Human Skeleton Model constitute the hard parts of the body that provide support and provide a proper shape to the body . The study about skeleton or skeletal system is known as osteology (osteon stands for bone and logos means study) or skeletology. In this article we will study about the human skeleton model. It is an important topic for biology class 12.
There are mainly two types of skeleton-
•Exoskeleton - It is found outside the body and you can see and touch it. It is moulded periodically in order to resume growth of the body. It consists of nails, hair, feathers, horns etc.
• Endoskeleton - It is found inside the body. It generally consists of bones and cartilages.
Human Skeleton Model
Human skeleton has 206 bones along with a few cartilages. It is mainly divided into two parts on the basis of position of its parts. These are-
1.Axial Skeleton
2.Appendicular Skeleton
1.Axial Skeleton -
It consists of skull, vertebral column, sternum and ribs.
•Skull - It has 29 bones which are joined to each other by immovable joints known as sutures. The bones found in the skull are the hardest and the densest bones of the human body. It has two parts-
(a) Cranium - It is the upper part of the skull that protects the brain as it encloses the brain in its cavity known as the cranial cavity. It has 29 bones and is round in shape. It has 8 flat bones.
Single bones of the cranium - Frontal, Occipital, Ethmoid, Sphenoid
Paired bones of the cranium - Temporal, Parietal
(b) Face - It is the lower part of the skull and has 14 bones.
Single bones of the face - Mandible, Vomer
Paired bones of the face - Zygomatic, Nasal, Maxilla, Mandible, Lacrymal, Palatine, Inferior Nasal Conchae
(c) Hyoid bone - It is found at the base of the tongue and is also known as tongue bone. It is not a proper part of the skull but is generally mentioned with this part of the skull. It is not connected with the other parts of the skeleton.
•Vertebral Column - Its length is 70 cm and is found in the mid-dorsal region of the neck and the trunk. It is connected with the skull, ribs, pectoral and pelvic girdle. It is made up of 33 vertebrae which are divided into five groups i.e cervical,thoracic, lumbar, sacral and coccygeal vertebrae.
A vertebrae has two main parts i. e a body (centrum)which is found anteriorly and a vertebral arch( neural arch) which is found posteriorly. There are two pedicles and two laminae found on the vertebral arch. There are 7 processes that arise from the pedicles and laminae. They are of 3 types-
(a) Spinous Process - It arises from the area where the laminae is joined and projects posteriorly and inferiorly. They help in the joining of muscles and ligaments.
(b) Transverse Processes - They arise from the area where the laminae and pedicle meets and extends laterally on each side. They serve the same function as that of Spinous process.
(c) Articular Processes - They also arise from the area where the pedicles and laminae meet and two of them extend anteriorly and two of them extend posteriorly. They help in the joining of vertebrae.
•Sternum - Its length is 15 cm and is found just below the skin in the middle of the chest. It has three parts-
(a) Manubrium
(b)Middle Body
(c)Xiphoid Process
•Ribs - Ribs along with the sternum and thoracic vertebrae form the rib cage. There are 12 pairs of ribs. They are of 3 types.
(a) True Ribs - They are attached directly to the sternum.
(b)False Ribs - They are attached to the 7th pairs of true ribs and not to the sternum.
(c)Floating Ribs - They are not attached with any rib or sternum and are free.
Structure of Ribs
 |
A rib consists of two parts-
(a) Vertebral Part - It joins with the thoracic vertebrae and is longer than the sternal part. It is generally bony.
(b)Sternal Part - The sternal part of true ribs joins with sternum and that of the false ribs joins with the e part of 7th rib while in floating ribs it is free.
2.Appendicular Skeleton - It has 126 bones and is present along the transverse axis of the body. It is divided into the following parts -
•Girdles- They join the axial skeleton with the limbs. There are two types of girdles-
(a) Pectoral Girdle - It is also known as the shoulder girdle. It is found on the postero-lateral position of the upper region of the thorax. It has 2 bones. These are-
Clavicle - It lies between the neck and the shoulder. It joins with the manubrium of the sternum and scapula. It is long and f-shaped.
Scapula - It extends above the 2nd to 7th rib at the back of the thorax. It is triangle shaped and also known as the shoulder blade.
There is a process called acrominon process which extends from the ridge called spine that crosses the body of the scapula.
(b)Pelvic Girdle - It is also known as hip girdle. It is present at the lower region of the trunk. It is formed of a fat, thick and strong bone called the hip bone or innominate which further consists of 3 bones- ilium,ischium and pubis.
•Limb Bones - There are 2 pairs of limbs in humans i.e fore limbs or arms and hind limbs or legs.
Bones of fore limbs or arms
Bones of hind limbs or legs
Related Topics
ECG - How to read? + Worksheets
Spinal Cord in Humans - Spinal Cord Structure and Spinal Cord Injury + Worksheets
Spinal Cord Injury + Worksheets
The Human Skull Bones + Worksheets
Infection in Kidneys + Worksheets
Kidneys Transplantation Cost +Worksheets
Healthy Diet Plan + Worksheets
0 Comments