Skeletal System PDF - Gulf Medical University

Objectives: – Describe the types of bones, giving examples for each type. – Define Joints. – Classify Joints by structure and by function. – Describe the anatomical features of synovial, cartilaginous and fibrous joints – Classify the types of muscles regarding their...

Objectives: – Describe the types of bones, giving examples for each type. – Define Joints. – Classify Joints by structure and by function. – Describe the anatomical features of synovial, cartilaginous and fibrous joints – Classify the types of muscles regarding their histological appearance and function – Classify the skeletal muscle according to the shape, direction of its fibers and action Hansen, John T. Netter’s clinical Anatomy, 4th edition, 2019. Chapter(1), introduction to the human body. https://www-clinicalkey-com.gmulibrary.com/#!/content/book/3-s2.0- B9780323531887000020?scrollTo=%23hl0000945  Skeletal system Dr. Sapna S Assistant Prof-Anatomy September 23, 2024 www.gmu.ac.ae COLLEGE OF ALLIED HEALTH SEIENCES  i. Axial skeleton: These are bones of skull, vertebral column and thoracic cage (ribs & sternum). ii. Appendicular skeleton: These are the bones of the limbs and girdles of limbs.  Parts of long bone: 1. Diaphysis: Is the shaft of a long bone which ossifies from primary center. 2. Epiphysis: It is the ends of bone which ossify from secondary center. Periosteum : outer covering of the bone Medullary cavity: It is a long cavity inside the diaphysis. It is filled with red bone marrow in children, which transitions to yellow bone marrow as they grow to become adults. Blood supply of the adult long bone: 1. Nutrient artery: supplies the inner 2/3 of mature bone. 2. Periosteal artery: supplies the outer 1/3 of bone. 3. Epiphyseal artery: To the epiphysis. 4. Metaphyseal artery: To the metaphysis. ii. Short bones They are roughly cube-shaped. Have no shaft or ends. E.g. carpal and tarsal bones. Sesamoid bones: They are shaped like a sesame seed. They are a special type of short bone that forms within a tendon. E.g. patella iii. Flat bones: Are thin, flat and somewhat curved. Most cranial bones of the skull are flat, as are the ribs, sternum. iv. Irregular bones: They have various shapes that do not fit into the previous categories. E.g. the vertebrae and hip bones. v. Pneumatic bone: Bone that contain air-filled spaces. E.g. frontal, sphenoid, ethmoid and maxilla. F SP M  JOINTS Dr Sapna Shevade September 23, 2024 www.gmu.ac.ae COLLEGE OF ALLIED HEALTH SEIENCES DEFINATION Junction between 2 or more bones. Device to permit movements. CLASSIFICATION A) FUNCTIONAL CLASSIFICATION 1. Synarthroses : immovable joints,(syn= together) 2. Amphiarthroses: slightly movable joints, (amphi= both ends) 3. Diarthroses : freely movable. D. STRUCTURAL CLASSIFICATION 1) FIBROUS JOINTS:- a) Sutures b) Syndesmosis c) Gomphosis 2) CARTILAGINOUS JOINTS:- a)Primary cartilaginous joints b)Secondary cartilaginous joints 3) SYNOVIAL JOINTS:- a) Ball and socket b) Saddle c) Condylar d) Ellipsoid e) Hinge f) Pivot g) Plane I. FIBROUS JOINTS: Bones are joined by fibrous tissue. Immovable or either slight degree of movement. A. SUTURES Peculiar to skull and are immovable. Neonatal skull reveals fontanelles which are temporary in nature. This allows the brain to increase in size. Anterior fontanelle is used to judge the hydration of the infant. B. SYNDESMOSIS Bones are connected by longer fibrous tissue band which is called interosseous ligament. Example: radio –ulnar & inferior tibio-fibular joints C. GOMPHOSIS Also called peg and socket joint. Example:-root of the tooth in its bony socket. II. CARTILAGINOUS JOINTS A. Synchondrosis - Primary cartilaginous: Bones are united by a plate of hyaline cartilage so that joint is immovable. ex: Joint between epiphysis and diaphysis, sterno- costal joints. B. Symphysis -- Secondary Cartilaginous Joint 2 bones joined by fibrocartilage. Articular surfaces are covered by thin layer of hyaline cartilage. Only slight amount of movement is possible ex:-symphysis pubis , intervertebral disc III. Synovial Joints Those joints in which the articulating bones are separated by a joint cavity filled with synovial fluid Freely movable (diarthroses) Found mainly in arms and legs. Characteristics of Synovial Joints i. Hyaline cartilage A protective layer that covers the ends of the articulating bones. ii. Joint cavity. iii. Capsule Join the articulating bones. May or may not have thickenings called extrinsic ligaments. iv. Synovial membrane Covers joint cavity, except over the surfaces of the articular cartilages. Secretes the lubrication fluid. v. Synovial fluid Lubricates the joint vi. Extrinsic ligaments Support the joint and connect the articulating bones of the joint Synovial Joint Shapes: a. Hinge: cylindrical end of 1 bone fits into trough (container) shape of other Angular movement-1 plane e.g. elbow, ankle, inter-phalangeal b. Plane: articular surface is flat Short gliding movement e.g. intercarpal ,inter-tarsal, articular processes of vertebrae. c. Condyloid: oval shape articular surface + oval concavity Side-to-side, back +forth movement e.g. wrist joint & metacarpo -phalangeal (knuckle) d. Pivot: round end fits into ring of bone + ligament rotation on long axis e.g. prox. radius/ulna and atlas /dens. e. Saddle: articular surface both concave + convex Side-to-side, back-forth movement e.g. carpometacarpal joint of thumb f. Ball + Socket: spherical head + round socket Multi-axial movement e.g. shoulder, hip  Anatomy & Histology of the Muscle September 23, 2024 www.gmu.ac.ae COLLEGE OF ALLIED HEALTH SEIENCES Types of muscle fibers: − There are 3 types of muscle tissues in the body: 1. Skeletal muscle, 2. Cardiac muscle, and 3. Smooth muscle. Skeletal muscle:Striated muscle: – The cells are long, cylindrical (exhibit cross-striations) and multinucleated. – The nuclei are peripherally placed. – Contraction is typically quick and strong and under voluntary control. – Used for locomotion, mastication, and phonation.  Connective tissue covering of the muscle fibers 1. Skeletal muscle is surrounded by a dense, irregular connective tissue layer called epimysium. 2. From epimysium, connective tissue layer, divides the muscle into smaller bundles (fascicles); surrounds each bundle ,which is called perimysium. 3. A thin layer of reticular connective tissue, called endomysium, surrounds each individual muscle fiber. Cardiac muscle: – Cardiac muscle fibers are short cylindrical and branched (exhibit cross-striations). – The nucleus is centrally placed. − The terminal ends of adjacent cardiac muscle fibers show characteristic and dense-staining, end-to-end junctional complexes called intercalated disks. − Intercalated discs contain gap junctions that enable ionic communication between cells. – They are located in the walls and septa of the heart & contraction is involuntary & rhythmic. Smooth muscle: − Its cells non-striated). − Cells are fusiform(spindle shaped with a central nucleus. − Contraction is involuntary, slow, and long lasting. − Found in blood vessels, gastrointestinal (esophagus, stomach, small & large intestine) and uro-genital organ walls (urinary bladder, ureter, urethra, uterine tube, uterus, vagina, vas deferens). 10-100mm in diameter Up to 30cm in length 10-15mm in diameter 80-100mm in length 0.2-2mm in diameter 20-200mm in length Skeletal Muscle Cardiac Muscle Smooth Muscle Definition: Refers mainly to the skeletal muscles, which are the muscles that make up the flesh of the body and produce many types of movements. Each muscle is formed from bundles of muscle fibers which are anchored to the bone through a tendon. According to the action: a. Prime mover: the chief muscle for primary action. b. Synergists: muscle that has the same action as prime mover. c. Antagonist: muscle that has the opposite action to prime mover. d. Fixator muscle: muscle that fix the joint in a given position during the movements of other joints. According to the direction of fibers: Unipennate: It is like half of feather, where the muscle fibers are coming from the side of the tendon. Bipennate: It is like the whole feather, where the muscle fibers are coming from both sides of the tendon. Multipennate: A collection of bipennate arrangement. Circular: Have circular muscle fibers. Strap: Have parallel running fibers. According to the shape of muscle: Quadrangular, triangular, rhomboidal, trapezoidal, spiral and fusiform. 2 heads = 2 parts with the same action 2 bellies = 2 parts with different actions