The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The shoulder joint also known as the glenohumeral joint, is the major joint of the shoulder, but can more broadly include the acromioclavicular joint. In human anatomy, the shoulder joint comprises the part of the body where the humerus attaches to the scapula, the head sitting in the glenoid cavity. The shoulder is the group of structures in the region of the joint.
There are two kinds of cartilage in the joint. The first type is the white hyaline cartilage on the ends of the bones (called articular cartilage) which allows the bones to glide and move on each other. When this type of cartilage starts to wear out (a process called arthritis), the joint becomes painful and stiff. The glenoid labrum is the second kind of cartilage in the shoulder which is distinctly different from the articular cartilage. This cartilage is more fibrous or rigid than the cartilage on the ends of the ball and socket. Also, this cartilage is also found only around the socket where it is attached.
The shoulder must be mobile enough for the wide range actions of the arms and hands, but also stable enough to allow for actions such as lifting, pushing and pulling. The compromise between mobility and stability results in a large number of shoulder problems not faced by other joints such as the hip.

View More On
  1. _torque_spec_

    40 degree shoulder (AI)

    I see a lot of rifles cartridges going Ackley Improved. Is that 40 degree should really worth all the hassle? Give me some thoughts/feedback on this. I know you can stuff more powder in the case but why not just choose another cartridge or faster powder or something instead of having to ream...
  2. User 1234

    Experience with Jackass shoulder holster

    Has anyone used this holster personally? Does the rear attachment point make it less likely to flop forward (leaning forward) when properly adjusted (near armpit, not resting on belt) compared to a Miami Classic I or II? If not I will save up for a Monarch rig.
  3. Lazyfaire

    Looking for a good shoulder holster

    So I am looking for a shoulder holster. Not sure which weapon I would carry in it but am looking for styles and costs for now. Probably leather but would want it to be thinner than heavier. Makers or sites to find them? Anyone have an preference for horizontal or vertical?
  4. The Heretic

    National  Shoulder fired Rail gun (EMG coil gun)?

    SPACE FORCE: An Electromagnetic Coilgun C/O ARCFLASH LABS - The Firearm Blog Muzzle velocity 45 m/s or 148 fps
  5. Mikej

    Strap on shoulder pad for recoil.....

    Any one else among us that had bad shoulders? I'm looking to get one of the Caldwell Past recoil shields. They have three thicknesses. 1", 1/2" and 1/4". I don't shoot enough to justify spending any more that the $30.00+/- for one. I'm thinking the 1". That folded hand towel doesn't stay...
  6. h4344

    They still make vertical carry shoulder holsters?

    Been looking for awhile now to find a vertical shoulder holster for my S&W 9mm shield but cannot seem to find anything already made. I have found a few horizontal options but thats all. Does this sound like a product I might have to have custom made?
Back Top