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At the edge of the first rib, the subclavian artery becomes the axillary artery, which continues to descend to the tendon of the teres major muscle and becomes the brachial artery. The artery divides into three branches around the pectoralis minor muscle, one above the muscle, one behind the muscle and one below the muscle. This artery brings a fresh blood supply to the upper arm and chest area.
 Research Axillary Artery
The brachial artery conveys blood to the upper arm. It begins at the tendon of the teres major and extends to just below the elbow joint. It then branches into the radial and ulnar arteries. You can feel your pulse by placing your fingertips along the brachial artery at the bend of the elbow along the inner margin of the biceps muscle.
Research Brachial Artery
The deltoid is a large, thick powerful muscle with a triangular form and a coarse texture. The muscle is divided into three portions: an anterior (clavicular) portion, and acrominal portion, and a posterior portion. The anterior portion forms the broad side of the muscle and the posterior portion is located on the back of the shoulder. The muscle originates from the clavicle and from the spine of the scapula covering the outer side of the shoulder joint, giving the shoulder its rounded appearance, and inserts in the humerus. The deltoid is innervated by the 5th and 6th cervical nerves through the circumflex nerve and supplied by the circumflex artery.
Almost any movement of the shoulder and upper arm involves the deltoid muscle. The anterior portion is used to raise the arm from the body and to lower it again. The acrominal portion is a powerful abductor and the posterior portion is used to move the arm backward. It works with the pectoralis major to move the arm forward and works with the teres major and latissimus dorsi to move the arm back.
Research Deltoid
The teres major is a short and thick, somewhat flattened muscle that extends from the scapula to the humerus. It originates from the inferior angle and lower portion of the scapula and inserts in the intertubercular groove of the humerus. The teres major is innervated by the fifth and sixth cervical nerves and supplied by the dorsal subscapular artery which branches from the subscapular artery. This muscle creates part of the posterior wall of the armpit and helps adduct the arm. It also rotates the arm medially behind the back. The teres major tenses when the arm lies next to the body. When the arm is extended the teres major is stretched, becoming elongated and thinner.
Research Teres Major
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The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
©1993 - 2009 The Probert Encyclopaedia
Southampton, United Kingdom
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