Lab2 - Module 2 - Anatomy of the Scapular Region: Page 2 of 7
| Other muscles help to form the shoulder joint. These are the Deltoidand the Teres major. |
| Add the Teres major muscle. |
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Origin - from the inferior angle of the scapula. Insertion - on the medial lip of the intertubecular groove (bicipital groove). Innervation - by the lower subscapular nerve (NRs C5, C6). Action - is adduction, extension and internal rotation of the arm. Blood supply - from the circumflex scapular and thoracodorsal arteries. Rotate the cadaver to visulaize this muscle. |
| The Deltoid has three portions; anterior, middle, and posterior |
| Add the Deltoid. |
| The Anterior portion of the Deltoid muscle. |
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Origin - from the lateral 1/3 of the clavicle. Insertion - with the other portions on the deltoid tuberosity on the shaft of the humerus. Innervation - by the axillary nerve (NR’s C5-C6). Action - is forward flexion of the shoulder and internal rotation of the shoulder. Rotate the cadaver to visulaize this muscle. |
| The Middle portion of the Deltoid muscle. |
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Origin - from the lateral border of the acromion and joins the other two portions. Insertion - on the deltoid tuberosity on the shaft of the humerus. Innervation - by the axillary nerve. Action - is abduction in the shoulder and it assists the anterior portion in forward flexion. Rotate the cadaver to visulaize this muscle. |
| The Posterior portion of the Deltoid muscle. |
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Origin - from the spine of the scapula. Insertion - into the deltoid tuberosity with the other two portions. Innervation - by the axillary nerve. Action - is shoulder extension and external rotation. Rotate the cadaver to visulaize this muscle. |
| The whole deltoid muscle receives its Blood supply from the anterior and posterior circumflex humeral arteries. |
| Note: All three portions of the Deltoid muscle converge to insert onto the Deltoid tuberosity of the Humerus. Additionally, all three portions are innervated by the Axillary nerve. |