Scapular Adduction & Downward Rotation (PDF)

# 1446 H/2024 A.D ## Scapular adduction ## Scapular downward rotation. ### Manual Muscle Test 200 PHT - Theoretical Part. Jazan University, College of Nursing and Health Sciences, Physical Therapy Department. ## 16th lecture - Theoretical Part: Scapular abduction, scapular downward rotation. ###...

# 1446 H/2024 A.D ## Scapular adduction ## Scapular downward rotation. ### Manual Muscle Test 200 PHT - Theoretical Part. Jazan University, College of Nursing and Health Sciences, Physical Therapy Department. ## 16th lecture - Theoretical Part: Scapular abduction, scapular downward rotation. ### Objectives: At the end of this lecture the student will be able to: 1. Identify the primary muscles involved in scapular adduction, and scapular downward rotation. 2. Identify the range of motion of scapular adduction, and scapular downward rotation. 3. Describe effect of weakness and contracture of scapular downward rotator muscles. ### Content: 1. Anatomy of primary muscles involved in scapular adduction and downward rotation. 2. Range of motion of scapular adduction and downward rotation. 3. Effect of weakness and contracture of scapular downward rotator muscles. ## Scapular Adduction Motion. ### Primary Muscles: 1. Middle fibers of trapezius. ### Accessory muscles: 1. Trapezius upper and lower fibers. 2. Rhomboid major and minor ### Range of motion: From the abduction position to the adduction position, the scapula travels a distance equivalent to the space formed by 3 to 4 fingers (Fig. 1). ## Anatomy of middle fibers of trapezius: ### Origin - Spinous processes of first through fifth thoracic vertebrae. ### Insertion - Superior lip of spine of scapula (Fig.2). ### Nerve supply - Accessory nerve. ### Action 1. The trapezius middle fibers are mainly responsible for the scapular adduction. 2. They also maintain a stabilization role during the scapula downward rotation. ## Scapular adduction and downward rotation motion. ### Primary Muscles: 1. Rhomboids major. 2. Rhomboids minor. ### Range of motion: The range of motion is similar in distance as for the adduction of scapula. ### Accessory muscles: - Middle fibers of trapezius. ## Anatomy of Rhomboids major and minor ### Origin - Rhomboids major: Spinous processes of second through fifth thoracic vertebrae. - Rhomboids minor: Ligamentum nuchae and spinous processes of first thoracic vertebrae. ### Insertion - Major: By fibrous attachment to medial border of scapula between the spine and inferior angle. - Minor: Medial border at root of spine of scapula (Fig.3). ### Nerve supply - Dorsal scapular nerve ### Action - Adduct and elevate the scapula, and rotate it so that the glenoid cavity faces caudally. ## Effect of weakness of the scapula adductor and downward rotator muscle. 1. Weakness of these muscles will cause the scapula to abduct and the inferior angle to rotate outward. 2. The strength of adduction and extension of the humerus is diminished by the loss of the rhomboids fixation of the scapula. ## Effect of contracture of the scapula adductor and downward rotator muscle. 1. The scapula is drawn into a position of adduction and elevation. This document describes the anatomy and function of the muscles involved in scapular adduction and downward rotation. This document also refers to figures(1, 2 and 3). The document explains how muscle weakness and contracture can affect the range of motion of the scapula.