the acromion process of the scapula articulates with the shoulder joint.
the acromion process of the scapula articulates with the shoulder joint.
the acromion process of the scapula articulates with the?
shoulder joint
the scapula (shoulder blade) was paddle-like and somewhat small. the lower portion of the scapula is where the glenoid (shoulder socket) is located, pointing backwards from the rear edge of the bone. this general area is the widest part of the bone when seen head-on, and underlies the thinnest part when seen from the side. directly above the glenoid lies a small pit, likely the origin point of the triceps muscle. meanwhile, the front edge of the scapula has a distinct ridge, probably the acromion process. the scapula of "nundasuchus" differs from advanced pseudosuchians due to its small triceps pit, but also from phytosaurs due to its distinct acromion. the lower edge of the scapula connects to the semicircular coracoid bone. the rear portion of the coracoid extends back and curves upwards to form the lower half of the glenoid, but is not offset from the socket by a distinct notch. however, a wide groove is present below the glenoid when seen from the side, similar to the case in aetosaurs and "postosuchus". in front of the glenoid, a hole known as the coracoid foramen pierces the coracoid, and, in a feature unique to "nundasuchus", this hole is surrounded by several knob-like structures. other fragments of the pectoral girdle, such as an interclavicle and clavicles, are also preserved. they are covered in grooves, with thin, blade-like edges. the interclavicle is spoon-shaped, concave from above and convex from below, although its true shape is unknown due to the rear portion being broken off. overall it is more similar to those of paracrocodylomorphs rather than phytosaurs.
nundasuchus
abnormal scapular function is called scapular dyskinesis. one action the scapula performs during a throwing or serving motion is elevation of the acromion process in order to avoid impingement of the rotator cuff tendons. if the scapula fails to properly elevate the acromion, impingement may occur during the cocking and acceleration phase of an overhead activity. the two muscles most commonly inhibited during this first part of an overhead motion are the serratus anterior and the lower trapezius. these two muscles act as a force couple within the glenohumeral joint to properly elevate the acromion process, and if a muscle imbalance exists, shoulder impingement may develop.
scapula