Skeleton - Movement and Locomotion
Solutions for Biology, Class 9, ICSE
Assertion Reason Type
6 questionsAnswer:
A is False and R is True.
Reason — The axial skeleton consists of the central core of the body: Skull, vertebral column, rib cage and sternum. It does not include the limbs or girdles.
The axial skeleton forms the central supporting axis of the body.
Assertion (A): Each hip bone is made up of three fused bones - ilium, ischium and pubis.
Reason (R): Hip bone is technically termed as pelvis. It is wider and trough-shaped in females.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Answer:
A is True and R is False.
Reason — Each hip bone is formed by the fusion of three bones: Ilium, Ischium and Pubis. These fuse during development to form a single structure.
The hip bone is a part of the pelvis, not the same as the pelvis. The pelvis includes: Two hip bones, sacrum and coccyx. The female pelvis is wider, shallower, and more rounded, to facilitate childbirth.
Assertion (A): Synovial fluid provides lubrication to the bones and removes friction.
Reason (R): Synovial joint is found between the bones of cranium. These joints contain synovial fluid between them.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Answer:
A is True and R is False.
Reason — Synovial fluid is a viscous fluid present in synovial joints. It reduces friction, lubricates the joint, and nourishes the articular cartilage.
The bones of the cranium are connected by immovable joints called sutures, not synovial joints. Sutures are fibrous joints that do not contain synovial fluid.
Assertion (A): Hinge joint occurs between the bones of wrist. It provides movement in only one direction.
Reason (R): Hinge joint is found in shoulders. It provides movement in all directions.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Answer:
Both A and R are False.
Reason — A hinge joint allows movement in one plane (like a door hinge) and is found in the elbow, knee, ankle, and fingers.
Ball-and-socket joints allow movement in all direction but the shoulder has a ball-and-socket joint, not a hinge joint.
Answer:
Both A and R are True.
Reason — The radius and ulna are the two long bones of the forearm. They extend from the elbow to the wrist. The tibia and fibula are the two long bones of the lower leg, also called the shank. They extend from the knee to the ankle.
Assertion (A): Sternum is a large bone formed by the fusion of five vertebrae. It is found between the lumbar vertebrae and соссух.
Reason (R): Sternum lies in the middle of the front part of the chest.
- A is True and R is False.
- A is False and R is True.
- Both A and R are True.
- Both A and R are False.
Answer:
A is False and R is True.
Reason — The sternum is not formed by vertebrae. It is a flat bone located in the center of the chest (anterior thoracic region).
It is located in the center of the chest, and connects to the ribs via cartilages, playing a vital role in protecting the heart and lungs.
Long Answer Type
3 questionsAnswer:
(a) Difference between true ribs and floating ribs:
True ribs | Floating ribs |
---|---|
The first seven pairs of ribs are called true ribs. | The last two pairs of ribs (11th & 12th) are called floating ribs. |
They are attached in front of the sternum by means of coastal cartilages. | They are not attached to the sternum at all. |
(b) Difference between ligaments and tendons:
Ligaments | Tendons |
---|---|
Ligaments connects two or more bones together. | Tendons connect muscle to a bone. |
Ligaments are elastic. | Tendons are inelastic. |
Ligaments are arranged freely. | Tendons are arranged in bundles. |
Ligaments stabilize joints. | Tendons pass tensile forces to the bones from muscles. |
Prevent chances of dislocation | Responsible to cause the muscles to stay intact with parts of the skeleton. |
(c) Difference between hinge joint and gliding joint:
Hinge joint | Gliding joint |
---|---|
Hinge joint allows restricted movement in one plane only. | Gliding joint allows bones to glide over each other to a limited extent. |
Example: Elbow, Knee | Example: Wrist bone, ankle bone |
(d) Difference between voluntary and involuntary muscles :
Voluntary muscles | Involuntary muscles |
---|---|
Voluntary muscles are under our control. | Involuntary muscles are not under our control. |
Voluntary muscles help in the movement of the bones of limbs. | Involuntary muscles are present in internal organs and help in movement of food, movement of urine from urinary bladder and so on. |
The cells are long, cylindrical and unbranched. | The cells are spindle shaped. |
They are multinucleate. | They are uninucleate. |
They are striated. | The are unstriated. |
(e) Difference between Bone and cartilage :
Bone | Cartilage |
---|---|
Bones consists of the ground substance or matrix that is filled with cells called osteocytes and various inorganic compounds. | Cartilage consists of ground substance called matrix that contains cells called chondrocytes. |
Bones comprise the hard framework of the body. | Cartilages are supporting and connecting structures. |
Bones provide support, protection, and anchorage for muscles. | Cartilage acts as a cushion between bones, reducing friction and absorbing shock in joints. |
Bones have a higher capacity for healing and regeneration. | Cartilage has a limited capacity for self-healing. |
Answer:
Uses of skeleton:
- Support and shape — The skeletal system provides a framework to the body. It provides support to all soft parts and gives a definite shape to the body and all body parts.
- Protection — Several delicate and important organs are well protected by a casing of bones.
Example — The skull provides protection to the delicate brain. - Movement — Some bones are movable on each other which is brought about by the action of muscles that originate on one bone and are inserted into another.
- Leverage — Some bones and joints form levers which causes the increase in the speed and distance of the muscle movement.
- Formation of blood cells — Certain types of blood cells including red and white blood cells are formed in the marrow of certain long bones such as the femur.
- The bones are storehouse of calcium and phosphorus for the rest of the body.
Answer:
Types of joints with examples are:
- Immovable joints — Skull bones
- Partially movable joints — Joints between the ribs and breast-bone
- Freely movable joints — Hip joint
- Gliding joint — Ankle bones
- Pivot joint — Joint between axis vertebrae and atlas
- Hinge joint — Elbow
- Ball and socket joint — Shoulder joint
Multiple Choice Type
11 questionsAnswer:
Periosteum
Reason — Periosteum is a complex structure composed of an outer fibrous layer that lends structural integrity and an inner cambium layer that possesses osteogenic potential.
Answer:
P — Pelvic, Q — Pelvic
Reason — Both ischium and pubis are part of the pelvic girdle, not different girdles. The pelvic girdle is made up of three bones: Ilium, Ischium and Pubis.
Progress Check 1
1 questionFill in the blanks
- Our skeleton consists of bones, ............... and ...............
- ............... is the chief component of our skeleton.
- Shapewise the bones can be classified as ............... , ............... , ............... and ............... .
- The central hollow part of the long bones is known as ............... .
- A bone becomes soft and flexible when placed in dilute ............... .
Answer:
- Our skeleton consists of bones, cartilages and ligaments
- Bone is the chief component of our skeleton.
- Shapewise the bones can be classified as long, short, flat and irregular .
- The central hollow part of the long bones is known as bone marrow .
- A bone becomes soft and flexible when placed in dilute hydrochloric acid .
Progress Check 2
1 questionMention if the following statements are true (T) or false (F)
- Humerus of the upper arm is the longest bone.
- Axial skeleton includes shoulder and hip girdles.
- There are 10 vertebrae in the neck.
- There are three kinds of ribs - true, false and floating.
- The shoulder girdle is large and trough-shaped.
Answer:
- False
Corrected statement — Femur in the thigh is the longest and strongest bone in the body. - False
Corrected statement — Axial skeleton includes skull, vertebral column, ribs and sternum. - False
Corrected statement — There are 7 vertebrae in the neck. - True
- False
Corrected statement — The shoulder girdle is flat and triangular.
Progress Check 3
2 questionsMention if the following statements are true (T) or false (F).
- The flexor and extensor muscles of the arm are antagonistic muscles.
- Muscles can contract as well as elongate.
- Muscles are attached to bones by ligaments.
- Cardiac muscle is a voluntary muscle.
- Bending of arm on elbow is an example of first order of lever mechanism.
Answer:
- True
- False
Corrected statement — The muscles can contract but cannot elongate. - False
Corrected statement — Muscles are attached to bones by tendons. - False
Corrected statement — Cardiac muscle is an involuntary muscle. - True
Answer:
Column I (Bones) | Column II (Joint) |
---|---|
Humerus and shoulder girdle | Ball and socket |
Two adjacent vertebrae | Gliding |
Skull and upper end of the backbone | Pivot |
Bones of brain box | Immovable |
Rib and breast bone | Partially movable |
Short Answer Type
6 questionsAnswer:
(a) Skeleton System refers to the internal framework of bones and other connective tissues including cartilage, ligaments, and tendons that provide support, shape, protection, movement and leverage to the human body.
(b) Bone marrow is a soft, spongy tissue found inside the central hollow space or the marrow of some of the long bones where certain types of blood cells including red and white blood cells are formed.
(c) A pad of cartilage intervertebral disc that forms a kind of cushion between two vertebrae is called Gristle.
(d) Joint that allow rotation about an axis is called Pivot joint.
(e) The muscles that cause opposing movements are called antagonistic muscles.
Answer:
The muscles in the body provide the means of all movements. Muscles pull the structures. Each muscle usually has two ends- a fixed end where the muscle originates and a movable end which pulls some other part. The movable end is shorter and thicker and hence pulls the bone at the movable end. Muscles can only contract and relax, they cannot lengthen or elongate.
The movable end is projected out to form a tough structure referred to as a tendon which is attached to the bone. When a muscle is triggered by a nerve, contraction of the muscle occurs and it becomes thicker and shorter which causes the bone to be pulled at the movable end.
Answer:
A structure that has been moved by a muscle cannot return to its original position without the action of another muscle. Such muscles causing opposing movements are called as antagonistic muscles.
Example of antagonistic muscles—
The flexor muscles or the biceps of the upper arm bends the lower arm over the upper arm (flexes). Extension of the lower arm is caused by the extensor muscles or the triceps. Hence these two muscles are antagonistic or work in the opposite direction.
Answer:
(a) Two-third of entire bone mass is made of calcium and phosphorous. It gives strength and hardness to bones. Therefore, when these inorganic substance are lost or the bone is decalcified, they become soft and flexible.
(b) The freely movable joints are well lubricated by synovial fluid to remove friction between the joint surfaces. With age, the production and quality of synovial fluid decreases, leading to less effective lubrication. This coupled with degeneration of cartilage and ligaments causes stiff joints in old age.
(c) In the female skeleton, the pelvis or hip bone is wider and trough-shaped to adapt for accommodating the foetus in the uterus during pregnancy.
(d) Bones are made up of living cells (osteocytes) that are responsible for their growth, maintenance, and repair. They receive blood supply through a network of blood vessels and they produce red and white blood cells within the bone marrow. Therefore, the bones are considered to be a living tissue.
(e) Vertebral column is curved in order to provide correct posture and balance to our body. It's curvature enables us to minimize all the stress on bones and muscles that arises due to activities.
Structuredapplicationskill Type
4 questionsAnswer:
(a) Thoracic vertebra.
(b) Thoracic region of vertebral column.
(c) The labelled guidelines are:
- 1 → Neural spine
- 2 → Neural canal
- 3 → Body of centrum
Abhay observed the given figure of a typical 'movable joint' which allows a considerable degree of movement. This type of joint is located in some places in the human body.

(a) Write the specific name of the freely movable joint shown above.
(b) Mention two locations of this joint in the human body.
(c) Name the fibrous connective tissue which holds the bones in proper position and prevent their dislocation during normal movement.
Answer:
(a) Synovial Joint
(b) The shoulder joint and the knee joint.
(c) Ligament
Very Short Answer Type
7 questionsAnswer:
Part of the skeleton | Location |
---|---|
Transverse process | Neural arches in the vertebra |
Glenoid cavity | Pectoral girdle |
Shoulder-blade | Shoulder girdle |
Acetabulum | Pelvic girdle |
Answer:
(a) Bones, Cartilages and Ligaments
(b) Axial skeleton and Appendicular skeleton
(c) Skull, Vertebral Column, Sternum, Ribs
(d) Cervical, Thoracic, Lumbar, Sacrum, Coccyx
(e) Gliding joint, Pivot joint, Hinge joint, Ball and Socket joint.
Given below is the structure of the forelimb of humans. Read the information below the diagram and fill in the blanks:

Limbs are a part of the appendicular skeleton system. Humans have one pair of forelimbs which are used for many purposes like - holding, writing, eating and grasping, etc. Each arm consists of a total of thirty bones.
The upper arm consists of a single long bone, called (a) ............... . Two long bones are found in the lower arm, (b) ............... found on the side of the thumb and (c) ............... . Forelimbs have eight (d) ............... in the wrist and five (e) ............... in the palm. Remaining fourteen bones are found in the fingers as phalanges.
Answer:
The upper arm consists of a single long bone, called Humerus . Two long bones are found in the lower arm, Radius found on the side of the thumb and Ulna . Forelimbs have eight Carpals in the wrist and five Metacarpals in the palm. Remaining fourteen bones are found in the fingers as phalanges.
Name the following :
(a) A joint which allows movements in all directions.
(b) The first vertebra of the vertebral column.
(c) A large hole at the back of cranium through which the spinal cord emerges out.
(d) The muscles which cause opposing movements.
(e) The fluid found between the two bones of freely movable joints.
Answer:
(a) Ball and socket joint
(b) Atlas
(c) Foramen Magnum
(d) Antagonistic Muscles
(e) Synovial fluid
The first pair indicates the kind of relationship that exists between the first two terms. Rewrite and complete the second pair on a similar basis :
(a) Humerus : Glenoid cavity :: Femur : ...............
(b) Thoracic vertebrae : 12 : ............... : 7
(c) Wrist : Carpals :: Ankle : ...............
(d) Biceps : Flexor :: Triceps : ...............
(e) Brain : Cranium :: Spinal cord : ...............
Answer:
(a) Humerus : Glenoid cavity :: Femur : Articular Cavity
(b) Thoracic vertebrae : 12 : Cervical : 7
(c) Wrist : Carpals :: Ankle : Tarsal
(d) Biceps : Flexor :: Triceps : Extensor
(e) Brain : Cranium :: Spinal cord : Vertebral column
Answer:
(a) Knee cap — Patella
(b) Shoulder blade — Scapula
(c) Collar bone — Clavicle
(d) Breast bone — Sternum
(e) Bones in the palm — Metacarpals