The Shoulder Complex Anatomy

Joint type Ball and socket joint ◦ Same as hip, but much shallower ◦ Relies on musculature for stability

Bones Clavicle Sternum Scapula Humerus

Clavicle “S ” shaped bone Spans between sternum to tip of shoulder Supports anterior shoulder Lying superficial w/ no muscle or fat protection subjects clavicle to direct blow

Sternum AKA “breastbone” Divided into 3 parts: ◦ Manubrium ◦ Body ◦ Xiphoid process Only source of axial attachment for shoulder complex

Scapula Flat and triang- ular 3 projections: ◦ Spine (supraspinous/infraspinous) ◦ Acromion (lateral tip) ◦ Coracoid process (hook-like projection) Glenoid Fossa ◦ Receives the head of the humerus

3 views of scapula

Humerus Bicipital groove ◦ Bicep tendon moves up and down in grove during flex/ext of elbow ◦ Proximal end of Humerus

Humerus

Articulations 4 Articulations ◦ Sternoclavicalar (SC joint) ◦ Acromioclavicular (AC joint) ◦ Glenohumeral (GH joint) ◦ Scapulothoracic – not a true joint

SC Joint Medial shock absorber AC Joint Thin fibrous capsule surrounds joint. Weak and easily injured

GH Joint ◦ Enarthrodial (ball and socket joint) ◦ Deepened by labrum in Glenoid Fossa Scapulothoracic Joint ◦ Not a true joint due to lack of bony articulation ◦ Important for stabilization of shoulder joint ◦ Motions – elevation, depression, protraction, retraction, abductions, adduction

Ligaments – able to identify Coracoacromial lig Coracohumeral lig Superior GH lig Middle GH lig Inferior GH lig Transverse humeral lig

Muscles Rotator Cuff ◦ Consist of four muscles:  Subscapularis  Infraspinatous  Teres Minor  Supraspinatous  Assoc tendons insert on humerous ◦ Responsible for InRot, ExRot, AB-duction Triceps ◦ 3 heads ◦ Lays over humerus, but acts on Elbow; secondary shoulder extention

Muscles Cont’d Deltoid ◦ Found over head of humerus ◦ 4 heads ◦ ROM: AB-ducts, Flex, Extend Shoulder Pecs ◦ Major and Minor Biceps ◦ Lays over Humerus, but act on Elbow w/ secondary shoulder flexion ◦ 2 heads

ROM Flexion *circumduction Extension (/) Abduction (abd) Adduction (add) Horizontal adduction (H add) Horizontal abduction (H abd) Internal rotation (In rot) External rotations (Ex rot)

Injuries Shallow structure of the shoulder joint makes it very susceptible to injury Ways to prevent injury: ◦ Address muscular weakness  Important to strengthen muscles OPPOSING common motion ◦ Use padding  Contact sports with shoulder contact ◦ Modify Activity  Overuse injury  Ath 9-14 no curve balls; 75 pitch/game; 600/season

Bone Injuries s/s: ◦ Pain, Inability to move arm, desire to hold or “coddle” arm, hearing/feeling “pop”, obvious deformity Clavicular Fx: ◦ Distal 1/3 where “S” changes direction, most common site for fx ◦ MOI: Direct Blow or falling on tip of shoulder ◦ Tx: fig-8 harness; ORIF if necessary; 6 to 8 wks to heal, minimal PT after release

Humeral Fx: ◦ Musculature can hide fx to humeral head ◦ Sprains can often mimic fx ◦ MOI: Direct blow (most common), falling on elbow (axial load), overuse (least common) ◦ Tx: cast, ORIF (if necessary), modify activity (stress fx)

Epiphyseal Injuries ◦ Injury to growth plate ◦ MOI: Direct blow, falling on elbow, overuse (most common) ◦ Can cause permanent growth impairment Avulsion Fx: ◦ Lig/tendon pulls away from bone ◦ Most commonly occurs during shoulder dislocation

Dislocation/Subluxation ◦ MOI: excessive abduction and external rotation ◦ Shoulder appears flat ◦ May be assoc fx or labral tear, must f/u with Ortho  Multiple disloc occur, surgery may be necessary

Muscle & Tendon Injuries Rotator Cuff Strain ◦ MOI: most commonly – overuse; excessive motion ◦ Graded 1, 2, 3  Supraspinatus most commonly injuries ◦ C/O p w/ and w/o movement, p w/ sleeping ◦ Tx: RICE, ROM activites, PRE

Impingement Syndrome:  MOI: untreated Rotator Cuff injury  Supraspinatus and Biceps tendon run through space beneath acromion process. When space narrows from swelling, tendinitis, poor posture, it impinges the muscle and tendon.  P w/ overhead movement  Tx: modify activity, PRE for posterior muscles, ROM (to improve flexibility of tight pecs)

Biceps Tendinitis ◦ Inflamed tendon in Bicipital groove ◦ Tx: same as other tendinitis injuries. Immobilizing in sling may provide further comfort Biceps Tendon Ruptre ◦ MOI: Direct blow, sever contraction forces. ◦ Ath unable to flex elbow, muscles balls up by elbow ◦ Tx: immediate immob, surgery

Ligament and Joint Injuries AC Joint and GH Joint most commonly injured. Acromioclavicular Joint Sprain ◦ “Separated shoulder” ◦ MOI: impact to top of shoulder; FOOSH; falling on bent elbow shoving head of Humerus up and into AC joint ◦ C/O P w/ ROM, “Step Deformity”

Step Deformity

Glenohumeral Joint Strain ◦ MOI: Direct blow when arm is AB-ducted and externally rotated (most often from disloc or sublux)  Can tear labrum as well

THE END