Explain: Pectoral girdle and Pelvic girdle.

(N/A) The $Pectoral$ and $Pelvic$ girdles are components of the appendicular skeleton that help in the articulation of the upper and lower limbs respectively with the axial skeleton.
$1$. $Pectoral$ $Girdle$: It consists of two halves. Each half is made up of a $Clavicle$ (collar bone) and a $Scapula$ (shoulder blade). 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 slightly elevated ridge called the $Spine$ which projects as a flat,expanded process called the $Acromion$. The $Clavicle$ articulates with this process. Below the $Acromion$ is a depression called the $Glenoid$ $cavity$ which articulates with the head of the $Humerus$ to form the shoulder joint.
$2$. $Pelvic$ $Girdle$: It 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 of these bones,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.