shoulder osteology

Glenohumeral Joint

shoulder joint formed by the humerus and the glenoid fossa of the scapula

Scapulothoracic Joint

An anatomical joint that involves the movements of the scapula against the thoracic rib cage.

Acromioclavicular Joint

A joint that connects the acromion of the scapula to the clavicle.

Sternoclavicular Joint

The joint connecting the sternum to the clavicle.

Humerus

The bone of the upper arm that articulates with the shoulder joint.

humerus, glenoid fossa, clavicle (anterior)

primary elements of the GH joint

Glenoid Fossa

The shallow socket in the scapula that receives the head of the humerus.

spine of scapula

runs from medial root to lateral aspect of the acromion. divides supraspinatus and infraspinatus

Subscapularis Fossa

The anterior aspect of the scapula that provides space for the subscapularis muscle.

lateral border of scapula

where do teres minor and major attach?

medial border of scapula

where do rhomboids and levator scapulae attach?

Coracoid Process

A bony protrusion above the glenoid fossa short head of biceps attachment.

medial border

where does serratus anterior attach on the scapula?

articular surface of glenoid (only covers 1/3 of head)

what allows for significant movement of the humeral head?

Glenohumeral Ligaments

Three fibrous bands that provide stability to the GH joint by connecting the glenoid rim to the humerus.

provides stability to the shoulder against anterior translation and external rotation of humeral head

glenohumeral ligaments function

inferior glenohumeral ligament

has significant importance during arm abduction and external rotation, acts as a primary stabilizer

Coracohumeral Ligament

ligament that connects the coracoid process of the scapula to the greater tubercle of the humerus

provides stability by resitricting inferior movement of the humeral head and supports the biceps tendon in subacromial space

coracohumeral ligament function

Transverse Humeral Ligament

A small ligament that holds the biceps tendon in bicipital groove during joint motion to prevent dislocation of the tendon

coracoclavicular ligament

comprises trapezius and conoid ligamentsm connects coracoid process to scapula

prevents superior subluxation of the clavicle and contributes to overall stability of shoulder girdle

coracoclavicular ligament function

coracoacromial ligament

Forms an arch over the humeral head, connecting the coracoid process to the acromion.

Acts as a protective arch, preventing superior displacement attachment of the Glenoid and contributing to joint stability.

coracoacromial ligament function

Subacromial Space

The area beneath the coracoacromial ligament and above the humeral head containing the supraspinatus tendon and subacromial bursa.

subacromial bursa

Facilitates movement of the supraspinatus tendon located under coracoacromial arch and of the deltoid over the joint capsule of the GH joint and greater tubercle of the humerus.

Scapular oreintation

positioned at a 30–40-degree angle anterior to the frontal plane. glenoid fossa faces approx 35 grees anteriorly from the frontal plane

scapular place

The anatomical plane defined by the orientation of the scapula, which influences shoulder mechanics and movements. glenoid faces 35 degrees anterior from frontal plane

humeral head in anatomical position

directed medially, superiorly, and posteriorly (retroverted) into scapular plane

humeral head in normal resting position

slight internal rotation of the humerus compared to anatomical position.