University:
Michigan State University
Course:
ANTR 211 | Human Tissues and Cells for Medical Illustrators
Academic year:

2019
Views:

271

Pages:

3
Author:

salcignofi9

Muscles of the Posterior Neck, Shoulders and Thorax Levator scapulae Trapezius Rhomboid minor Rhomboid major Clavicle Deltoid Scapular spine Supraspinatus Infraspinatus Teres minor Teres major Latissimus dorsi Muscles of the Posterior Neck, Shoulders and Thorax 1) Trapezius (posterior): a. Actions: stabilizes, raises, retracts and rotates scapula abducts upper limbs b. Innervation: Accessory Nerve (Xl) c. Origin: from occipital bone down spinous processes through the thorax (ligamentum nuchae) d. Insertion: along the acromion and spine of the 1 scapula and later end of clavicle 2) Deltoid (antagonist of Pectoralis major and Latissimus dorsi) (arm swinging): a. Actions: anterior fibers flex and medially rotate arm, posterior fibers extend and laterally rotate arm b. Innervation: Accessory Nerve (Xl) c. Origin: from the lateral end of the clavicle and the acromium and spine of scapula d. Insertion: to deltoid tuberosity on the humerus 2 4 5 6 7 8 10 3 3) Latissimus dorsi: a. Actions: arm extension and adductor, medial rotator at shoulder, brings arm down (extension) for hammering, swimming and hitting b. Innervation: Thoracodorsal Nerve c. Origin: from lumbodorsal fascia attachment to thoracic spines, lumbar vertebrae, lower 3-4 ribs and the iliac crest of the pelvis d. Insertion: to intertubercular groove of humerus 4) Levator scapulae: a. Actions: elevates and adducts scapula with the trapezius (this drops glenoid cavity down), flexes neck to same side b. Innervation: Dorsal Scapular Nerve (C3-5) c. Origin: from transverse processes of C1-4 d. Insertion: to superior vertebral border of scapula 5) Rhomboid minor: a. Actions: acts together with trapezius to “retract scapula”, “squaring shoulders”, rotates glenoid cavity down b. Innervation: Dorsal Scapular Nerve (C3-5) c. Origin: from spinous processes of C7 and T1 d. Insertion: to medial border of scapula 9 Muscles of the Posterior Neck, Shoulders and Thorax (continued) 6) Rhomboid major: a. Actions: acts together with trapezius to “retract scapula”, “squaring shoulders”, rotates glenoid cavity down b. Innervation: Dorsal Scapular Nerve (C3-5) c. Origin: from spinous processes of C7 and T1 and T2-5 d. Insertion: to medial border of scapula 7) Supraspinatus: a. Actions: assists in arm abduction, stabilizes joint and prevents downward dislocation (as when carrying a heavy object on one side - book bag with anatomy text book inside) b. Innervation: Suprascapular Nerve c. Origin: from the suprascapular fossa d. Insertion: to greater tubercle of humerus 4 8) Infraspinatus: a. Actions: assists in stabilizing shoulder joint, rotates joint laterally b. Innervation: Suprascapular Nerve c. Origin: from infrascapular fossa d. Insertion: to greater tubercle of humerus 1 2 9) Teres minor: a. Actions: assists in stabilizing shoulder joint, rotates joint laterally b. Innervation: Axillary Nerve c. Origin: from the lateral border of dorsal scapular surface (the back of the scapula) d. Insertion: to greater tubercle of humerus (below infraspinatus) 10) Teres major: a. Actions: extends and medially rotates arm, adducts arm b. Innervation: Lower Subscapular Nerve c. Origin: from dorsal scapula (the back of the scapula) at inferior angle d. Insertion: to lesser tubercle of anterior humerus 5 6 7 8 10 3 9