How is the appendicular skeleton formed? Describe its various parts with a diagram.

(N/A) The bones of the limbs along with their girdles constitute the appendicular skeleton.
$(i)$ Forelimb - Each limb is made up of $30$ bones.
Bones of forelimb:
- Humerus: $1$
- Radius and Ulna: $2$
- Carpals (wrist bones): $8$
- Metacarpals (palm bones): $5$
- Phalanges (digits): $14$
Total = $30$ bones.
(ii) Hind limb - Each limb has $30$ bones.
- Femur (thigh bone): $1$
- Patella (knee cap): $1$
- Tibia and Fibula: $2$
- Tarsals (ankle bones): $7$
- Metatarsals: $5$
- Phalanges (digits): $14$
Total = $30$ bones.
Femur is the longest and strongest bone of the body.
(iii) Girdles: These help in the articulation of the upper and lower limbs with the axial skeleton.
- Pectoral girdle: Each half consists of a clavicle and a scapula. The scapula is a large triangular flat bone situated in the dorsal part of the thorax between the $2^{nd}$ and $7^{th}$ ribs. It has a spine that projects as a flat,expanded process called the acromion. Below the acromion is the glenoid cavity,which articulates with the head of the humerus. The clavicle is a long,slender bone with two curvatures,commonly called the collar bone.
- Pelvic girdle: Consists of two coxal bones. Each coxal bone is formed by the fusion of three bones: ilium,ischium,and pubis. At the point of fusion,there is a cavity called the acetabulum to which the thigh bone (femur) articulates. The two halves of the pelvic girdle meet ventrally to form the pubic symphysis containing fibrous cartilage.