateral lip (crest of greater tubercle) provides attachment for the pectoralis major and the medial lip (crest of lesser tubercle) provides attachment for the latissimus dorsi and teres major
Joint Capsule
thin-walled, spacious container that attaches around the rim of the glenoid fossa of the scapula and the anatomical neck of the humerus; formed by fibrous membrane and inner synovial membrane
Glenohumeral Ligaments (Superior, Middle, Inferior)
reinforce the anterior portion of the capsule;not well-defined ligaments but actually pleated folds of the capsule
Coracohumeral Ligament
attaches from the lateral sides of the coracoid process and spans the joint anteriorly to the medial side of the greater tubercle; strengthens the upper part of the joint capsule
Bursae of the Shoulder
-subdeltoid bursae, large and located between the deltoid muscle and the joint capsule
-subacromial bursa, lies below the acromion and coracoacromial ligament, between them and the joint capsule
Rotator Cuff
tendinous band formed by the blending together of the tendinous insertions of the:
-subscapularis
-supraspinatus
-infraspinatus
-teres minor muscles
Note: these muscles help to keep the head of the the humerus "rotating" against the glenoid fossa during joint motion
Thoracolumbar Fascia
"lumbar aponeurosis"; superficial fibrous sheet that attaches to the spinous processes of the lower thoracic and lumbar vertebrae, the supraspinal ligament, and the posterior part of the iliac crest, covering the sacrospinalis muscle; provides a very broad attachment for the latissimus dorsi muscle
Deltoid (Anterior, Middle, Posterior) Muscle: Origin, Insertion, Action, Nerve
O- AD: lateral third of the clavicle
MD: acromion process
PD: spine of scapula
I- deltoid tuberosity
A- AD: shoulder abduction, flexion, medial rotation, and horizontal adduction
MD: shoulder abduction
PD: shoulder abduction, extension, hyperextension, lateral rotation, horizontal abduction
N- axillary nerve (C5,C6)
Note: AD=anterior deltoid; MD=middle deltoid; PD=posterior deltoid
Pectoralis Major Muscle (Clavicular Portion): Origin, Insertion, Action
O-medial third of clavicle
I- lateral lip of bicipital groove
A- shoulder flexion -- first 60 degrees
Pectoralis Major Muscle (Sternal Portion: Origin, Insertion, Action
O-sternum, costal cartilage of first six ribs
I-lateral lip of bicipital groove of the humerus (same as clavicular)
A-shoulder extension -- first 60 degrees (from 180 to 120)
Pectoralis Major Muscle (Clavicular and Sternal Portion) Action, Nerve
A-shouder adduction, medial rotation, and horizontal adduction
N-lateral and medial pectoral nerve (C5,C6,C7,C8, T1)
Latissimus Dorsi Muscle: Origin, Insertion, Action, Nerve
O-spinous process of T7 through L5 (via dorsolumbar fascia), posterior surface of sacrum, iliac crest, and lower three ribs
I-medial floor of bicipital groove of humerus
A-shoulder extension, adduction, medial rotation, hyperextension
N-thoracodorsal nerve (C6,C7,C8)
Teres Major Muscle: Origin, Insertion, Action, Nerve
O- axillary border of scapula near the inferior angle
I- crest below lesser tubercle inferior to the latissimus dorsi muscle attachment
A-shoulder extension, adducton, and medial rotation
N-lower subscapular nerve (C5,C6,C7)
Supraspinatus Muscle: Origin, Insertion, Action, Nerve
O- supraspinous fossa of the scapula
I- greater tubercle of humerus
A-shoulder abduction
N-suprascapular nerve (C5,C6)
Infraspinatus Muscle: Origin, Insertion, Action, Nerve
O-infraspinous fossa of the scapula
I- greater tubercle on humerus
A-shoulder lateral rotation, horizontal abduction
N-suprascapular nerve (C5,C6)
Teres Minor Muscle: Origin, Insertion, Action, Nerve
O- axillary border of scapula
I- greater tubercle of humerus
A-shoulder lateral rotation, horizontal abduction
N- axillary nerve (C5,C6)
Subscapularis Muscle: Origin, Insertion, Action, Nerve
O- subscapular fossa of the scapula
I- lesser tubercle of the humerus
A- shoulder medial rotation
N- upper and lower subscapular nerve (C5,C6)
Coracobrachilalis Muscle: Origin, Insertion, Action, Nerve
O- coracoid process of the scapula
I- medial surface of the humerus near the midpoint
A- stabilizes the shoulder joint
N- musculocutaneous nerve (C6,C7)
Flexion
anterior deltoid, pectoralis major (clavicular)
Extension
posterior deltoid, latissimus dorsi, teres major, pectoralis major (sternal)
Hyperextension
latissimus dorsi, posterior deltoid
Abduction
deltoid, supraspinatus
Adduction
pectoralis major, teres major, latissimus dorsi
Horizontal Abduction
posterior deltoid, infraspinatus, teres minor
Horizontal Adduction
pectoralis major, anterior deltoid
Lateral Rotation
infraspinatus, teres minor, posterior deltoid
Medial Rotation
latissimus dorsi, teres major, subscapularis, pectoralis major, anterior deltoid