Shoulder Joint Muscles PDF
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Uploaded by GlowingPiccoloTrumpet
Hebron University
Dr. Amjad Shatarat
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Summary
This document provides an in-depth look at the rotator cuff muscles of the shoulder, such as supraspinatus and infraspinatus. It details their origins, insertions, actions, and the nerves that innervate them.
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The shoulder joint What does this mean? Dr. Amjad Shatarat A-POSTERIOR SCAPULAR REGION Dr. Amjad Shatarat It contains four muscles, which pass between the scapula and proximal end of the humerus; Supraspinatus...
The shoulder joint What does this mean? Dr. Amjad Shatarat A-POSTERIOR SCAPULAR REGION Dr. Amjad Shatarat It contains four muscles, which pass between the scapula and proximal end of the humerus; Supraspinatus Infraspinatus Teres minor Teres major Dr. Amjad Shatarat The posterior scapular region also contains part of one additional muscle, the long head of the triceps brachii, which passes between the scapula and the proximal end of the forearm. Teres major muscle long head of the triceps brachii, Posterior view Dr. Amjad Shatarat Supraspinatus muscle Posterior view Dr. Amjad Shatarat Supraspinatus Insertion: They form tendons that insert Origin: Supraspinous fossa of the scapula on the greater tubercle of the humerus (upper facet) (above the spine) on the posterior surface of the scapula Action: The supraspinatus initiates abduction of the arm( 0-15degree) Posterior view NS: Suprascapular N. Dr. Amjad Shatarat The tendon of the supraspinatus passes under the acromion where it is separated from the bone by a subacromial bursa The tendon Passes over the glenohumeral joint Inserts on the superior facet of the greater tubercle S Remember I T Dr. Amjad Shatarat Posterior view Infraspinatus muscle Dr. Amjad Shatarat The tendon of the infraspinatus passes posteriorly to the glenohumeral joint and inserts on the middle facet of the greater tubercle Action The infraspinatus laterally rotates the humerus NS: Suprascapular N. Posterior view Dr. Amjad Shatarat Dr. Amjad Shatarat Teres minor muscle It is a cord-like muscle Origin: from the lateral border of the scapula below the infraglenoid tubercle Insertion: inferior facet of the greater tubercle of the humerus Action: laterally rotates the humerus NS: Axillary n Dr. Amjad Shatarat Dr. Amjad Shatarat S Remember I T Dr. Amjad Shatarat Teres major muscle Origin: from a large oval region on the posterior surface of the inferior angle of the scapula Insertion: medial lip of the intertubercular sulcus on the anterior surface of the humerus Action: medially rotates and extends the humerus. NS : Lower subscapular n Dr. Amjad Shatarat Anterior view Dr. Amjad Shatarat Subscapularis Origin: Subscapular fossa. Insertion: Lesser tubercle. Action: Medial rotation of the arm. NS: Upper and lower subscapular nerves. Dr. Amjad Shatarat Rotator cuff muscles of shoulder Four muscles 1. Supraspinatus 2. Infraspinatus 3. Teres minor 4. Subscapularis The tendons of these muscles flatten at their insertion and blend with the capsule of the shoulder joint. They act as a handcuff that strengthen shoulder joint (superior, posterior & anterior). But NOT inferior? Why? not to compromise the arm's flexibility and range of motion Dr. Amjad Shatarat
