Introduction To Musculoskeletal System DR. REHAN

Objectives Describe the musculoskeletal system Enlist different functions of musculoskeletal system Describe the primary functions of the various organs or structures Explain the meaning of the basic terminology related to musculoskeletal system Recall three different types of muscular tissue Describe how muscles perform in groups Define tendon, ligament and bursa Identify clinical application related to muscular system

Functional Anatomy of the Musculoskeletal System The skeletal system consists of the specialized supporting connective tissues of the bony skeleton Associated structures are cartilage, tendon and ligaments Cartilage is the fetal precursor tissue in the development of many bones Bone provides a rigid framework which protects and supports most of the soft tissues of the body It acts as a system of struts and levers Action of attached skeletal muscles, permits movement of the body

Bones of the skeleton are connected with each other at joints According to their structure, allow varying degrees of movement Skeletal muscles are attached to bone by strong flexible tendons which insert into bone tissue. The entire assembly forms the musculoskeletal system All its cells are derived from mesenchymal stem cells

General Classifications of Bones Long Bones: "longer than they are wide" Clavicle, humerus, radius, ulna, femur, tibia, fibula, metatarsals, metacarpals Short Bones: carpals and tarsals: consist mainly spongy bone covered with a thin layer of compact bone Allow movement, provide elasticity, flexibility, & shock absorption Flat Bones:  ribs, sternum and scapula Protect and provide attachment sites for muscles Irregular Bones:  skull, pelvis, and vertebrae Support weight, dissipate loads, protect the spinal cord, contribute to movement and provide sites for muscle attachment Sesamoid Bones: a short bone embedded within a tendon or joint capsule, i.e. patella

Parts of long bone and joints Diaphysis: main shaft like structure, its hollow cylindrical shape, its functions of providing strong support bone Epiphysis: both end of long bone A joint, or articulation, is a union of two or more bones Fibrous joints, e.g. skull bones; immovable Cartilaginous joints, e.g. intervertebral discs slightly movable Synovial joints, e.g. limb joints freely movable Synovial joints permit the greatest degree of flexibility The ends of bones are covered with a connective tissue (synovial membrane) filled with joint (synovial) fluid

Typical Synovial Joint Four main features: joint capsule -  the joint enclosure, reinforced by and strengthened with ligaments synovial membrane -  a continuous sheet of connective tissue lining the capsule Its cells produce synovial fluid that lubricates the joint Synovial fluid - produced by the synovial membrane, the fluid lubricates the joint Hyaline (articular) cartilage - where the bones actually "meet"

Skeletal System: Overview The adult skeleton is composed of 206 separate bones Division of skeleton Axial skeleton Appendicular skeleton Axial Skeleton: Includes the bones of: skull, vertebral column, and rib cage These bones are involved in protection, support, and carrying other body parts

Appendicular skeleton Bones of upper & lower limbs and the girdles (shoulder bones and hip bones) that attach them to the axial skeleton. Involved in locomotion and manipulation

Axial Skeleton (80 bones) Skull (28) Facial Bones Cranial Bones Parietal (2) Temporal (2) Frontal (1) Occipital (1) Ethmoid (1) Sphenoid (1) Maxilla (2) Zygomatic (2) Mandible (1) Nasal (2) Platine (2) Inferior nasal concha (2) Lacrimal (2) Vomer (1)

Auditory Ossicles: Malleus (2), Incus (2) and Stapes (2) Hyoid (1) Vertebral Column: Cervical vertebrae (7), Thoracic vertebrae (12), Lumbar vertebrae (5), Sacrum (1), Coccyx (1) Thoracic Cage: Sternum (1), Ribs (24)

Appendicular skeleton 126 bones, 64 in the shoulders and upper limbs 62 in the pelvis and lower limbs Upper Extremity : The arms (humerus ) are attached to the thorax,  via synovial joints, at the collarbone (clavicle) and shoulder bone (scapula) (shoulder joint) The scapula is attached to the thoracic cage only by muscles

The elbow joint unites the humerus with the two lower arm bones - the ulna and radius Three sets of joints connect the radius and ulna to the bones of the palm (metacarpals), via the eight small wrist carpals knuckles (metacarpophalangeal Joints) connect the metacarpals to the proximal phalanx of the fingers Each finger has 3 phalanges (proximal, middle, distal), except the thumb which has only two

It begins as 3 hip bones (ilium, ischium, and pubis) Lower Extremity: pelvic girdle , thigh and leg knee, foot, ankle and toe The pelvis transmits the upper body weight from the sacrum (at the sacroiliac joint) to the legs It begins as 3 hip bones (ilium, ischium, and pubis) The hip joint unites the pelvis to the thigh bone (femur)

The knee joint, which includes the knee cap (patella), links the femur to the lower leg bones - the tibia and fibula The ankle joint links the lower leg bones to the talus The body weight is then transmitted to the heel (calcaneus) and to the balls of the feet via the tarsal and metatarsal foot bones The toes have a phalangeal structure like the fingers

Functions of Skeletal System Protection: protects the brain and internal organs Support: maintains upright posture Blood cell formation: hematopoiesis Mineral homeostasis Storage: stores fat and minerals. Leverage: A lever is a simple machine that magnifies speed of movement or force

Clinical Application Osteomalacia Literally “soft bones” Includes many disorders in which osteoid is produced but inadequately mineralized. Causes can include insufficient dietary calcium Insufficient vitamin D fortification or insufficient exposure to sun light Rickets Signs include bowed legs, and deformities of the pelvis, ribs, and skull

RRADIOLOGICAL ANATOMY

Osteomyelitis: bone inflammation caused by the body's reaction to a bacterial or fungal infection Ankylosis: abnormal stiffness of a joint or fusion of bones at a joint Arthralgia: pain in a joint Acromegaly: abnormal enlargement of facial features, hands, and feet in adults Result of overproduction of growth hormone Arthroplasty: Surgical repair of joint Arthritis: is inflammation of one or more joints

Diagram showing osteomyelitis

Fracture Types Open (compound): bone ends penetrate the skin Closed (simple): bone ends don’t penetrate the skin

Resources http://webschoolsolutions.com/patts/systems/skel eton.htm Clinical Anatomy by Regions: Richard. S. Snell, 9th edition Last's Anatomy: Regional and Applied, 12th edition