Shoulder Complex Kinesiology and Biomechanics

Comprehensive practice flashcards covering the anatomy, joints, ligaments, and biomechanics of the human shoulder complex based on lecture notes.

Sternum

A dagger-shaped or breastbone, T-shaped vertical bone that forms the anterior portion of the chest wall centrally.

Manubrium

The superior part of the sternum that forms part of the bony framework of the neck and thorax, containing clavicular facets and costal facets.

Sternal Angle (Angle of Louis)

The angle formed at the manubriosternal junction between the manubrium and the body of the sternum.

Xiphoid Process

The most inferior and smallest part of the sternum, with a tip located at the level of the $T10$ vertebra.

Clavicle

Also known as the strut or collar bone, it is the only bony attachment between the trunk and the upper limb and is the most commonly fractured bone.

Sternal End (Clavicle)

The quadrangular medial end of the clavicle that articulates with the clavicular notch of the manubrium to form the sternoclavicular joint.

Acromial End (Clavicle)

The broad, flat, lateral end of the clavicle that articulates with the acromion of the scapula to form the acromioclavicular joint.

Costoclavicular Ligament Impression

A roughened oval impression near the inferior surface and sternal end of the clavicle where the costoclavicular ligament connects the clavicle to the first rib.

Conoid Tubercle

A landmark on the inferior surface of the clavicle near the posterior border providing attachment for the conoid part of the coracoclavicular ligament.

Scapula

Also known as the shoulder blade, it is a large, flat, triangular bone on the posterolateral chest wall covering ribs $2$ through $7$.

Glenoid Fossa

A slightly concave cavity tilted upwardly about $5^\circ$ relative to the medial border that articulates with the humeral head.

Acromion Process

Known as the shoulder's summit, it is an anterolateral projection of the scapular spine that arches over the glenohumeral joint.

Coracoid Process

A hook-like structure projecting anterolaterally from the scapula, positioned inferior to the lateral clavicle.

Spine of the Scapula

A projection on the upper dorsal surface corresponding to the $T3$ vertebral level and a frequent site of referred pain from the cervical spine.

Suprascapular Notch

A passageway for the suprascapular nerve, artery, and vein, located medial to the root of the coracoid process.

Anatomical Neck

A short constriction of the humerus located immediately distal to the head, between the head and the tubercles.

Surgical Neck

A constriction distal to the humeral tubercles where fractures often occur, potentially damaging the axillary nerve.

Greater Tubercle

A prominent landmark on the proximal humerus with three facets for the attachments of the supraspinatus, infraspinatus, and teres minor.

Intertubercular Groove (Bicipital Groove)

A sulcus separating the greater and lesser tubercles that accommodates the tendon of the long head of the biceps brachii.

Sternoclavicular Joint

A structural sellar/saddle joint and functional planar joint that is the only direct connection between the upper extremity and the thorax.

Glenohumeral Joint

A synovial diarthrodial ball and socket joint formed by the large humeral head and small glenoid cavity, possessing $3$ degrees of freedom.

Angle of Inclination

The angle of $135^\circ$ at which the humeral head medially rotates against the glenoid fossa.

Angle of Retroversion

The posterior rotation of the humeral head by $30^\circ$ against the glenoid fossa.

Scaption

Shoulder abduction occurring in the plane of the scapula, approximately $30^\circ$ to $40^\circ$ anterior to the frontal plane.

Subacromial Space

An area with a height of approximately $1\,\text{cm}$ between the coracoacromial arch and the humeral head, containing the supraspinatus tendon and subacromial bursa.

Foramen of Weitbrecht

The weakest point of the shoulder capsule located between the superior and middle glenohumeral ligaments, often a site of injury.

Serratus Anterior

Known as the "saw muscle," it is the primary scapular protractor; weakness causes "medial winging of the scapula."

Trapezius

Known as the "shawl muscle" or "musculus cucullaris," it is a superficial muscle responsible for scapular elevation, depression, and retraction.

Rotator Cuff (SITS)

A group of muscles comprising the Supraspinatus, Infraspinatus, Teres minor, and Subscapularis that provide dynamic stabilization to the glenohumeral joint.

Scapulohumeral Rhythm

The coordinated simultaneous motion of the GH and ST joints where $120^\circ$ of elevation is GH and $60^\circ$ is ST ($2:1$ ratio).

Setting Phase

The early phase of shoulder abduction (the first $30^\circ$) where the scapula seeks stability in relation to the humerus.

Force Couple

Two equal forces applied on opposite sides of an axis in opposite directions to produce rotation, such as the upper and lower trapezius producing upward rotation.