Adult Medical-Surgical Adult Medical-Surgical Nursing Nursing

Musculoskeletal Module: Musculoskeletal Module: Introduction Introduction

The Bones of the Skeleton: The Bones of the Skeleton: ClassificationClassification

206 bones make up the skeleton:206 bones make up the skeleton: Axial skeleton (skull and vertebral column)Axial skeleton (skull and vertebral column) Appendicular skeleton (limbs)Appendicular skeleton (limbs) Bone classification: Bone classification: Long bones (eg. femur)Long bones (eg. femur) Short bones (metacarpals, metatarsals)Short bones (metacarpals, metatarsals) Flat bones (scapula, ileum, facial)Flat bones (scapula, ileum, facial) Irregular bones (vertebrae)Irregular bones (vertebrae)

Joints, Ligaments, TendonsJoints, Ligaments, Tendons

Classification of joints:Classification of joints: Immoveable (skull, sacro-iliac)Immoveable (skull, sacro-iliac) Limited motion (symphysis pubis, Limited motion (symphysis pubis,

vertebral)vertebral) Synovial/ freely moveable (synovial Synovial/ freely moveable (synovial

membrane lining the joint, secreting membrane lining the joint, secreting lubricating synovial fluid for movement)lubricating synovial fluid for movement)

Ligaments: articulate bone with boneLigaments: articulate bone with bone Tendons: attach bone to adjacent muscles Tendons: attach bone to adjacent muscles

Bone TissueBone Tissue

Cancellous (spongy): more open planCancellous (spongy): more open plan Cortical (compact): more close togetherCortical (compact): more close together Lacunae (bone matrix units): arranged in Lacunae (bone matrix units): arranged in

irregular network, “trabeculae”irregular network, “trabeculae” Periosteum: dense fibrous covering of the Periosteum: dense fibrous covering of the

bones (attaches ligaments, tendons)bones (attaches ligaments, tendons) Yellow bone marrow: long bone diaphysisYellow bone marrow: long bone diaphysis Red marrow: flat bones, vertebrae, ribs, Red marrow: flat bones, vertebrae, ribs,

sternum, ileum, epiphyses:haematopoiesissternum, ileum, epiphyses:haematopoiesis

Long BonesLong Bones

The shaft of long bones (diaphysis) is The shaft of long bones (diaphysis) is cortical tissue for weight-bearingcortical tissue for weight-bearing

The ends of long bones (epiphyses) The ends of long bones (epiphyses) are cancellous tissue are cancellous tissue

The ends of long bones are covered The ends of long bones are covered at joints with cartilageat joints with cartilage

The epiphyseal plate: area of growth The epiphyseal plate: area of growth in childhood, puberty. This is calcified in childhood, puberty. This is calcified in adulthood in adulthood

Types of Bone Cells (Osteocytes)Types of Bone Cells (Osteocytes)

Bone is a dynamic tissue constantly Bone is a dynamic tissue constantly reforming and resorbing:reforming and resorbing:

Osteoblasts (bone formation)Osteoblasts (bone formation)

Osteoclasts (bone destruction, Osteoclasts (bone destruction, resorption, remolding)resorption, remolding)

Ossification (Bone Formation): Ossification (Bone Formation): Osteoblasts Osteoblasts

Osteoblasts secrete collagen and Osteoblasts secrete collagen and glycoproteins to form a bone matrixglycoproteins to form a bone matrix

Deposit minerals in the matrix (calcium, Deposit minerals in the matrix (calcium, magnesium, phosphorus, chloride)magnesium, phosphorus, chloride)

Two ways:Two ways: Intramembranous (face and skull) from Intramembranous (face and skull) from

fibrous tissuefibrous tissue Endochondrial (long bones) from cartilage Endochondrial (long bones) from cartilage

Bone Maintenance: Bone Maintenance: Osteoblasts and Osteoclasts Osteoblasts and Osteoclasts

Bone formation by osteoblasts and Bone formation by osteoblasts and resorption by osteoclasts is influenced by:resorption by osteoclasts is influenced by:

Local stress: usage/ weight-bearing aids Local stress: usage/ weight-bearing aids bone formationbone formation

(Immobility leads to increased calcium (Immobility leads to increased calcium resorption from bone and osteoporosis)resorption from bone and osteoporosis)

Vitamin D (intestinal absorption of calcium)Vitamin D (intestinal absorption of calcium) ParathormoneParathormone CalcitoninCalcitonin Blood supply (inadequate → necrosis)Blood supply (inadequate → necrosis)

Stages of Bone Healing following Stages of Bone Healing following Fracture Fracture

Initial trauma → haemorrhage and Initial trauma → haemorrhage and haematomahaematoma

Inflammation/ revascularisationInflammation/ revascularisation

Callus formation and ossificationCallus formation and ossification

RemodellingRemodelling

Bone Healing: Stage 1Bone Healing: Stage 1

Haemorrhage and haematoma from Haemorrhage and haematoma from initial trauma → initial trauma →

Interrupted blood supply causing Interrupted blood supply causing devitalisation of fractured endsdevitalisation of fractured ends

Bone Healing: Stage 2 Bone Healing: Stage 2

Inflammatory process and Inflammatory process and neovascularisation: neovascularisation:

Macrophages promote physiological Macrophages promote physiological debridement (inflammation, swelling, debridement (inflammation, swelling, pain, loss of function for several days) pain, loss of function for several days)

Fibrin strands form within fracture Fibrin strands form within fracture haematoma as network for haematoma as network for revascularisation, fibroblasts, revascularisation, fibroblasts, osteoblasts osteoblasts

Bone Healing: Stage 3Bone Healing: Stage 3

Callus formation:Callus formation: Collagen and fibrous connective tissue Collagen and fibrous connective tissue

(formed by fibroblasts and (formed by fibroblasts and osteoblasts) grow towards each other osteoblasts) grow towards each other from fractured ends (3-4 weeks)from fractured ends (3-4 weeks)

Ossification of callus (3-4 months in Ossification of callus (3-4 months in long bone)long bone)

Encouraged by immobility, disturbed Encouraged by immobility, disturbed by excessive movementby excessive movement

Bone Healing: Stage 4Bone Healing: Stage 4

Remodelling to former structure Remodelling to former structure (months-years)(months-years)

Factors Influencing HealingFactors Influencing Healing

Type of fracture and contact of segmentsType of fracture and contact of segments Blood supplyBlood supply General health, age, nutritional status of General health, age, nutritional status of

the patient: (calcium, vitamin D the patient: (calcium, vitamin D supplement)supplement)

Immobilisation until callus formation with Immobilisation until callus formation with ossification on Xray (serial monitoring)ossification on Xray (serial monitoring)

Surgery: firm approximation/ fixation → Surgery: firm approximation/ fixation → quicker healing by direct growth of bone quicker healing by direct growth of bone from the endosteum (space within bone) from the endosteum (space within bone)