Orthopedic assessment is a fundamental EMS skill that requires a working knowledge of not only the anatomy and physiology of the musculoskeletal system, but elements of peripheral vascular and neurological assessment as well. While the focus of EMT training in orthopedic injuries in recent years, particularly at the EMT-B level, can fairly be described as “splint ’em all and let the radiologists sort ’em out,” a thorough and comprehensive orthopedic assessment is within the capabilities of most EMS providers. While the musculoskeletal system includes all 206 bones of the human body and their attached muscles, tendons and ligaments, this article will focus on assessment of extremity trauma only.
A 16-year-old skateboarder injures himself at a local office park. His companions call 9-1-1, and EMTs find the young man sitting on a concrete bench complaining of left ankle pain. He gestures to a flight of steps 20 feet away, and says he was attempting to ride its metal handrail to the next flight and landed awkwardly, twisting his left ankle. He is wearing a helmet and knee and elbow pads, and denies loss of consciousness or any other injuries. He says he was able to walk to the bench, where he is now sitting without assistance, but that the ankle “really tightened up on him,” and he now reports considerable pain.
Vital signs are: heart rate 124 and regular, strong radial pulses; respirations 18 per minute, non-labored; blood pressure 128/76; SpO2 98% on room air. Examination of the injured joint reveals mild swelling over the lateral surface of the ankle and intact dorsalis pedis pulses. Palpation of the distal ends of the tibia and fibula, including medial and lateral malleoli, reveal no significant point tenderness, and the patient only complains of “soreness” rated at 5 on a 10-point scale.
Anatomy and Physiology
The division of the musculoskeletal system responsible for locomotion and manipulation of objects is known as the appendicular skeleton and comprises the 126 bones of the arms, legs, and pectoral and pelvic girdles. While the bones of the axial skeleton protect the central nervous system and vital organs and are thus quite robust, the bones of the appendicular skeleton protect less-vital structures and, often being subjected to greater mechanical forces, are more likely to fracture. The clavicle is the single most commonly fractured bone in the human body; as a group, the eight bones of the wrist make up the most commonly fractured area in adults under age 75. In adults 75 and over, hip fractures are most common.
Bones are attached to one another by means of connective tissue known as cartilage. Muscles attach to bones by means of fibrous tendons. Skeletal muscles consist of three basic parts: the fibrous tendon that attaches to the bone to which the muscle is anchored is the origin; the meaty part of the muscle is the belly; and the fibrous tendon that attaches to the bone upon which the muscle acts is the insertion.
In common terminology, injuries to muscles are known as strains, injuries to joints are known as sprains, and injuries to bones are known as fractures. While a thorough assessment may be helpful in differentiating the three, treatment in the field is the same, because proper stabilization of musculosketal injuries is essential to reducing pain and inflammation.
Proper assessment of orthopedic injuries focuses on three main findings: pain, swelling and instability. Gently palpate the area in question, feeling for point tenderness, swelling or discernable deformities. It is not necessary to check for instability in the field, but this is often done in the emergency department.
Often the instability will be readily apparent to visual inspection, and manipulation of the limb may yield a finding of crepitus, the characteristic sound or feel of jagged bone ends rubbing together.