COURSE TITLE: Skeletal Anatomy and Fractures of the Lower Arm, Wrist, and Hand

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1 COURSE DESCRIPTION Few parts of the human body are required to pivot, rotate, abduct, and adduct like the wrist and hand. The intricate and complicated movements of the arm, wrist, and hand exist partly because of the internal skeletal structures found in this area. This continuing education course will review the skeletal anatomy of the lower arm and describe signs/symptoms, types, diagnosis, treatment, and complications of fractures frequently seen in the lower arm. Rev 2.0 February

2 COURSE TITLE: Skeletal Anatomy and Fractures of the Lower Arm, Wrist, and Hand Author: Robert Sturgeon, M.D. Number of Clock Hours Credit: 1.0 Course # P.A.C.E. Approved: _ Yes X_ No OBJECTIVES Upon completion of this continuing education course, the professional should be able to: 1. Identify the long bones of the arm. 2. Identify the bones of the wrist, hand, and fingers. 3. Describe the common fractures of the lower arm bones. 4. Describe symptoms, treatment, and complications of fractures of the lower arm bones. Disclaimer The writers for NCCT continuing education courses attempt to provide factual information based on literature review and current professional practice. However, NCCT does not guarantee that the information contained in the continuing education courses is free from all errors and omissions. 2

3 INTRODUCTION Few parts of the human body are required to pivot, rotate, abduct, and adduct like the wrist and hand. The intricate and complicated movements of the arm, wrist, and hand exist partly because of the internal skeletal structures found in this area. Any pathology in these bones can therefore greatly limit the patients ability to manipulate these structures, making everyday tasks complicated. THE SKELETON The adult human skeleton contains 206 bones of varying sizes. In simplest terms, bone is classified as a type of connective tissue called osseous tissue. It is the framework for the body, bringing strength and structure to the organism. Like other tissues, bone is comprised of living cells requiring a blood supply full of oxygen and nutrients. The interior of the bone, the marrow, functions as a manufacturing center for new blood cells. SKELETAL ANATOMY OF THE LOWER ARM The human arm contains three bones: one long bone in the upper arm and two long bones in the lower arm. Both of the lower arm bones articulate with the bone of the upper arm, the humerus. The two long bones in the lower arm include the radius, which is of smaller diameter at its proximal end and larger at the distal end. The radius is the lateral of these two bones and is often described as following the thumb. The medial bone of the lower arm is the ulna, with its dimensions opposite that of the radius. The ulna is found to be larger at the proximal end with a bony extension designated as the olecranon. The olecranon is a small bony projection palpable as the elbow bone. The ulna is smaller at the distal end and is said to follow the pinkie. (See Figure 1) Figure 1. Anterior view of the lower right arm Radius Humerus Ulna Olecranon Each of these long bones is divided into three sections, a straight shaft called the diaphysis, and two widened ends called the epiphyses. Located near each epiphysis is the epiphyseal plates, or growth plates. These areas allow for lengthening of the bones 3

4 and, therefore, lengthening of the fingers and limbs until fusion occurs, indicating the end of the growth stage. The hand and wrist are comprised of eight small bones called the carpal bones. The carpal bones include the scaphoid, trapezium, trapezoid, capitate, hamate, triquetral, pisiform, and lunate. (See Figure 2) Figure 2. Palmer aspect of the right wrist and hand Capitate Trapezoid Trapezium Scaphoid Distal radius Lunate Hamate Triquetral and Pisiform Distal ulna Extending from the carpal bones are five metacarpal bones, the distal of each creating the proximal articulation of the knuckle. Each finger contains three phalanges, with the exception of the thumb, which contains only two. In each finger, the phalanges are simply designated as the proximal, middle, or distal phalanx. For example, to describe the bone encircled by a wedding ring, we would refer to this as the left fourth proximal phalanx. SKELETAL FRACTURES Although the bones are one of the strongest components found in the human body, they are still susceptible to insult. Because of the daily use of our arms and hands, fractures in this area can compromise the patient s ability to perform everyday tasks. Healing of these fractures is often dependent on several factors including age of the patient, bone density, extent and direction of the fracture, and intact vascular supply. 4

5 SYMPTOMS/SIGNS OF FRACTURES Symptoms/signs of fractures include the following. Not all symptoms/signs are present with every fracture. Inability to use fingers or thumb, or to make a fist Deep dull aching Severe pain that increases during gripping or squeezing Tenderness Bruising Swelling Obvious crookedness or deformity of the bone Stiffness or inability to move wrist, fingers, thumb Coldness or numbness in hand FOOSH FRACTURES The acronym FOOSH stands for Falling On an Out-Stretched Hand, describing the mechanism these fractures occur. The best known of these fractures is the Colles fracture, which is a fracture of the distal radius. Named after the physician who first identified the location and cause of the injury, the Colles fracture demonstrates the importance of a complete patient physical history. The emergency room physician will first suspect a Colles fracture in a patient with swelling and discoloration of the wrist and recent history of a fall. Confirmation with X-rays will then dictate treatment options. The physician may also notice soft tissue and nerve injuries in this area causing the patient to experience paralysis, numbness, and/or tingling in the hand and fingers as well as a decreased range of motion. Another fracture often included as a FOOSH injury is the Monteggia fracture. This injury borrows its name from the very insightful physician who described the fracture even decades before the introduction of the radiograph. The Monteggia fracture is a break of the proximal ulna with a consequent displacement of the proximal radius. This may be the result of a transfer of stress during a fall or a secondary lateral force. More often, however, the Monteggia fracture is a defensive injury, seen when a patient attempts to block the strike of a blunt instrument. This fracture is further classified by the emergency room physician or orthopedic surgeon based on the extent of the displaced radial head. Together with the factors listed previously, healing of the Monteggia fracture will also depend on the secondary injuries associated with the displaced radius. OTHER FRACTURES OF THE LOWER ARM, WRIST, AND HAND Other fractures of the ulna, radius, wrist, and hand are described below. 5

6 Ulna: Another fracture of the ulna is the Hume fracture. This is a fracture of the olecranon with an associated anterior dislocation of the radial head. Radius: The Essex-Lopresti fracture is a fracture of the radial head with simultaneous dislocation of the distal radio-ulnar joint with disruption of the interosseous membrane. The interosseous membrane is a broad and thin plane of fibrous tissue that separates the radius and ulnar bones. Distal radius fractures: In addition to the Colles fracture, there are three other types of distal radius fractures. Galeazzi fracture: Fracture of the radius with the dislocation of the distal radioulnar joint. Smith s fracture: Distal fracture of the radius with ventral displacement of the wrist and hand. Barton s fracture: An intra-articular fracture of the distal radius with dislocation of the radiocarpal joint. Hand and wrist fractures: Following are types of fractures that occur in the wrist and hand. Scaphoid fracture: Fracture of one of the small bones in the wrist, the scaphoid. This bone is located on the thumb side of the wrist. Rolando fracture: An intra-articular fracture through the base of the first metacarpal bone; with this fracture the bone is crushed or splintered. Bennett s fracture: Fracture of the base of the first metacarpal bone which extends into the carpometacarpal. Boxer s fracture: Fracture at the neck of a metacarpal. DIAGNOSIS OF FRACTURES Bone fractures are diagnosed based on the history, physical exam, and X-ray imaging. At times, X-rays may be insufficient to confirm or identify certain fractures. Then CT (computed tomography) or MRI (magnetic resonance imaging) scans are needed. TREATMENT OF FRACTURES If the ends of the bones are not aligned, the physician will adjust them. This manipulation is called closed fracture reduction. Reduction may require general anesthesia or it may require only a sedative and muscle relaxant. In some instances, fractures require open reduction where surgery is performed under general anesthesia and the bones are manipulated together. Sometimes hardware such as plates, screws, rods, and sometimes bone grafts, may be needed to assure the bones are in the proper position for healing. The use of hardware is called internal fixation. 6

7 After fracture reduction and/or open reduction/fixation, the bone must be immobilized to assure the bones successfully grow back together. Immobilization can be a sling, splint, or cast, depending on the type of fracture. After removal of the immobilization device, physical therapy may be needed to assure full functionality of the joint. COMPLICATIONS OF FRACTURES The most common complications of lower arm, wrist, and hand include: Infection, Non-healing fracture, Decreased motion, and Painful hardware. Other complications include ongoing aching or disability, osteoarthritis, and nerve or vessel damage. QUESTIONS Skeletal Anatomy and Fractures of the Lower Arm, Wrist, and Hand # Directions: Before taking this test, read the instructions on how to complete the answer sheets correctly. If taking the test online, log in to your User Account on the NCCT website Select the response that best completes each sentence or answers each question from the information presented in the module. If you are having difficulty answering a question, go to and select Forms/Documents. Then select CE Updates and Revisions to see if course content and/or a test questions have been revised. If you do not have access to the internet, call Customer Service at Which of the following is TRUE regarding bone? a. Bone is completely dead tissue b. Bone is comprised of living cells c. Bone requires no blood d. Bone has only one purpose 2. Which of the bones located in the lower arm is said to follow the thumb? a. Ulna b. Radius c. Humerus d. Hamate 7

8 3. This bone is said to follow the pinkie. a. Radius b. Carpal c. Humerus d. Ulna 4. The olecranon is located on the. a. proximal ulna b. distal ulna c. proximal radius d. distal radius 5. The bone of the upper arm is the. a. ulna b. radius c. humerus d. hamate 6. How many carpal bones are found in the wrist and hand? a. 5 b. 7 c. 8 d The ends of the long bones are called the. a. phalanges b. phalanx c. diaphysis d. epiphyses 8. All of the following are factors to consider in determining the prognosis of a fracture EXCEPT. a. age of the patient b. height of the patient c. bone density d. vascular supply 8

9 9. Another name for the epiphyseal plates is. a. growth plates b. phalanges c. olecranon d. carpals 10. There are metacarpal bones. a. 1 b. 3 c. 5 d The straight shaft of a long bone is called the. a. phalanx b. diaphysis c. radius d. epiphysis 12. Which of the following is the bone of the finger most often used for wearing a wedding band? a. left fourth proximal phalanx b. left fifth distal phalanx c. left first proximal phalanx d. left first middle phalanx 13. There are number of phalanges found in the thumb. a. 2 b. 4 c. 6 d Bone is known as tissue. a. fragile b. dead c. phalanx d. osseous 9

10 15. Fusion of the growth plates indicates the. a. beginning of puberty b. death of the tissue c. end of the growth stage d. fractures are healing 16. The number of bones in the adult human body is. a. 602 b. 206 c. 620 d Which of the following is NOT a symptom/sign of a fracture? a. Atrophy b. Bruising c. Deformity d. Dull ache 18. The fracture of the proximal ulna is the. a. Colles fracture b. lateral fracture c. Monteggia fracture d. pathologic fracture 19. A secondary injury of a Monteggia fracture is. a. hamate displacement b. displacement of the proximal radius c. displacement of the distal radius d. fracture of the distal radius 20. The common FOOSH injuries described in the reading are. a. Monteggia and lunate b. Colles and lunate c. Monteggia and Colles d. lunate and phalanx 21. Which of the following is a type of ulna fracture? a. Bennett s b. Boxer s c. Galeazzi d. Hume 10

11 22. Which of the following is a fracture of one of the small bones in the wrist? a. Barton s b. Rolando c. Scaphoid d. Smith s 23. The use of hardware to assure bones heal together is called. a. Closed reduction b. Internal fixation c. Open reduction d. Revised fixation *End of Test* 11