Skeletal System Notes PDF

Skeletal System I Asst Prof A.Taha Demirbaş Faculty of Medicine, Anatomy Department The Skeletal System In art and history, nothing has symbolized death so much as a skull or skeleton Bones and teeth are the most durable remains of a once-living body and the most vivid reminder of the...

Skeletal System I Asst Prof A.Taha Demirbaş Faculty of Medicine, Anatomy Department The Skeletal System In art and history, nothing has symbolized death so much as a skull or skeleton Bones and teeth are the most durable remains of a once-living body and the most vivid reminder of the impermanence of life The bones are alive organs The skeleton is permeated with nerves and blood vessels, evidence of its sensitivity and metabolic activity  The skeletal system consists of bones, cartilages, and ligaments tightly joined to form a strong, flexible framework for the body Cartilage, the embryonic forerunner of most bones, covers many joint surfaces in the mature skeleton Ligaments hold bones together at the joints Tendons are structurally similar to ligaments but attach muscles to bones Functions of the Skeletal System Support: Bones of the legs, pelvis, and vertebral column hold up the body Movement: Skeletal muscles would serve little purpose if not for their attachment to the bones Protection: Bones enclose and protect such delicate organs and tissues as the brain, spinal cord Blood formation: Red bone marrow is the major producer of blood cells Electrolyte balance: The skeleton is the body’s main reservoir of calcium and phosphate Acid–base balance: Bone buffers the blood against excessive pH changes by absorbing or releasing alkaline salts such as calcium phosphate  And the detoxification: Bone tissue absorbs heavy metals and other foreign elements from the blood and thus mitigates their toxic effects on other tissues It can later release these contaminants more slowly for excretion ✓ Factories employed women to paint luminous numbers on clock dials with radium paint. As they moistened the paint brushes with their tongues to keep them finely pointed, the women ingested radium. ✓ Their bones readily absorbed it and many of the women developed osteosarcoma, the most common and deadly form of bone cancer Bones and Osseous Tissue Bone is a connective tissue in which the matrix is hardened by the deposition of calcium phosphate and other minerals The hardening process is called mineralization or calcification The study of bone, or osseous tissue, is called osteology Osseous tissue, however, is only one of the components of a bone Also present are blood, bone marrow, cartilage, adipose tissue, nervous tissue, and fibrous connective tissue  Bones have a wide variety of shapes correlated with their varied protective and locomotor functions Flat bones: In the form of thin curved bones ✓ Most of the cranial bones, sternum (breastbone), scapula (shoulder blade), ribs, and hip bones Long bones: The most important bones in body movement ✓ The humerus, radius, and ulna of the arm and forearm; the femur, tibia, and fibula of the thigh and leg; and the metacarpals, metatarsals, and phalanges of the hands and feet Short bones: The wrists and ankles have a total of 30 carpal and tarsal bones Irregular bones: The vertebrae and the sphenoid and ethmoid bones of the skull General Features of Bones When we look inside of the bone; Much of it is composed of an outer shell of dense white osseous tissue called compact (dense) bone The shell encloses a space called the marrow cavity or medullary cavity, which contains bone marrow At the ends of the bone is a more loosely organized form of osseous tissue called spongy (cancellous) bone  The principal features of a long bone are its shaft, called the diaphysis, and an expanded head at each end, called the epiphysis The diaphysis of a long bone provides leverage, whereas the epiphysis is enlarged to strengthen the joint and provide added surface area for the attachment of tendons and ligaments In children and adolescents, an epiphyseal plate of hyaline cartilage exists On X-rays, it appears as a transparent line at the end of a long bone The epiphyseal plate is a zone where the bones grow in length. It is not present in adults Periosteum The bone is covered externally with a membrane layer called periosteum Periosteum: Fibrous and cellular layer ✓ Provides continuity from muscle to tendon and bone ✓ Important in bone growth and repair Periosteal vessels penetrate the bone through holes called foramina nutricium Bone Materials Bone tissue consists of approximately 1/3 organic and 2/3 inorganic material Organic matter includes collagen and various large protein carbohydrate complexes called glycosaminoglycans, proteoglycans, and glycoproteins The inorganic material is approximately 85% hydroxyapatite, a crystallized calcium phosphate salt [Ca10(PO4)6(OH)2]; 10% calcium carbonate (CaCO3); and smaller amounts of magnesium, sodium, potassium, fluoride, sulfate, carbonate and hydroxide ions Skeleton System Having knowledge of skeletal anatomy will be useful when studying later systems Because bones are reference points Other anatomical structures may be named after bones Additionally, the position and shape of the bones serve as a function for a clinician to determine where to inject, where to take a pulse, or what to look for on an X-ray The Bones An adult human has 206 bones A newborn has approximately 270 bones Sesamoid bones: Formed inside tendons in response to stress. ✓ Patella is the largest one. Others are small round bones (in the hands and feet) Sutural bones (Wormian bones) Anatomical Structures in Bones Bones has different terminological structures such as protrusions, cavities, holes Knowing this terminological basis is important for later Use yourself as a model while learning Palpation: Feeling from the outside through the skin  The skeleton is divided into two parts Appendicular skeleton: The bones of the upper limb and pectoral girdle, and bones of the lower limb and pelvic girdle Axial skeleton: Cranium, vertebral column, ribs and sternum Appendicular Skeleton Pectoral girdle ✓Clavicle ✓Scapula Upper limb ✓Humerus ✓Radius and ulna ✓Carpal bones (8), metacarpal bones (5) ve phalanges (14)  Pectoral Girdle The pectoral girdle (shoulder girdle) supports the arm and links it to the axial skeleton It consists of two bones on each side of the body: ✓ Clavicle (collarbone) ✓ Scapula (shoulder blade) The medial end of the clavicle articulates with the sternum at the sternoclavicular joint, and its lateral end articulates with the scapula at the acromioclavicular joint The scapula also articulates with the humerus at the glenohumeral (shoulder) joint pect = chest; oral = pertaining to / acr = extremity, peak; omo = shoulder/ gleno = socket  Clavicula Slightly S-shaped Articulates with sternum and acromion (scapula) Easily seen and palpated ✓ Conoid tubercle: Near the acromial end a rough tuberosity clav = hammer,club; icle = little/ con = cone; oid = shaped  Scapula A triangular plate that overlies ribs 2 through 7 Its only direct attachment to the thoracic cage is by muscles; it glides over the rib cage as the arm and shoulder move The three sides of the scapular triangle are called the superior, medial (vertebral), and lateral (axillary) borders Its three angles are the superior, inferior, and lateral angles scap = spade, shovel; ula = little  Scapula Suprascapular notch Subscapular fossa Spine Supraspinous fossa Infraspinous fossa ✓Lateral angle has; Acromion Coracoid process Glenoid cavity corac = crow; oid = shaped, resembling  Upper Limb Brachium: Humerus Antebrachium: Radius and ulna Manus: Carpal, metacarpal, and phalanges man = hand / carp = wrist Humerus ✓ Proksimal; Head Anatomical neck Greater and lesser tubercles and an intertubercular sulcus (groove) between them that accommodates a tendon of the biceps muscle The surgical neck, a common fracture site, is a narrowing of the bone just distal to the tubercles Corpus (shaft); Deltoid tuberosity: Deltoid muscle has an insertion  Humerus Distal; Capitulum Trochlea Lateral and medial epcondyles 2 anterior, 1 posterior deep pits are, Radial and coronoid fossa (anterior) Olecranon fossa (posterior) capit = head; ulum = little / troch = wheel, pulley Radius ✓ Proksimal; Head Neck Radial tuberosity ✓ Distal; Styloid process of radius Articular facets (scaphoideum-lunatum) Ulnar notch of radius  Ulna ✓Proksimal; Olecranon Trochlear notch Coronoid process Radial notch of ulna ✓Distal; Styloid process of ulna olecranon = elbow / coron = something curved; oid = shaped Carpal bones ✓Proksimal (4); From lateral to medial: Scaphoid, lunate, triquetrum, psiform ✓Distal (4); From lateral to medial: Trapezium, trapezoid, capitate, hamate Metacarpal bones and phalanges Base (proksimal) Head (distal) Body (shaft) ✓Metacarpal bones (5) ✓Phalanges(14) ✓Pollex-indicis-medius-annulus- digiti minimi  Pelvic Girdle and Lower Limb Pelvic girdle ✓ Coxae (ilium, ischium, pubis) Femoral region ✓ Femur Crural region ✓ Tibia ✓ Fibula Pedis ✓ Tarsal bones (7) ✓ Metatarsal bones (5) ✓ Phalanges (14) Pelvic girdle 2 os coxae ve os sacrum (skeleton axiale-vertebral column) Pelvis makes up a place by covered with the ligaments and muscles (cavitas pelvicis) Pelvis supports the trunk upward of the lower limb Protects the pelvic viscera (colon, urinary vesicle, genital organs)  Coxae Ilium Ischium= postero- İnferior Pubis= antero- inferior ischium = hip / ili = flank, loin; ac = pertaining to / pubis: groin bone  Coxae 3 landmarks; ✓Ilıac crest ✓Acetabulum ✓Obturator foramen acetabulum = vinegar cup / obtur = to close, stop up; ator = that which Femur and Patella The longest bone Proksimal; ✓ Greater and lesser trochanter ✓ Head ✓ Neck Distal; ✓ Patellar surface ✓Medial and lateral condyles (med-lat epicondyles) ✓ Intercondylar fossa  Tibia and Fibula A thick strong tibia on the medial side and a slender fibula on the lateral side tibia = shinbone / malle = hammer; olus = little / fib = pin; ula = little  Pedis (ankle and foot) Tarsal bones (7) ✓Talus ✓Calcaneus Metatarsal bones (5) Phalanges (14) calc = stone, chalk / talus = ankle