SKELETAL MUSCULAR SYSTEM / UPPER LIMB
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MUSCLES OF SCAPULAR STABILIZATION
TRAPEZIUS. CN: (1) Color the six muscles of scapular stabilization. Note that the two RHOMBOID MAJOR, MINOR rhomboids receive the same color (B). In the two main views, color gray LEVATOR SCAPULAE, the nuchal ligament and its line. (2) Color the attachment site diagrams at upper right. (3) In the illustrations below describing scapular movement, SERRATUS ANTERIOR. Note that the three regions of trapezius (A) play different roles. Color gray the scapulae, the arrows, and the movement titles. PECTORALIS MINOR
The scapula lies on the posterior thorax, roughly from T2 to T8. It has no direct bony attachment with the axial skeleton. Enveloped by muscle, it glides over the fascia-covered thorax during upper limb movement (scapulothoracic motion). Bursae have been reported between the thorax and the scapula; so has bursitis. The scapula is dynamically moored to the axial skeleton by muscles attaching the scapula to the axial skeleton. These muscles of scapular stabilization make possible considerable scapular mobility and, therefore, shoulder/arm mobility.
Note the roles of these six muscles in scapular movement, and note how the shoulder and arm are affected. Pectoralis minor assists serratus anterior in protraction of the scapula such as in pushing against a wall; it also helps in depression of the shoulder and downward rotation of the scapula. Consider the power resident in serratus anterior and trapezius in pushing or swinging a bat. Note the especially broad sites of attachment of the trapezius muscle. Trapezius commonly manifests significant tension with hard work. A brief massage of this muscle often brings quick relief.
MOVEMENTS OF THE SCAPULA
RETRACTION, PROTRACTION. Military posture Pushing forward with outstretched arms and hands
ELEVATION. Shrugging the shoulders Or protecting the head
DEPRESSION. Straight arms on parallel bars, holding weight.
UPWARD ROTATION. Lifting or reaching overhead.