Term
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Definition
Origin: Spinous processes of inferior thoracic and all lumbar and sacral vertebrae, ribs 8-12, and thoracolumbar fascia
Insertion: Floor of intertubercular sulcus of the humerus
Action: Extension, adduction, and medial rotation at shoulder
Innervation: Thoracodorsal nerve (C6-C8) |
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Term
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Definition
Origin: Supraspinous fossa of scapula
Insertion: Greater tubercle of humerous
Action: Abduction at shoulder
Innervation: Suprascapular nerve (C5) |
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Term
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Definition
Origin: Infraspinous fossa of scapula
Insertion: Greater tubercle of humerus
Action: Lateral rotation at shoulder
Innervation: Suprascapular nerve (C5-C6) |
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Term
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Definition
Origin: Ligamentum nuchae and the spinous processes of vertebra T2 to T5
Insertion: Vertebral border of scapula from spine to inferior angle
Action: Adducts and performs downward rotation of the scapula
Innervation: Dorsal scapular nerve (C5) |
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Term
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Definition
Origin: Spinous processes of vertebrae C7-T1
Insertion: Vertebral border of scapula
Action: Adducts and performs downward rotation of the scapula
Innervation: Dorsal scapular nerve (C5) |
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Term
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Definition
Origin: Lateral border of scapula
Insertion: Greater tubercle of humerus
Action: Lateral rotation and adduction at shoulder
Innervation: Axillary nerve (C5) |
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Term
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Definition
Origin: Inferior angle of scapula
Insertion: Medial lip of intertubercular sulcus of humerus
Action: Extension and medial rotation at shoulder
Innervation: Lower subscapular nerve (C5-C6) |
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Term
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Definition
Origin: Occipital bone, ligamentum nuchae, and spinous processes of thoracic vertebrae
Insertion: Clavicle and scapula (acromion and scapular spine)
Action: Depends on active region and state of other muscles; may elevate, retract, depress, or rotate scapula upward and/or clavicle; can also extend neck when the position of the shoulder is fixed
Innervation: Accessory nerve (N XI) |
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Term
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Definition
Origin: Transverse processes of first four cervical vertebrae
Insertion: Vertebral border of scapula near superior angle and medial end of scapular spine
Action: Elevates scapula
Innervation: Cervical nerves C3-C4 and dorsal scapular nerve (C5) |
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Term
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Definition
Origin: Clavicle and scapula (acromion and adjacent scapular spine)
Insertion: Deltoid tuberosity of humerus
Action:
Whole muscle - abduction of shoulder
Anterior part - flexion and medial rotation of humerus
Posterior part - extension and lateral rotation of humerus
Innervation: Axillary nerve (C5-C6) |
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Term
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Definition
Origin: Subscapular fossa of scapula
Insertion: Lesser tubercle of humerus
Action: Medial rotation at shoulder
Innervation: Subscapular nerve (C5-C6) |
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Term
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Definition
Origin: Spinous processes and ligaments connecting inferior cervical and superior thoracic vertebrae
Insertion: Mastoid process, occipital bone of skull, superior cervical vertebrae
Action: The two sides act together to extend neck; either alone rotates and laterally flexes neck to that side
Innervation: Cervical spinal nerves |
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Term
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Definition
Origin:
Superior - spinous processes of C7-T3 and ligamentum nuchae
Inferior - Aponeurosis from spinous processes of T10-L3
Insertion:
Superior - Superior borders of ribs 2-5 near angles
Inferior - Inferior borders of ribs 9-12
Action:
Superior - elevates ribs, enlarges thoracic cavity
Inferior - Pulls ribs inferiorly; also pulls outward, opposing diaphragm
Innervation:
Superior - Thoracic nerves (T1-T4)
Inferior - Thoracic nerves (T9-T12) |
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