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Human Anatomy

Contents

Three Planes of Space
The Skeletal System
The Spinal Cord
Erect Posture
Joints
Muscles
Levers and Muscles
Muscles and their Movements
Maintaining Posture
My Birth



Three Planes of Space

Transversal:
To find a Transversal Plane, my partner and I took turns standing on our tip-toe and gently applying pressure on the shoulder of the person standing on their toes. We found that the slightest pressure could knock you off your toes. This also showed that we balance best on our flat feet.
Sagittal:
We placed one foot next to our partner's and clasped their hand. Then we moved our hands and arms to attempt to throw our opponent off balance, thereby discovering the Sagital plane.
Frontal:
In our effort to find the frontal plane, the class formed two parallel lines. Then, with the person facing me, I raised my hands and slapped at the other's hands, trying to push them off balance.

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The Skeletal System

There are three different sections of bone in your body There is the Axial Skeleton, which consists of your ribcage and spinal column. It supports your torso. There are the appendicular limbs which are in you arms and legs. And there is the foundation. It is simply your pelvis, which supports you entire upper body.
As an embryo, you have 350 bones in your tiny body. These may be considered as cartilage because they haven't had time to calcify. As you grow, your bones fuse together and when you are fully grown (around age 25)you have only 206 bones.
There are four different types of bones: long, short, irregular and flat. Long bones are in your limbs. They are very strong and hold a lot of weight. Long bones are in the commonly known bone shape. Short bones are delicate structures. They maintain a shape of a structure, e.g. the ear. Irregular bones are used mainly for protection, e.g. your kneecap, but are also used for support, e.g. your pelvis. These bones are in an irregular shape and sometimes are knobby. Flat bones are mainly for protection, e.g. ribcage and cranium. They protect all your vital organs.
Bone cannot be connected to bone directly. If that was so, your bones would grind away to nothing in a very short time. So, there are ligaments to connect bone to bone, Likewise, there are tendons to connect muscle to bone.
Animals have skeletons designed for one specific thing, for example, bats have hands that are webbed which allow them to fly. Their claws allow them to grab on and hold certain things. A bat can't play the piano or do many of the things humans can. This is because human skeletons aren't designed for anything specific.

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The Spinal Cord

Seven cervical This flexible group of cervical vertebrae supports the skull and neck. Holding the head erect develops and maintains it's curvature. The series of vertebral foramina form a canal for the spinal cord.
Seven Thoracic
This rather rigid group of thoracic vertebrae and the 24 ribs with which they articulate support the thorax. The prominent curvature is developed in fetal life. Five Lumbar
These stubby quadrilateral lumbar vertebrae, the most massive of it's column, carry a large share of the body weight, balancing the torso on the sacrum. The Lumbar curvature results from walking and standing erect.

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Erect Posture

The human body is different than all other animals in the respect that we can stand erect. Our legs are what makes us able to stand erect. We have straight femurs instead of curved ones like in a gorillas'. We have the quadricep muscle in the front of our thighs to pull our kneecap up and keep our thighs erect. We also have the soleus muscle in the back of our calf to help keep our ankle aligned with our calf.

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Joints

A. Gliding joint - e.g. tarsal in your feet - doesn't move much and only on one plane.
B. Hinge joint - e.g. elbow - can move a great deal, but only up and down.
C. Pivot joint - e.g. top two vertebrae.
D. Ellipsoidal joint - e.g. wrist - can move a lot.
E. Saddle joint - e.g. ankle.
F. Ball-and-socket joint - e.g. hip - the most moveable in the entire body.
G. Suture joint - e.g. Cranium - the least moveable joint in the body.

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Muscles

Muscles are the organs of movement in our bodies. When we wish to go somewhere, reach for something or someone, or to create art, our muscles are the vehicles that listen to our will. Over %40 of our body weight is made up of muscle. Over 600 skeletal muscles operate under conscious control to move the body, stabilize joints, and main body posture. How is this movement accomplished?
Your muscles are made up of millions of cells. Your brain triggers the release of chemicals which causes the cells to overlap and contract. When the chemicals are used up, your muscles stop contracting. Muscles, when contracted can shorten by up to one third of their resting lengths. When you contract a muscle, each cell inside contracts completely. When more cells contract, the contraction is stronger.
Your muscles require energy (glucose) to move. Glucose is sent to your bloodstream where it is stored until used. In order for the glucose to be used, it must be first combined with oxygen which is supplied by the bloodstream.
Your skeletal muscles consist of two types of cells, white and red. White cells exert a stronger force over a shorter period of time. Red cells exert less force over a longer period of time. In a human, these cells are mixed together, but in animals, such as chickens, their muscles may be made up of one type of cell.
When you exercise, and work your muscles, the muscle cells actually tear. The cells regenerate themselves quickly. When they do, they end up bigger than thy were before, making them stronger. Sometimes our muscles need more oxygen than what is supplied. A chemical called lactic acid builds up causing cramps. To eliminate this lactic acid, your muscles must continue to use oxygen even after the movement has stopped. Stretching is a good way to accomplish this. After exercising, you pant supplying the oxygen need to your muscles.

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Levers and Muscles

1st Class:
The fulcrum always lies between the effort and the resistance. This is the most efficient class lever. With a constant weight, the longer distance F - E, relative to the distance F - L, the less muscle is required.
2nd Class:
The resistance always lies between the fulcrum and the effort, such as when pushing/lifting a wheelbarrow. In this case, the longer F - E distance relative to the shorter F - L distance provides a good mechanical advantage for the muscle lifting the body weight onto the heads of the metatarsals.
3rd Class
The muscular effort is placed between the weight and the joint, providing the least efficient mechanical advantage. To compare 3rd and 2nd class levers: lifting a fifty pound box with your upper arms takes significantly more muscular effort than lifting your 150-pound body by standing on your metatarsals.

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Muscles and their Movements

Location Muscle Function Muscle Function
Neck sterno- cleidomastoid Flexes head  
Back Trapezius Extends upper arm Lattissimus Dorsi Extends upper arm
Abdominal Wall External Oblique Compresses abdomen  
Shoulder Deltoid Abducts upper arm Pectoralis Major Abducts upper arm
  Serratus anterior Abducts shoulder  
Upper arm Biceps Brachii Flexes forearm Triceps brachii Extends forearm
  Brachialis Flexes forearm  
Forearm Brachiradialis Flexes forearm Promatorterea Promates, flexes arm
Buttocks Gluteus Maximus Extends thigh Gluteus Minimus Abducts thigh
  Gluteus Medius Abducts thigh  
Thigh  
  Anterior surface, Quadricep femoris group:           
  Rectus Femoris Flexes thigh Vastus Lateralis Extends leg
  Vastus Medialis Extends leg Vastus Intermedius Extends leg
  Medial Surface:  
  Gracilis Abducts thigh Abductor group (brevis, longus, magnus)
  Posterior surface:  
  Hamstring group Flexes leg  
Leg  
  Anterior surface: Tibialis Anterior Abducts foot  
  Posterior surface: Gastrocnemius Extends foot Soleus Extends foot
Pelvic floor Levator ani Forms pelvic floor Levator coccygeus Forms pelvic floor

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Maintaining Posture
When you stand upright, your body weight rests on your pelvis and your feet. In order to maintain good posture, you can straighten your pelvis and your spine, leaving a healthy curve in your spine. Your feet must have a good arch. If you are flat-footed, you will develop back problems if you don't have them already. To improve your arch, you can take off your socks and lay them in front of your feet. Next try to scrunch up the socks so the it ends up under your arch by scrunching up the sock a little at a time with your toes. If you lower back has too much of a curve, you can straighten it by pushing in and up with your right hand just below your stomach and with your left hand just above your buttocks.

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My Birth
My mom and dad moved up to Portland from San Francisco with two kids. They knew that they wanted to have another child and I was conceived in December, 1988, right after they moved.
My mom was very lucky in her first trimester, because she didn't ever have morning sickness. However, she was hungry a lot and awoke with a pain all the way down her legs. My mom was working part-time with a company that designs kitchens. After I was born, she quit and started a home business, Parecki Designs Inc.
I have two siblings, both older than me. Their names are Aaron and Ilana. When my mother was pregnant with Aaron, who was the first, she went from 110 pounds to 140 pounds. With Ilana, she gained the same weight (30 pounds). With me however, my mother went from 100 pounds (she was getting a lot of exercise caring for two kids) to 140 pounds.
My parents were planning on delivering at home since they knew the routine from the first two births. They had hired a Naturopathic Doctor (ND) who too care of my mother during the pregnancy. After nine months, I wouldn't come out. The ND checked on me every week, but she saw no signs of labor. After three weeks, the ND decided that we shouldn't wait any longer. We drove to the clinic where our ND gave my mother Blue Co hash (an herb) which helps make the contractions start, unfortunately it didn't help. Since in the previous two births, my mother's water broke before she started having contractions, the doctors punctured the water bag hoping that would help. About six pounds of water came out. Finally, my mother started to have contractions.
When the midwife put her fingers in the birth canal to see if my mom was full dilated, she felt my head right at the opening. There was a problem, my mouth was what she felt. In an ideal situation, the back of the head comes out first. I however was in what is known as a face presentation. Not good! An X-ray technician took an X-ray and indeed I was in a face presentation. He also told my parents that I was a boy. The doctors gave my mom acupuncture in her toe to make my head move, but that didn't work. They rushed my mother to the hospital. Even though the ride in the car was ten minutes, my mother tells me that it felt an hour.
In the hospital, the doctors performed a C-section. They gave my mother anesthetic in her spine to numb her from the waist down. When she couldn't feel her legs. they cut a slit under her bully button and popped out the baby. My mother said the process after the anesthetic kicked in took about five minutes. They sewed her up and gave me to her. My mother stayed in the hospital for two days recovering.
I was a big baby. I was nine pounds six ounces and twenty-one inches long. She says that for the first year I never stopped smiling. I was very quiet and was interested in everything around me.
Personally I want to have children. I think that deep down, everyone does. It is our nature. I probably wouldn't get married until I have a steady, well-paying job and a house of my own. I think it means a lot to be a father. It seems that it would be very gratifying to watch my children turn into adults.

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