THE SHOULDERStarting with movements

AROM Flexion 180/Extension 50-60 Abduction170-180 Adduction IR 70-80/ ER 80-90(at 0 and 90

degrees)

PROS/CONS Great ROM Little stability Inconsistent support from the ligaments Increased reliance on muscular support Many structures in a small area

BONEY ANATOMY Shoulder Complex:

Sternum(manubrium)ClavicleScapulaHumerus

MUSCLES OF THE SHOULDER

The Deltoid muscle is used in all side lifting movements and any movement of the humerus on the Scapula. It is divided into three portions, anterior, middle and posterior, with the fibres having different roles due to their orientation.

Actions:• Anterior portion – Shoulder flexion and internal rotation.• Posterior portion – Shoulder extension and external rotation.• All fibres – Shoulder abduction.

Typical Use:• Lifting.

MUSCLES OF THE SHOULDER

The Supraspinatus muscle is one of the four muscles which make up the rotator cuff. Its main function is to stabilize the upper arm by holding the head of the humerus in position.It is important in throwing motions to control any forward motion of the head of humerus.

Actions:• Abduction .• Stabilization of the humerus and shoulder joint.

Typical use:• Holding shopping bags away from the body

MUSCLES OF THE SHOULDER

The Infraspinatus muscle assists the lifting of the arm while turning the arm outward (external rotation). It is the main external rotator of the shoulder joint.

It is one of the four rotator cuff muscles crossing the shoulder joint and is commonly injured.

Actions:• Shoulder abduction.• External rotation.• Stabilizes the shoulder joint

Typical use:• Brushing hair

MUSCLES OF THE SHOULDER

The Teres Major is only functional when the Rhomboids fix the scapula. This muscle mainly helps the Latissimus Dorsi.

Action: • Medially rotates and adducts arm.

• Stabilizes the shoulder joint. Typical use:

• Tucking your shirt into the back of your jeans.

MUSCLES OF THE SHOULDER

The Teres Minor is one of the four rotator cuff muscles surrounding the shoulder. Its main action, along with the Infraspinatus  is to externally rotate the shoulder joint. It assists the lifting of the arm during outward turning (external rotation) of the arm.

There are two Teres muscles, the other being Teres Major.The other muscles whose tendons form the rotator cuff are:•    The infraspinatus muscle, which (like the teres minor) helps in the outward turning (external rotation) of the arm.•    The supraspinatus muscle which is responsible for elevating the arm and moving it away from the body; and•    The subscapularis muscle, which moves the arm by turning it inward (internal rotation).

Actions:•    External rotation.•    Shoulder abduction and stabilizes shoulder joint.

MUSCLES OF THE SHOULDER The Latissimus Dorsi muscle is one of the

largest in the body. It is a powerful extensor muscle of the arm

and is used extensively in chinning and climbing and its basic function is to pull the shoulders downward and towards the back.

It extends from the spine, hip and ribs to the upper arm.

They are commonly known at ‘the lats’. Actions:

• Extends, adducts and medially rotates arm.• Helps with deep inspiration and forced expiration

MUSCLES OF THE SHOULDER Pectoralis major is the largest and most

superficial of the two chest muscles. Pec Major and the anterior fibres of Deltoid work closely together. Pec-fly and push-up exercises are good for the Pectoralis major.

Actions:• Clavicular head : flexes and adducts arm.• Sternal head : adducts and medially rotates arm .• Accessory for inspiration.

Typical use:• Applying a roll-on deodorant.

ROTATOR CUFF MUSCLES Supraspinatus

abduction/external rotation Infraspinatus

external rotation/horizontal abduction Teres Minor

external rotation/horizontal abduction Subscapularis

internal rotation

BURSA VS. LIGAMENTS Bursa- fluid filled sack between a tendon

and a bone, consistency of a raw egg. Basically the bursa is a cushion that reduces friction.

Ligaments-a sheet or band of tough fibrous tissue that connects bones or cartilage at a joint or supports an organ, muscle, or other body part

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