Chapter 52

Assessment of the Musculoskeletal System

2

Skeletal System

Bone types Bone structure Bone function Bone growth and

metabolism affected by calcium and phosphorous, calcitonin, vitamin D, parathyroid hormone, growth hormone, glucocorticoids, estrogens and androgens, thyroxine, and insulin

3

Liver Mj

Vitamin D Mj

Kidney Mj

Intestine Mj

Parathyroid MjGland Mj

Bone Mj

Serum MjCalcium Mj

+ Mj- Mj

+ = Simulation Mj

- Mj = Inhibition Mj

Kidneys release hormone Mjto activate Vitamin D Mj

Kidneys release hormone Mjto activate Vitamin D Mj

Low Ca++ Mj

Increase Mjabsorption of Mj

Ca++ Mj

Bone Mjresorption of Mj

Ca++ Mj

High Ca++ Mj

4

Figure 36-1.   Bone cells. A, Osteoblasts are responsible for the production of collagenous

and noncollagenous proteins that compose osteoid. Active osteoblasts are lined up on the

osteoid. Note the eccentrically located nuclei. B, Scanning electron micrograph showing an

osteocyte within a lacuna. The cell is surrounded by collagen fibers and mineralized bone. C,

Osteoclasts actively resorb mineralized tissue. The scalloped surface in which the

multinucleated osteoclasts rest is termed Howship lacuna.

A and C from Damjanov I, Linder J, editors: Anderson's pathology, ed 10, St Louis, 1996,

Mosby; B from Erlandsen S, Magney J: Color atlas of histology, St Louis, 1992, Mosby.

5

Figure 36-2.   Cross section of bone.

Longitudinal section of long bone (tibia)

showing spongy (cancellous) and

compact bone.

From Thibodeau GA, Patton KT: Anatomy

& physiology, ed 5, St Louis, 2003,

Mosby.

6

Figure 36-3A, B.   Structure of compact and cancellous

bone. A, Longitudinal section of a long bone showing both

cancellous and compact bone. B, A magnified view of

compact bone.

From Thibodeau GA, Patton KT: Anatomy & physiology, ed 5,

St Louis, 2003, Mosby.

Figure 36-3C.   Structure of compact and cancellous

bone. C, Section of a flat bone. Outer layers of

compact bone surround cancellous bone. Fine

structure of compact and cancellous bone is shown to

the right.

From Thibodeau GA, Patton KT: Anatomy &

physiology, ed 5, St Louis, 2003, Mosby.

7

Figure 36-5.   Bone remodeling. In the remodeling

sequence, bone sections are removed by bone-resorbing

cells (osteoclasts) and replaced with a new section laid

down by bone-forming cells (osteoblasts). The cells work

in response to signals generated in that environment. The

first phase of remodeling is mediated only by the

multinucleated osteoclastic cells. They are activated,

scoop out bone, A, and resorb it; then the work of the

osteoblasts begins, B. They form new bone that replaces

bone removed by the resorption process, C. The

sequence takes 4 to 5 months. D, Micrograph of active

bone remodeling seen in the settings of primary or

secondary hyperparathyroidism. Note the active

osteoblasts surmounted on red-stained osteoid. Marrow

fibrosis is present.

A to C from Mundy GR: Bone remodeling and its disorders, St Louis, 1995, Mosby;

D from Damjanov I, Linder J, editors: Anderson's pathology, ed 10, St Louis, 1996,

Mosby.

8

Joints Types include synarthrodial, Types include synarthrodial,

amphiarthrodial, diarthrodialamphiarthrodial, diarthrodial Structure and function of the diarthrodial

or synovial joint

Synarthrosis =

Immovable

Amphiarthrosis =

Slightly movable

Diathrosis = freely

moveable

9

Bone Types

Subtyped by anatomic structure:• Ball-and-socket• Hinge• Condylar• Biaxial• Pivot

10

Figure 36-14.   Myofibrils. Myofibrils of a skeletal muscle fiber

(cells) and overall organization of skeletal muscle.

From Thibodeau GA, Patton KT: Anatomy & physiology, ed 5, St

Louis, 2003, Mosby.

11

Muscular System

Structure Function Supporting structures Musculoskeletal

changes associated with aging

Cultural considerations

12

Properties of the three different muscle types

  Skeletal Cardiac Smooth

Histologic appearance

Cross-striated, multinucleated muscle fibers

Cross-striated, single nucleated muscle fibers containing intercalated disc

Nonstriated, spindle cells with a single nucleus

Site skeletal coverings muscular component of the heart

found in wall of blood vessel, airways glands, and walls of hollow organs

control

voluntary/reflex: contolled by somatic nervous system

self-regulated by pacemaker cells; heart rate can be altered by autonomic nervous system

Involuntary control or regulation by inhrent contraction initiation (visceral smooth muscle)

nature of the contraction

rapid contraction and relaxation

spontaneous and thythmic contraction slow and sustained contraction

Function

voluntary movement of skeletal and posture maintenance

contraction pump blood around the body

related to the structure (e.g. regulation of blood wessel diameter, hair erection)

Source:Walji, A. (2006). Crash Course: Musculoskeletal system. Mosby

13

Types of Muscle tissue

This slide contains a section of cardiac muscle, which is striated like

skeletal muscle but well adapted for involuntary, rhythmic contractions

like smooth muscle. Although the myofibrils are transversely striated,

each cell has only one centrally located nucleus.  Note the faintly stained

transverse bands called intercalated disks (indicated by the blue arrows)

that mark the boundaries between the ends of the cells.  These specialized

junctional zones are unique to cardiac muscle.

The nuclei are centrally located, there are no

striations, and the muscle fibers do not branch.

Another good clue that this is smooth muscle is

that when smooth muscle contracts, the nuclei

take on a corkscrew appearance.

14

Excitement

Coupling

Depoloraization

Contraction

Repolorization

Resting Potential

15

Physiology of skeletal muscle contraction

Excitation• Change in action potential

• Changes the permeability of the cell to allow movement of Na++ and K+

Coupling• Migration of Ca • Coupling with Ca and muscle proteins

Contraction• Binding of muscle proteins (actin + myosin) causing a

shortening of the muscle fibers = contraction Relaxation

• Ca is absorbed by sarcoplasimc teticulum (muscle protein) causing the muscle to lengthen.

Muscle metabolism• Na++ / K+ ATPase pump• Balance between intracellular and extracellular electrolytes

(Na++, K+, Cl-)• ATPase (protein that results in energy production)

16

Assessments

Family history and genetic risk Personal history Dietary history Socioeconomic status and ability to

afford food Current health problems including

obesity

17

Physical Assessment

General inspection Posture Abnormality in gait such as

antalgic gait or lurch Goniometer, which provides a

measure of ROM Head and neck: evaluate the

temporomandibular joints(Continued)

18

Physical Assessment (Continued)

Spine: lordosis, scoliosis Upper extremities Lower extremities

LORDOSIS SCOLIOSIS KYPHOSIS

SPONSCOLIOSIS

LORDOSIS

19

Diagnostic Assessment

Laboratory tests: serum calcium and phosphorus, alkaline phosphatase, serum muscle enzymes

Radiographic examinations: standard radiography, tomography and xeroradiography, myelography, arthrography, and CT

Other diagnostic tests: bone and muscle biopsy

Normal Levels (Chart 52-3, p. 1148)Ca2 : 9.0-10.5 mg/dLPhosphorus: 3.0 -4.5 mg/dLAlkaline phosphatase

•30-120 Units/LSerum Muscle Enzymes

•Creatine Kinase: (CK)•Men = 55 -170 units/L•Women = 30-135 untis/L

•Aspartate aminotrnasferase (AST)•0-35 IU/L

•Aldolase (ALD)•3.0-8.2 units/Dl

•Lactic dehyrogenase (LDH)•100-190 units/L

20

Electromyography

EMG aids in the diagnosis of neuromuscular, lower motor neuron, and peripheral nerve disorders; usually with nerve conduction studies.

Low electrical currents are passed through flat electrodes placed along the nerve.

If needles are used, inspect needle sites for hematoma formation.

21

22

Arthroscopy

Fiberoptic tube is inserted into a joint for direct visualization.

Client must be able to flex the knee; exercises are prescribed for ROM.

Evaluate the neurovascular status of the affected limb frequently.

Analgesics are prescribed. Monitor for complications.

23

24

Other Tests

Bone scan Gallium or thallium scan Magnetic resonance imaging Ultrasonography

25

26

27

Musculoskeletal Changes Associated with Aging

Aging Bones• Loss of bone tissue: bones less stiff, less strong, and more brittle• Bone remodeling takes longer• Stem cells in bone marrow perform less efficiently• Postural changes• Increase risk of fractures (Osteoporosis

Aging Joints• Cartilage becomes more rigid, fragile, and susceptible to

fibrillation, water decreases in cartilage Synovial Joint cartilage becomes less elastic and compressible

• Osteorarthritis Aging Muscle

• Muscle fiber composition change• Changes in the muscle proteins:

Changes results in decreased coordination, muscle strength loss, gait changes, predisposition to falls with injury (see chart 53-1)