Shoulder Girdle

Protraction

(Abduction) scapula moves laterally away from the spinal column Ex:reaching for an object in front of the body

Retraction

(Adduction) scapula moves medically toward the spinal column Ex: pinching the shoulder blades together

Posterior Tilt

(Downward tilt) Consequential rotational scapula movement about the frontal axis occurring during glenohumeral joint hyperextension Superior border moves posteroinferiorly, inferior angle moves anterosuperiorly

Medial Tilt

(Inward tilt) Consequential movement during extreme adduction/retraction. Medial border moves anteriorly, lateral border moves posteriorly

Lateral Tilt

(Outward tilt) Consequential movement during abduction/protraction. Medial border moves posteriorly, lateral border moves anteriorly

Anterior Tilt

(Upward tilt) Consequential rotational scapula movement about the frontal axis; occurs during glenohumeral joint hyperextension Superior border moves anteroinferiorly, inferior angle moves posteroinferiorly

Acromioclavicular Joint movements

20-30 degrees, total sliding and rotational motion (accompanying other shoulder girdle and shoulder joint moves)

Shoulder Girdle Muscles

5 total separate from the shoulder joint Origin: axial skeleton Insertion: scapula and/or clavicle Don't attach to the humerus; don't cause shoulder joint actions Stable base for shoulder joint muscles during activities like throwing

Scapular elevation agonist, comments, example

Agonist: Levator Scapulae, Upper Trapezius, Middle Trapezius, Rhomboids Comments: Lifting the scapula without rotation in the anatomical position Example: Shoulder Shrugs

Scapular depression agonist, comments, example

Agonist: Lower Trapezius, Pectoralis Minor Comments: Returns scapula to normal position after a shoulder shrug Example: Body Dips

Scapula retraction agonist muscle, comments, example

Agonist: Middle Trapezius, Lower Trapezius, Rhomboids Comments: Returm from abduction; occurs with retractions Example:Bent over rows, lifting a wheelbarrow

Scapular downward rotation agonist, comments, example, movement

Agonist: Pectoralis Minor, Rhomboids Comments: Downward and medial movement, glenoid fossa rotated downward Example: Lat pulls (pulling weight down)

Scapula protraction agonist muscle, agonist, comments, example

Agonist: Pectoralis Minor, Serratus Anterior Comments: Moves laterally away from spinous processes without rotation Example: Push-up, Bench Press

Scapula upward rotation agonist, comments, example movement

Agonist: Upper Trapezius, Middle Trapezius, Lower Trapezius, Serratus Anterior Comments: Scapula lateral and upward movement Example: Raising the arms above the head

Sternoclavicular Joint ligamentous support

Anterior: anterior sternoclavicular ligament Posterior: posterior sternoclavicular ligament Stability vs. superior displacemen: costoclavicular and interclavicular ligaments

Acromioclavicular Joint Classification

Anthrodial, often injured

Strengthening exercises of the serratus anterior

Bench press Overhead press

Example Major and Minor Rhomboid Muscle Movements

Chin-ups Hanging from a bar pulls the scapula away from the top of the chest. Rhomboids rotate scapula medial border down and back to the spinal column when the chin-up movement begins.

Major & Minor Rhomboid Muscle Strengthening Exercises

Chin-ups, dips, bent-over rowing

Acromioclavicular Joint ligamentous support

Coracoclavicular ligaments (conoid & trapezoid); greatly increases the joints stability Superior Acromioclavicular ligament Inferior Acromioclavicular ligament

Shoulder joint superior muscles

Deltoid, supraspinatus

Scapulothoracic Joint Movement

Depends totally upon the SC & AC joints Scapula movements: Abduction/Adduction 25 degrees Upward/Downward 60 degrees Elevation/Depression 55 degrees

Major and Minor Rhomboid Muscles Innervation

Dorsal Scapular Nerve (C5) Rhomboid muscles fix the scapula in retraction (adduction) when the shoulder joint muscles adduct or extend the arm

Levator Scapulae Muscle Innervation

Dorsal Scapular Nerve (C5) and C3, C4 Branches Very common site for tenderness, tightness and discomfort secondary to chronic tension from carrying items with straps over the shoulders along with the trapezius

Benefit of maintaining lumbar lordosis and keeping head over trunk in a balanced position

Enhanced easier respiration (less weight and mass over the rib cage and thoracic cavity)

Shoulder Girdle movements vs Shoulder Joint movements

Girdle: Protraction/Retraction, Elevation/Depression, Upward/Downward Rotation Joint: Flexion/Extension, Internal/External Rotation, Abduction/Adduction, Horizontal Abduction/Adduction, Diagonal Abduction/Adduction

Shoulder Girdle posterior muscles vs Shoulder Joint posterior muscles

Girdle: Trapezius, Rhomboids, Levator Scapulae Joint: Teres Major, Teres Minor, Lat. Dorsi, Infraspinatus

Shoulder girdle anterior muscles vs shoulder joint anterior muscles

Girdle: pectorals MINOR, serratus anterior Joint: Pectoralis MAJOR, corachobrachialis, subscapularis

Shoulder girdle joints vs shoulder joint joints

Girdle: scapulothoracic, acromioclavicular, sternoclavicular Joint: Glenohumeral

Shoulder Girdle specific bony landmarks movements

Inferior Angle (posteriorly), Glenoid fossa (laterally), Acromion Process (anteriorly)

Trapezius Muscle Example Movements

Lifting wheelbarrow handles Lifting something with the arms or holding something overhead Holding the arms out to the sides horizontally (trapezius fixes the scapula while the deltoid muscles hold the arms)

Key Shoulder Girdle Bony Landmarks

Manubrium, coracoid process, acromion process, glenoid fossa, lateral border, medial border, superior angle, inferior angle, scapula spine

Pectoralis Minor muscle innervation

Medial pectoral nerve (C8-T1) Used along with serratus anterior muscle in true protraction (abduction) without rotation. Muscles work together requiring pushing with the hands Serratus Anterior draws scapula forward with slight upward rotation. Pectoralis Minor pulls scapula forward with slight downward rotation

Sternoclavicular Joint Classification

Multi-axial anthrodial

Scapulothoracic Joint support

No ligamentous support, dynamically supported by its muscles

Scapulothoracic Joint Classification

Not a true synovial joint, doesn't have regular synovial features

Shoulder Joint muscles insertion

On the humerus

Shoulder girdle muscles insertion

On the scapula

Trapezius Muscle Upper Fibers Origin, Insertion, Action, When

Origin: Skull base, occipital protuberance & neck posterior ligaments Insertion: Posterior clavicle lateral 1/3 Action: Scapula elevation, scapula upward rotation, head extension & rotation When: Elevation & extension of the head at the neck

Major & Minor Rhomboid Muscles Origin, Insertion, Action, When

Origin: Spinous process C7-T5 Insertion: Scapula medial border, below scapular spine Action: Retraction-moves scapula to spinal column Downward scapula rotation Elevation (accompanies adduction) When: During glenohumeral internal rotation and scapula downward rotation

Trapezius Muscle Middle Fibers Origin, Insertion, Action, When

Origin: Spinous processes C7-T3 Insertion: Acromion process medial border & scapular spine upper border Action: Scapula elevation, Scapula upward rotation & retraction (adduction) When: During adduction

Trapezius Muscle Lower Fibers Origin, Insertion, Action, When

Origin: Spinous processes T4-T12 Insertion: Scapular spine base Action: Scapula depression, Scapula upward rotation & retraction (adduction) When: During depression & adduction

Levator Scapulae Muscle Origin, Insertion, Action, When

Origin: Transverse processes C1-C4 Insertion: Scapula medial border, from superior angle to scapular spine Action: Elevates scapula medial margin, weak downward rotation, weak retraction (adduction) When: During slight elevation

Serratus Anterior Muscle Origin, Insertion, Action, When

Origin: Upper 9 ribs of the chest surface Insertion: Scapula medial border (anterior aspect) Action: Protraction- Draws scapula medial border away from the vertebrae Upward Rotation- Draws scapula inferior angle away from the vertebrae When: During abduction, glenohumeral joint in 90 degree flexion

Pectoralis Minor muscle origin, insertion, action, when

Origin: anterior surface ribs 3-5 Insertion: coracoid process (scapula) Action: protraction (abduction) draws scapula forward, tilts lower border away from the ribs Downward rotation of the scapula Scapula depression When: During resisted scapula depression

Sternoclavicular Joint movements in relation to the manubrium

Protraction- moves anteriorly 15 degrees Retraction- moves posteriorly 15 degrees Elevation- moves superiorly 45 degrees Depression- moves inferiorly 5 degrees Some slight gliding movements

Pectoralis Minor example movements

Pushing the body upward during body dips (depresses & rotates the scapula downward from an upwardly rotated position)

Example of Shoulder Joint and Shoulder Girdle synergistic movement

Raising the hand out to the side laterally as high as possible: Serratus anterior and trapezius upwardly rotate the scapula, Deltoid initiates glenohumeral abduction

Downward rotation

Returning the inferior angle inferomedially to the spinal column and the glenoid fossa to its normal position

Scapula movement during shoulder girdle movements

Scapula moves on the rib cage as a consequence of joint motion occurring at the Sternoclavicular and Acromioclavicular joints

Scapula muscles spinal posture role

Scapula retractors weaken over time while scapula protractors and depressors become stronger/tighter. This causes further shoulder depression and protraction leading to a forward shoulder posture. Contributes to kyphosis, cervical spine lordosis, glenohumeral joint placed in a less functional position.

Trapezius Muscle Strengthening Exercises

Shoulder shrugging exercises (upper and middle fibers) Parallel dips or body dips (lower fibers) Bent-over rowing or shoulder joint horizontal abduction from a prone position (mid & lower fibers)

Levator Scapulae Example Movements

Shoulder shrugs, Neck extension and lateral flexion when the scapula's fixed by the pectoralis minor

Trapezius Muscle Innervation

Spinal Accessory Nerve and C3, C4 Branches When all trapezius parts are working together, they tend to pull upward and adduct at the same time. Upper and lower fibers are generally weak, whereas the middle fibers are stronger and thicker Typical trapezius action is scapula fixation for deltoid action. It prevents the scapula from being pulled downward.

Shoulder Joint and Shoulder Girdle Synergistic Movements

Stable base for shoulder joint muscles so they exert force for powerful UE movements involving the humerus. Shoulder girdle muscles contract to maintain scapula in relatively static position during shoulder joint actions. Shoulder girdle muscles contract to move the shoulder girdle and enhance UE movement when the shoulder goes through extreme ROMs (glenoid fossa moves to a more appropriate position allowing humerus movement)

Scapula effect on the humerus

The humerus can only be raised approximately 90 degrees of total shoulder abduction and flexion without scapula movement

Example movements of the serratus anterior muscle

Throwing a baseball Punching Tackling Push-ups

Upward rotation

Turning the glenoid fossa upward and moving the inferior angle superiorly and laterally away from the spinal column Ex:raising the arm

Pivot point

Where the clavicle joins the sternum at the SC joint