Introduction to musculoskeletal system
dr. Irwan
Content:Vignette ►Bone
Learning objectives ►Functions of bones ► Bone structure ►Bone Development ►Types of bones ►
Muscle ►
A 45-year-old man with:– Experience sciatica– Continuous pain at thigh– Numbness in the toe. Dermatome– Symptom are experienced only on left side of the
body– Characteristic posture
Using your knowledge of anatomy, make the diagnosis.
Vignette
After studying this section you should be able to:• list five types of bones and give an example of each• outline the general structure of a long bone• describe the structure of compact and cancellous bone
tissue• describe the development of bone• state the functions of bones.
Learning objectives
• Support - framework that supports body and cradles its soft organs
• Protection - for delicate organs, heart, lungs, brain
• Movement - bones act as levers for muscles
• Mineral storage - calcium & phosphate
• Blood cell formation - hematopoiesis
Function of the Skeletal System
• There are 206 bones in the adult human body. • The largest bones in the adult human body is
the femur.• There are about 300 bones in a newborn baby
but they grow together to make 206 when an adult.
Facts
• One function of spongy bone is to produce red blood cells.
• The smooth, flexible layer of tissue covering the ends of bones is called cartilage.
• The hard, strong layer of bone is called compact bone.
• Minerals make bones strong.• The human skeleton has 206 bones of various
sizes and shapes.
The Facts About Bones.
• Bone enclosed in periosteum, which is continuouswith tendons and ligamentsblood vessels in periosteum Fig. 1
• Epiphysis- endsspongy bone contains red marrowcompact bone, articular cartilage
• Diaphysis- middlecompact bonemedullary cavity- contains yellow marrow (fat)lined with endosteum (squamous epithelium)
Bone Structure
• Compact boneosteocytes within lacunaearranged in concentric circles called lamellae
• This surround a central canal; complex is called
Haversian system Fig. 2 • Canaliculi connect osteocytes to central canal and
to each other
• skeleton is mostly cartilaginous Fig. 3• Cartilage cells and then osteoblasts start to
deposit minerals• Cartilaginous disk (epiphyseal disk) remains
in epiphysis• Cells eventually stop dividing
Prenatal development
• Initial skeleton of cartilage in infants Fig. 3• Replaced with bone by osteoblasts• More than 300 bones at birth – fuse to 206• Always growing and breaking down
– Osteoblasts – form new bone cells– Osteoclasts – break bone cells down– Osteocytes – mature bone cells
Bone Development
• Adults continually break down and build up bone
• Osteoclasts remove damaged cells and release calcium into blood
• Osteoblasts remove calcium from blood and build new matrix. They become trapped→ osteoclasts
• Red marrow – produces blood cells and clotting factors– Found in humerus, femur, sternum, ribs, vertebrae,
pelvis– Produces RBC 2 million per second
• Yellow marrow – stores fat– Found in many bones
Bone Marrow
Broken Bones• Fracture is a break of the bone Fig. 4• Simple or Complex fracture• Regrowth of bone:
o Spongy bone forms in first few dayso Blood vessels regrow and spongy bone hardens o Full healing takes 1-2 months
Fracture repair Fig. 4• Hematoma- blood clot in space between edges of
break• Fibrocartilage callus - begins tissue repair• Bony callus - osteoblasts produce trabeculae
(structural support) of spongy bone and replace fibrocartilage
• Remodeling - osteoblasts build new compact bone, osteoclasts build new medullary cavity
• Long Bones - metacarples, metatarsals, phelangies, humerus, ulna, radius, tibia, fibula
• Short Bones - carpals, tarsals• Flat Bones - rib, scapula, skull, sternum• Irregular Bones - vertebrae, some facial
bones• Sesamoid – patella Fig. 5
Types of bones
Axial skeleton (Fig. 6)• Forms the long axis
of the body• 80 bones in three
major regions– skull– vertebral column– bony thorax
RibsSternum
Appendicular Bones of upper & lower extremities and girdles126 bones in three major regions•Girdles
Shoulder girdle Pelvic girdle
•upper extremity•lower extremity
both bone and cartilage tend to deteriorate• cartilage: chondrocytes die, cartilage becomes
calcified• osteoporosis; bone is broken down faster than
it can be built• bones get weak and brittle; tend to fracture
easily
Aging and bones
• Skin makes vitamin D which enhances calcium absorption
• Skeleton stores calcium for muscle contraction, nervous stimulation, blood clot formation
• Red marrow - site of blood cell formation• Calcium levels regulated by
o parathyroid hormone and calcitonino kidneys (can help provide vitamin D)o digestive system (can release calcium into
blood
Skeleton and other systems
• Growth hormone regulates skeletal growth stimulates cell division in epiphyseal disks in long bones
• Growth stops when epiphyseal disks are converted to bone
• When excess growth hormone is produced in childhood → gigantism
• In adulthood → acromegaly. Bones can’t grow but soft tissue can Fig. 21
• There are three types of muscle tissue– Skeletal muscle– Cardiac muscle– Smooth muscle
• These muscle tissues differ in the structure of their cells, their body location, their function, and the means by which they are activated to contract
Overview of Muscle Tissue
Muscle Tissue
Muscle Tissue
• Patellar tendon reflex (knee jerk): L2, 3, and 4 (extension of the knee joint on tapping the patellar tendon)
• Achilles tendon reflex (ankle jerk): S1 and S2 (plantar flexion of the ankle joint on tapping the Achilles tendon)
Segmental Innervation of Muscle
Segmental Innervation of Muscle
Created by:dr. Irwan
Bagian AnatomiFK Unsri
Palembang
Fig. 1 Bone structure
Fig. 2 Haversian system
Fig. 3 Bone development
Fig. 4 Remodeling
Fig. 5 Bone Classification
Fig. 6 Axial skeleton
Fig. 7 Skull
Fig. 8 Cranial base
Fig. 9 Skull posterior view
Fig. 10 Suture
Fig. 11 Suture & fontanelle
Fig. 12 Orbita
Fig. 13 Nasal cavity
Fig. 14 Sinuses
Fig. 15 Fontanelle
Fig. 16 Vertebra & curvature
Fig. 17 Deviasi vertebra
Fig. 18 Curvature development
Fig. 19 HNP
Fig. 20 Thoracic cage
Fig. 21 Acromegaly & gigantisme