All of the following are examples of fibrous joint EXCEPT:

 # All of the following are examples of fibrous joint EXCEPT:

A. Symphysis

B. Gomphosis

C. Sutures

D. Syndesmosis

The correct answer is A. Symphysis.

Fibrous joints: Consists mainly of collagenous junctions between bones, Eg: Sutures, Gomphosis and syndesmosis

Cartilaginous joints: Synchondrosis (Primary cartilaginous joint) and Symphysis (Secondary cartilaginous joint)

Symphyses: All symphyses are median and almost confined to the axial skeleton.

Negative growth is a characteristic of:

 # Negative growth is a characteristic of:

A. Testis

B. Brain

C. Mandible

D. Thymus

The correct answer is D Thymus.

According to Scammon’s curves for growth, the growth of the neural tissues is nearly complete by 6 or 7 years of age. General body tissues, including muscle, bone, and viscera, show an S-shaped curve, with a definite slowing of the rate of growth during childhood and an acceleration at puberty. Lymphoid

tissues proliferate far beyond the adult amount in late childhood and then undergo involution at the same time that growth of the genital tissues accelerates rapidly. 

(From Scammon RD. The measurement of the body in childhood. In: Harris JA, ed. The Measurement of Man. Minneapolis: University of Minnesota Press; 1930.)

In sutures, there is proliferation of connective tissue followed by replacement of bone. This is called:

 # In sutures, there is proliferation of connective tissue followed by replacement of bone. This is called:

A. Endochondral bone growth

B. Intramembranous growth

C. Appositional growth

D. Periosteal growth

The correct answer is B. Intramembranous growth.

During the fourth month in utero, there is an ingrowth of blood vascular elements into various points of the chondrocranium (and the other parts of the early cartilaginous skeleton). These areas become centers of ossification, at which cartilage is transformed into bone in the process called endochondral ossification, and islands of bone appear in the sea of surrounding cartilage. The cartilage continues to grow rapidly but is replaced by bone with equal rapidity. The result is that the amount of bone increases

rapidly and the relative (but not the absolute) amount of cartilage decreases. Eventually, the old chondrocranium is represented only by small areas of cartilage interposed between large sections of bone, which assume the characteristic form of the ethmoid, sphenoid, and basioccipital bones. Growth at these cartilaginous connections between the skeletal bones is similar to growth in the limbs.

Not all bones of the adult skeleton were represented in the embryonic cartilaginous model, and it is possible for bone to form by secretion of bone matrix directly within connective tissues, without any intermediate formation of cartilage. Bone formation of this type is called intramembranous ossification. This type of bone formation occurs in the cranial vault and both jaws. 

Ref: Contemporary Orthodontics, William R. Proffit

Epigenetic factors controlling the growth of skeleton are:

 # Epigenetic factors controlling the growth of skeleton are:

A. Genetic factors present within skeleton

B. Genetic factors present outside skeleton

C. Local genetic factors

D. General non-genetic factors

The correct answer is B. Genetic factors present outside the skeleton.

According to "Van Limborgh's" multifactorial theory, growth is under control of genetic and environmental factors. Intrinsic genetic factors are the factors present within the skeleton. Epigenetic factors present outside the skull and manifests their influence in indirect way by intermediary action on associated structures Eg:- Eyes, brain etc.