Appendicular skeleton

In the human body we can find different types of bones which make up the human skeleton , these are divided into two large and important groups, the axial skeleton , which includes all the bone structures that exist along the axis of the human body and on the other hand, the bones that make up the appendicular skeleton , where all the other bones are located

Definition

The appendicular skeleton is the set of bones that make up part of the skeletal system of the human body, which is made up of the lower and upper extremities , including the pelvis and the shoulder girdle . They are the bones of the skeleton that are responsible for functioning as an anchor and joints between the two types of skeletons that exist.

Characteristics of the appendicular skeleton

Among its most notable features are the following:

• It is considered one of the main skeletal groups in the human body.
• It is made up of the upper and lower extremities .
• Its components also include the pelvis and shoulder .
• The pelvis, in the appendicular skeleton, has the function of being a connection point between the two types of skeleton that exist.
• It has a total of 126 bones .
• Your bones are held together by ligaments , cartilage, and tendons .
• Provides greater range of motion to the body.
• It is responsible for producing the locomotion and holding of objects.

Function

The main function of the appendicular skeleton is related to a series of locomotion and motor functions , it directly influences various aspects of human life such as the mobilization and correct holding of objects. It has a support function , storage of minerals for the human body and especially the production of blood cells . They also turn out to be the main places where the muscles can be fixed and thanks to this, it is possible to perform the movements.

Parties

The parts that make up the appendicular skeleton are the following:

• Bones of the upper extremities and shoulder girdle : they are responsible for fixing the extremities to the upper part of the trunk. In the shoulder girdle we find bones such as the clavicle and scapula. In the arm we can find the humerus while in the forearm, the radius and the ulna. In the wrist, the scaphoid, lunate, triquetral, pisiform, trapezius bones are located, and in the hand, bones such as the metacarpals and phalanges.
• Bones of the lower extremities and the pelvic girdle : they are attached to the lower part of the torso and it is made up of two lower limbs that are joined to the torso through the pelvic girdle . We can find in the pelvic girdle bones such as the ischium, ilium and the pubis; In the muscus the femur is located (the longest bone in the human body; in the leg are the tibia and fibula, while in the tarsal bones are located the talas, calcaneus, cuboid, navicular. Finally, in the feet we have metatarsals and phalanges.
• Joints located between the appendicular and the axial skeleton: These two types of bones are articulated through the sternoclavicular joint and the sacroiliac joint .

How many bones does the appendicular skeleton have?

The appendicular skeleton is made up of a total of 126 bones out of the 206 bones that make up the human skeleton.

Appendicular skeletal muscles

The muscles found in the appendicular skeleton have a number of important functions, including the one that involves surrounding all the joints to provide protection. Among them are the following muscles:

• Upper limb muscles
  • Deltoid region : they are divided into an anterior or ventral group in which the subscapularis muscle is found and a posterior or dorsal group where the deltoid , supraspinatus , teres major , infraspinatus and teres minor are found .
  • Arm region : it is also divided into two important groups. The muscles of the anterior group that include the branchial biceps muscle, the branchial and the coracobrachialis. The posterior group has the triceps branchial muscles and the anconeus muscle.
  • Forearm region : there are quite a few muscles found in this group and most of them are long. They are responsible for giving movement to the forearm and are divided into an anterior and posterior group.

In the muscles of the anterior group, we find the superficial layer formed by the pronator teres, flexor carpi radialis, palmar longus and flexor ulnar. In the deep layer we find the flexor muscles, the deep flexor of the fingers, the pronator square.

In the muscles of the posterior group we find those of the superficial layer . In them the radial muscle group is located, such as the extensor carpi radialis longus and the carpal brevis; and the ulnar group that includes the extensor digiti minimi muscle, the extensor carpi ulnaris, and the common extensors of the fingers.

The supinator muscle, the abductor pollicis longus, and the extensor of the index finger are located in the deepest layer .

• Muscles of the hand region

These muscles are located in the palm of the hand and on the back of it. They are located in the tendons and are characterized by being short muscles . Their insertion of origin and the place where they end is in the bones of the hand. They are further divided into three groups: those that are in the radial part of the palm of the hand, in the ulnar border and in the palmar depression of the hand.

In the thenar group we find the flexor brevis muscle of the thumb, the adductor muscle and the opponent of the thumb. In the hypothenar group we find the flexor brevis of the little finger, adductor, opponent of the little finger and palmar breif.

How it differs from the axial skeleton

Its main difference is that the axial skeleton is made up of the bones that are located in the midline or the axis of the body , they also have the function of supporting all the weight of the human body and protect all the internal organs of the body. The appendicular skeleton, for its part, is formed by the rest of the bones that make up the human skeleton which belong to the attached parts of the body, in other words the lower and upper extremities .

Importance of the appendicular skeleton

The appendicular skeleton is of utmost importance for the human body as it is basically in charge of mobilization because within this group of bones we find both the lower and upper extremities , parts of the human body that help movement. Thanks to it, the human being can move from one place to another and also gives him the ability to hold objects .

It is also important because by joining with the axial skeleton, they make possible the proper functioning of the entire human body thanks to the joints that are part of the bones and skeletons. In addition, in the bones, a large number of blood cells are produced , necessary for the survival and proper functioning of the human body.