[CORRECT] Kines Shoulder Complex

Shoulder Complex

The collection of bones, joints, and muscles that make up the shoulder, allowing for a wide range of motion and functional significance.

1. Provides a wider range for hand replacement

2. Stabilization for hand use

3. Lifting and pushing

4. Elevation of the body

5. Weight bearing (crutch walking)

6. Force inspiration and expiration

Enumerate the 6 functional significance of the shoulder complex

1. Sternoclavicular joint

2. Acromioclavicular joint

3. Glenohumeral joint

True joints or bony articulations of the shoulder complex

1. Scapulothoracic Articulation

2. Suprahumeral or Subacromial articulation

3. Bicipital groove

False joints or functional articulations of shoulder complex.

Clavicle

The long bone that lies horizontally at the root of the neck, providing lateral strut support and shock absorption for the shoulder complex.

Medial 2/3

Part of clavicle where it is convex anteriorly and concave posteriorly

Lateral 1/3

Part of clavicle where it is concave anteriorly and convex posteriorly

Middle and outer 3rd

It is the weak spot of the clavicle.

Scapula

The large, flat triangular bone on the posterior thoracic wall, providing attachment sites for muscles and contributing to shoulder movement and stability.

2nd to 7th

Scapula lies on the ______ to _______ rib

T2

Superior/Superomedial angle of scapula is a landmark of _________.

T3

Spinous process of scapula is a landmark of _________.

T7-T9

Inferior angle of scapula is a landmark of _________.

Humerus

The longest and largest bone of the upper extremity, consisting of the humeral head, anatomical neck, surgical neck, and tuberosities, and allowing for movement and stability of the shoulder complex.

Humeral head

Part of humerus where it forms 1/3 or ½ of a sphere.

Anatomical Neck

Part of humerus considered as the end connection of the joint capsule.

Surgical Neck

Most common site of humeral fracture.

Sternum

The breastbone, consisting of the manubrium, body, xiphoid process, and sternal angle, providing attachment sites for muscles and contributing to shoulder stability.

Sternal Angle

Formed by the junction of the manubrium and body of the sternum.

Infrasternal Angle

Formed by the cartilage of some of the lower ribs of each side as they ascend to attach to the sternum.

True joints

The bony articulations (sternoclavicular joint, acromioclavicular joint, glenohumeral joint) that directly connect the upper extremity to the thorax and allow for movement and stability of the shoulder complex.

False joints

The functional articulations (scapulothoracic articulation, bicipital groove, subacromial joint) that contribute to shoulder mobility and stability, but are not true anatomical joints.

1. Increases the range of motion of the arm

2. Maintains favorable length-tension relationships for the deltoid muscle to function above 90 degrees of elevation

3. Provides glenohumeral stability for work in the overhead position

4. Provide shock absorption for forces applied to the outstretched
   

Functions of the Scapulothoracic joint.

1. Floor: Latissimus Dorsi

2. Roof: Transverse Humeral Ligament

3. Medial: Teres Major

4. Lateral: Pectoralis Major

Muscular boundaries of the bicipital groove of humerus

Subacromial joint

Also known as the suprahumeral articulation, it is the structure that overlies the subacromial bursa and protects the top of the humeral head, muscles, tendons, and bursae from direct trauma.

1. Subacromial and subcoracoid bursae

2. Supraspinatus muscle and tendon

3. Superior glenohumeral capsule

4. Loose connective tissue

5. Biceps tendon

Structures within the subacromial joint.

Sternoclavicular joint (SC joint)

The double plane or sellar joint between the sternal end of the clavicle, manubrium sterni, and 1st costal cartilage, providing stability and allowing for movement of the shoulder complex.

Sternoclavicular joint

It is the only bony articulations that directly connect the UE to the thorax - "Base of Operation" for the scapula.

Acromioclavicular joint (AC joint)

The plane joint between the lateral end of the clavicle and the acromion process, providing stability and allowing for movement of the shoulder complex.

Fibrocartilaginous articular disk (Sternoclavicular Disc)

An accessory structure of the SC joint that separates the joint into two synovial cavities and also provides congruency of the SC joint.

SC Ligament

This ligament prevents both upward and lateral displacement of clavicle.

Posterior SC Ligament

The ligament that prevents anterior displacement of clavicle.

Anterior SC Ligament

The ligament that prevents posterior displacement of clavicle.

1. Depression and Elevation (z-axis)

2. Protraction and Retraction (y-axis)

3. Longitudinal / Axial Rotation (x-axis)

Enumerate the 3 planes and 3 axes of the SC Joint.

Elevation/Depression

It is the motion of SC disc wherein it becomes part of the Sternum

Protraction/Retraction

It is the motion of SC disc wherein it becomes part of the Clavicle

AC Ligaments

The ligament that assists the capsule and controls the horizontal joint stability.

Superior AC Ligament

A ligament that is a primary restraint against inferior stability of clavicle.

Inferior AC ligament

A ligament that restraints clavicle against superior instability

1. Upward and Downward Rotation

2. Internal and External Rotation

3. Anterior and Posterior Tilting

Enumerate the 3 planes and 3 axes of the AC joint.

Upward Rotation

The movement of the AC joint where the glenoid fossa tilts superiorly.

Downward Rotation

The movement of the AC joint where the glenoid fossa tilts inferiorly.

Internal Rotation

The movement of the scapula where it moves anteromedially based on the glenoid fossa or acromion process.

External Rotation

The movement of the scapula where it moves posterolaterally based on the glenoid fossa or acromion process.

Anterior Tilting

The movement of the scapula where the acromion moves anteriorly and the inferior angle moves posteriorly.

Posterior Tilting

The movement of the scapula where the acromion moves posteriorly and the inferior angle moves anteriorly.

Oblique A-P axis

Axis of the upward/downward rotation of AC joint

Y-Axis

Axis of the Internal/External Rotation

Oblique Coronal Axis

Axis of the anterior/posterior tilting

Glenohumeral joint (GH joint)

A ball-and-socket joint with 3 degrees of freedom, consisting of the articulations between the humeral head and the glenoid fossa.

SPM: Superior, Posterior, Medial

Orientation of the humeral head.

SAL: Superior, Anterior, Lateral

Orientation of the glenoid fossa.

Angle of Torsion

The angle formed by the axis of the humeral head and neck and the humeral condyles.

Angle of Inclination

The angle formed by the longitudinal axis of the humeral shaft and the humeral head and neck.

130-150 deg

It is the angle of inclination of the GH joint.

Glenoid Fossa

A shallow cavity that forms part of the glenohumeral joint.

Glenoid Labrum

A ring of cartilage that surrounds and is attached to the periphery of the glenoid fossa, providing enhancement to the joint.

Glenohumeral Capsule

A large and loose capsule that tightens during shoulder abduction and external rotations.

1. Shallow glenoid cavity

2. Wide range of motions

3. Loose-articular capsule

4. Superficial or exposed location of the shoulder

Enumerate possible reasons why GH joint is easily dislocated.

1. Upward Rotation

2. Internal Rotation

3. Posterior Tipping

Movements of the AC joint during shoulder abduction

1. Elevation

2. Retraction

3. Posterior Rotation

Movements of the SC joint during shoulder abduction

Anteriorly

GH joint slides ______________ during external rotation

Posteriorly

GH joint slides ______________ during internal rotation

Inferiorly

GH joint slides ______________ during shoulder abduction.

Superiorly

GH joint slides ______________ during shoulder adduction.

Coracohumeral Ligament

A ligament that prevents dislocation of the long head of the biceps brachii and prevents antero-inferior translation.

Glenohumeral Ligaments

Ligaments that form a "Z" on the anterior capsule and tighten during external rotation and anterior glide of the humeral head.

Superior Glenohumeral Ligament

A ligament that prevents anterior and inferior translation with the hands at the side (0 deg)

Middle Glenohumeral Ligament

A ligament that prevents anterior translation (0 - 60 deg)

Inferior Glenohumeral Ligament

A ligament that prevents anterior translation and inferior translation (>45 deg) at the end of elevation.

Foramen of Weitbrecht

It is the clear area of weakness between the superior and middle GH ligament.

Scapulohumeral Rhythm

The coordinated movement between the scapula and humerus during shoulder abduction, with a 2:1 ratio of motion at the glenohumeral joint and scapulothoracic joint.

Superior Transverse Ligament

A small triangular fibrous band that runs from the upper border of the scapula to the base of the coracoid process.

Inferior Transverse Ligament

A ligament that runs from the lateral border of the scapular spine to the margin of the glenoid cavity, forming a foramen for the passage of nerves.

Serratus Anterior

A muscle of the shoulder girdle that is important in raising the arm overhead and is known as the "SAW MUSCLE."

Serratus Anterior

It is the strongest portion of the muscle is the last 5 digitations that converge on the inferior angle. It is also important in PUSHING and REACHING activities.

Trapezius

Paralysis of this muscle still allow arms to be raised overhead but shoulder slopes down shifting the orientation of the glenoid fossa resulting to humeral head subluxation

Rhomboid Major and Minor

Muscles that, along with the middle and lower trapezius, are important in maintaining good shoulder posture and stabilizing during abduction.

Pectoralis Minor

A muscle that participates in scapular rotation, upward tilt, depression, abduction, and lateral tilt.

Deltoid

A large superficial muscle responsible for the roundness of the shoulder and covers the glenohumeral joint on all sides except the axilla.

Infraspinatus and Teres Minor

Muscles closely related in location and action, supplied by two different nerves.

Subscapularis

The only rotator cuff muscle that inserts into the lesser tubercle and is the chief internal rotator of the shoulder.

Teres Major

A round muscle located at the axillary border of the scapula, acts in most pulling activities when the shoulder is extended or adducted against resistance.

Biceps Brachii and Triceps Brachii

Muscles that cross the shoulder joint and have different actions, with the biceps being a flexor and an abductor, and the triceps being an extensor and an adductor of the glenohumeral joint.

Latissimus Dorsi

The broadest muscle of the back and lateral thoracic region, helps in lifting the pelvis when the arms are stabilized.

1. Pushing

2. Throwing

3. Punching

Enumerate the activities where pectoralis major is important.

Pectoralis Major

A large muscle of the chest that is important in pushing, throwing, and punching activities.

Dynamic Stability of SH Joint

The stability of the shoulder joint provided by the deltoid, rotator cuffs, supraspinatus, and long head of the biceps brachii.

1. Deltoid & GH Stab.

2. Rotator Cuffs & GH Stab.

3. Supraspinatus & GH Stab.

4. Long head of biceps brachii & GH Stab.

Enumerate the factors affecting the dynamic stability of shoulder joint.

1. Parallel Forces (Compressive)

2. Perpendicular Force (Rotary)

3. Compressive > Rotary

4. Joint Reaction Force and Offset of Humeral Head

Enumerate the factors that contributes in the deltoid and GH stabilization.

1. Negative intra-articular pressure

2. Upward tilt of fossa which provides bony block against inferior translation

3. Passive tension from the ligaments

Abbrev: NUP

Enumerate the factors that contributes to the static stabilization of the GH joint.

Force Coupling

It is a factor that affects dynamic stability and it means two opposing forces creating tension.

(+) Translatory Force

It is a force directed upward.

(-) Translatory Force

It is a force directed downward.

Larger (+) TF, Smaller (-) TF

In the dynamic stabilization of deltoids and GH, it has a larger _________ TF and smaller _______ TF.

Larger (+) TF, Smaller (-) TF

In the dynamic stabilization of rotator cuff and GH, it has a larger _________ TF and smaller _______ TF.