Chapter 8, Problem 8.1.1AYLO

The function of the pectoral girdle; the bones that compose it; and all points at which these bones articulate with each other, with the upper limb, and with the axial skeleton

Summary Introduction

To determine:

The function of the pectoral girdle; the bones that compose pectoral girdle; all points at which bones composing pectoral girdle articulate with each other, upper limb, and with axial skeleton.

Introduction:

The appendicular system is the skeleton system that is composed of the bones of upper limbs, lower limbs, pelvic girdle, and the pectoral girdle. The bones of the appendicular skeleton are categorized based upon six regions. Pectoral girdle contains four bones, arms and forearm possess six bones, clavicle, scapula, humerus, ulna, and radius contain two bones.

Explanation of Solution

The bones of upper limbs attach to the axial skeleton and form the pectoral girdle. The pectoral girdle is the flexible bone that makes the shoulder joints easy to dislocate and movement. The axial skeleton allows the extensive mobility to the pectoral girdle and thus to upper limbs and shoulders.

The pectoral girdle along the axis connects with the upper limb. The pectoral girdle (also called shoulder girdle) consists of two types of bones: the clavicle (or collarbone) and scapula bones (or shoulder blade).

Clavicle possesses three parts, the shaft, medial end, and lateral end. The shaft is the body of the clavicle. The medial end of the clavicle is attached to the sternum through the sternoclavicular joint. The lateral end is supported by articulation with scapula through the acromioclavicular joint. The clavicle provides the articulation with the axial skeleton through the medial end.

The scapula is the triangular bone dorsal to the collarbone and is divided into three borders, medial, lateral, and superior. Scapula connects the upper extremity of the upper limb to the trunk. The humerus is the portion of the upper limb that is articulated with scapula through the glenohumeral joint.

Conclusion

Axial skeleton articulates with the pectoral girdle at the trunk and includes the vertebrae, rib, coccyx, sacrum, and sternum. The bones supporting at the left and right region of the shoulder connect the muscles that are necessary for the movement. Scapula and clavicle together as a unit can be felt by palpation.