The skeleton, composed of bones, cartilages, joints, and ligaments, accounts for about 20% of body mass.

  There are 206 bones in the human body.

The axial skeleton forms the long axis of the body and includes the bones of the skull, vertebral column, and rib cage.

There are 80 bones in the axial skeleton.

The Appendicular skeleton consists of the bones of the upper and lower limbs, and the shoulder bones and hip bones.

There are 126 bones in the Appendicular Skeleton.

The skull consists of two sets of bones – the cranium and the facial bones. There are eight cranial bones and fourteen facial bones.

 The joints between bones of the skull are immovable and called sutures.

• The SPHENOID BONE- acts like a bridge between the cranial & facial bones

Only the mandible is attached by a freely movable joint.

The hyoid bone is the only bone in the body that does not articulate (match up with) another bone. The hyoid bone acts as an attachment point for several muscles that help with speech and swallowing. The hyoid bone is attached to the skull by ligaments.

The vertebral column consistsof vertebrae separated by disks of fibro-cartilage.

7 cervical vertebrae   12 thoracic vertebrae   5 lumbar vertebrae  The bony thorax forms a cageto protect major organs

SPINAL (VERTEBRAL) COLUMN

The spinal column (or vertebral column) extends from the skull to the pelvis and is made up of 33 individual bones termed vertebrae.

The bony thorax is made up of three parts:

1)Sternum

2)Ribs

3)Thoracic vertebrae

You have three different types of ribs True ribs are the first seven pairs of ribs. True

ribs attach directly to the sternum by costal cartilages.

False ribs are the next five pairs. They either attach indirectly to the sternum or not at all.

Floating ribs are the last two pairs of false ribs. They lack sternal attachments.

 

The 3 parts of the appendicular skeleton are:

1)Limbs (appendages)

2)Pectoral girdle (shoulder)

3)Pelvic girdle (pelvis)

The pectoral girdle (or shoulder) is composed of two bones

1)Clavicle – collarbone2)Scapula – Shoulder blade The clavicle and the scapula allow the

upper limbs to have free movement 

The arm is formed from a single bone, the humerus.

The forearm has two bones: the ulna and radius

The hand contains three types

of bones:

1)Carpals – wrists

2)Metacarpals – palm

3)Phalanges - fingers

The thigh has one bone – the femur.

 The lower leg has two bones – the tibia and

fibula.

The foot has three types of bones:

1)Tarsals – ankle

2)Metatarsals – sole

3)Phalanges - toes

The pelvic girdle is made up of the hip bones.

 

The “hip bones” are composed of three pair of fused bones – the ilium, ischium, and pubic bone.

 

 

The total weight of the upper body rests on the pelvis.

The pelvic girdle protects several organs – the reproductive organs, the urinary bladder, and part of the large intestine.