Question

Phalangeal formula of hand of man is:
A. 1, 2, 2, 2, 2
B. 2, 1, 1, 1, 1
C. 2, 3, 3, 3, 3
D. 2, 3, 3, 2, 2

Answer 1

Hint: Mammal limbs are simple, including the pentadactyl limb (i.e. each limb ends in five digits). The legs and upper limbs are supported by the limb bones (lower limbs).

Complete Step by Step Answer:
Each arm has 30 bones, including the upper arm's humerus, the forearm's radius and ulna, the wrist's 8 carpals, the palm's 5 metacarpals, and the 14 phalanges. Bone arrangement:
Humerus: 1, Radius: 1, Ulna: 1, Carpals: 8, Metacarpals: 5, Phalanges: 14
The arrangement of the radius and ulna in the forelimbs permits the radius to revolve around the ulna.

The large, arched, horny nails are supported by the distal phalanges. The wrist and hand contain a large number of tiny bones that enable us to hold objects, write, paint, etc. The human hand's phalanges are 2,3,3,3,3. Compared to animal forelimbs, the joints in the human arm are more mobile. Humans utilise their arms for gripping, writing, sewing, and painting, while animals use their forelimbs mostly for mobility (e.g., joints between the carpal and tarsal bones) (in lower limb). Saddle joints—Joints between the metacarpals and phalanges, for example—allow movement in two planes, back and forth and side to side.

Hence, the correct option is C. 2, 3, 3, 3, 3



Note: It is believed that the legs are stronger than the forelimbs (arms). The long bone in the forelimbs of land vertebrates is called the humerus. It creates the elbow joint below, where it articulates with the projection of the ulna and the radius, and the shoulder joint above, where it articulates with the lateral depression of the shoulder blade, or glenoid cavity of the scapula.