Skeleton

Prepared
by;
Dr. Zmnako Othman
DEFINITION-
The skeletal system is the structural

framework that supports a body. It also
provides protection for a soft tissues and
internal organs and serves as an attachment
for the body's muscles that push against it
and apply force, resulting in movement.
Support and protects of soft tissues and vital
organs.
To give attachment to muscles.
Formation of red blood corpuscles in the

bone marrow.
Storage of mineral salts like phosphorus and

calcium.
1. Long bone-
They found in the limbs. A long bone contains shaft
and two extremities.
e.g. Humerus, femur
2. SHORT BONE-
These have no shaft, but they contain a spongy
substance covered by a shell of compact bone.
e.g. Wrist, ankel.
3. Flat bone-
Flat bones are as they sound, strong, flat plates of
bone with the main function of providing
protection to the bodies vital organs and being a
base for muscular attachment.
E.g. Scapula (shoulder blade), Sternum (breast
bone).
4.Irregular bone-
These are bones in the body which do not fall into any other
category, due to their non-uniform shape. They primarily
consist of cancellous bone, with a thin outer layer of compact
bone.
E.g. Vertebrae, Mandible etc.
5.Sesasmoid bone-
Sesasmoid bones are usually short or irregular bones,
embedded in a tendon. The most obvious example of
this is the Patella.
Composition of bone-
Extracellular matter Cellular component
*OSTEOBLASTS
Inorganic
Organic matrix
matrix (bone *OSTEOCLASTS
(osteoid tissue)
mineral) calcium
Collagen fibers
phosphate *OSTEOCYTES
Each long bone has an elongated shaft or
diaphysis and two expanded ends (epiphyses)
which are smooth and articular.
The shaft typically has 3 surfaces separated

by 3 borders, a central medullary cavity, a
nutrient foramen and periostium directed
away from the growing end.
Limb bones are typical long bones.

C RA N I U M
F a ci a l b o n e
Thoracic bone
V e r t e b r a l co l u m n
Ap p e n d i c u l a r s k e l e t o n
It consist of 8 bones:
a. One frontal bone
b. Two parietal bone
c. Two temporal bone
d. One occipital bone
e. One sphenoid bone
f. One ethmoid bone
1. Coronal suture
2. Saggittal suture
3. Lambdoid suture
The bones which make the face are14 in number.
These are-
1. Two maxillae (upper jaw)

2. One mandible (lower jaw)
3. Two palate bones
4. Two zygomatic bones
5. Two lacrimal bones
6. Two nasal bones
7. Two inferior conchae bones
8. One vomer
The skeleton of thorax is made up of the
following bone-
1. Sternum in the front
2. Twelve pairs of ribs
3. Twelve thoracic vertebrae

Sternum: It is also called Breast bone. It is a
flat bone which is divided into three parts
namely-
a. Manubrium sterni
b. Body of sternum
c. Xiphoid bone
RIBS- They are arranged in 12 pairs, on the back
side, all of them are attached to thoracic vertebrae.
Depending on their attachment in the front, they are
classified as:
a.True ribs- They are upper five pairs, and
are attached to sternum directly.
b. False ribs-They are lower five pairs, and are
attached to the sternum indirectly.(through costal
cartilages).
c.Floating ribs- Lowest two pairs. They are not
attached in front.
The vertebral column is made up of number of bones.
These bones are called vertebrae. These are 33 in no.
Classification of vertebrae- According to the
region they occupy:
1. Cervical vertebrae- 7 in no. They form the neck.
2. Thoracic vertebrae- 12 in no. they form back of
thorax.
3. Lumbar vertebrae- 5 in no. they form lumbar
region.
4. Sacral vertebrae- 5 in no. they form sacrum.
5. Coccygeal vertebrae- 4 in no. they form coccyx.
A body which is a box shaped anterior part. It is slightly
concave in the upper and lower surface.
Neural arch which is the posterior part.
Two transverse processes, one on each side. They lie in the

junction between pedicle and lamina.
One spinous process which is a backward projection.
Neural canal which is a circular opening. The spinal cord is

passing through this.
The pelvic girdle is the connection between
the trunk and lower extremities. It is formed
by 4 bones-
a. Two inominate bones, one on each side
b. Sacrum
c. Coccyx
SCAPULA- It lie at the back of thorax. It forms
the posterior part of shoulder girdle.
Clavicle- It is also called as collar bone. It is
long and curved bone. It form the anterior
part of shoulder girdle.
Humerus- It is the longest bone of upper
limb. It contains shaft and two extremities.
Ulna- it is the inner most bone of forearm. It
contains two extremities and a shaft
Radius-It is the lateral or outer most bone of
forearm. It contains two extremities and a
shaft.
Bones of hand and wrist-
Bones of wrist/ carple are arranged in two row.
They are-
1. Proximal row- It is made of :
a. Scaphoid
b. Lunate
c.Triquetral
d.pisiform bones
2. Distal row- It is made up o f -
a.trapezium
b.trapezoid,
c.capitate
d.hamate bone.
Bones of palm-
They are made of metacarple bones. They
are long bones which contain a head, a
shaft and a base. The base is articulate with
the distal row of carple bone.
Bones of finger- They are made up of
phalangial bones. The thumb has two
phalanges. Other finger has three phalanges.
They are proximal, middle, and distal.
Bones of lower limb:
1.Femure- It is also called as thigh bone. It is
the longest and strongest bone of the
skeleton. It contains two extremities and a
shaft.
2. Patella- It is sesamoid bone. Developed in
the tendons of quadriceps femoris muscle.
3. Tibia- It is the innermost bone of the leg. It
is long bone containing two extremities and a
shaft.
4. Fibula- It is the lateral and outermost bone
of the leg. It also contain two extremities and
a shaft.
Bones of foot can be classified as:
1. Tarsal bones (7 bones)
2. Metatarsal bones (5 bones)
3. Phalangial bones (14 bones)
Thank you

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Prepared

The skeletal system is the structural

To give attachment to muscles.

Formation of red blood corpuscles in the

Storage of mineral salts like phosphorus and

Extracellular matter Cellular component

The shaft typically has 3 surfaces separated

Limb bones are typical long bones.

1. Two maxillae (upper jaw)

1. Sternum in the front

2. Twelve pairs of ribs

3. Twelve thoracic vertebrae

Neural arch which is the posterior part.

Two transverse processes, one on each side. They lie in the

One spinous process which is a backward projection.

Neural canal which is a circular opening. The spinal cord is

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