What Is the Pectoral Girdle?

The pectoral girdle, in humans, consists of the two clavicles and two scapulas in the shoulders.
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  • Written By: Claudette M. Pendleton
  • Edited By: C. Wilborn
  • Last Modified Date: 10 September 2014
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The pectoral girdle, also called the shoulder girdle, consists of a set of bones that make up the shoulder. In human beings, it includes two clavicle bones and two scapula bones. The clavicle is also referred to as the collar bone, and the scapula, the shoulder blade. Some species have three bones in the pectoral girdle. Animals such as dogs and horses, for example, have only scapula bones, but no clavicle bones.

Although a girdle generally refers to a complete ring or full circle, the pectoral girdle does not consist of a complete circle. The two clavicle bones are divided on the front side by the breastbone, also referred to as the sternum. In addition, there is a space separating the two scapula bones on the backside of the area.

The shoulder girdle provides essential structural support and connection to several muscles that are situated primarily in the elbow and shoulder joint area. Human beings have only joints that connect the shoulder girdle and the axial skeletal structure, the 80 bones within the head and chest of the human body. These joints are called sternoclavicular joints and are positioned on both sides.

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There are no joints that connect the thoracic cage, also called the rib cage, to each scapula. The muscles, however, that connect the two allow the girdle bones to have a substantial range of movement. Species that have only scapula bones have muscular attachment, but no joints connecting the front limb and the thorax, the part of an animal's body positioned between the head and the abdomen.

The clavicle, one of the sets of bones that make up the shoulder girdle, is slim and S-shaped. It connects the bones in the upper arm to the trunk of the body. In addition, the clavicle maintains the girdle by keeping the shoulder in its proper setting and away from the trunk area. This allows more freedom of movement.

The scapula, the other set of bones that make up the pectoral girdle, are flat, triangular bones. They are positioned on the second to the seventh rib on the backside of the rib cage. A number of muscles are attached to the scapula bones, and one edge has a thin, hollow space called the glenoid cavity. This is where the top of the humerus, upper arm bone, is positioned. A thin border that runs alongside the surface of the scapula forms the spine of the bone, which provides strength to the scapula to keep it from breaking or bending.

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OeKc05
Post 3

The pectoral girdle helps our movements to be more fluid. Our shoulder blades on our backs are connected to the clavicles out front, so the whole thing moves as one.

Everything in the human body works together, so the load is spread out. The pelvic girdle helps distribute our upper body weight to the legs, so no one section has to take on too much.

I guess the body is like one big warehouse with workers divided into departments. Each section does its own job, but in doing this, it helps out the whole warehouse.

lighth0se33
Post 2

@Perdido – No, what you are feeling is his scapula. It doesn't form a girdle.

I saw a skeleton model of a dog in biology class years ago, and I remember seeing those shoulder bones right on top of the dog's front legs. Dogs have very compact bodies, so they missed out on a few bones.

JackWhack
Post 1

I thought dogs had a clavicle bone! I can feel some sort of bone protruding on either side of my dog's chest above his legs. Does it not go all the way across?

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