Shoulder Anatomy

Shoulder  It is a ball and socket joint that moves in all three planes and has: Most mobile and least stable joint.

Shoulder joint motions  Flexion- is raising the arm in the lateral plane from degrees.  Extension- return to anatomical position.  Hyperextension degrees back through the lateral plane.

Shoulder joint motions  Abduction- arm moving in the frontal plane away from the body, with a degrees of motion.  Adduction- arm moving back to midline, with degrees of motion.

Shoulder joint motions  Internal Rotation- occur in the transverse plane. This can go to 90 degrees into body  External Rotation- occurs in the transverse plane, 90 degrees out from neutral.

Shoulder joint motions  Horizontal abduction/adduction- occurs in the transverse plane. Neutral is 90 degrees of shoulder abduction, so horiz abduction is 120 degrees and adduction is 30 degree.

Shoulder joint motions  Scaption- flexion in the scapular plane, vs the lateral or frontal plane. 180 degree of motion can occur.

Shoulder Landmarks Scapula Glenoid labrum-fibrocartilage ring attached to the rim of the glenoid fossa, which deepens the cavity.

Shoulder Landmarks  Humerus- Head- is the semi round proximal end, articulates with the scapula. Shaft- body of the humerus is the area between the neck and the epicondyles.

Shoulder Landmarks  Surgical Neck- where the head meets the body.  Anatomical neck- where the head meets the tubercles.

Shoulder Landmarks  Greater Tubercle/Tuberosity- large projection lateral to the head. Supraspinatus, infraspinatus and teres minor attach here.

Shoulder Landmarks  Lesser Tubercle/Tuberosity- smaller projection on the anterior surface, subscapularis attaches here.

Shoulder Landmarks  Deltoid tuberosity- lateral side, near the midpoint, deltoid attaches here.

Shoulder Landmarks  Bicipital Groove- groove between the tubercles containing the long head of the biceps tendon.

Impingement Syndrome  A condition that occurs when the space between the humeral head and the acromion above becomes narrowed.  The three things that can get pinched are the: joint capsule, tendons of rotator cuff, and bursa.

Impingement Syndrome  Impingement can create either bursitis, or tendonitis depending on what structure is being squeezed.  Overhead athletes are more likely to have problems with this injury.  1/3 of shoulder problems are due to impingement.

Impingement Syndrome  Signs and Sx Pain and tender GH joint Pain and weak active abd in mid range Limited internal rotation + Hawkins Test Tender subacromial area possibly into the deltoid  Treatment Correct technique Strengthen inferior muscles Strengthen weak rotator cuff muscles

Rotator Cuff Tears  In the young person it is more of a traumatic injury, fall on outstretched arm, arm yanked back.  Young person can have chronic injury that ultimately tears a tendon.  In the older person it is a result of lose of elasticity in the muscle and tendon and can tear with everyday activities or a bone spur.

Rotator Cuff Tears  Signs and Sx With a parcial tear the athlete will feel pain but still be able to move with normal ROM. With a complete tear the athlete will not have normal ROM. Overhead motions are hardest. A shrug motion will result. Pain sleeping on injured side.

Muscles of the Shoulder Joint  The four rotator cuff muscles cover the humeral head and hold the head against the glenoid fossa.

Rotator Cuff Muscles  Know these muscles if you remember nothing else. Infraspinatus Supraspinatus Subscapularis Teres Minor

Rotator Cuff Muscles  Teres Minor- posterior shoulder External rotation Insertion on greater tubercle of humerus

Rotator Cuff Muscles  Infraspinatus- posterior inferior shoulder region Inferior to the spine of the scapula External rotation Insertion is greater tubercle of humeus

Rotator Cuff Muscles  Supraspinatus-anterior superior shoulder. It is superior to the spine of the scapula. abduction

Rotator Cuff Muscles  Subscapularis-anterior shoulder Internal rotation Insertion is lesser tubercle of humerus

Rotator Cuff Muscles

Biceps Tendonitis  Discomfort in the front of the shoulder.  Can be caused by impingement.  Special Tests- Speed’s Test Yergeson’s Test

Traumatic Shoulder Injuries  Shoulder Dislocation  Glenoid Labrum Injuries  Multidirectional Instabilites  Acromioclavicular Separation  Brachial Plexus Injury  Fractures

Anterior Shoulder Dislocation  A humerus can dislocate Anteroinferiorly-front and down (most common) Inferiorly – down Posteriorly -back

Anterior Shoulder Dislocation  Anterior dislocation happens when the arm is abducted to the side and a forceful external rotation happens.  It happens due to gravity, shallow fossa, weight of upper extremity.  Even if it goes back a Hill-Sach’s Lesion can occur.

Anterior Shoulder Dislocation  Rehabilitation is very important to this injury.  Reinjury will likely happen if a first time injury happens before the age of 20.  Surgery may be necessary if repeated dislocation occurs.

Special Test-Dislocation  Apprehension test

Muscles of the shoulder joint  Coracobrachialis- attaches to the coracoid process and the arm or Brachium. Stabalizes the humerus in the fossa.

Muscles of the shoulder  Triceps brachii- entire muscle mass of posterior arm. It attaches to the olecranon process when all 3 heads of the muscle combine. Function is extension. Radial nerve.

Muscles of the Shoulder Joint  Teres Major- it is the little helper of the lats. It runs from the axillary boarder of the scapula to the lesser tubercle of the humerus.

Glenoid Labrum Injury  Glenoid Labrum-a ring of cartilage attached to the margin of the glenoid cavity of the scapula.  The labrum acts to keep the humeral head positioned on the glenoid by blocking unwanted movement.

Glenoid Labrum Injury  A labral tear can occur with a shoulder dislocation, more likely to occur with numerus dislocations.  A degenerative tear can occur when a shoulder becomes loose, letting the humeral head slip over the labrum numerus times and eventually the labrum will fail/tear.

Glenoid Labrum Injury  Signs and Sx Pain with catching and popping Possible weakness Possible limited ROM  Special Tests Clunk Test Cross Over Test  Treatment Rotator Cuff strengthening Surgery

Multidirectional Instabilities  Typically an anatomical problem.  Multiple dislocations will make it worse.  Exercise may help with the problem, surgery sometimes, but not always  Weight bearing exercise are helpful. Like what?

Acromicavicular Separation  Also known as an AC sprain.  Occurs due to fall on outstretched arm or tip of shoulder. May be due to blow to tip of shoulder

AC separation  Signs and Sx deformity Pain in vicinity of AC  Special Test Shear Test Sulcus Sign  Treatment Three grades –the grade determines treatment Grade one is exercise and ice Grade two immobilize 3 weeks and then exercise Grade three immobilize 5 weeks and then exerccise

Muscles of the Shoulder Joint  Deltoid is superficial muscle. All three parts of it attach to the deltoid tuberosity.  Axillary Nerve

Muscles of the Shoulder Joint  Pectoralis Major- Clavicular portion-most effective during flexion from 0-90 Sternal portion- most effective in extension degrees of shoulder extension Both of them adduct, internally rotate and horizontally adduct the shoulder.

Muscles of the Shoulder Joint  Latissimus Dorsi- means widest, back, so the widest back muscle. It is mostly superficial and is involved with shoulder extension, adduction and internal rotation