Skeletal System Practice Questions
20 free Skeletal System practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
The human skeletal system is divided into two main parts. How many bones constitute the axial skeleton and the appendicular skeleton respectively?
- A 100 and 106
- B 80 and 126
- C 126 and 80
- D 206 and 0
Correct answer: 80 and 126
The human skeleton consists of 206 bones in total. The axial skeleton comprises 80 bones distributed along the main axis of the body, while the appendicular skeleton consists of 126 bones belonging to the limbs and girdles.
Which of the following bones is a U-shaped bone present at the base of the buccal cavity and is included in the skull?
- A Malleus
- B Stapes
- C Hyoid bone
- D Ethmoid
Correct answer: Hyoid bone
The hyoid is a single U-shaped bone located at the base of the buccal cavity. It is unique in that it does not articulate directly with any other bone and is counted as part of the skull.
The 'Atlas' is which part of the vertebral column?
- A The last lumbar vertebra
- B The first cervical vertebra
- C The second cervical vertebra
- D The first thoracic vertebra
Correct answer: The first cervical vertebra
The first vertebra of the cervical region is called the atlas. It articulates with the occipital condyles of the skull, allowing for the nodding motion of the head.
How many pairs of 'true ribs' are present in the human body?
- A First 5 pairs
- B First 7 pairs
- C 8th, 9th, and 10th pairs
- D Last 2 pairs
Correct answer: First 7 pairs
The first seven pairs of ribs are called true ribs. They are dorsally attached to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage.
Which ribs are known as 'floating ribs' because they are not connected ventrally to the sternum?
- A 8th and 9th rib pairs
- B 9th and 10th rib pairs
- C 11th and 12th pairs
- D 7th and 8th rib pairs
Correct answer: 11th and 12th pairs
The last two pairs of ribs (11th and 12th) are not connected ventrally to either the sternum or another rib. Because they remain free at their anterior ends, they are termed floating ribs.
The pectoral girdle consists of two bones: the clavicle and the scapula. The scapula is a large triangular flat bone situated in the dorsal part of the thorax between:
- A The second and seventh ribs
- B The first and fifth ribs in the back
- C The third and eighth ribs on the dorsal side
- D The second and fifth ribs posteriorly
Correct answer: The second and seventh ribs
The scapula is located on the dorsal side of the rib cage. It extends from the level of the second rib down to the seventh rib.
The 'Glenoid cavity' is a depression that articulates with the head of the humerus to form the shoulder joint. It is found in the:
- A Pelvic girdle
- B Sternum
- C Clavicle
- D Scapula
Correct answer: Scapula
The scapula has a process called the acromion, and below it is a depression called the glenoid cavity. This cavity serves as the socket for the ball-and-socket joint of the shoulder.
Which of the following is a characteristic of 'Synovial joints'?
- A Bones are fused together by fibrous connective tissue
- B Bones are joined with the help of a cartilaginous pad
- C A fluid-filled synovial cavity separates the articulating surfaces
- D They permit no movement between the joined bones
Correct answer: A fluid-filled synovial cavity separates the articulating surfaces
Synovial joints are characterized by the presence of a fluid-filled synovial cavity between the articulating surfaces of the two bones. This arrangement allows for considerable movement and is found in most limb joints.
The joint between the atlas and axis is an example of a:
- A Hinge joint
- B Pivot joint
- C Gliding joint
- D Saddle joint
Correct answer: Pivot joint
The joint between the first (atlas) and second (axis) cervical vertebrae is a pivot joint. It allows for the rotational movement of the head (the 'no' gesture).
Sutures in the flat skull bones are examples of which type of joint?
- A Fibrous connective tissue joints
- B Cartilaginous joints
- C Synovial joints
- D Ball and socket joints
Correct answer: Fibrous connective tissue joints
Fibrous joints do not allow any movement. In the skull, flat bones are fused end-to-end with the help of dense fibrous connective tissues in the form of sutures.
Which bone is commonly known as the 'Collar bone'?
- A Scapula (shoulder blade)
- B Clavicle
- C Sternum (breastbone)
- D Humerus (upper arm)
Correct answer: Clavicle
Each clavicle is a long slender bone with two curvatures. It is commonly referred to as the collar bone and forms part of the pectoral girdle.
The 'Acetabulum' is a cavity found in the pelvic girdle for the articulation of the:
- A Humerus
- B Femur (thigh bone)
- C Tibia
- D Radius
Correct answer: Femur (thigh bone)
At the point of fusion of the ilium, ischium, and pubis in the pelvic girdle, there is a deep cup-shaped cavity called the acetabulum. This is where the head of the femur (thigh bone) articulates.
Which of the following represents the correct vertebral formula for an adult human?
- A C7 T12 L5 S1 Co1
- B C7 T10 L5 S5 Co4
- C C5 T12 L7 S5 Co4
- D C7 T12 L5 S5 Co4
Correct answer: C7 T12 L5 S1 Co1
The human vertebral column is formed by 26 serially arranged units. While the sacral (S) and coccygeal (Co) vertebrae are fused in adults into single units, the formula is expressed as C7 (cervical), T12 (thoracic), L5 (lumbar), S1 (sacral-fused), and Co1 (coccygeal-fused).
The cup-shaped bone that covers the knee ventrally is called the:
- A Carpal bone
- B Patella
- C Tarsal bone
- D Fibula bone
Correct answer: Patella
The patella, also known as the knee cap, is a sesamoid bone. It covers and protects the knee joint ventrally.
Cartilaginous joints are found:
- A Between adjacent carpal bones of the wrist
- B Between adjacent vertebrae in the spinal column
- C Between the humerus and pectoral girdle
- D Within the skull between flat bones as sutures
Correct answer: Between adjacent vertebrae in the spinal column
In cartilaginous joints, the bones are joined together with the help of cartilages. This type of joint is found between adjacent vertebrae and permits limited movement.
Which of the following is NOT a bone of the hind limb?
- A Tibia
- B Femur
- C Ulna (forearm bone)
- D Fibula
Correct answer: Ulna (forearm bone)
The ulna is a bone of the forelimb (arm), paired with the radius. The tibia, femur, and fibula are all part of the human leg or hind limb.
The total number of ear ossicles in a human being is:
- A 3
- B 4
- C 6
- D 2
Correct answer: 6
Each middle ear contains three tiny bones: the malleus, incus, and stapes. Since humans have two ears, there are a total of six ear ossicles.
The joint between the carpal and metacarpal of the thumb is a:
- A Saddle joint
- B Hinge joint
- C Gliding joint
- D Pivot joint
Correct answer: Saddle joint
The saddle joint is a type of synovial joint. It is specifically found between the trapezium (a carpal bone) and the first metacarpal bone of the thumb.
Which autoimmune disorder affects the neuromuscular junction leading to fatigue, weakening, and paralysis of skeletal muscle?
- A Muscular dystrophy
- B Myasthenia gravis
- C Tetany
- D Arthritis
Correct answer: Myasthenia gravis
Myasthenia gravis is an autoimmune disorder where antibodies destroy the receptors for acetylcholine at the neuromuscular junction. This prevents normal muscle contraction and leads to progressive weakness.
Inflammation of joints due to accumulation of uric acid crystals is called:
- A Osteoporosis
- B Rheumatoid arthritis
- C Gouty arthritis
- D Osteoarthritis
Correct answer: Gouty arthritis
Gout is a specific form of arthritis caused by high levels of uric acid in the blood. The acid forms sharp crystals in the joints, leading to sudden and severe pain and inflammation.