Understand skeletal structure of human body

Hyderabad: This article is in continuation to the previous articles focusing on Locomotion and Movement. The Appendicular Skeleton • The bones of the limbs along with their girdles constitute the appendicular skeleton. Limbs • Each limb is made of 30 bones. • The bones of the hand (fore limb) are humerus, radius and ulna, carpals […]

Hyderabad: This article is in continuation to the previous articles focusing on Locomotion and Movement.

The Appendicular Skeleton

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• The bones of the limbs along with their girdles constitute the appendicular skeleton.

Limbs

• Each limb is made of 30 bones.

• The bones of the hand (fore limb) are humerus, radius and ulna, carpals (wrist bones – 8 in number), metacarpals (palm bones – 5 in number) and phalanges (digits – 14 in number).

• Femur (thigh bone – the longest bone), tibia and fibula, tarsals (ankle bones – 7 in number), metatarsals (5 in number) and phalanges (digits – 14 in number) are the bones of the legs (hind limb).

• A cup-shaped bone called patella cover the knee ventrally (knee cap).

Girdles
• Pectoral and Pelvic girdle bones help in the articulation of the upper and the lower limbs respectively with the axial skeleton.
Pectoral Girdle
• Each girdle is formed of two halves.
• Each half of pectoral girdle consists of a clavicle and a scapula.
• Scapula is a large triangular flat bone situated in the dorsal part of the thorax between the second and the seventh ribs.
• The dorsal, flat, triangular body of scapula has a slightly elevated ridge called the spine which projects as a flat, expanded process called the acromion.
• The clavicle articulates with this. Below the acromion is a depression called the glenoid cavity which articulates with the head of the humerus to form the shoulder joint.
• Each clavicle is a long slender bone with two curvatures. This bone is commonly called the collar bone.
Pelvic girdle
• 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 of the above bones is a cavity called acetabulum to which the thigh bone articulates.
• The two halves of the pelvic girdle meet ventrally to form the pubic symphysis containing fibrous cartilage.
To be continued…
By

Dr.ModalaMallesh

Subject Expert
Palem, Nakrekal, Nalgonda
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