sports med shoulder anatomy

Anatomy of the shoulder

Joints: ball and socket joint

1st component

Humerus- upper arm (large)

2nd component

Clavicle- collar bone

3rd component

Scapula- shoulder blade (posterior)

Glenoid fossa

• The saucer-like portion of the scapula

• It is very shallow, making the joint susceptible to injury

• The socket where the humerus sits inside of the scapula, makes the glenohumeral shoulder joint

• The labrum stabilizes the head and the humerus of the glenoid cavity. 

• Common to injuries 

Shoulder joint 1

Acrimimioclavicualr (AC): attaches the distal end of the clavicle to the acromion process of the scapular

Shoulder joint 2

Sternoclavicular (SC): attaches the clavicle to the sternum

Shoulder joint 3

Glenohumeral: attaches the humerus to the glenoid fossa of the scapula

Attachers to the scapula

Supraspinatus (rotator cuff muscle + most often injured) 

Infraspinatus 

Teres minor 

Subscapularis

Deltoid muscle

• Main and large shoulder mover

• Abducts, flees and extends the shoulder

Cause of shoulder injuries

• Muscular weakness (imbalance) 

• Postural problems 

• Nature of the game: any time the elbow is above the shoulder there is risk 

Overuse- throwing swimming, swinging a racket, continual or repetitive overhead motions 

AC sprain (injury to ligament) bone to bone

• Also known as separated shoulder

• Acromioclavicular ligament sprain

Mechanism for AC injuries

• Falling on an outstretched arm 

• Direct blow to the end of the acromion clavicle 

1st, 2nd, 3rd, degree AC sprain

• The more serious the sprain the more movement superiorly (upwards) of the clavicle 

• In 2nd and 3rd degree separation the clavicle will leave a large abnormal bump at the end of the clavicle

• The athlete is usually unable to move the arm so they put it against the abdominal 

Special test

AC sprains: piano test (2 finger push down on clavicle + looking to pain, movement, and laxity) 

Treatment

• Price 

• Sling and swab 

Impingement syndrome

• Mechanisms: repetitive over the head motion

• The supraspinatus and the biceps run under the acromion process, when there is swelling present the space narrows causing pain and weakness. 

• Treatment: ICE, rest, anti-inflammatories, stringing of the scapular region is a must

Bicep tendonitis

• Mechanisms: the repetitive nature of movement will cause irritation of the tendon in the bicipital groove 

• Pain and crepitation may be present 

• Overhead repetitive motion must be stopped

Bicep tendon rupture

• Mechanisms: a direct blow or serve contractional forces 

• The athlete will be unable to flex the elbow 

• There will be noticeable change in the muscle

Clavicle fractures

• Most injured is the distal third because it is the weakest point

• Mechanism: direct blow or a fall on the tip of the shoulder

Bursitis of the shoulder

Mechanisms: the repetitive nature of movement

Dislocation vs Subluxation

• The head of the humerus is out of its socket= dislocation 

• The had of the humerus come out of the socket and goes back in = subluxation 

• Mechanisms: abduction and external rotation (most common is anterior)

Empty can

• Rotator cuff special test (supraspinatus) (most injured) 

• Shoulder 90 degree flexion and 45 degree abduction 

• Thumbs down 

• Resisting downward pressure 

• Positive test is pain and weakness