Shoulder &Pectoral Regions,

Objectives Identify the bony components of the shoulder girdle including the clavicle, scapula and humerus Describe how primary muscles are responsible for the following shoulder motion: adduction, abduction, flexion, extension

Surface Anatomy

Bony Skeleton Axial? Appendicular Can you name some? Shoulder Girdle..

Bony Skeleton

Shoulder Girdle

Anterior Scapula. -angles, borders -glenoid cavity, -acromion, -coracoid process, -Subscapular fossa Humerus. -Head, -Surgical neck -Anatomical neck -Greater tubercle -Lesser tubercle -Intertubercular (bicipital) groove

Posterior Clavicle. Acromioclavicular joint Scapula. - Spine - Acromion - Supraspinous fossa - Infraspinous fossa Humerus. - Head - Anatomical neck, - Surgical neck, - Deltoid tuberosity - Spiral (radial) groove.

Pectoral Girdle Direct : Clavicle, scapula from the trunk Pectoralis minor, trapezius, rhomboids… Most will be discussed in the scapular region lecture Indirect : muscles of the great axillary folds as Pectoralis Major, and Latismus dorsi

Movements of the shoulder joint (Scapulohumeral): Abduction / adduction Flexion / extension Rotation – internal (medial) - external (lateral) Movements of the scapula (Thoracoappendicular): (increase range of movement of upper limb) Protraction / Retraction Elevation / Depression Rotation:Superior / Inferior Circumduction

Name the action

We need MUSCLES for all that!! Muscles are named by either their attachments “Sternohyoid”, location ”Pectoralis”, action “levator”, shape ”quadratus”,direction of fibers “rectus” Will make our life easier memorizing all the names.. Nerve supply of the muscles tells us the story about it’s embryological origin..please pay attention in the embryology classes and enjoy the integration

Clavicular Sternocostal Pectoralis Major: 2 parts - Together (adduction, medial rotation) - Clavicular head (flexion) - Sternocostal head (extension) - (common insertion: lateral lip of intertubercular groove) Pectoralis minor - deep to pec. major - protraction of scapula - guide to axilla

Poland Syndrome Congenital Absence of Pectoralis Major Partial or complete absence

Trapezius: 3 parts -Superior fibres elevate (insert lateral 1/3 of clavicle) -Middle fibres retract (insert acromion) -Inferior fibres depress (insert spine of scapula) - Acting together, the superior and inferior fibres will rotate scapula. Superior Middle Inferior

Latissimus Dorsi: -(inserts floor of intertubercular groove) -Extends, adducts and medially rotates humerus. Butterfly swimming, Crutch Climbing a tree

Anterior Deltoid: 3 parts -Anterior (flexion, med. rotation) -Middle (abduction) -Posterior (extension, lat. rotation) -(common insertion: deltoid tuberosity) Posterior

Posterior view: - Trapezius - Latissimus Dorsi - Deltoid Rhomboids: - minor and major - retract / inferior rotate scapula Teres major: - inserts near latissimus dorsi - adduct / medially rotate arm

Anterior Arm. – Biceps brachi – Coracobrachialis Actions: Biceps – supination + flexion (shoulder, elbow) Coracobrachialis – weak flexion / adduction (shoulder) Shoulder Flexion

Posterior Arm. -Triceps (3 heads) -long head extends shoulder. Action: Extension Shoulder Extension

Adduction – pectoralis major, lattisimus dorsi. Abduction– deltoid, supraspinatus. Flexion – pectoralis major, deltoid (anterior), – coracobrachialis, biceps. Extension – latissimus dorsi, deltoid (posterior); – pectoralis major from flexed position - triceps (long head). Medial Rotation – subscapularis, pectoralis major, deltoid (anterior), – latissimus dorsi, teres major; Lateral Rotation – infraspinatus, teres minor, deltoid (posterior). Key Muscles that act across the Shoulder Joint.

Dermatomes

Case 9 Years old boy fell on his shoulder while playing on the monkey bars, he is experiencing pain, and inability to Lift his left arm this is his X-ray What’s your diagnosis?

Clavicle Fractures

Fracture Clavicle

Glossary Pectoral: Worn on the chest or breast Girdle: Something that encircles like a belt

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