Origin/Insertion of Muscles - Shoulder - Deltoid (Posterior Head)

Deltoid (Posterior Head)
Origin: (Proximal Attachment) Spine of Scapula
Insertion: Deltoid Tuberosity of the humerus
Action: Laterally rotates the arm at the shoulder (glenohumeral) joint. Extends the arm at the shoulder joint

Spine of Scapula

Deltoid Tuberosity

Origin/Insertion of Muscles - Shoulder - Deltoid (Anterior and Middle Heads)

Deltoid (Anterior and Middle Heads)
Origin: Proximal attachments
            a) Anterior head: anterior surface of lateral clavicle
            b) Middle head: acromion process and spine of the scapula
Insertion: Deltoid tuberosity of the humerus
Action: Anterior Head: Flexes the arm at the shoulder; Medially rotates the arm at the shoulder
             Middle Head: Abducts the arm at the shoulder

Anterior Surface; Lateral Clavicle



Acromion Process; Spine of Scapula



Deltoid Tuberosity

Origin/Insertion of Muscles - Shoulder - Teres Minor

Teres Minor
Origin: Middle part of lateral (axillary) border of scapula
Insertion: Inferior aspect of greater tubercle of humerus
Action: Laterally rotates and weakly adducts arm at shoulder; draws humerus toward glenoid fossa of scapula to help stabilise shoulder

Lateral (axillary) border

Greater Tubercle

Glenoid Cavity



Origin/Insertion of Muscles - Back - Teres Major

Teres Major
Origin: Lower lateral border and inferior angle of the scapula
Insertion: Medial lip of the intertubercular (biciptial) groove of the anterior humerus
Action: Adducts the arm, medially rotates the arm and extends the arm at the shoulder

Teres Major

Lower Lateral Border and Inferior Angle

Medial Lip of Intertubercular groove of humerous

Origin/Insertion of Muscles - Back - Latissimus Dorsi

Latissimus Dorsi
Origin: Spinous processes of lower 6 thoracic vertebrae, ribs and lumber vertebrae
Insertion: Intertubercular groove of humerus
Action: Extension, adduction and medial rotation at shoulder; extends arm at shoulder, adducts arm at shoulder, medially rotates arm at shoulder

Latissimus Dorsi

Spinous Processes

Intertubercular Groove of Humerus

Origin/Insertion of Muscles - Back - Trapezius

Trapezius
Origin: Medial superior nuchal line and external protuberance of occipital bone and spinous processes of C7-T12
Insertion: Lateral clavicle and scapula (acromion and scapular spine)
Action: Upper Fibres: elevate and upwardly rotate scapula; extend neck
             Middle Fibres: adducts (retracts) scapula
             Lower Fibres: depress and help upper fibres upwardly rotate scapula



Superior Nuchal Line

 


External Protuberance of Occipital bone

Spinous Processes

Acromion and Scapula Spine



Lack of Exercise more deadly than Obesity

An interesting article for contemplation.

http://www.acefitness.org/blog/5258/study-lack-of-exercise-twice-as-deadly-as-obesity

Have a great afternoon!

J