Classification of muscles of the trunk

Figure 4.1 2

Section 2 The Muscles of Trunk  Section 2 The Muscles of Trunk . The muscles of back trapezius, latissimus, levattor scapulae, rhomboid muscles erector spinae (sacrospinelis) thoracolumbar fascia . The muscles of thorax 1) The extrinsic muscles pectoralis major, pectoralis minor, serratus anterior 2) The intrinsic muscles intercostales extrerni, intercostales interni  . The diaphragm  . The muscles of abdomen 3

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Muscles of Thorax Muscle Origin Insertion Action Innervation Page 118, 646 Muscles of Thorax Muscle Origin Insertion Action Innervation Pectoralis major Sternum, Ribs 2-6 Inter-tubercular groove of humerus Adduct, Flex, Med Rotate Arm M & L pectorals Pectoralis minor Ribs 3-5 Coracoid process of scapula Depress, Rotate scapula Serratus anterior (ventralis) Ribs 1-9 Scapula Protract, Rotate scapula Long Thoracic

Muscles of Thorax Muscle Origin Insertion Action Innervation Trapezius Page 49 Muscle Origin Insertion Action Innervation Trapezius Ligamentum nuchae, C7-T12 Clavicle, Spine & acromion of scapula Elevate, Adduct, Rotate, Depress Accessory Levator Scapulae C1-C4 Medial border of scapula Elevate scapula D. Scapular Rhomboids C7-T5 Adduct, Elevate, Rotate

Muscles of Thorax Muscle Origin Insertion Action Innervation Deltoids Clavicle, Spin & acromion of scapula Deltoid tuberosity of humerus Flex, Abduct, Extend, Lat & med. rotate arm Axillary Latissimus dorsi Iliac crest, Sacrum, T7-12, Lumbar fascia Inter-tubercular groove of humerus Extend, Adduct, Med. rotate arm Thoraco-dorsal

Anterior Surface of Thorax Palpate the following Sternum (3 parts) Jugular notch Sternal Angle (= 2nd rib) Clavicle Costal margin Xiphosternal joint Midclavicular Line Midaxillary Line Page 201

Posterior Surface of Thorax Palpate the following Spinous Process of C7 Scapula (ribs 2-7) Scapular spine Acromion Process Inferior Angle of Spine Inferior Border Page 90

Locating Internal Structures Pleural Cavities Inferior margin = adjacent to T12 in Posterior Midline To Rib 10 at Midaxillary line To Rib 8 at Midclavicular line To Xiphosternal joint medially Lungs posterior border is 2 ribs superior to pleural cavity (rib 8) Heart Deep to xiphisternal angle Page 206

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Pectoralis Major Pectoralis Minor

Trapezius In more primitive species used for opening and closing gills - a BRANCHIAL muscle. In humans, used to move scapula and keep head up

Trapezius Origin: Occipital bone, Spines of C7 and T1-12 Insertion: Acromion Spine of scapula Lateral 1/3 of clavicle

Trapezius Innervation: Accessory Nerve (Cranial Nerve XI) Action: Extension of the head Elevation and depression of scapula

Trapezius

Serratus Anterior Origin: First 9 ribs Insertion: Medial edge of scapula’s deep surface

Serratus Anterior Innervation: Long thoracic nerve Action: Rotates scapula Primitively a BODY WALL MUSCLE

Serratus Anterior

Levator Scapulae Origin: Transverse processes of C1-4 Insertion: Medial edge of scapula

Levator Scapulae Innervation: Ventral Rami of C3 and C4 Action: Retracts scapula Depresses glenoid

Rhomdoidius Major Origin: Spines of T2-T5 Insertion: Medial edge of scapula

Rhomdoidius Major Innervation: Dorsal Scapula Action: Retracts scapula Depresses glenoid

Rhomdoidius Minor Origin: Spines of C7 and T1 Insertion: Medial edge of scapula Note: minor is superior (cranial), but SMALLER

Rhomdoidius Minor Innervation: Dorsal Scapula Action: Retracts scapula Depresses glenoid

Levator Scapulae Rhomboid Minor Rhomboid Major

Levator Scapulae Depression Rhom- boids Pecoralis Minor

Elevation Trapezius Serratus Anterior Trapezius

Latissimus Dorsi Origin: Spines of T7-T12 Thoracolumbar fascia Insertion: Humerus: Inertubecular groove And lesser tubecular crest Innervation: Thoracodorsal Nerve

Latissiumus: Extends, adducts and medially rotates humerus Pectoralis: is large, fan-shaped muscle opposing it ventrally

Pectoralis Major: Clavicular Head: Sternal Head: Origin: inferior margin of clavicle Insertion: Delto-pectoral crest of HUMERUS Sternal Head: Origin: Ventro-lateral margin of sternum

Pectoralis Major: Clavicular Head: Origin: inferior margin of clavicle Insertion: Greater tubercular crest of HUMERUS Innervation: Medial and lateral pectoral nerves

Pectoralis Major: Sternal Head: DEPRESSOR, ADDUCTOR of humerus Origin: Ventro-lateral margin of sternum; costal cartilages 1-6 Insertion: Greater tubercular crest of HUMERUS Innervation: Medial and lateral pectoral nerves

Pectoralis MINOR: Deep to Pec. Major Origin:Ribs 3-6. Insertion: Coracoid Process of Scapula Innervation: Function: Stabilization of scapula Positionally important for understanding location of other structures.

Elevators Teres Major Origin: Lower edge of scapula Insertion: Lesser tubercular crest Action: Extends, Adducts & Medially rotates humerus Innervation: Lower scapular

Elevators Subscapularis Origin: Deep surface of scapula Insertion: Lesser tubercle Action: Medially rotates humerus Innervation: Upper and lower scapular

Internal View: Subscapularis

Elevators Teres Minor Origin: Lower edge of scapula Insertion: Greater tubercle Action: Laterally rotates humerus Innervation: Axillary

Teres Minor