Comparative Skeletal System — MCQs
From which branchial arches does the hyoid bone develop?
Branchial arches give rise to various structures in the head and neck region. From which arch does the maxillary artery develop?
Which of the following types of joint is found in the small joints of the vertebrae?
Most common muscle involved in Volkmann's ischemic contracture is
What type of joint is formed by the costal cartilages of the 8th and 9th ribs?
A skull was recovered from a forest. According to inquest papers, a girl had gone missing 15 days back. The skull was sent to the forensic research lab. Which of the following would identify it as a female skull? 1. Large frontal and parietal eminence 2. Heavy cheek bones 3. Smooth glabella 4. Square orbits 5. Narrow mastoid
Arthritis mutilans is seen in?
Malleus and incus are derived from?
Which of the following movements is least permitted in the lumbar region of the vertebral column?
What differences can be seen in skulls of male and female before puberty?
Comparative Skeletal System Indian Medical PG Practice Questions and MCQs
Question 1: From which branchial arches does the hyoid bone develop?
- A. Second and third branchial arches (Correct Answer)
- B. Third and fourth branchial arches
- C. First and third branchial arches
- D. First and second branchial arches
Explanation: ***Second and third branchial arches*** - The **lesser horns** and **upper part of the body** of the hyoid bone originate from the **second branchial arch**. - The **greater horns** and **lower part of the body** develop from the **third branchial arch**. *Third and fourth branchial arches* - While the *third branchial arch* contributes to the hyoid, the *fourth branchial arch* forms structures of the larynx, such as the **thyroid cartilage**, not the hyoid. - Therefore, this combination does not fully account for the hyoid's development. *First and third branchial arches* - The *first branchial arch* forms the **malleus, incus**, and parts of the mandible, maxilla, and zygoma, which are distinct from the hyoid. - Although the *third branchial arch* contributes to the hyoid, the first arch does not. *First and second branchial arches* - The *first branchial arch* is primarily involved in forming the bones of the **mandible and maxilla** and ossicles of the ear. - While the *second branchial arch* contributes significantly to the hyoid, this option omits the crucial contribution from the *third branchial arch*.
Question 2: Branchial arches give rise to various structures in the head and neck region. From which arch does the maxillary artery develop?
- A. 3rd arch
- B. 4th arch
- C. 1st arch (Correct Answer)
- D. 5th arch
Explanation: ***Correct Option: 1st arch*** - The **maxillary artery** develops from the **first pharyngeal arch artery** (mandibular arch). - The first arch artery is the arterial component of the mandibular arch and gives rise to the **maxillary artery**, which supplies the maxillofacial region. - This is consistent with the first arch's role in forming structures of the **maxilla and mandible**. *Incorrect Option: 3rd arch* - The third arch artery contributes to the **common carotid artery** and the **internal carotid artery**. - It is not involved in the formation of the maxillary artery. *Incorrect Option: 4th arch* - The fourth arch artery forms part of the **aortic arch** on the left and the **subclavian artery** on the right. - Its contributions are primarily to the systemic great vessels, not the maxillofacial vasculature. *Incorrect Option: 5th arch* - The fifth pharyngeal arch is often **rudimentary** or **absent** in humans, and when present, it regresses entirely. - It does not contribute to any significant adult arterial structures.
Question 3: Which of the following types of joint is found in the small joints of the vertebrae?
- A. Hinge joint
- B. Saddle joint
- C. Gliding joint (Correct Answer)
- D. Condyloid joint
Explanation: ***Gliding joint*** - The **facet joints** (zygapophyseal joints) between the vertebrae are classified as synovial **gliding joints**, allowing limited, flat-surface movements. - These joints enable the spine to **flex, extend, and rotate** by allowing the vertebral bodies to slide past one another. *Hinge joint* - **Hinge joints** allow movement primarily in one plane, like the **elbow** or **knee**, and are characterized by a cylindrical bone end fitting into a trough-shaped surface. - This type of joint would not permit the complex range of motion required in the vertebral column. *Saddle joint* - **Saddle joints** allow movements similar to a horse saddle, providing a wide range of motion but preventing rotation, as seen in the **thumb's carpometacarpal joint**. - Their specific bone congruence is not found in the vertebral joints. *Condyloid joint* - **Condyloid joints** allow movement in two planes (flexion/extension, adduction/abduction, circumduction) but not full rotation, such as the **radiocarpal joint** of the wrist. - The vertebrae do not articulate in a convex-into-concave manner typical of condyloid joints.
Question 4: Most common muscle involved in Volkmann's ischemic contracture is
- A. Flexor-indicis
- B. Flexor pollicis longus
- C. Abductor pollicis
- D. Flexor-digitorum profundus (Correct Answer)
Explanation: ***Flexor-digitorum profundus*** - The **flexor digitorum profundus (FDP)** is the most commonly involved muscle in Volkmann's ischemic contracture due to its deep location and long course, making it highly susceptible to **ischemia** in the forearm compartment. - Its involvement leads to the characteristic **flexion deformities** of the digits at the interphalangeal joints. *Flexor-indicis* - The **flexor indicis** is not a formally recognized muscle, and while finger flexors are involved, the FDP is explicitly the most common. - This option likely refers to muscles that flex the index finger, but the primary pathology affects the entire FDP muscle group. *Flexor pollicis longus* - While the **flexor pollicis longus (FPL)** can be affected in Volkmann's contracture, it is not the *most common* muscle involved compared to the FDP. - The FPL is responsible for **thumb flexion**, and its involvement would manifest primarily in thumb deformities. *Abductor pollicis* - The **abductor pollicis** muscles (e.g., abductor pollicis longus, abductor pollicis brevis) are involved in **thumb abduction**, not flexion, and are typically less affected by the ischemia that causes Volkmann's contracture. - These muscles are generally located in different compartments or are more superficial, offering them some protection.
Question 5: What type of joint is formed by the costal cartilages of the 8th and 9th ribs?
- A. Synovial joint
- B. Costochondral joint
- C. Costovertebral joint
- D. Interchondral joint (Correct Answer)
Explanation: ***Interchondral joint*** - The **8th, 9th, and 10th costal cartilages** articulate with the cartilage immediately above them, forming **interchondral joints**. - These are typically **synovial plane joints** that allow for some gliding movement during respiration. *Costochondral joint* - This joint type is formed between the **rib bone** and its respective **costal cartilage**. - These are **primary cartilaginous joints (synchondroses)** and are generally immobile. *Synovial joint* - While interchondral joints are a type of synovial joint, this option is too general and does not specify the unique anatomical arrangement. - Synovial joints are characterized by a **joint capsule**, **synovial fluid**, and **articular cartilage**, allowing for free movement. *Costovertebral joint* - This joint is formed between the **head of a rib** and the **bodies of two adjacent vertebrae** and their intervertebral disc. - It is a **synovial plane joint** crucial for respiratory mechanics, but not related to the articulation of costal cartilages with each other.
Question 6: A skull was recovered from a forest. According to inquest papers, a girl had gone missing 15 days back. The skull was sent to the forensic research lab. Which of the following would identify it as a female skull? 1. Large frontal and parietal eminence 2. Heavy cheek bones 3. Smooth glabella 4. Square orbits 5. Narrow mastoid
- A. 1,3 and 5 (Correct Answer)
- B. 2,3 and 4
- C. 1 and 4 only
- D. 3,4 and 5
Explanation: ***1,3 and 5*** - **Large frontal and parietal eminences** are characteristic features of a **female skull**, indicating a more rounded appearance. - A **smooth glabella** (the area between the eyebrows) is typical for females, as males tend to have a more prominent brow ridge. A **narrow mastoid** process is also characteristic in females. *2,3 and 4* - **Heavy cheekbones** and **square orbits** are features more commonly associated with a **male skull**. - While a **smooth glabella** is a female characteristic, its combination with male features makes this option incorrect. *1 and 4 only* - **Large frontal eminences** are indicative of a female skull, but **square orbits** are a feature of a **male skull**. - This combination presents conflicting information regarding gender identification. *3,4 and 5* - A **smooth glabella** and **narrow mastoid** are features of a **female skull**. - However, **square orbits** are typically found in **male skulls**, rendering this option incorrect.
Question 7: Arthritis mutilans is seen in?
- A. Rheumatoid arthritis
- B. Spondyloarthropathy
- C. Reactive arthritis
- D. Psoriatic arthropathy (Correct Answer)
Explanation: ***Psoriatic arthropathy*** - **Arthritis mutilans** is a severe, destructive form of psoriatic arthritis characterized by marked **osteolysis** and telescoping deformities of the digits [1]. - This condition is almost exclusively associated with **psoriatic arthritis**, representing its most aggressive subtype [1]. *Rheumatoid arthritis* - While rheumatoid arthritis can cause severe joint destruction, it typically manifests as **erosive arthritis** with joint deformities like **swan-neck** and **boutonnière deformities**, but not true arthritis mutilans [3]. - The pattern of bone destruction (osteolysis) seen in arthritis mutilans is distinct from the erosions in rheumatoid arthritis. *Spondyloarthropathy* - This is a broad category that includes diseases like ankylosing spondylitis and reactive arthritis, which primarily affect the **axial skeleton** and entheses. - While some spondyloarthropathies can cause peripheral joint involvement, they generally do not lead to the extreme osteolysis and telescoping digits characteristic of arthritis mutilans. *Reactive arthritis* - Reactive arthritis is an aseptic inflammatory arthritis that often follows infection, characterized by **oligoarthritis**, dactylitis, and enthesitis [2]. - This condition does not typically cause the severe, mutilating joint destruction seen in arthritis mutilans.
Question 8: Malleus and incus are derived from?
- A. 3rd Arch
- B. 4th Arch
- C. 1st Arch (Correct Answer)
- D. 2nd Arch
Explanation: ***1st Arch*** - The **malleus** and **incus** are ossicles of the middle ear that develop from the **cartilage of the first pharyngeal arch** (Meckel's cartilage). - This arch also contributes to the development of the **mandible** and muscles of mastication. *2nd Arch* - The **second pharyngeal arch** (Reichert's cartilage) gives rise to the **stapes**, a different ossicle of the middle ear. - It also forms the **styloid process**, **lesser cornu of the hyoid**, and muscles of facial expression. *3rd Arch* - The **third pharyngeal arch** contributes to the development of the **greater cornu of the hyoid bone** and the **stylopharyngeus muscle**. - It plays no direct role in the formation of the malleus or incus. *4th Arch* - The **fourth pharyngeal arch** contributes to the formation of the **thyroid cartilage**, **cricoid cartilage**, and muscles of the pharynx and larynx. - It is not involved in the development of the ear ossicles.
Question 9: Which of the following movements is least permitted in the lumbar region of the vertebral column?
- A. Flexion
- B. Extension
- C. Lateral flexion
- D. Rotation (Correct Answer)
Explanation: ***Rotation*** - The **lumbar spine permits the LEAST rotation** of all movements (~5° total rotation), making this the correct answer. - The PRIMARY limiting factor is the **sagittal (near-vertical) orientation of the lumbar facet joints**, which are oriented in the coronal plane and face medially/laterally. - This facet orientation creates a **mechanical block to rotational movement**, acting like interlocking barriers. - The thick **intervertebral discs** in the lumbar region also resist torsional forces, further limiting rotation. *Flexion* - The lumbar region permits **excellent flexion** (forward bending), with approximately 50-60° of range. - The **large, wedge-shaped intervertebral discs** allow substantial anterior compression and movement. - This is one of the primary movements of the lumbar spine. *Extension* - **Extension** (backward bending) is moderately permitted in the lumbar spine, with approximately 15-20° of range. - Eventually limited by contact between **spinous processes** and the posterior ligamentous structures. - Still considerably more movement than rotation. *Lateral flexion* - **Lateral flexion** (sideways bending) is well permitted, with approximately 20° of movement to each side. - The structure of the vertebral bodies and **compressible intervertebral discs** allows good range of motion in the coronal plane. - Significantly more mobile than rotation.
Question 10: What differences can be seen in skulls of male and female before puberty?
- A. Difference in capacity
- B. None of the options (Correct Answer)
- C. Difference in size
- D. Difference in weight
Explanation: ***None of the options*** - Before **puberty**, the **skulls** of males and females are largely indistinguishable in terms of differentiating characteristics. - **Sex-specific differences** in skull morphology, such as pronounced brow ridges or larger mastoid processes, primarily develop during and after puberty due to hormonal influences. *Difference in capacity* - While adult males typically have slightly larger cranial capacities than adult females, this difference is not significant or reliably identifiable **before puberty**. - **Cranial capacity** continues to develop throughout childhood, and pre-pubertal variations are more reflective of individual growth rather than sex. *Difference in size* - **Skull size** differences between sexes become noticeable mostly **after puberty** due to the impact of sex hormones on bone growth. - In children, skull size varies greatly among individuals, with no consistent or significant difference based on sex that allows for reliable differentiation. *Difference in weight* - **Skull weight** is directly correlated with its size and bone density. - Similar to size and capacity, significant and consistent differences in skull weight between males and females appear **post-puberty**, not before.
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