shoulder biomechanics by 김송준

[문형철]

어깨 통증을 glenohumeral joint와 관련된 좁은 사고에서 벗어나는 것이 치료의 핵심이다.

3개의 anatomical joint, 2개의 physiological joint(scapulothoracic arrticulation, acromiohumeral articulation)

Glenohumeral joint

The glenohumeral joint is the articulation between the head of the humerus and the glenoid cavity of the scapula. It is a ball and socket type of synovial joint. The glenohumeral joint allows for adduction, abduction, medialand lateral rotation, flexion and extension of the arm.

Acromioclavicular joint

The acromioclavicular joint is the articulation between the acromion process of the scapula and the lateral end of the clavicle. It is a plane type of synovial joint. The acromion of the scapula rotates on the acromial end of the clavicle.

Sternoclavicular joint

The sternoclavicular joint is the articulation of the manubrium of the sternum and the first costal cartilage with the medial end of the clavicle. It is a saddle type of synovial joint but functions as a plane joint. The sternoclavicular joint accommodates a wide range of scapula movements and can be raised to a 60° angle during elevation of the scapula.

Scapulocostal joint

The scapulocostal joint (also known as the scapulothoracic joint) is a physiological joint formed by an articulation of the anterior scapula and the posterior thoracic rib cage. It is musculotendinous in nature and is formed predominantly by the trapezius, rhomboids and serratus anterior muscles. The pectoralis minor also plays a role in its movements. The gliding movements at the scapulocostal joint are elevation, depression, retraction,protraction and superior and inferior rotation of the scapula.

Suprahumeral joint

The suprahumeral joint (also known as the subacromial joint) is a physiological joint formed by an articulation of the coracoacromial ligament and the head of the humerus. It is formed by the gap between the humerus and the acromion process of the scapula. This space is filled mostly by the subacromial bursa and the tendon of supraspinatus. This joint plays a role during complex movements while the arm is fully flexed at the glenohumeral joint, such as changing a lightbulb, or painting a ceiling.

shoulder girdle을 구성하는 뼈

1) scapular - 잊지 말자. acromion, coracoid process, glenoid fossa는 모두 scapular의 일부임을

2) humerus - 움직임의 부속물일 뿐

3) clavicle - acromioclavicular joint에서 어깨 full flex, adduction시 45도 회전을 해야 한다

4) rib - scapularthoricic joint(rib2-7).  치료에 joint play가 필수임을 잊지말자. 

5) sternum - interclavicular ligament의 긴장

가장 중요한 뼈. scapular

- 어깨통증 치료의 초점은 scapular가 neutral position에 오게 하는 것이다. 

- 어깨의 문제는 scapular 가 neutral position에 오게 하면 많은 어깨 통증문제가 해결된다.

- brachial plexus에서 분지되는 많은 신경에 영향을 고려해야

- shoulder girdle의 문제는 lower kinetic chain에 반사적으로만 영향을 미치기 때문에 판단이 어렵다

scapular 안정화 근육 두가지

1) serratus anterior -=> suction mechanism이라는 표현을 쓴다. winging scapular, long thoracic nerve가 작용

2) trapezius muscle의 lower part

- coracoclavicular ligament와 근육이 안정성에 도움을 준다.

-=> 안정화 근육 운동법 추가해야..

The Role of the Scapula in the Rehabilitation of Shoulder I.pdf

scapular movement

1) protraction- scapular의  anatomical term of motion for anterior movement of an anatomical part of the body forward

2) retraction

3) elevation

4) depression

5) rotation - inward rotation, outward rotation

6) adduction

7) abduction

유튜브 동영상으로 보기

http://www.youtube.com/watch?v=rRIz6oOA0Vs

glenoid fossa

- 1/3은 bone, 1/3은 laborum, 나머지 1/3은 joint capusle로 둘러쌈.

Scapulohumeral rhythm:

(describes the timing of movement at these joints during shoulder elevation.)

1. first 30 degrees of shoulder elevation involves a "setting phase":
   • The movement is largely glenohumeral.
   • Scapulothoracic movement is small and inconsistent.
   • 5:1 ratio of glenohumeral to scapulothoracic movement
2. after the first 30 degrees of shoulder elevation:
   • The glenohumeral and scapulothoracic joints move simultaneously.
   • Overall 2:1 ratio of glenohumeral to scapulothoracic movement.

You can observe scapulohumeral rhythm by palpating the scapula's position as a person elevates the shoulder. Helpful scapular landmarks for palpation are the base of the spine and the inferior angle.

Scapulohumeral rhythm serves at least two purposes.

1. It preserves the length-tension relationships of the glenohumeral muscles; the muscles do not shorten as much as they would without the scapula's upward rotation, and so can sustain their force production through a larger portion of the range of motion.
2. It prevents impingement between the humerus and the acromion. Because of the difference in size between the glenoid fossa and the humeral head, subacromial impingement can occur unless relative movement between the humerus and scapula is limited. Simultaneous movement of the humerus and scapula during shoulder elevation limits relative (arthrokinematic) movement between the two bones.

glenoid laborum

- fibrocartilagnous rim that act to deepen the glenoid fossa

- slap(superior labrum with anterior posterior extension) tear

O'Brien test SLAP lesion test

http://www.youtube.com/watch?v=LCBnJCsC5hI

[heoss]

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