Hand and Foot

The Hand contains a total of 27 bones and is the most flexible part of the human skeleton. Like other higher primates, humans possess nails instead of claws and have a thumb that can be rotated to oppose the other digits, enabling them to manipulate objects delicately and precisely. Higher primates other than humans, however, also use hands for locomotion; the development of an upright posture and consequent use of the hands for manipulation alone probably took place concurrently with the increase in brain size in humans. Shown here are some of the major muscle and tendon systems for moving the bones of the thumb and other digits.


The human foot differs from the feet of other higher primates in that it is used solely for locomotion, so that the big toe is no longer opposable to the other digits as it is in the great apes. Instead the bones of the feet have evolved in a way that enables humans to stride, and toes other than the big toe begin to show signs of degeneration. The heel bone bears most of the weight of the body and helps to form the longitudinal arch of the foot, along with the transverse arch formed by the metatarsal bones. If the ligamens between the bones weaken, the result is flatfoot, in which all instead of only part of the sole rests on the ground.


Comments

Post a Comment

Popular posts from this blog

Human Organs

Image
The human organs is drawn such as on the picture belows: Each organ have certain function to our body, if there is a disturbance to certain organ function the body will feel inconvenience and actually the nerve will give an alarm through the network and will sent to the brain. Our brain than should think about what the abnormal condition, and should have any solution to maintain an abnormal situation.
Read more

Nose

The nose, the site of the sense of smell is the organ through which mammals take in air. It is supported by cartilage and bone, covered with skin , lined with a mucous membrane, and provided with muscle. A nasal septum divides it into passages, each of which begins with a vestibule and contains a respiratory and olfactory region. The lining of the vestibule is continuous with the skin and contains hairs, sweat glands, and sebaceous (oil producing) glands . The respiratory region includes nearly all of the septum and the lateral walls of the nose. Goblet cells, which produce and secrete a watery mucus, are present in the lining, as is a type of erective tissue, composed of large, thin-walled veins whose blood supply serves to warm incoming air. The olfactory region is located on the superior concha and adjacent septum. Olfactory cells are present in its lining and have delicate, slender process (modified cilia) at their free surface. Odors from chemicals in the air are received by
Read more

Nervous System on Sole of Foot

Image
The palms of the hands and the soles of the feet have some sweat glands than any other part of body. Excessive hand sweating is the most common sweating problem, sweaty hands usually come along with sweaty feet. When sweaty hands and feet become a severe problem, they are called palmar hyperhidrosis and pedal hyperhidrosis respectively. This tend happen begin in early childhood and become worse after teenage years and early adulthood. The sweaty hands and feet are likely to develop cracking and scaling of the skin, blister, frostbite , warts and fungal infections . According to traditional Chinese medicine, the spleen system controls the muscles and the limbs, the four extremities must be nourished by the nutrient essence transformed and transported by the spleen. Several nervous system on the sole of foot as on the picture below:
Read more

Muscle

Muscle tissue, which comprises about 40 percent of human body weight, consist of threads, or muscle fibers, supported by connective tissue. All living cells can move to some degree, but this ability is highly developed in muscles, which act by fiber contraction; the fibers can shorten to two thirds of their resting length. Muscle vary greatly in structure and function in different organs and animals. Based on structure there are two types of muscles; smooth and s treated, "Involuntary", or smooth, muscles are found in the walls of all the hollow organs and tubes of the body (for example, blood vessels and intestines). There react slowly to stimuli from the autonomic nervous system. The "voluntary," or striated, muscles of the body attach mostly to the bones to move the skeleton, and under the microscope their fibers have a cross striped appearance. Striated muscle is capable of fast contractions. The heart wall is made up of special muscle fibers (cardiac muscle),
Read more