(3.58)
Now it's time to look at the muscles which hold the scapula in place, and move it in relation to the trunk. There are six of them, four on the back, one in the front, and one underneath.
The one on the underneath is the large and powerful serratus anterior muscle. This is just part of it. To see it all, we need to move the scapula away from the body. This big expanse of muscle is all serratus anterior. It arises from the side and front of the first eight ribs. In runs back under the scapula, and it's inserted all the way back here, along the medial border of the scapula.
When the whole serratus anterior muscle contracts, it pulls the scapula forward around the rib cage: that's protrusion. When its upper, or lower fibers contract separately, they help to produce downward or upward rotation of the scapula.
When the whole serratus anterior muscle contracts, it pulls the scapula forward around the rib cage: that's protrusion. When its upper, or lower fibers contract separately, they help to produce downward or upward rotation of the scapula.
Levator scapulae arises here, on the outermost point of the first three cervical vertebrae. It inserts here, on the upper medial corner of the scapula. Levator scapulae helps to elevate the scapula. The rhomboids arise here, from the fourth cervical to the fifth thoracic vertebrae. They insert here, along the medial border of the scapula.
Levator scapulae arises here, on the outermost point of the first three cervical vertebrae. It inserts here, on the upper medial corner of the scapula. Levator scapulae helps to elevate the scapula. The rhomboids arise here, from the fourth cervical to the fifth thoracic vertebrae. They insert here, along the medial border of the scapula.
The upper part of trapezius arises from the occiput, and from the nuchal ligament, and from T1 to T3 in the mid-line. It's inserted along the upper edge of the spine of the scapula, around the acromion, and along the lateral third of the clavicle.
The lower part of the trapezius muscle is not so massive. It arises from T4 to T12 in the mid-line. It inserts here, on the lower edge of this part of the spine of the scapula. When the whole of trapezius contracts, it powerfully retracts the scapula. When the upper part contracts, it powerully elevates the scapula.
Last on the list of muscles passing from the trunk to the scapula is the one on the front. It's pectoralis minor. Pectoralis minor arises between the second and the fourth ribs. It's inserted on the coracoid process. Pectoralis minor produces depression of the scapula.
Last on the list of muscles passing from the trunk to the scapula is the one on the front. It's pectoralis minor. Pectoralis minor arises between the second and the fourth ribs. It's inserted on the coracoid process. Pectoralis minor produces depression of the scapula.