In order to properly evaluate a Colles’ fracture a set of x-rays will be taken to determine the type of fracture and the degree of displacement present. Other studies have shown as much as a 60% increase in risk for individuals that are more active especially outdoors due to the greater risk of tripping and falling and also a delayed onset of menarche after the age of 15. 2,3,7 One reason for the increase rate of fractures in women is due to decreased bone mass density which has shown to be a high predictor in increasing the risk of Colles’ fracture up to 50% compared to individuals with a normal bone mass density. Previous studies have shown that women over 65 years are at the highest risk for suffering Colles’ fractures over 7 times more than men as well as children between 6 and 10 years of age. 6 The rate of distal radius fracture is approximately 75% of all forearm fractures. Due to the intense forces traveling through the wrist there is high association in not only a fracture at the distal radius but an avulsion fracture of the ulnar styloid process as the force travels through the TFCC. Specifically, a Colles’ fracture occurs when the wrist is in 40 to 90 degrees of extension when the hand makes contact with a hard surface causing the dorsal displacement of the radius.
The deep layer muscles of the posterior compartment are supinator, abductor pollicis longus, extensor pollicis brevis, extensor pollicis brevis, extensor indicis. The superficial layer of the posterior compartment is composed of brachioradialis, extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, and anconeus.
The posterior compartment is similar to the anterior compartment except it is lacking an intermediate compartment. The intermediate layer is made up of the flexor digitorum superficialis while the deep layer is the flexor digitorum profundus, flexor pollicis longus, and pronator quadratus. The superficial layer is comprised of the flexor carpi ulnaris, palmaris longus, flexor carpi radialis, and pronator teres. The anterior compartment of the forearm is divided into 3 layers: superficial, intermediate, and deep. Many of the muscles in the forearm function to control wrist motion but also movement of the digits. The other sets of joints that complete the wrist and hand complex are the intercarpal, midcarpal, carpometacarpal, intermetacarpal, metacarpophalangeal, and interphalangeal joints. Without the TFCC the radius would transmit 95% of the forces from the hand whereas, with the TFCC the radius experiences only 60% of the force and the ulna bears the other 40%. The major function of the TFCC is to add stability at the wrist and allow forces to be dissipated between the radius and the ulna. The TFCC traverses between the ulnar aspect of the distal radius and the base of the ulnar styloid process contacting the triquetrum, hamate, and base of the 5th metacarpal. Unlike the radius, the ulna does not articulate with the carpal bones instead articulating with a cartilaginous disc known as the triangular fibrocartilage complex (TFCC) which lies between each. Uniquely, the radius is angled toward the ulnar aspect of the body at an angle between 15-20 o. The distal radioulnar joint is occurs where the radius articulates with both the scaphoid and the lunate. The proximal row of carpals consists of the scaphoid, lunate, triquetrum, and pisiform bones where the distal row is made up of the articulations between trapezium, trapezoid, capitate, and hamate. The carpals are arranged in two distinct rows, a proximal and a distal row. The next major joint is the radiocarpal joint commonly referred to as the wrist where is radius contacts the carpal bones. The distal radioulnar joint has both a proximal and distal component and is found between the articulation of the distal radius and ulna allowing for pronation and supination. The interosseous membrane also provides an attachment site for many anterior and posterior muscles. This membrane spans the medial border of the radius to the lateral border of the ulna holding the bones together without restricting any movement specifically pronation and supination. The radius and ulnar form the bony structure of the forearm and are held together by an interosseous membrane. The main bones in the wrist and hand include: radius, ulna, carpals, metacarpals, and phalanges. The wrist and hand complex is an intricate system of many bones, joints, muscles, ligaments, and the neurovascular system that supplies the region.
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