10 Anatomy of Shoulder region.pptx222222

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1. ANATOMY OF THE SHOULDER REGION by Dr. Francis Abu Bayor CHO, MBChB

2. OBJECTIVES At the end of the lecture, students should: List the name of muscles of the shoulder region. Describe the anatomy of muscles of shoulder region regarding: attachments of each of them to scapula & humerus , nerve supply and actions on shoulder joint List the muscles forming the rotator cuff and describe the relation of each of them to the shoulder joint . Describe the anatomy of shoulder joint regarding: type, articular surfaces, stability, relations & movements.

3. MUSCLES OF SHOULDER REGION Extrinsic group Trapezius Latissimus dorsi Levator scapula Rhoboidius maj. & min. Serratus anterior Intrinsic group Deltoid Teres major Rotaror cuff muscles Subscapularis Supraspinatus Infraspinatus Teres minor

4. Muscles of the shoulder Trapezius Origin: External occipital protuberance, superiot nuchal ine , ligamentum nuchae , spine of C7-T12. Insertion Spine of the scapula, acromium , lateral 1/3 of clavicle Nerve: XI (C3,4) Blood: transverse cervical dorsal scapular Actions: upward rotation of scapula elevation/depression of scapula retraction of scapula 1. Extrinsic shoulder muscles (superficial back muscles)

5. Muscles of the shoulder latissimus dorsi Origin: Spines of T5-T12, thoracodorsal fascia, iliac crest, spines of ribs 9-12 Insertion: Floor of thee bicipital groove of the humerus Nerve: thoracodorsal Blood: thoracodorsal Actions: extends humerus adducts humerus medially rotates humerus 1. Extrinsic shoulder muscles (superficial back muscles)

6. Muscles of the shoulder levator scapulae Origin: Transverse processes of C1-C4 Insertion: Medial border of scapula Nerve: dorsal scapular C3,4 Blood: dorsal scapular Actions: elevation of scapula downward rotation of scapula 1. Extrinsic shoulder muscles (superficial back muscles)

7. Muscles of the shoulder Rhomboids (minor & major) Origin: Spines C7-T5 Insertion Root of the spine of scapula Nerve: dorsal scapular Blood: dorsal scapular Actions: retraction of scapula downward rotation of scapula fixation of scapula to thoracic wall 1. Extrinsic shoulder muscles (superficial back muscles)

8. Muscles of the shoulder Serratus anterior Origin: External surfaces of the first eight ribs Insertion: Medial border of the scapula Nerve: long thoracic Blood: lateral thoracic Actions: protracts scapula holds scapula against thoracic wall rotates scapula 1. Extrinsic shoulder muscles (superficial back muscles)

9. Muscles of the shoulder Damage to the long thoracic nerve produces: winging of the scapula

10. DELTOID Origin: lateral 1/3 of clavicle + acromion and spine of scapula (look to insertion of trapezius ) . Insertion: deltoid tuberosity of humerus . Nerve supply: axillary nerve. Blood: post. humeral circ. Thoracoacromial Actions: Anterior fibers: flexion & medial rotation of humerus (arm, shoulder joint). Middle fibers: abduction of humerus from 15° - 90 °. Posterior fibers: extension & lateral rotation of humerus .

11. TERES MAJOR Origin: lateral border of scapula. Insertion: bicipital groove of humerus ( look to insertion of latissimus dorsi & pectoralis major ). Nerve supply: lower subscapular nerve. Blood: subscapular a. circumflex scapular a. Actions: extension, adduction & medial rotation of humerus ( look to action of latissimus dorsi ) .

12. Muscles of the shoulder Rotator cuff 2. Intrinsic shoulder muscles :

13. ROTATOR CUFF It is formed of 4 muscles : supraspinatus , infraspinatus , teres minor & subscapularis ( SITS ). Muscles form a tendinous cuff around the shoulder joint covering its anterior, posterior and superior aspects. The cuff is deficient inferiorly and this is the site of potential weakness. The tone of these muscles help in stabilizing the shoulder joint. S I T S

14. 1. SUBSCAPULARIS Origin: subscapular fossa . Insertion: lesser tuberosity of humerus . Nerve supply: upper & lower subscapular nerves. Blood: subscapular a. circumflex scapular a. Action: medial rotation of humerus .

15. 2 & 3 SUPRASPINATUS & INFRASPINATUS Origin: Supraspinatus : supraspinous fossa . Infraspinatus : infraspinaous fossa . Insertion: greater tuberosity of humerus . Nerve supply: suprascapular nerve. Action: Supraspinatus : abduction of humerus from 0° - 15°. Infraspinatus : lateral rotation of humerus . S I

16. 4. TERES MINOR Origin: lateral border of scapula. Insertion: greater tuberosity of humerus . Nerve supply: axillary nerve. Blood: circumflex scapular a. Action: lateral rotation of humerus .

17. Muscles of the shoulder attachment of rotator cuff muscles Rotator cuff 2. Intrinsic shoulder muscles :

18. ROTATOR CUFF Rotator cuff can be damaged due to trauma (during playing baseball) or disease (in older individuals). Trauma can tear or rupture one or more tendon (s) forming the cuff. Patients with rotator injury will present with pain, shoulder instability, and limited range of motion. Supraspinatus tendon is the most common site of rotator cuff injury.

19. SHOULDER JOINT TYPE: Synovial, multiaxial (ball & socket) ARTICULAR SURFACES: Head of humerus Glenoid cavity of scapula STABILITY: NOT STABLE Head of humerus is 3 times larger than glenoid cavity Capsule is redundant. Few ligamentous support: glenoid labrum, coracohumeral Main support: muscles around the joint (ROTATOR CUFF) Wide range of movement

20. BURSAE IN RELATION TO SHOULDER JOINT They reduce friction between tendons, joint capsule & bone. They are liable to be inflammed following injury of rotator cuff muscles. Subscapularis bursa: between subscapularis tendon & capsule. Infraspinatus bursa: between infraspinatus tendon & capsule. Subacromial bursa: between deltoid, supraspinatus and capsule. 3 1 2

21. RELATIONS OF SHOULDER JOINT ANTERIOR: subscapularis POSTERIOR: infraspinatus , teres minor SUPERIOR: supraspinatus INFERIOR: axillary nerve Subscapularis Infraspinatus Teres minor Supraspinatus Axillary nerve

22. MOVEMENTS OF SHOULDER JOINT FLEXION: Anterior fibers of deltoid Pectoralis major Coracobrachialis (muscle of arm) Short head of biceps brachii (muscle of arm) EXTENSION: Posterior fibers of deltoid Latissimus dorsi Teres major

23. MOVEMENTS OF SHOULDER JOINT ABDUCTION: From 0° - 15°: Supraspinatus From 15° - 90 °: Middle fibers of deltoid ADDUCTION: Pectoralis major Latissimus dorsi Inserted in bicipital groove Teres major

24. MOVEMENTS OF SHOULDER JOINT MEDIAL ROTATION: Pectoralis major Latissimus dorsi Inserted in bicipital groove Teres major Anterior fibers of deltoid Subscapularis LATERAL ROTATION: Posterior fibers of deltoid Infraspinatus Teres minor

25. Blood supply to the shoulder deep branch of transverse cervical a. ~or~ dorsal scapular a. suprascapular a. circumflex scapular a. from subscapular a.

26. Blood supply to the shoulder

27. “Spaces” of the shoulder region 1. quadrangular space boundaries teres minor teres major long head of triceps humerus/lateral head contents axillary nerve post. humeral circumflex a.

28. “Spaces” of the shoulder region 2. triangular space boundaries teres minor teres major long head of triceps contents twig of circ. scap. a.

29. “Spaces” of the shoulder region 3. triangular interval boundaries teres major long head of triceps lateral head of triceps contents radial nerve deep brachial a.

30. Surface anatomy of the shoulder clavicle palpable along its entire length coracoid process deltoid Anterior view

31. Surface anatomy of the shoulder acromion scapular spine Posterior view

32. Surface anatomy of the shoulder trapezius rhomboids deltoid teres major

33. Surface anatomy of the shoulder Palpate spinous processes of vertebrae here . . .

34. Surface anatomy of the shoulder triangle of auscultation superior border of latissimus dorsi medial border of scapula inferolateral border of trapezius

35. SUMMARY Shoulder joint: Type: synovial, ball & socket Articular surfaces: head of humerus & glenoid cavity of scapula Stability: depends on rotator cuff Relations: rotator cuff and axillary nerve Movement: flexion, extension, abduction, adduction, medial & lateral rotation

36. QUESTION 1 Which one of the following muscles is inserted into the lesser tuberosity of the humerus ? Subscapularis Deltoid Teres major Infraspinatus

37. QUESTION 2 Which one of the following muscles belong to the rotator cuff ? Subscapularis . Deltoid. Teres major. Rhomboid minor.