- Appendicular skeleton: 126 bones
- Fore limb – 60 ( 30 in each)
- Humerus – 1 bone
- Radius and ulna – 2 bones
- Carpals (wrist bones) – 8 in numbers.
- Metacarpals (palm bones) – 5 in numbers
- Phalanges (digits) – 14 in number.
- Hind limb – 60 (30 in each)
- Femur (thigh bone- the longest and heaviest bone) – 1 number.
- Tibia and fibula – 2 bones.
- Tarsals (ankle bone) – 7 bones.
- Metatarsals – 5 in numbers.
- Phalanges (digits) – 14 in numbers.
- Patella (knee cap) – 1 bone.
- Pectoral girdles: consists of 2 bones each = 4 bones.
- Helps in articulation of fore limb with the axial skeleton.
- Each pectoral girdle made of two half.
- Each half made of two bone the clavicle and scapula.
- Scapula is a large triangular flat bone situated in the dorsal part of the thorax between the second and the seventh ribs.
- Scapula is characterized by spine with acromion process.
- Below acromion, is glenoid cavity to which head of humerus fits.
- Clavicle is commonly called collar bone.
- Pelvic girdle: 2 bones.
- Pelvic girdle consists of two coxal bones.
- Each coxal bone is formed of fusion of three bones
- At the point of fusion of the three bones is a cavity called acetabulum to which the femur articulates.
- Two halves of the pelvic girdle meets ventrally to form the pubic symphysis containing fibrous cartilage.
JOINTS :
- Joints are the points of contact between bones, or between bones and cartilages.
- Force generated by the muscles is used to carry out movement through joints, where joint acts as a fulcrum.
- Joints are classified into three types:
- Fibrous joint
- Cartilaginous joint
- Synovial joint
Fibrous joints :
- Do not allow any movements.
- Found in flat bones which fuse end-to-end with the help of dense fibrous connective tissues in the form of sutures.
- These types of joints are found in the bones of cranium.
Cartilaginous joints :
- The bones involved are joined together with the help of cartilages.
- Permits very little movements.
- Joint between the vertebral column are the example of such joints.
Synovial joints :
- Characterized by the presence of a fluid filled synovial cavity between the articulating surfaces of the two bones.
- Allow free movement between two bones.
- The fluid inside it called synovial fluid covered by synovial membrane.
- Ball and socket joint - between humerus and pectoral girdle
- Hinge joint – knee joint
- Pivot joint – between atlas and axis.
- Gliding joint – between carpals.
- Saddle joint – between carpals and metacarpals of thumb.
DISORDERS OF MUSCULAR AND SKELETAL SYSTEM :
Myasthenia gravis :
- It is an auto-immuno disorder.
- Affects the neuromuscular junction leads to fatigue.
- Caused weakening and paralysis of skeletal muscle.
Muscular dystrophy : Progressive degeneration of skeletal muscle mostly due to genetic disorder.
Tetany: rapid spasms (wild contractions) in muscle due to low Ca++ in body fluid.
Arthritis : inflammation of joints.
Osteoporosis : age related disorder characterized by decreased bone mass and increased chances of fractures. Decrease levels of oestrogen are a common cause.
Gout : inflammation of joints due to accumulation of uric acid crystals.
