Appendicular skeleton pectoral/ shoulder girdle Biology

The pectoral girdle holds the upper limbs or arms to the axial skeleton. It consists many of four separate bones, two large flat, triangular, bones called shoulder blade or scapula at the back and two small slender bone called collar bone or clavicle in front. The scapula is attached to the vertebral column by muscles, each scapula has a depression called the glenoid cavity into which the head of the upper humerus fits to form the shoulder joint. The calvicles are attached to the scapula at one end and to the sternum and the other end.

The pelvic griddles consist of two half which have joint to each other ventrally to form a sacrum. The line of fusion of two half bones is called pubis symphysis .Each half is made up three bones namely ilium, ischium and pubis. The ilium is the largest and the longest of the three bones.

Pelvic griddle or hips

Pelvic girdles or hip consist of two bones, the right and the left pelvic. These are joined to form sacrum at the back and held together by cartilage at the back and in front to form a complete hip girdle. At the outer edge of each pelvic is a deep cavity called acetabulum cavity into which the bone of the thigh bone or( femur )fits to form the hip joint.

The pelvic girdle consist of two halves which are joined to each other ventrally to form a sacrum. The line of fusion of the two halves bones is called pubis symphysis, each halve is made up of three bones namely ilium, ischium and pubis . the ileum is the largest and longest of the three bones. At the lower and of ischium and of ischium and pubis encloses an opening or a hole called obturator foramen. It is through this hole blood vessels and muscles pass.

The limbs are made up of fore limbs i.e bones of the arm and limbs. The limbs of most vertebrates are built on the same basic plan called pentadacty limb plan < 5 digit plan>.The fore limbs of mammals is made up of an upper arm bone which a long bone called humerus. The humerus has a rounded head which fix to the glenoid cavity of scapula of the pectoral girdle. The humerus are grooved- like surface called trochlea which join with ulna and radius are foliated by the bones of the wrist called carpals which are followed by the bones of the digit called metacarpals or phalanges.

HIND LIMBS

The hind limbs is made up of the tight bone called Femur. The femur is the largest and the strongest bone in the body. Very close to the femur and three projections called TROCHANTERS, they are important for the attachment femur to muscle. At the distal end of the femur are two rounded knobs called condoyle for articulation. The Shank is made up of two bones called Tibia and Fibula. The knee joint is found at the junction of the femur with tibia and fibular ,the there is a short bone called patella or knee cap . the inner tarsal’s project backward to form the heel bone .