: Know how locomotion and movement happen in body #IndiaNEWS #Education Today Hyderabad: This article is in continuation to the previous articles focusing on Locomotion and Movement. In the last article,

Know how locomotion and movement happen in body #IndiaNEWS #Education Today
Hyderabad: This article is in continuation to the previous articles focusing on Locomotion and Movement. In the last article, we discussed the skeletal muscle, the skull and the vertebral column. Lets continue today by understanding the functioning of the ribs and limbs.
Vertebral column (contd)
• First vertebra is the atlas and it articulates with the occipital condyles.
• The vertebral column is differentiated into cervical (7), thoracic (12), lumbar (5), sacral (1-fused) and coccygeal (1-fused) regions starting from the skull.
• The number of cervical vertebrae is seven in almost all mammals, including human beings.
• The vertebral column protects the spinal cord, supports the head and serves as the point of attachment for the ribs and musculature of the back.
Sternum
• Sternum is a flat bone on the ventral midline of thorax.
Ribs
• There are 12 pairs of ribs.
• Each rib is a thin flat bone connected dorsally to the vertebral column and ventrally to the sternum.
• It has two articulation surfaces on its dorsal end and is hence called bicephalic.
• First seven pairs of ribs are called true ribs.
• Dorsally, they are attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage.
• The 8th, 9th and 10th pairs of ribs do not articulate directly with the sternum but join the seventh rib with the help of hyaline cartilage.
• These are called vertebra-chondral (false) ribs.
• Last 2 pairs (11th and 12th) of ribs are not connected ventrally and are, therefore, called floating ribs.
• Thoracic vertebrae, ribs and sternum together form the rib cage.
The Appendicular Skeleton
• The bones of the limbs along with their girdles constitute the appendicular skeleton.
Limbs
• Each limb is made of 30 bones.
• The bones of the hand (fore limb) are humerus, radius and ulna, carpals (wrist bones – 8 in number), metacarpals (palm bones – 5 in number) and phalanges (digits – 14 in number).
• Femur (thigh bone – the longest bone), tibia and fibula, tarsals (ankle bones – 7 in number), metatarsals (5 in number) and phalanges (digits – 14 in number) are the bones of the legs (hind limb).
• A cup shaped bone called patella cover the knee ventrally (knee cap).
Girdles
• Pectoral and Pelvic girdle bones help in the articulation of the upper and the lower limbs respectively with the axial skeleton.
Pectoral Girdle
• Each girdle is formed of two halves.
• Each half of pectoral girdle consists of a clavicle and a scapula.
• Scapula is a large triangular flat bone situated in the dorsal part of the thorax between the second and the seventh ribs.