Locomotion and Movement Test - 21

• Pivotal joints are freely movable joints. 
• They allow free movement about a single axis. 
• This movement is usually rotary. 
• As a result of the pivot joint, our face can move about freely over the neck.
  

The pelvic girdle is made up two hip bones which are connected to each other anteriorly at the pubic symphysis. However, posteriorly these are connected to the sacrum at the sacroiliac joints and forms the pelvic ring.

The outer ear is the most external portion of the ear. The outer ear includes the fleshy visible outer ear, called as the pinna or auricle, the ear canal, and the outer layer of the tympanic membrane, also known as the eardrum. The outer ear is the only visible portion of the ear in humans and almost all vertebrates, and consequently, the word "ear" may be used to refer to the pinna alone. The auricle consists of the curving outer rim (the helix), the inner curved rim (the antihelix), and opens into the ear canal, properly called as the external acoustic meatus. The tragus protrudes and partially obscures the ear canal. The ear canal stretches for a distance of about 1 inch and consists of an inner portion surrounded by bone, and an outer portion surrounded by cartilage. The skin surrounding the external acoustic meatus contains glands that produce ear wax (cerumen). The ear canal ends at the external surface of the ear drum (tympanic membrane). So, the given figure is outer ear and is made of cartilage and not soft bones or fixed joints.

• The sarcomere is the smallest contractile unit of striated muscle fibre.
• Sarcomere occurs as repeating units along the length of a myofibril, occupying the region between Z lines of the myofibril. 
• Sarcoplasm is the cytoplasm of muscle fibre. It is a water solution containing ATP and phosphogens, as well as the enzymes of intermediate end product molecules involved in many metabolic reactions. 
• Neuromere is a metameric segment of CNS. 
• Metamere is a linear series of primitively similar segments into which the body of higher invertebrate and vertebrate is divisible.

Several diseases including cholera, tuberculosis, small pox and hepatitis can be prevented by vaccination. There is no vaccine available for osteoporosis. Osteoporosis is an age related problem in which bones becomes very weak due to which even due to sudden or slight jerk leads to bone fracture.

An immovable joint is a place in the body where two bones are joined together but where little or no movement is normally possible and where no joint cavity exists. e.g. skull.