the humerus is the name of your upper arm bone.
the humerus is the name of your upper arm bone.
what is the name of your upper arm bone?
the humerus
the shoulder joint is composed of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) (see diagram). two joints facilitate shoulder movement. the acromioclavicular (ac) joint is located between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle. the glenohumeral joint, to which the term "shoulder joint" commonly refers, is a ball-and-socket joint that allows the arm to rotate in a circular fashion or to hinge out and up away from the body. the "ball" is the top, rounded portion of the upper arm bone or humerus; the "socket," or glenoid, is a dish-shaped part of the outer edge of the scapula into which the ball fits. arm movement is further facilitated by the ability of the scapula itself to slide along the rib cage. the capsule is a soft tissue envelope that encircles the glenohumeral joint. it is lined by a thin, smooth synovial membrane.
shoulder problem
like derived troodontids, the slender upper arm bone is about 70% of the length of the thighbone. on the upper arm bone, however, the deltopectoral crest, the bone plate serving for muscle attachment, is short compared to "linhevenator" and other derived troodontids, occupying only 20% of the shaft length. the ulna, the main lower arm bone, which is 88% of the length of the upper arm, exhibits a slight backward bow. "mei" shows a much stronger bow, whereas it is absent in most other troodontids altogether. the olecranon of the ulna, the process for the attachment of muscles that stretch the arm, is mildly developed, and appears to be accompanied by a prominent flange further down on the bone. compared to the ulna, the radius, the parallel lower arm bone, is slightly thinner, having a shaft diameter that is 76% of that of the ulna. contrary to most other theropods, the top portion of the radius bears a backwards bow similar to that of the ulna.
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