Download The Skeletal System

The Skeletal System
By Rafael Perez
Israel Torres
Khristopher Bandong
Skeletal System
• The human skeleton consists of 206 bones
• The skeleton is used as a barrier and defense to protect the vital
organs. (Brains, heart, stomach, etc)
• Allows muscles to attach to
• It maintains balance and maintains the shape of the body.
• The most important function of the skeleton is to allow limbs to move
Bone Composition.
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There are 4 different types of bones: long bones, short bones, flat bones, and
irregular bones. Long bones work as levers. The short bones are the bones in the
wrists and ankles. The flat bones are used for protection of organs or attachment of
muscles, and the irregular bones are all the other bones, that do not fit into the other
categories.
Bones are composed of tissue that take one of two forms: Compact or Spongy
bone.
– Compact Bones are dense, hard, and forms the protective exterior of all
bones.
– Spongy Bones occur in most bones, and are inside the contact bones.
Bone tissue is made of several types of bone cells, fused with a large amount
of inorganic salts such as calcium and phosphorus, to give the bone strength,
and collagenous fibers and ground substances to give the bone flexibility.
The Skull
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The skull is the biggest bone In your
body, consisting of many parts. It is one
of the most useful bones in your body
because it protects the brain. Divided
into two parts. Cranial and Facial Skull
Usually made up of about 22 bones.
The large bone that covers the backside of
the brain is called the Parietal bone.
The front bone that is connected to the
parietal bone is called the Front bone
The Hyoid bone connects to the tongue and
causes the movement of it.
Spinal Cord
• Extends from the medulla
oblongata.
• Divided into 31 segments, with
motor nerve exiting the ventral,
and nerve roots entering the
dorsal
• Ventral and Dorsal roots later
join to form paired spinal
nerves.
• Seperated into 5 parts: The
Cervical, Thoracic, Lumbar,
Sacral, and Coccyx.
• Primary purpose is to send
signals to the brain and back.
Works with the nervous
system.
The Arm
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The arm, or branchium, is the region between the shoulder and elbow.
It consists of a single long bone called the humerus
The humerus is the longest bone in the upper body. The head is large, smooth,
and rounded and fits into the scapula in the shoulders.
On the bottom of the humerus, are two depressions where the humerus connects to
the ulna and radius of the forearm.
The radius is connected on the side away from the body and the ulna is connected to
the side towards the body . Together the humerus and the ulna make up the elbow.
The bottom of the humerus protects the ulnar nerve, or otherwise known as the
“funny bone”
The forearm
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The forearm is the region between the elbow and the wrist. It is formed
by the radius on the lateral side of the ulna. The ulna is longer than the
radius and connected more to the firmly to the humerus.
The radius contributes more to the movement of the wrist and hand then the
ulna does.
Both the ulna and the radius connects to the bottom of the humerus and the
top of the bones in the hand.
The Hand
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Consists of the wrist, palm, and fingers. Has 27 bones.
The wrist consists of 8 small bones called carpal bones; lightly bound by
ligaments.
The bones are arranged in two rows.
– The first row contains scaphoid, lunate, triquetral, and pisiform bones
– The second row contains trapezium, trapezoid, capitate, and hamate.
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The palm (Metacarpas) consists of 5 metacarpal bones.
The base of the metacarpal bones are connected to the wrist bone, and the
head is connected to the bones in the finger. They form the knuckles in a
clenched fist.
The fingers are made up of 14 bones called “phalanges”. Each finger except
the thumb has three phalanx. A proximal phalanx, a middle phalanx, and a
distal phalax.
Rib Cage
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The primary function of the rib cage is to protect the heart, lungs, and major blood vessels.
The sternum is a flat, dagger shaped bone located at the middle of the chest. Along with the ribs
they form the rib cage. Consists of three parts.
– The manubrim, which located at the top of the sternum and slightly moves. Connects to the
first two rows of ribs.
– The body, located at the middle of the sternum and connects the third to seventh ribs
directly, and the eighth through tenth indirectly.
– The xiphoid Process, located at the bottom of the sternum, often cartilaginous.
The ribs are thin, flat curved bones that form a cage around the organs in your body. Composed
of 24 bones arranged in 12 pairs.
– The true ribs, which are the first 14 bones, connected to the spine and sternum. Are made of
coastal cartilage.
– The false ribs, which are the next 6 bones. These are slightly shorter and are connected to
the spine, but not to the sternum, instead to the lowest true rib.
– The floating ribs which are the 4 last bones. They are the smallest and are attached to the
spine, but to nothing in the front.
One very important use of the ribcage is when you inhale the muscles in between the rib cage lift
up, allowing the lungs to expand. When you exhale, the rib cage moves back down, squeezing air
back out.
Lower Body
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Pelvis – Is a ring of bones in the lower trunk of the body, protecting abdominal organs
like the bladder, rectum and for the woman which is the uterus.
Ischium – supports the body’s weight in the sitting position.
Femur – The thigh bone, which is the longest bone of the body.
Femur head – Top of the femur that fits into the socket of the pelvis that forms the hip
joint
Patella – Technical name for the kneecap, triangular shape bone at the bone of the
knee joint, also connected to the tibia which is the shin.
Obturator Foramen – Large opening of the Ischium, formed by the rami and the
ischium together with the pubis.
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This creates an opening that allows the passage of the major blood vessels and the nerves
to the legs and feet.
Lower Body cont.
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Tibia – Is the inner and thicker of the two long bones in the lower leg, bigger shin
bone.
– Upper end is divided into two sections : Medial and Lateral Condyles which
attaches to the femur.
– At the ankle, there is medial malleolus which is the inside of the ankle of the
large bony prominence of the table.
– Lateral malleolus which is the protrusion of the outside ankle. Common area of
ankle sprains.
Fibula – Is the outer and thinner of the two long bones in the lower leg, smaller skin
bone
– Upper end doesn’t reach the knee
– Lower end descended below the shin and also a part of the ankle
Phalenges – The phalanges are the small bones that make up the skeleton of the
fingers, thumbs, and toes. Each finger and smaller toe has three phalanges; The big
toe each have two. The phalange nearest the body of the hand or foot is called the
Proximal phalange; the one at the end of each digit is the distal phalange. And of
course there are three, the middle one is called the middle phalange.
Tarsal Bones.
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Tarsal Bones- The foot consists of an ankle, an instep, and five toes. The ankle is
composed of seven tarsal bones forming a group called the Tarsus. These bones are
arranged so that one of them, the Talus, can move freely where it joins the tibia and
fibula (lower leg bones.). This is known as the head of the Talus.
The remaining tarsal bones are bound firmly together, forming a mass on which the
talus rests. The other bones which compose the tarsus are the Calcaneus, the largest
of the ankle bones.
The talus, the navicular, the cubiod, the lateral cuneiform, the intermediate cuneiform,
and the medial cuneiform.
The calcaneus, or “heel bone”, is located below the talus where it projects backward
to form the base of the heel. It helps to support weight of the body and provides an
attachment for muscles that move the foot.
Metatarsal – The metatarsal is one of the five long, cylindrical bones in the foot. The
bones make up the central skeleton of the foot and are held in an arch formation by
surrounding ligaments. The metatarsal bones are joined to the toe at the
metatarsophatangeal joint; a fancy name for the knuckles on the toes.
Tarsal Bone
Ligaments (Lower Body)
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Ligaments – Is a band of tissue, used to connect the bones, hold organs in place, and
more.
Iliofemoral Ligaments – A Y-shape band of very strong fibers that connect the lower
front iliac spine of the coxal bone to the bony line.
Pubofemoral Ligaments – Bone that extends between upper portion of the pubis and
the iliofemoral ligaments . Its fiber also blends with fibers of the joint capsule of the
hip joints.
Obturator Membrane – A portion of the pubis passes down and in the back to join an
ischium. Between the bodies of these bones, on either side, there is a gap, called the
obturator foramen in the skeleton.
Patellar Ligament – Is the center of the common tendon, which continues from the
patella to the tibia. Allows muscle and tissue to pass through from the femur.
Tibial Collateral Ligament – Flat band of tissue that connects the medial condyle of
the femur to the medial condyle of the tibia at the knee joint.
Fibular Collateral Ligament – Consists strong, round cord located between the lateral
condyle of the femur and the head of the fibula at the knee joint.
Interosseous Membrane – Layer of tissue that separates the space between the
joints or bones.