BONES OF THE FOREARM- ULNA

Pivot joint

The atlantoaxial joint is a joint in the upper part of the neck between the first and second cervical vertebrae; the atlas and axis. It is a pivot joint. 

The radius and the ulna are connected at their upper and lower extremities by synovial joints, termed the superior and inferior radio-ulnar joints. The superior radioulnar joint is a pivot-joint between the circumference of the head of the radius and the osseofibrous ring formed by the radial notch of the ulna and the annular ligament. The inferior radioulnar joint is a pivot-joint formed between the head of the ulna and the ulnar notch of the lower end of the radius;

Joints: A joint or place of articulation is formed where 2 or more bones come in close contact in the body and are attached by ligaments or cartilage

Classification of joints: The articulations are divided into three classes: synarthroses or immovable, amphiarthroses or slightly movable, and diarthrosis or freely movable.

B i.e. Lateral condyle

Ans: B i.e. Both ulnar fracture and head of radius is displaced anteriorly

* This is a fracture of the upper-third of the ulna with dislocation of the head of the radius. It is caused by a fall on an out­stretched hand. It may also result from a direct blow on the back of the upper forearm.

  – These fall into two main categories depending upon the angulation of the ulna fracture – extension and flexion type. The extension type, is the commoner of the two, where the ulna fracture angulates anteriorly (extends) and the radial head dislocates anteriorly. The flexion type is where the ulna fracture angulates posteriorly (flexes) and the radial head dislocates posteriorly.

C i.e. Only plates

• Fracture both bones of forearm may result in severe loss of function unless adequately treated by restoring normal relationship of radius and ulnaQ. The relationship of radio humeral, ulno humeral, proximal radioulnar, radio carpal and distal radioulnar joints and the interosseous space must be anatomical or some functional impairment will occur.
• In addition to regaining length, and axial alignment (by reducing angulation) , achieving normal rotational alignment is necessary if a good, range of pronation & supination is to be restored.
• Forearm rotation is vulnerable to any malalignment of radius and accurate rotational as well as axial reduction is necessary
• Malunion and nonunion occur more frequently because of the difficulty in reducing and maintaing the reduction of two parallel bones in the presence of pronating and supinating muscles that have angulating and rotational influences
• Because of these factors OR&IF (by plating)Q of displaced diaphyseal fractures in adult is accepted as best method of treatment.

Ans. A i.e. Fracture scaphoid

Scaphoid

• Only carpal bone to undergo fracture as well as AVN: Scaphoid
• Fragment undergoing necrosis in fracture scaphoid: Proximal
• MC site of fracture scaphoid: Waist

Ans. 16 years

Ans. is ‘b’ i.e., Trochlear notch

• The olecranon is a strong process of the proximal and posterior ulna that, together with the coronoid process, forms the trochlear notch. This notch holds the trochlea of the distal humerus forming the ulnohumeral articulation, the hinge joint of the elbow.

The fracture shown in the picture above represents Monteggia fracture.

 In Monteggia fracture, both ulnar fracture and head of radius is displaced anteriorly.