1. بسم الله الرحمن الرحيم

2. BACK MUSCLES A- SUPERFICIAL LAYER 1- Trapezius 2- latissimus dorsi
The superficial layer is formed of two muscles:
1- Trapezius
2- latissimus dorsi

6. 1- Trapezius muscle Insertion: Origin:
External occipital protuberance, superior nuchal line of the occipital bone.
From the ligamentum nuchae, the spinous process of the seventh cervical.
The spinous processes of all the thoracic vertebrae.
 Insertion:
Posterior border of the lateral third of the clavicle.
The medial margin of the acromion.
The superior lip of the posterior border of the spine of the scapula.

8. 1- Trapezius muscle
Nerve supply: Spinal part of accessory nerve (CN XI). The ventral rami of the third (C3) and fourth (C4) cervical nerves carries proprioception sensation. Action: 1-The upper fibres elevate the shoulder. 2-The lower fibres depress the scapula. 3-The middle fibres retract the scapula.

9. 2- Latissimus dorsi muscle
Origin:
spinous processes of T7-T12
supraspinous ligament.
thoracolumbar fascia.
outer lip of iliac crest .
inferior 3 or 4 ribs.
inferior angle of scapula
Insertion:
Floor of bicipital groove of the humerus.
Nerve supply:
Nerve to latissmus dorsi (C6,C7,C8).
Action:
Adducts, extends and medially rotates the arm.

11. B- DEEP LAYER
The deep layer is formed by : 1-levator scapulae 2- Rhomboideus minor 3- Rhomboideus major muscles.

12. 1- Levator scapulae muscle
Origin:
Transverse processes of C1 - C4 vertebrae.
Insertion:
Medial border of dorsal surface of scapula from the superior angle to the spine.
Nerve supply:
Dorsal scapular nerve (C5).
Action:
Elevates scapula.

13. 2- Rhomboidus minor muscle
Origin:
Nuchal ligaments and spinous processes of C7 to T1 vertebrae.
Insertion:
Small area of medial border of dorsal surface of scapula at level of spine.
Nerve supply:
Dorsal scapular nerve (C5).
Action:
1-Retracts the scapula
2-Rotates the scapula so that the glenoid cavity faces downwards (depress the shoulder).

14. 3- Rhomboideus major muscle
Origin: Spinous processes of the T2 to T5 vertebrae. Insertion: Medial border of the scapula, inferior to the insertion of rhomboideus minor muscle. Nerve supply: Dorsal scapular nerve (C5). Action: Retracts the scapula and rotates the scapula so that the glenoid cavity faces downwards.

15. SCAPULAR REGION

16. Supraspinatus muscle Origin:
Supraspinous fossa (medial2/3) of scapula.
Insertion:
Superior facet of greater tuberosity of humerus.
Nerve supply:
Suprascapular nerve(C5,C6).
Action:
Abduction of arm from
0˚-18˚.

17. Infraspinatus muscle Origin:
Infraspinous fossa (medial2/3) of scapula.
Insertion:
Middle facet at the back of the greater tuberosity of the humerus.
Nerve supply:
Suprascapular nerve (C5,C6).
Action:
Lateral rotation of arm.

19. Teres minor muscle Origin: Lateral border(upper 2/3) of the scapula.
Insertion:
Inferior facet at the back of the greater tuberosity of the humerus.
Nerve supply:
Axillary nerve (C5,C6).
Action:
Lateral rotation and adduction of arm.

20. Teres major muscle Origin:
Posterior aspect of the inferior angle of the scapula.
Insertion:
Medial lip of bicipital groove of the humerus.
Nerve supply:
Lower subscapular nerve (C5,C6).
Action:
Medial rotation,adduction and extension of the humerus.

21. Subscapularis muscle Origin: Subscapular fossa (medial 2/3).
Insertion:
Lesser tuberosity of humerus.
Nerve supply:
Upper and lower subscapular nerves (C5, C6).
Action:
Rotates the humerus medially.

22. Deltoid muscle Origin: anterior border of lateral 1/3 of clavicle.
,lateral margin of the acromion and
crest of the spine of the scapula.
Insertion:
Into deltoid tuberosity on the middle of the lateral aspect of the shaft of the humerus.
Nerve supply:
Axillary nerve (C5, C6).
Action:
Anterior fibers: flexion and medial rotation of humerus.
Middle fibers: abduction from1
8˚-90˚.
Posterior fibers: extension and lateral rotation of humerus.

23. ROTATOR CUFF MUSCLES
Rotator cuff muscles surround the shoulder joint, they include:
Subscapularis.
Supraspinatus.
Infraspinatus.
Teres minor.

24. INTERMUSCULAR SPACES 1- Quadrangular space: Boundaries
It is bounded by:
Superiorly: Teres minor.
Inferiorly: Teres major.
Medially: the long head of the Triceps brachii.
Laterally: the surgical neck of the humerus.
Contents
It transmits the axillary nerve and posterior circumflex humeral artery.

25. 2-Medial triangular space
Boundaries:
Teres minor superiorly.
Teres major inferiorly.
Long head of the Triceps laterally.
Contents:
It contains the circumflex scapular vessels.

26. 3- Lateral triangular space
Boundaries:
Teres major superiorly.
Long head of the Triceps medially.
Humerus laterally.
Contents:
The radial nerve and profunda brachii artery.

27. Thank You