Shoulder Muscles and Fascia with a Direct Relationship with the Spine

Shoulder Muscles and Fascia with a Direct Relationship with the Spine

The trapezius muscle originates from the medial third of the superior nuchal line and from the external protuberance of the occipital bone. The muscle also extends from the nuchal ligament, from the spinous processes of the seventh cervical and all thoracic vertebrae, and from the intermediate supraspinal ligament. This muscle attaches to the lateral third of the clavicle, the medial margin of the acromion, and the superior margin of the crest of the scapula spine. The trapezius helps with shoulder girdle suspension, arm pulling or extension movements, arm abduction, and upward rotation of the shoulder blade. With the fixed shoulder, the trapezius can bend the head and neck back and to the side. The great dorsal muscle arises medially from the tendon fibers that attach to the six lower thoracic spines. The muscle also originates from the thoracolumbar fascia, which unites the lumbar and sacral spines, the supraspinatus ligaments and the posterior portion of the iliac crest. It also arises from muscle insertions on the outer lip of the iliac crest, on the lower three or four ribs, and on the lower corner of the scapula. This large muscle attaches posteriorly to the floor of the intertubercular sulcus of the humerus. The great dorsal muscle is active in the adduction, extension and medial rotation of the humerus. It helps support body weight when walking with crutches and is often active during swimming, pulling movements, coughing, sneezing and deep inspiration.

The levator scapulae muscle originates by four separate tendons Afrom the transverse processes of the first three or four cervical vertebrae. The origin of this muscle often has various accessory attachments that may include the mastoid process, occipital bone, first or second rib, scaleni, trapezius, and serrate muscles.  It inserts into the medial border of the scapula from the superior angle to the spine. The levator scapulae works with the rhomboids to control scapula motion and to stabilize the position of the scapula. The levator scapulae, working with the rhomboids and pectoralis minor muscles, assists in the downward rotation and depression of the scapula. It works with the trapezius and assists in elevation of the scapula. With the distal attachments to the scapula fixed, the levator scapulae produces ipsilateral side bending of the cervical spine. The rhomboideus minor muscle originates from the lower

part of the ligamentum nuchae, the spinous process of the last cervical and first thoracic vertebrae, and the associated segment of the supraspinal ligament.  It inserts into the medial border of the scapula at the root of the scapular spine.  The rhomboideus major muscle originates from the spinous processes of the

second to the fifth thoracic vertebrae and the corresponding segment of the supraspinous ligament.  It inserts into the medial border of the scapula below its spine. The rhomboideus minor and major muscles work together with the serratus anterior muscle to hold the scapula firmly to the chest wall.  The trapezius and rhomboid muscles are the primary movers for scapula retraction. Rotating and depressing the scapula require the coordinated efforts of the rhomboids, levator scapulae, and pectoralis minor muscles.

The deep cervical fascia, internal to platysma, is fibroareolar tissue between muscles, viscera, and vessels.  Its superficial layer is continuous with the ligamentum nuchae and the periosteum

of the seventh cervical spine.  It covers the trapezius and sternocleidomastoid (SCM) muscles and adheres to the symphysis menti and the body of the hyoid bone. The deep fascia is attached to the acromion, clavicle, and manubrium sterni, and it fuses with their periosteal.

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