Test: Skeletal System (NCERT) - NEET MCQ

Six ear ossicles are present, three in each ear. They are malleus, incus and stapes.

Topic in NCERT: Skeletal system

Line in NCERT: "each middle ear contains three tiny bones - malleus, incus and stapes, collectively called ear ossicles."

Upper rounded end of the humerus (bone of arm) is called head that articulates into the glenoid cavity of the pectoral girdle (shoulder girdle).

Topic in NCERT: Pectoral girdle

Line in NCERT: "below the acromion is a depression called the glenoid cavity which articulates with the head of the humerus to form the shoulder joint."

Stapes, one of the bones in the ear, is the smallest bone in the human body. Here are some key points about the stapes:

• It is part of the ossicles, a group of three tiny bones in the middle ear.
• The stapes helps transmit sound vibrations from the outer ear to the inner ear.
• Its size is approximately 2.5 mm, making it the smallest bone.

This bone plays a crucial role in our ability to hear.

Topic in NCERT: Skeletal system

Line in NCERT: "each middle ear contains three tiny bones - malleus, incus and stapes, collectively called ear ossicles."

Each pectoral girdle consists of two bones -1 clavicle and 1 scapula. The scapula consists of a sharp ridge, the spine and a triangular body. The end of the spine projects as a flattened and expanded process called acromion. This process articulates with the clavicle

Topic in NCERT: Scapula and clavicle

Line in NCERT: "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."

Each hind limb consists of 30 bones 1 femur, 1 patella, 1 tibia, 1 fibula, 7 tarsals, 5 metatarsals and 14 phalanges.

Topic in NCERT: Appendicular skeleton

Line in NCERT: "the bones of the limbs alongwith their girdles constitute the appendicular skeleton. each limb is made of 30 bones."

Trasals, femur, metatarsals and tibia are bones of the legs which are involved in running during chasing the ball by a cricket player.

Topic in NCERT: Skeletal system

Line in NCERT: "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)."

Scapula or shoulder blade is a bone of the pectoral girdle. It is a flat triangular bone, providing anchoroge for the muscle of the forelimb and an articulation for the humerus at the glenoid cavity.

Topic in NCERT: Pectoral girdle

Line in NCERT: "each half of pectoral girdle consists of a clavicle and a scapula."

Cranium consists of 8 bones-1 frontal, 2 parietal, 2 temporal, 1 occipital, 1 sphenoid and 1 ethmoid.

Topic in NCERT: Skeletal system

Line in NCERT: "the skull (figure 17.6) is composed of two sets of bones - cranial and facial, that totals to 22 bones. cranial bones are 8 in number."

There are five lumbar found in the abdominal region in humans. They extend from the twelfth thoracic vertebra down to the sacral vertebrae.

Topic in NCERT: Skeletal system

Line in NCERT: "the vertebral column is differentiated into cervical (7), thoracic (12), lumbar (5), sacral (1-fused) and coccygeal (1-fused) regions starting from the skull."

Clavicle is a bone that forms part of the pectoral girdle (part of appendicular skeleton) linking the scapula to the sternum (part of axial skeleton).

Topic in NCERT: Skeletal system

Line in NCERT: "pectoral and pelvic girdle bones help in the articulation of the upper and the lower limbs respectively with the axial skeleton."

Clavicle and glenoid cavity are parts of the pectoral girdle, not the pelvic girdle.

This is important because:

• The pectoral girdle connects the upper limbs to the axial skeleton.
• The pelvic girdle connects the lower limbs to the axial skeleton.
• Understanding these differences is crucial for studying human anatomy.

Topic in NCERT: Appendicular skeleton

Line in NCERT: "the bones of the limbs alongwith their girdles constitute the appendicular skeleton."

The pelvic girdle is composed of two coxal (hip) bones. Each coxal bone consists of three separate parts: the ilium (short and straight bone), the ischium (lower elongated bone running parallel to vertebral column) and the pubis (inner smaller bone).

Topic in NCERT: Pelvic girdle and lower limb bones

Line in NCERT: "each coxal bone is formed by the fusion of three bones - ilium, ischium and pubis."

Patella is a cup-shaped bone covering and protecting the anterior surface of the knee joint. Scapula is a large triangular flat bone, situated on the dorsal side of the thorax.

Topic in NCERT: Skeletal system

Line in NCERT: "the skull (figure 17.6) is composed of two sets of bones - cranial and facial, that totals to 22 bones."
"scapula is a large triangular flat bone situated in the dorsal part of the thorax between the second and the seventh ribs."
"a cup shaped bone called patella cover the knee ventrally (knee cap)."
"pelvic girdle consists of two coxal bones (figure 17.10)."

The endoskeleton of mammals have two major divisions: (i) Axial skeleton, that lies along the longitudinal axis of the body. It supports and protects the organs of the head, neck and trunk. It includes skull, ribs, sternum and vertebral column, (ii) Appendicular skeleton, which is associated with the appendages. It consists of two girdles, the pectoral and pelvic girdles and the limb bones.

Topic in NCERT: Appendicular skeleton

Line in NCERT: "the bones of the limbs alongwith their girdles constitute the appendicular skeleton."

The last two pairs of ribs (11^th and 12^th) are called floating ribs as their anterior ends are not attached to either the sternum or the cartilage of another rib. The floating ribs provide protection to kidneys.

Topic in NCERT: Skeletal system

Line in NCERT: "last 2 pairs (11th and 12th) of ribs are not connected ventrally and are therefore, called floating ribs."

Tarsals and metacarpals are the bones of the limb, therefore, they are the part of appendicular skeleton and not the axial skeleton which consists of vertebral column.

Topic in NCERT: Vertebral column

Line in NCERT: "the vertebral column protects the spinal cord, supports the head and serves as the point of attachment for the ribs and musculature of the back."

A - Sternum
B - Ribs
C - Vertebral column

Topic in NCERT: Skeletal system

Line in NCERT: "the bones of the limbs alongwith their girdles constitute the appendicular skeleton. each limb is made of 30 bones. the bones of the hand (fore limb) are... there are 12 pairs of ribs. each rib is a thin flat bone connected dorsally to the vertebral column and ventrally to the sternum."

Actin is a globular protein present in thin filaments. There are 12 pairs of ribs in man. Sternun is a flat bone present on the ventral side of the body in the middle of the front of the chest.

Topic in NCERT: Locomotion and movement

Line in NCERT: "actin is present in thin filament."
"there are 12 pairs of ribs."
"sternum is present on the ventral side of the body."
"last 2 pairs (11th and 12th) of ribs are not connected ventrally and are therefore, called floating ribs."

The first 7 pairs of ribs are called true ribs as their anterior ends are attached directly to the sternum. The 8^th, 9^th and 10^th pairs are called false ribs as they are attached indirectly to the sternum. The 11^th and 12^th pairs are called floating ribs as their anterior ends are not attached to sternum.

Topic in NCERT: Skeletal System

Line in NCERT: First seven pairs of ribs are called true ribs. Dorsally, they are attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage. The 8th, 9th and 10th pairs of ribs do not articulate directly with the sternum but join the seventh rib with the help of hyaline cartilage. These are called vertebrochondral (false) ribs. Last 2 pairs (11th and 12th) of ribs are not connected ventrally and are therefore, called floating ribs. Thoracic vertebrae, ribs and sternum together form the rib cage