What Are Muscles?

* Joints between the vertebrae in spine: are connected to each other by pads of cartilage. These joints can only move a small amount.

Figure 8.1 Using Figure 8.1, match the following: 1) Periosteum. Answer: A Diff: 2 Page Ref: 251; Fig. 8.3 2) Articular cartilage. Answer: C Diff: 2 Page Ref: 251; Fig. 8.3 3) Joint (synovial) cavity. Answer: B Diff: 2 Page Ref: 251; Fig. 8.3 4) Synovial membrane. Answer: E Diff: 2 Page Ref: 251; Fig. 8.3

9. Hyaline cartilage is found on many joint surfaces, it has a very firm consistency. It contains no nerves or blood vessels, and its structure is relatively simple. Elastic cartilage, also called yellow cartilage, is present in the ears; it contains elastic fiber networks and collagen fibers. Fibrocartilage is found in the pubic symphysis, the annulus firbrosus of the intervertebral discs, menisci and the TMJ. During labor, the pubic symphysis is loosened to aid in delivery.

From the days of Still we are reminded that structure and function are a primary focus reciprocally interrelated-so much so that the basic structure of the skeleton and the parts that make it up are designed to operate a certain mechanical way. The physiological and deeper functional

Secondly it allows movement as muscles cross joints and attach bone to bone. Muscles work in pairs and skeletal muscles can pull in one direction and for this reason they always come in pairs. Due to the fact that two muscles work together, as one muscle in the pair contracts the other muscle relaxes for example as the bicep contracts the triceps relaxes to once again straighten the joint out.

There are about 600 muscles in the body working together to create movement. Muscle contractions pull both ends of the muscle towards one another. One bone attached to each muscle is always more stabilized than the other. The less stabilized bone moves during muscle contraction due to the weaker stability. The points of attachment determine which bone will move. The least movable part is called the origin; it is the part that attaches closer to the midline of the body. This leaves the most movable part called the insertion. Each of these points can be identified in individual muscles to assist trainers in understanding how the muscles and joints work together to create motion.

Meniscus is a piece of cartilage in the joint space where two bones meet. They are found between the ends of upper and lower leg bones in the knee. They absorb the shock and protect the joint surface from activities like running, walking and jumping. The menisci are mainly composed of type I collagen which supports the meniscal structure. Type I collagen is the main difference between menisci and articular cartilage which is composed of type II collagen. Another component of menisci is fibrochondrocytes intermixed with extracellular matrix. These fibrochondrocytes synthesize and maintain collagen and exhibit properties of chondrocytes and fibroblast. There are three layers of collagen fibers arranged to convert compressive loads into circumferential or stresses. The fibers run radially serve to resist splitting or shearing in the superficial layer where as they run parallel to resist stress during weight bearing in the middle layer. In the deep layer, they are aligned parallel to the

There are two methods of classifying joints: function and structure. Functional classifications include: synarthrosis (immovable joint), diarthrosis (freely movable joint and amphiarthrosis (slightly movable joint). Structural classifications are: bony, fibrous, cartilaginous and synovial

The bones in the upper and lower leg of Human body are connected by complex pivotal hinge joint called knee. The upper and lower extremities are encompassed of cartilage, tendons and ligaments. There are two cartilage pads called menisci that diffuse the friction created at the tibial and femur joint. The main ligaments of the knee are Medial Collateral ligament (MCL), Lateral Collateral ligament (LCL), Anterior cruciate ligament (ACL), Anterolateral ligament (ALL), and Posterior Cruciate ligament (PCL).

The back of the hand is called the dorsal side. The half of the hand from the middle finger to the thumb is called the radial side. The other side is called the ulnar side. There are 27 bones within the wrist and hand. The wrist itself contain 8 small bones called the carpals. The carpels join with the 2 forearm bones, radius and ulna, forming the wrist joint. Further into the palm the carpals connect to the metacarpals. There are 5 metacarpals forming the palm of the hand. One metacarpal connect at each finger and thumb. Small bone shafts called phalanges line up to form each finger and thumb. The main knuckle joint is formed by the connection of the phalanges and the metacarpals. These joints are called the metacarpophalangeal joints. These joints work like a hinge when you bend and straighten your fingers. The three phalanges are separated by interphalangeal joints. These are defined as proximal, distal and medial interphalangeal joints.The joints in the hand are covered on the inside with articular cartilage, this white shiny material is has a rubbery consistency. The function is to absorb shock and provide an extremely smooth surface to provide motion. There is articular cartilage everywhere when two bones are moving with each other // or

The shoulder and hip are considered ball and socket joints. In the shoulder, the “ball” of the humerus fits into the “socket” formed by the shoulder blade. In the hip, the “ball’ of the femur fits into the “socket” of the pelvis. These joints allow the motion in the body. Also, the shoulder joint and the joint are both synovial joints (diarthroses), meaning they both consists of:

Muscles origin are always connected to the immovable bone, on the other side, the intersection is connected to the movable bone. Movement of the body occurs when muscles contract across joints and their attachments move toward the origin. Movements that are called Angular can increase or decrease the angle between the bones. Flexion can decrease the angle of the joint and can make the articulating bone come closer, an example could be nodding you head. An extension is the opposite and can make the angle larger.

form out from the bone where tendons and ligaments attach and where adjacent bones articulate.

There are two types of cartilaginous joints. Synchondroses and Symphyses. Synchondroses are joints in which the bones are bound by hyaline cartilage. Examples of this are the temporary joint between the epiphysis and diaphysis of a long bone in children, and the attachment of the FIRST rib to the sternum by a hyaline costal cartilage. Symphyses are joints where two bones are connected by fibrous cartilage. An example of this is pubic symphysis, where the cartilaginous interpubic disc join the left and right pubic bones anteriorly.

Anatomy is the branch of medicine where study of structures of human body is done at the level of first year of academic course of every medical profession. The study is based on systemic pattern. So many systems of human body like respiratory system, cardiovascular system, central nervous system are studied theoretically & practically as well. Students has to dissect the human body & observe anatomy of each & every part of the body. Musculoskeletal system is one of the systems of the human body which is related to movements of body parts. Any pathological or structural change in this system leads to non functioning of the joints. Hyperuse of any joint of the body causes different clinical conditions & may become diseased. Wrist joint is the widely used joint of the human body in our day to day work. But its overuse in particular professionals like rickshaw drivers becomes worrysome after prolonged use.