Take a moment to stand up and position yourself in anatomical posture. For yoga practitioners, this is the same as Mountain Pose.
Ground your feet and engage your thighs. Gently tuck your pelvis forward to meet your belly button. Extend your arms along your sides, with palms facing forward. With your gaze looking forward, imagine your crown reaching to the sky, like a strong mountain.
Your body is supported by its skeleton, and the skeleton is referenced by two parts, the axial and the appendicular. The axial skeleton consists of your skull, ribs and spinal column. The appendicular skeleton consists of your pectoral girdle and upper extremities, and your pelvic girdle and lower extremities. An easy way to remember the distinction between the two is the axial is your axis, around which the rest of your body rotates, and the appendicular consists of your external appendages, such as your arms and legs.
Our shoulders are our “shuddas” – holding the tension for all the things we think we “should a” done
said by Deb, my first yoga teacher
I love my shoulders and arms in the summer, those lovely triceps and biceps. As an avid outdoor swimmer doing free style and breast stroke, my upper extremities become sculpted and strong. I marvel at how repeated exercise over a span of weeks can alter the look and feel of my muscles, and give me a healthy feeling.
Several years ago, my right shoulder suffered from a calcium deposit that caused a bit of pain. Worse, I could not raise my right arm to open cabinets or lift objects. It was mid-winter, a saving grace that provided time to address the issue! I had an inkling of what it could be like to develop decreased mobility. While long since healed, this was a vivid lesson in body anatomy.
The shoulder is a synovial joint, of the ball and socket type. (More about synovial joints in a future post.) To get a sense of what this joint looks like, cup one of your hands and make a fist with the other hand. Place the fisted hand inside the cupped hand and rotate the fist and its arm. Uh oh, if you move too fast or too far, your fist will slide out of the cup. This is what happens when a shoulder is dislocated, as the ball and socket form a shallow pocket, thereby allowing for greater movement but less stability. The shoulder is similar to the hip joint of the lower extremities, but the hip joint has a much deeper pocket to provide stability for standing.
The elbow consists of three bones, the humerus, ulna and radius, that meet to form another synovial joint of the lever type. The humerus is your upper arm bone and runs from your shoulder to your elbow, where it meets the ulna and radius, the two bones of your forearm. The humerus bone is often the one that gets broken when someone breaks their shoulder, and the joke is that this is not a humorous event .
The ulna and radius are interesting because when you rotate your wrist from side to side, the ulna and radius criss-cross over one another. The radius is the bone along the thumb side of your forearm and the ulna is along the pinky side. That bump at the base of your thumb is the larger portion of the radius; the smaller portion is at the elbow. It is opposite for the ulna, which has its larger portion at the elbow. When you bang your “funny bone” it is the ulna nerve that is getting twanged, as Matt described in our anatomy lab.
SCAPULA, CLAVICLE & STERNUM
The sounds of those three words make me smile – could be the name of a legal firm in a Marx Brothers movie! The scapula (shoulder blade) and clavicle (collar bone) form the shoulder girdle. The scapula attaches the clavicle to the humerus. At its other end, the clavicle attaches to the axial skeleton at the sternoclavicular joint. This is the only bony attachment of the upper extremity to the axial skeleton! The sternoclavicular joint is an incredibly strong synovial joint providing support and assist with movement of the humerus.
The sternum (breast bone) descends from the center of the chest to connect the rib bones. This is actually part of the axial skeleton but is part of my mnemonic for remembering which bone is which: SCS – Scapula (shoulder) – Clavicle (collar) – Sternum (breast).