1. Human Chest, Arm, and back Muscles

2. Pectoralis Major
Pectoralis Minor

3. Rotator Cuff Muscles Supraspinatus Infraspinatus Teres minor
Subscapularis
Another shoulder muscle, but not part of the Rotator Cuff:
Teres Major

4. ROTATOR CUFF: Subscapularis Teres minor Supraspinatous Infraspinatous
(Teres major)
Teres minor
ROTATOR CUFF: Subscapularis Teres minor Supraspinatous Infraspinatous
(Biceps brachii)

5. ROTATOR CUFF: Subscapularis Teres minor Supraspinatous Infraspinatous

6. Rotator Cuff Injury Symptoms
Pain and tenderness in your shoulder, especially when reaching overhead, reaching behind your back, lifting, pulling or sleeping on the affected side.
Diagnosis
X-rays
MRI
Ultrasound

7. Causes of Rotator Cuff Injuries
Normal wear and tear.
Poor posture. When you slouch your neck and shoulders forward, the space where the rotator cuff muscles reside can become smaller. This can allow a muscle or tendon to become pinched under your shoulder bones (including your collarbone), especially during overhead activities, such as throwing.
Falling. Using your arm to break a fall or falling on your arm
Lifting or pulling. Lifting an object overhead Likewise, pulling something, such as a high-poundage archery bow, may cause an injury.
Repetitive overhead movement. This occurs often in athletes, especially baseball pitchers, swimmers and tennis players. It's also common among people in the building trades, such as painters and carpenters.

8. Deltoid

9. Deltoid
Biceps brachii

10. Deltoid
Coracobrachialis
Triceps brachii
Biceps brachii

11. Deltoid
Coracobrachialis
Biceps brachii
Brachialis (deep to biceps brachii)

12. Deltoid
Biceps brachii
Triceps brachii

13. Pronator teres
Brachioradialis

14. Extensor digitorum
Extensor carpi radialis
Extensor carpi ulnaris

15. Ext carpi radialis
Ext digitorum Extensor carpi ulnaris

16. Flexor retinaculum
Palmaris longus
Flexor carpi ulnaris
Flexor carpi radialis

17. Flexor carpi ulnaris
Palmaris longus Flexor carpi radialis

18. Pronator teres
Ext pollicis longus Ext pollicis brevis Abd pollicis longus Brachioradialis

19. Extensor pollicis longus
Extensor pollicis brevis
Abductor pollicis longus

20. Rhomboids
Trapezius
Latissimus dorsi

21. Upper Trapezius Strain
An upper-trapezius strain can be triggered quite easily by consistently overusing the muscle group, even at a low intensity. Because repetitive motions do not allow the affected tissue to rest between movements, they can cause stress and irritation.
The members of today’s work force don’t often get up to sharpen a pencil, fax documents or walk to the post office to deliver a package. The easy and convenient access of working tools promotes inactivity and therefore a rise in repetitive stress injuries associated with desk and computer work. Simple, everyday movements—like habitually holding a telephone between the ear and shoulder—can trigger upper trapezius pain.

22. Upper Trapezius Strain
It is easy to understand how the upper trapezius could be in a state of active insufficiency in certain situations; for example, when the shoulder is elevated and the neck is extended, side-bent and rotated, as when you are cradling a phone between your ear and shoulder.
Shrugging the shoulders and overhead movements also fatigue trapezius.
Throughout the day, the upper trapezius might be actively insufficient, while, alternatively, the rhomboids might be passively insufficient (when the shoulders are rounded).
Developing better posture and moving out of these positions intermittently throughout the workday will place the muscles back at their optimal length.

23. Trapezius Exercises at the Office
Sitting with upright posture, perform 15–20 reps an hour of the following upper trapezius exercises.
1. Scapular Pinches. Roll the shoulders back, and pinch the shoulder blades together.
2. Shoulder Shrugs. Raise the shoulders up toward the ears, then lower them back down.
3. Neck Side-Bending. Tilt one ear toward the shoulder, and hold briefly. Repeat on the opposite side.
4. Neck Rotation. Look over one shoulder, and pause briefly. Repeat on the opposite side.
5. Neck Side-Bending/Rotation Stretch.
In a standing or seated position, place the right hand on top of the head and let the left arm rest at the side.
Gently pull the head toward the right shoulder with the right hand.
Rotate the head down and look at the right hip. (The stretch should be felt on the left side of the neck/shoulder area.)
Repeat on the opposite side.

24. Serratus anterior

25. Pectoralis minor
Serratus anterior

26. Internal intercostals
Pectoralis minor
Serratus anterior
External intercostals
Internal intercostals are for expiration and external intercostals are for inspiration

27. Internal intercostals
Pectoralis minor
Serratus anterior
External intercostals

28. Internal intercostals
External intercostals

29. Diaphragm: Primary muscle for respiration