Skeletal system of human body || Skeleton system parts structure and function.

Function of the skeletal summery 

1. Protection :- cranium protects the soft tissue of the brain.

2. Movement :- the vertebrae allow us to band stretch and rotate our body.

3. Blood production :- red blood cell are made in the ribs and limbs bone.

4. Support :- the bones of the leg support the body.

The vertebrae supports the head.

5. Protection :- the ribcage protects delicate heart and lungs.

6. Mineral storage - the bone act as a reserver staring vital minerals such as calcium.

BONES :- 

Osteology is the study of bones and teeth.

osteology is usually applied in field in anthropology forensic science and archaeology for function like determination of nutritional value health and also to determine the position of bone within the body.

Types of bones 

• the femur is an example of a long bone.

• The frontal bone is a flat bone.

• The patella also called the kneecap is sesamoid bone.

• Carpals and tarsals are example of short bones.

• Vertebrates are example of irregular bone.

1) flat bones protect internal organs

flat bones are characterized by a thin shaped structure.

they offer a wide surface for muscle attachment and thus provide substantial mechanical production.

Ex- cranial bones( protecting the brain) the sternum and ribs (protecting the organ in the thorax) and the scapulae (shoulder blades).

2) Irregular Bones  

• irregular bones as the name suggests they are symmetrical in shape and therefore are said to have complicated shapes.

They are shaped to fulfill certain specific function within the body.

For ex- The vertebrate and some facial bone.

• These bones provide major mechanical support To the body while also protecting the spinal cord.

3) long bones 

Long bones are characterized by process of a a shaft.

They have longer length as compared to the width.

Ex- femur, tibia, fibula, humerus, ulna, and radius.

4) short bones 

Short bones are characterized by an almost equal length and width.

Ex- short bones include of ankle and wrist.

They are more or less cubical in shape.

5) sesamoid bones 

they develop in some tendons in area where there is considerable friction, tension and physical stress.

• therefore there these bones are formed in the palms of the hand and soles of the fee. (Patellae knee caps).

Skeletal system 

• at the simplest level the skeleton is the Framework that provide structure to the rest of the body and facilitates movement.

• the skeletal system include over 206 bones cartilage and ligaments.

--- Devision of skeletal system 

The skeletal system divided into two parts are :- 

1.Axial Division - bones of the body axis (skull, vertebrae, ribs).

2. Appendicular -  bones appended to the axial bones of the body (arms, legs, solder, hands, feet etc).

1. Axial skeletal 

there are roughly 80 bones in the axial skeleton and they form the bones of the longitudinal axis of the body (roughly 40% of the bone in the human body).

Skull bones :-  8cranial, 14 facial 

Associate skull bones :- 6 auditiry ossicles, 1hyoid bone.

Thoracic bones :-  1sternum, 24 ribs 

Vertebral bones :-.  24 vertebrae, 1sacrum, 1coccyx.

Function of axial skeleton are :-

Create a framework to support and protect organ in the dorsal and ventral cavity.

Provide extensive surface area for the attachment of muscles.

a. Adjust the position of the head, neck and trunk.

b. Perform respiratory movement.

c. Stabilizer position the perpendicular skeleton.

1) skull bones :-

Two sets of bones 

- cranium 

- facial bones

• bones are joined by sutures.

• only the mandible is attached by a freely movable joint.

--Cranium bones are :- 

1)Frontal bones :- the subdivision of frontal bones include.

i) frontal squama.

ii) supraorbital margin.

iii) frontal Sinuses.

2) pariental bones :- these are form major portion of both side of the skull 

• there is two parental bones one left and one right.

3) temporal bones :- temporal bones are present along the ear.

• there is two temporal bones one in left and one in right side.

4) occipital bones :- was present at the back of the skull occipital bones  bones.

5) Sphenoid :- it forms a bad like structure present in the centre of the skull.

6) Ethmoid  :- the bones present in the anterior part of the skull and separate the nasal cavity from the brain.

•It form the upper part of the nasal cavity and some part of the orbit as well.

FACIAL BONES :- 

Also known as which keral skull forms the point of attachment for the anterior and inferior surface of the cranium.

Different bones are face includes are :-

1 Nasal bone :- 

these bonds provide flexibility and formation of national bridge.

2 Nasal septum :-  the right and left part of the nose (external nares) are separated by nasal septum.

3 Maxillae :- • these are paired bones.

• this born is responsible for holding the upper set of teeth.

• there is two bone of maxillae.

4 cleft :-  these bonds form the roof of the mouth and separate oral cavity.

5 Zygomatic bones  :- these are also known as cheekbones.

• there is a to zygomatic bones.

6 Mandible :- • among the facial bone mandible is the strongest as well as the largest bone.

• it is the movable bone of face.

7 Vomer :- it is the only unpaired bone of the face which form the nasal septum.

8 Lacrimal bones  :- it is a face bone, lacrimal bone are the smallest and most delicate ones.

There is two lacrimal bone

9 orbit  :- desiccator cavity holding the eye is called orbit.

HYROID BONE 

• hyroid bone is a horseshoe shape bone and is also known as lingual bone.

• It is located in middle of neck in between thyroid cartilage and chin.

• Hyroid bone is the only skeletal bone which is not attached to any other bone of the skeleton.

• Structurally hyroid bone divide into following parts.

1. Centrally located part called the body

2. Two pairs of cornua greater cornu and lesser cornu new.

Function

• sabse as an anchoring structure for tongue and Larynx.

• Aids in tongue movement.

• Help in swallowing.

• Help in production of sound and its variations.

Vertebral column (vertebrae)

• the backbone of human being comprises of 33 vertebrae and represent the vertebral column it is also known as spine.

• the vertebral also provide protection to the spinal cord and its membranes.

Basic structure of a vertebra 

a typical vertebra of the vertebral column consists of following parts :-

1. Body = the interior portion of a vertebra which is joined to the intervertebral disc is called the body.

2. Vertebral arch = the arch on the posterior part of the body is the vertebral arch and protect spinal cord.

3. Vertebral foramen = it is opening through the arch spinal cord passes through its foramen.

4. Processes = these are projection or outgrowth of tissue from vertebra.

Parts of vertebra 

the human vertebral column b for the divided into following five parts.

1. Cervical :-  7 cervical vertebrae.

2. Thoracic :- thoracic vertebrae are in 12 number.

3. Lumbar :- it includes 5 lumbar vertebrae.

4. Sacral :- the fusion of 5 sacral vertebrae.

5. Coccyx  :- coccyx is formed by the fusion of 4 coccygeal vertebrae in the lower part of pelvis.

Function of vertebral column  

• provide a strong and flexible support for the body and the ability to keep the body erect.

• the point of attachment for the muscles of the back.

• Protect the spinal cord and nerves.

• Absorb shocks through the intervertebral without causing damage to other vertebrae.

Thoraciccage / thorax 

the thoracic cage of thorax is a reason of the human vertebral column that lies between the head and abdomen excluding upper limbs.

Thorax consists of three major parts are

1. Ribs 

2. Sternum 

3. Thoracic vertebrae 

• Twelve pair 

• Made up of :- 

- bone 

- catilage which strength the chest cage and permit it to expand.

• curve and slightly twisted making it ideal to protect the chest area.

1. Ribs - all 12 pairs of ribs articulate with the 12 thoracic vertebrae posteriorly.

• classified into three group based on anterior attachment

a) true ribs 

• 1--7

• attached to both the vertebrae and the sternum.

b) False ribs  - 

• 8-10

• attach only to the sternum indirectly through 7th rib.

c) Floating ribs :-

• 11 and 12

• only attached to the vertebral column.

2.Sternum  

• midline breastbone.

• the clavicles and rips 1 to 7 articulate with the sternum.

Function

• sternum complete the rib cage circle does protecting vital organs.

• rips and connected to sternum via costal cartilage there by providing flexibility.

• it also protect the aorta, Vena cava and thymus.

Appendicular Skeleton :- 

• it is the bony framework of upper and lower limbs and their supporting girdles including 126 bones that anchor the appendages to the axial skeleton.

• it consists of

1. The pectoral gridle (chest ) 

2. Pelvic girdle (hip)

3. The upper limbs.

4. The lower limbs.

1. The pectoral grindle (sholder)

• left and right half area the two distinct division of pectoral girdle.

Where each half contain a scapula and clavicle bone.

- scapula - Sholder blade

- Clavicle - collar bone 

• these bones allowed the upper limb to have exceptionally  free movement.

Scapula  => • it is larger regular and triangular flat bone.

• it compromise following process.

1. Spinous process

2. Acromion process

3. Coracoid process

Clavicle -> • the clavicle is an s-shaped subcutaneous bone having a long and narrow structure.

• it is present on both side of neck and connect the upper limbs with trunk just above the first pair of ribs.

Function 

1. the pectoral gradle act as a support as well as suspension system for the upper extremities.

2. It acts as a shock absorber of a body after the act of jumping and leaping.

3. it maintain the shape of thorax and provide space for the insertion of muscles of the back.

4.  It forms the site of attachment for muscles of upper limb and help in their locomotive actions.

2. Pelvic girdle 

• formed by pair of coxae (hip bone)

• support the bladder and abdominal contents.

• attachments :- 

--Posteriorly - join with sacrum

--Anteriorly - join to each other

-- Laterally  - join to the head to thigh bone through a cup shaped  acetabulum.

3.Upper limbs 

• each upper limb consists of 30 bones which are divided broadly into the following three parts.

a) Humerous or Armbones :-

• it is the longest bone of the fore limbs.

• the bone enables the upper extremity to perform physical activity like pull, push, lift and rotation of object within the arm's length.

b) Ulna and radius :- 

Radius and ulna together form the bones for arm.

1.Ulna  :- ulna forms the medial bone of the limbs.

2. Radius  :- radius is the lateral bone of the fore arm of the body.

c) Carples and Metacarpals

• 8 irregular shaped bones known as carpals.

• there are 5 metacarpals which are numbered from lateral to the medial side and have the head, the shaft and a base.

4. Lower limb  

• lower limb comprises of 32 bones as give are :-

1. Femur  - strongest and longest bone of human body.

2. Patella - patella is a sesamoid bone located right in front of the distal end of femur.

3. Tibia - tibia is a longer bone of the lower leg.

4. Fibula - Fibula is a lateral bone present in the lower limb.

5. Tarsal. - there are seven tarsal bones

- ankle bone 

- calcaneus or heelbone

- talus

6. Metatarsal  - • 5 bone of the foot.

- Unite with the toes.

7. Phalanges - 

• there are total 14 palanges in a single foot.

• two of them for great to each 

• three are present in the rest for finges each.

6. Metatarsals

7. Phalanges