anatomy shoulder complex joints

What are the three synovial joints of the shoulder complex?

Sternoclavicular (SC), Acromioclavicular (AC), and Glenohumeral (GH)

What is the functional (physiological) joint of the shoulder complex?

Scapulothoracic joint.

What type of joint is the sternoclavicular joint?

Synovial saddle joint.

Sternoclavicular joint artculates between?

Medial clavicle, sternum, and first rib cartilage.

What is the only true bony connection to axial skeleton?

Sternoclavicular joint

Fibrocartilaginous articular disc.

What motions occur at the Sternoclavicular joint?

Elevation, depression, protraction, retraction, and axial rotation.

Anterior sternoclavicular ligament.

reinforces the anterior capsule

Posterior sternoclavicular ligament

reinforces the posterior capsule

Interclavicular ligament

spans the jugular notch and connects medial ends of clavicles

Costoclavicular ligament

first rib cartilage — clavicle

stablizes the joint through most motions

What type of joint is the Acromioclavicular joint?

Synovial gliding joint

Acromioclavicular joint artculates between?

acromion of scapula

acromial end of clavicle

oval articular facets

What motions occur at the Acromioclavicular joint ?

anteroposterior movement

vertical movement

axial rotation

contributes to shoulder girdle

superior Acromioclavicular liagament

reinforces superior joint capsule

reinforced by deltoid and trapezius

Coraclavicular ligament

primary extrinsic stabilizer

provides superior - inferior stability

• trapeziod ligament

• coniod ligament

What is a shoulder separation?

Injury to the AC joint

commonly caused by fall directly onto the shoulder.

May involved acromioclavicular ligament , corcoclavicular ligament

different from glenohumeral joint dislocation

What type of joint is the glenohumeral joint?

Synovial ball-and-socket joint.

mutiaxial joint

large range of motion

stability relies heavily on soft tissues

glenohumeral joint articulates between?

head of humerus and glenoid cavity of scapula

What motions occur at the Glenohumeral joint?

Flexion, extension, abduction, adduction, internal rotation, external rotation, and circumduction

What is the glenoid labrum?

Fibrocartilaginous ring surrounding the glenoid cavity.

Deepens and expands the glenoid cavity.

increases congruency between joint surfaces.

attachment sit for joint capsule

continous superiorly with Long head of the biceps tendon.

contributes to joint stability

Synovial membrane

• lines inner surface of joint capsule

• attaches to margins of articular cartilage

• produces synovial fluid

• reduces friction within the joint

• surrounds long head of biceps tendon

• redundant inferiorly to accommodate

Bursae

synovial -lined fluid filled sacs

reduce friction between structures

Faciliate smooth movement of muscles and tendons

help protect surrounding soft tissues

Name the three major bursae associated with the shoulder.

Subacromial, subdeltoid, and subscapular bursae.

Joint capsule

fibrous sleeve enclosing the Glenohumeral joint

attaches: around gleniod cavity, anatomical neck of humerus

relatively loose capsule

inferior folds increase mobility

reinforced by ligaments and muscle tendons

provides passive joint stability

Glenohumberal ligaments

thickened region of anterior joint capulse

attach from the gleniod rim and labrum to the humerus

reinforce the anterior and inferior joint capsule

What are the three GH ligaments

Superior glenohumeral ligament. (SGHL)

Middle glenohumeral ligament (MGHL)

Inferior glenohumeral ligament (IGHL)

What three parts make up the Inferior glenohumeral ligament complex?

Anterior band,

posterior band,

axillary pouch.

Which ligament resists inferior and anterior translation in neutral?

Superior glenohumeral ligament. (SGHL)

Which ligament resists anterior translation and external rotation?

Middle glenohumeral ligament (MGHL)

What is the primary stabilizer during shoulder abduction?

Inferior glenohumeral ligament (IGHL)

Which structure is the primary restraint to anterior humeral head translation?

Anterior band of the Inferior glenohumeral ligament

Which structure resists posterior translation and internal rotation stresses

Posterior band of the Inferior glenohumeral ligament

What supports the humeral head during abduction?

Axillary pouch

Coracohumeral ligament

Coracoid process to humerus.

Reinforces the superior capsule.

resist inferior and posterior translation; limits external rotation

assist in maintaining joint stability

Transverse humeral ligament

spans the intertubercular groove

secured long head of biceps tendon

assist in maintaining joint stability

Dynamic stabilizers

active stabilizers of glenohumeral joint

rotator cuff muscles: SITS

Tendons blend with joint capsule

compress humeral head into gleniod cavity

long head of biceps assists with stabilization

Rotator Cuff impingment

compression of strcutures within the supraspinatus outlet

What structure is most commonly affected in rotator cuff impingement?

Supraspinatus tendon

subacromial bursa

rotator cuff impingement may result from

thickened coracoaromial ligament

Acromoclavicular joint osetophytes

Hooked acromion

can lead to inflammation, tendon, dengeration, and pain

Scapulothoracic Joint

Functional articulation between scapula and thoracic wall

NOT A TRUE SYNOVIAL JOINT

NO direct bony contact between scapula and ribs

What muscles separate the scapula from the thoracic wall?

Subscapularis and serratus anterior, bursae

What primary motions occur at the scapulothoracic joint

Elevation, depression, protraction, retraction, upward rotation, and downward rotation

Between which ribs does the scapula normally rest?

Ribs 2-7

Resting postion: slight anterior tilt, upward rotation, and internal rotation (scapular plane)

Essential for normal shoulder mobility and function