Pectoral Scapular Regions ANATOMY 28012013 1 What is

Pectoral & Scapular Regions ANATOMY 28/01/2013 1

What is Muscle ? q A contractile organ consisting of a special bundle of muscle tissue, which moves a particular bone, part, or substance of the body. 28/01/2013 3

Types of muscles … q Skeletal muscles : a form of striated muscles attached to bones by tendons and they under control of somatic nervous system ((voluntary controlled)). . . existing throughout the human body. q Smooth muscles : Non striated muscles and they under control of autonomic nervous system ((involuntary controlled))… existing in wall of blood vessels , lymphatic vessels, the urinary bladder , male and female reproductive system, gastrointestinal tract, respiratory tract. . etc. q Cardiac muscles : striated muscles controlled by the autonomic nervous system ((involuntary controlled)). . Found only in the walls of the heart. 28/01/2013 4

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Functions of skeletal muscles 1. Movement. 2. Posture (( ))ﻭﺿﻌﻴﺔ ﺍﻟﺠﺴﻢ 3. Support & protection. 4. Heat regulation. 28/01/2013 6

How muscles are named ! 1. Size of muscles : minor , major 2. Shape of muscles: Deltoid , Teres 3. Main action: Flexor, Extensor 4. Number of tendons of origin : Bicecps, Triceps 5. Relation of muscle to the bone : Supraspinatus, Infraspinatus 6. Origin &insertion : Brachioradialis (from Brachium(humerus) to radius) 28/01/2013 7

I should memorize all these muscles !! Scapular regions : Supraspinatus Infraspinatus Teres minor Teres major Subscapularis Deltoid Pectoral regions : Pectoralis major Perctoralis minor Subclavius Serratus antreior 28/01/2013 8

What should we know about each muscle ? 1. Origin 2. Insertion 3. Nerve Supply 4. Action 28/01/2013 9

LAW: When the muscle perform its action, its insertion moves towards its origin. 28/01/2013 10

Scapular Muscles ((muscles connecting scapula to humerus)) 28/01/2013 11

Revision. . ! Soulder Joint 28/01/2013 The Scapula 12

Revision. . ! Proximal end of Humerus bone 28/01/2013 Clavicle 13

Supraspinatus (Supra=above. . -spintaus =spine of scapula Origin : Supraspinous fossa of scapula Insertion: Greater tuberosity of humerus Nerve supply: Suprascapular nerve Action : 1 -Initiation of abduction (0 -15 degree) 2 -stabilization of the shoulder joint 28/01/2013 14

Infraspinatus (infra=below, -spinatus= spine of scapula) Origin: Infraspinous fossa of scapula Insertion: Greater tuberosity of humerus Nerve supply: Suprascapular nerve Action: 1 - Lateral rotation 2 - Stabilization of shoulder joint 28/01/2013 15

Teres minor (teres=rounded) Origin: Upper two thirds of lateral border of scapula Insertion: Greater tuberosity of humerus Nerve supply: Axillary nerve Action: 1 - Lateral rotation 2 - stabilization of shoulder joint 28/01/2013 16

Teres major Origin: Lower third of lateral border of scapula Insertion: Medial lip of intertubercular groove of humerus Nerve supply : Lower subscapular nerve Action: 1 -Medial rotation 2 -adduction 3 -stabilization of shoulder joint 28/01/2013 17

Minor & Major 28/01/2013 18

Subscapularis Origin: Subscapular fossa Insertion: Lesser tuberosity of humerus Nerve supply: Upper and lower subscapular nerve Action: 1 -Medial rotation 2 -stabilization of shoulder joint 28/01/2013 19

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Rotator cuff of shoulder joint. . !! 4 muscles and their tendons : Supraspinatus (superior) Infraspinatus (posterior ) Teres minor (posterior) Subscapularis (Anterior) Function: maintaining glenohumeral (shoulder joint) stability. Note: The cuff is deficient inferiorly, and this is a site of potential weakness. 28/01/2013 21

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Deltoid muscle (delt= triangular, oid=like ) Origin : 1 -anterior border & upper surface of lateral third of the clavicle 2 - lateral margin of acromion 3 -posteroir border of the spine Insertion: Deltoid tuberosity of humerus Nerve supply: Axillary nerve Action: 1 - Abduction (15 -90 degrees) 2 - Flexion ((Calvicular fiber)) 3 - Extension((Posterior fibers)) 28/01/2013 23

Pectoral muscles 28/01/2013 24

Pectoralis major (pector=Breast) Origin : 1 -medial half (sternal Half) of Clavicle 2 - Anterior surface of Sternum Insertion: Lateral Lip of intertubercular head Nerve supply : Medial & Lateral pectoral nerves Action : 1 -Adduction 2 -Medial rotation 28/01/2013 25

Pectoralis minor Beneath pectoralis major Origin: Anterior surface & superior border of ribs III to V Insertion: coracoid process of scapula Nerve supply: medial pectoral nerve Action: Depression of shoulder joint 28/01/2013 26

Subclavius (sub=under, clavius=clavicle) Origin : Rib I Insertion: groove at the middle third of inferior surface of clavicle Nerve Supply: nerve to subcalvius Action: 1 - pulls clavicle medially 2 -protects underlying structures 28/01/2013 27

Serratus anterior(serratus=saw, anterior=front side of body ) Origin: lateral surface of upper 9 ribs Insertion: medial border the scapula Nerve supply : long thoracic nerve Action: protraction &rotation of scapula 28/01/2013 28

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