Question

Write short notes on different parts of the skeletal system

Answer 1

The human skeleton is the internal framework of the body. It is composed of around 300 bones .... The human pelvis exhibits greater sexual dimorphism than other bones

Answer 2

The two components of skeletal system making up the body are consisting of tough external structures and hard internal structures of a typical animal or an organism's body framework which altogether conserves a highly complex system called the $\textbf{Skeletal System}$.  

Skeleton which constitutes the internally made structures are called as $\textbf{Endoskeleton}$ presenting inside the body framework of an animal "internally". these contains all the bones, cartilages, ligaments, tendons, etc. Skeleton which constitutes the externally made organ structures is called as $\textbf{Exoskeleton}$ these contain Hairs, nails, dead skin cells, etc.

The Skeletal system serves many functions for it's body:  

1) They're supporting the organism, protecting them from internal and external damages from environment.

2) Attaching those muscles needed for locomotion and movement of body parts.

3) Assist in the functioning of hearing by attachment of bones in internal ear and Breathing by the help of cartilaginous structures supporting larynx or the voice box, breastbone or sternum and tracheal wall.  

4) Reserving most important mineral components in Bones as the form of Calcium and also phosphorous and meeting the demands for it.

5) Maintains Body formations and Body shape of an organism, Assist in formation of Blood cells inside bone marrow as RBCs and WBCs.

6) Helps in movement and locomotion.

Talking about the Skeletal system it constitutes two parts of Skeletal Or Skeleton system, that is,  

A) Axial Skeleton System: This system is found mainly on the median or middle of a longitude Axial plane in an organism it'll definitely contain the Rib structures, Breastbone, Skull as a whole and the Vertebrae column (or vertebral column).

B) Appendicular Skeleton System: This system is found mainly on the laterally inclined regions that're moving forward and outwards (or out of it) from a axis called the Principle Axial planar formations. It's containment would've been of Pectoral Girdle, Pelvic Girdle or the Hip bone along with constituting All the bones for Arms including the Legs.

Axial Skeleton Systems consists of a grand total of 80 Bones, as follows:

1) A Skull that further has 8 Number of Bones Namely, Cranial Bones that're containing the $\textbf{2 Parietal Bones}$, $\textbf{2 Temporal Bones}$, $\textbf{1 Occipital Bone}$, $\textbf{1 Frontal Bone}$, $\textbf{1 Ethmoid Bone}$ and the $\textbf{1 Sphenoid Bone}$.

2) Our Face consists of 14 bones in a gist, Namely, 1 Vomer, 2 Maxillae, 2 Palatine Bones, 2 Zygomatic Bones, 1 Dentary Mandible, 2 Nasal or Nose Bones, 2 Lacrimal Bones and one last facial Bone called as Inferior Nasal Conchae present in Nasal chambers or also called as Turbinating Bones or Inferior Turbinate Bones.

3) Just above our voice box or larynx there consist a Hyoid Bone which's one in number. A Hyoid bone when simply said is sitting in the uppermost part of the anterior region of throat and is into a consideration as a part of the Skull in a part of of the Skeletal system that joins muscular structures of our tongue and basal floor of our mouth which'll not show any articulation with bones of other parts.

4) Ossciles of the bones present in our ears three in number for each bones. Total 6 Bones that is, Stapes, 2 in number, Incus, 2 in number and Malleus, 2 in number.

5) Column of Vertebrae are having 26 Bones in total, namely, Cervical Vertebrae, total 7 bones, Thoracic and Lumbar Vertebrae, 12 and the bones respectively, Sacrum and Coccyx, 5 and 4 Vertebrae or bones respectively.

6) Thoracic parts contain two components namely, Breastbone or Sternum, 1 on number and all the 24 Ribs which have True and False Ribs (7 and 5 in pairs, respectively).

Appendicular Skeleton System consists of a grand total of 126 bones, as follows:

1) Pectoral Or Shoulder Girdles have two Bones, Clavicle and Scapula, both are one in number.

2) Arms or basically the extremities in the upper regions are 60 in number. They contain 1 Humerus, 1 Ulna, 1 Radius, 8 Bones of Carpal, 5 Bones of Metacarpal, 14 bones of Phalanges in digits of 5 for each arm. $\bf{30 \times 2 = 60}$ in both arms.

3) Pelvic Girdle or Pelvis are containing Innominate or Hip Bones that are 2 in number

4) The legs or extremities in the lower regions contain Femur, Tibia, Fibula, Patella, Tarsals, Metatarsals and Phalanges which are 2, 2, 2, 2, 14, 10 and 28 in numbers for both the legs respectively.

Number of bones in Infantile Stage is about 306 and decreases to 270 at first stage of Parturition and maintains a total of 206 Bones in adult stage or form. Formula for calculating vertebral column or Vertebral formula is $\bf{C_7 T_{12} L_5 S_{(1 - 5)} C_{(1 - 4)}}$, where, alphabetical letters represent the Vertebrae present in a typical Vertebral column.

Hope this helps.