Starting Strength, 3rd Edition - Mark Rippetoe [74]
The humerus is attached quite thoroughly to the scapula at the glenoid, or shoulder joint, by several ligaments, the deltoids, the rotator cuff tendons and musculature, the long head of the triceps, the biceps, and the teres major muscles. The delts have a long origin all along the inferior side of the spine of the scapula, directly across the bone from the trap attachment, and they wrap around to the front along the acromion and the outside one-third of the clavicle. The delts insert on the deltoid tuberosity on the lateral side of the humerus, a large bump almost halfway down the shaft. This assembly – of spine to trapezius to scapula/clavicle to deltoid to humerus – produces a very robust, effective piece of force-transfer architecture. The teres major ties the bottom of the scapula to the front of the humerus, close to the glenoid, adding to the musculature connecting the two bones.
The latissimus dorsi muscles have a very important role to play here, too: they arise from a very broad origin on the lower back, starting for most people (there are variations between individuals) at the T7 spinous process and sweeping down with the thoracolumbar fascia, a broad sheet of connective tissue with fibers on the sacrum and the iliac crest of the pelvis. The insertion of the lat is on the front of the humerus at the top, very close to the pectoralis major insertion, so its function is to pull the humerus back; this function is very important to the mechanics of the pull. So the humerus has attachments both from the scapula and directly from the spine, and every spinous process in the spinal column, from skull to sacrum, is connected by either lats or traps to the humerus, with both overlapping from T7 through T12. All of these attachments form a rather thorough and effective connection between the back and the arms.
Figure 4-20. Muscles involved in force transfer between the arms and the spine, posterior view.
Figure 4-21. Muscles of the upper body involved in the deadlift, anterior view.
The correct position from which to pull will be one in which the scapulas, the bar, and the mid-foot are aligned vertically. The back will be held rigid in its normal anatomical position, the elbows will be straight, and the feet will obviously be flat against the floor. This is the position in which the skeleton most effectively and most efficiently transfers force – produced by the muscles that extend the hips and knees – up the back and down the arms to the loaded barbell. Furthermore, this principle is true for any pull off the floor, with any grip or stance. This alignment produces optimum balance between the lifter/barbell system