Skeleton (2) PDF

Skeleton (2) Cartilages Joints Muscles By Dr. Diana Eid  Cartilages It is strong flexible connective tissue. There are 3 types of cartilages: 1- hyaline cartilage. 2- white fibrocartilage, 3- yellow elastic fibrocartilage. 1- Hyaline cartilage: Homogenous &...

Skeleton (2) Cartilages Joints Muscles By Dr. Diana Eid  Cartilages It is strong flexible connective tissue. There are 3 types of cartilages: 1- hyaline cartilage. 2- white fibrocartilage, 3- yellow elastic fibrocartilage. 1- Hyaline cartilage: Homogenous & translucent, it may ossify at old age. Present in: 1. In the developing bones. 2. In the articular cartilage. 3. In the larynx (except epiglottis), tracheal rings &costal cartilage. 2- White Fibrocartilage: White & opaque. It doesonot ossify Present in: 1. Intervertevral discs 2. Symphysis pubis 3- Yellow Elastic Fibrocartilage: Yellow fibers. It does not ossify. Present in: 1. Auricle of ear. 2. Tip of nose. 3. Epiglottis.  Definition A joint is a meeting point between two bone or more with or without movements.  Types of joints 1. Fibrous immobile 2. Cartilagenous. Limited movement 3. Synovial. Free movement  Fibrous joints The bones are joined with fibrous tissue. They are immobile. Eg: sutures of the skull Gomphosis  Cartilaginous joints The bones are connected by cartilage. There is limited or no movement according to the type of cartilage. Eg: intervertebral disc.  Synovial joints They are most common type and most mobile. Characters of synovial joints: - The articulating bones are covered by cartilages. - Has outer fibrous capsule. - The capsule is lined by synovial membrane. - There is free space between bones, this space filled with synovial fluid. - They are freely mobile. - Has ligaments to support the joints.  Classification of synovial joints 1- uniaxial joints: allow two movements along one axis. e.g.: hinge (elbow) – pivot (radio-ulnar joint) 2- Biaxial joints: allow four movements along two axis. e.g.: ellipsoid(wrist) – condyloid (knukle joints) – saddle (carpometacarpal joint of thumb). 3- Polyaxial joints: multiaxial e.g.: ball and socket (shoulder & hip) – plane (acromio-clavicular) Types of synovial joints  Muscles There are three types of muscles: 1- skeletal muscles: attached to the skeleton. 2- cardiac muscles: makes up myocardium. 3- smooth muscles: makes up walls of the organs and blood vessels. SMOOTH MUSCLES: Involuntary, unstriated and visceral. These are the muscles of the respiratory, alimentary and vascular systems.  CARDIAC MUSCLE: Involuntary but striated. The muscles of the heart.  Skeletal muscles Group of muscles attached to the skeleton, it has two ends: -origin: is the end that remains fixed during muscle contraction (proximal attachment). -insertion: is the other end that moves during muscle contraction (distal attachement).  Types of insertion: 1-Tendon. 2-apponeurosis. 3-fleshy.  Types of skeletal muscles: Circular.  Triangular.  Parallel (eg:Fusiform).  spiral.  Cruciate.  Pennate.