One end of the tRNA contains an anticodon loop which pairs with a mRNA specifying a certain amino acid. The other end of the tRNA has the amino acid attached to the 3' OH group via an ester linkage. tRNA with an attached amino acid is said to be charged. The enzyme that attaches the amino acid to the 3'-OH is called an aminoacyl tRNA synthetase (aaRS). There is a specific tRNA for each amino acid, 20 in all.
With this tool, they have been able to identify and treat a shoulder injury called a glenoid labrum tear. The shoulder joint has three bones: the shoulder blade (scapula), the collarbone (clavicle), and the upper arm bone (humerus). The head of the upper arm bone (humeral head) rests in a shallow socket in the shoulder blade called the glenoid. The head of the upper arm bone is usually much larger than the socket, and a soft fibrous tissue rim called the labrum surrounds the socket to help stabilize the joint.
The appendicular skeleton contains the bones of the pectoral girdle, upper limbs, pelvic girdle, and lower limbs. The pectoral girdle (shoulder girdle) contains four bones: two clavicles and two scapulae (Fig. 6.11). It supports the arms and serves as a place of attachment for muscles that move the arms.