Bones PDF

Bones By Dr. Raneen Sweity , Dr Ibraheem AbuAlrub & Dr Muawiya Abu-Rajab Lecture outline Skeletal system and its divisions Bones, Bone classification and Bones functions Long bone structure and Flat bone Axial skeleton Skull Vertebral column and vertebral structure Thoracic cage Stern...

Bones By Dr. Raneen Sweity , Dr Ibraheem AbuAlrub & Dr Muawiya Abu-Rajab Lecture outline Skeletal system and its divisions Bones, Bone classification and Bones functions Long bone structure and Flat bone Axial skeleton Skull Vertebral column and vertebral structure Thoracic cage Sternum and ribs Parts of the skeletal system Bones Joints Cartilages : thin hyaline layer covering the articular surfaces Ligaments structures from dense connective tissues that connect 2 bones Tendons structures from dense connective tissues that connect muscle to a bone Skeletal system divisions Axial skeletal system Appendicular skeletal system Bones Strong and durable type of connective tissue. Highly vascularized structure. It consists of: Water (25%). Organic constituents including osteoid and bone cells (25%). Inorganic constituents, mainly calcium phosphate (50%). Bone classification Long such as femur, humerus Short such as carpals and metacarpals bones Flat such as cranial bones and ribs Irregular such as vertebrae Sesamoid bones such as patella  Bones functions Not only a support but also play role in Spongy bone vs compact bone Spongy bone (also called cancellous or trabecular bone) is a porous, lighter type of bone tissue. It has a honeycomb-like structure filled with bone marrow and blood vessels, which makes it ideal for shock absorption and metabolic activities like producing blood cells. Compact (bone also called cortical bone) is dense and forms the outer layer of all bones. It provides strength, protection, and support, allowing bones to bear weight and withstand stress. Compact bone is organized into tightly packed structural units called osteons or Haversian systems. Long bone structure Epiphysis is the rounded end of a long bone, which is primarily composed of spongy bone and covered by articular cartilage. Metaphysis is the region of a long bone between the epiphysis and the diaphysis. Diaphysis is the long, cylindrical shaft of a long bone, composed mainly of compact bone. It provides structural support and contains the medullary cavity, which houses bone marrow. Other Long bone structures Articular cartilages is a smooth tissue that covers the ends of bones at joints. It reduces friction during movement and helps absorb shock, allowing for smooth and pain-free joint function. Periosteum: Outer covering of the long bone. It is a vascular membrane. Has 2 layers: Outer fibrous layer and Inner osteogenic layer Gives attachment to muscles and tendons and protects bones from injury. And it is crucial for the process of bone healing  Epiphysial line is a remnant of the epiphyseal (growth) plate, which is found in adults after the bone has stopped growing. It marks the point where the epiphysis and diaphysis fuse together once bone growth is complete. Medullary cavity is the central, hollow region within the diaphysis of long bones. It is filled with yellow bone marrow Growth plate Epiphysial line Flat bone Composed of two layers of compact bone surrounding a central layer of spongy bone filled with red bone marrow. The outer layers provide strength and protection, while the spongy bone helps absorb impact. Axial skeleton Skull Vertebral column Thoracic cage Skull The skull is a complex structure composed of 22 bones, primarily designed to protect the brain and support facial structures. It is divided into two main parts: 1.Cranium: The portion that encloses and protects the brain, consisting of eight bones (frontal, parietal, occipital, temporal, sphenoid, and ethmoid). 2.Facial bones: These include 14 bones that form the face, such as the nasal bones, maxilla, zygomatic bones, mandible (the lower jaw), and others. The bones of the skull are connected by immovable joints called sutures, except for the mandible, which is movable and forms the jaw. The skull also contains cavities such as the orbits (eye sockets) and sinuses. Vertebral column The vertebral column, also known as the spine, is a flexible, bony structure that supports the body and protects the spinal cord. It consists of 33 vertebrae, grouped into five regions: 1.Cervical (7 vertebrae): Located in the neck, these vertebrae (C1-C7) support the skull and allow head movement. 2.Thoracic (12 vertebrae): Found in the upper and mid-back (T1-T12), these vertebrae are attached to the ribs and form the thoracic cage. 3.Lumbar (5 vertebrae): The lower back vertebrae (L1-L5), responsible for bearing most of the body's weight. 4.Sacral (5 fused vertebrae): These fuse to form the sacrum, connecting the spine to the pelvis. 5.Coccygeal (4 fused vertebrae): These form the coccyx or tailbone.  Vertebral column The vertebral column provides flexibility and stability, allowing movement while protecting the spinal cord and nerve roots. Intervertebral discs between the vertebrae act as cushions to absorb shock and enable flexibility. Vertebrae Each vertebra has space in the center, forming a hollow tube when stacked on top of each other so that they protect the spinal canal. Discs: Soft, cushion-like structures located between adjacent vertebrae. They provide shock absorption, flexibility, and support for the spinal column. Spinal cord: A long, tubular bundle of nerves that extends from the brainstem down the vertebral column, protected by fluid in the spinal canal and surrounded by ligaments and bone for protection. The spinal cord serves as the central pathway for transmitting sensory and motor signals between the brain and the body through specific nerves. Vertebrae Facet joints: Small joints that connect the vertebrae and allow for the movement and stability of the spinal column. Ligaments: Tough, fibrous bands of connective tissue that help stabilize and support the vertebrae. Vertebrae types Cervical Thoracic lumber Thoracic cage The thoracic cage, also known as the rib cage, is a bony structure that surrounds and protects vital organs in the thoracic cavity, such as the heart and lungs. It is composed of: 1.Ribs (12 pairs): 1. True ribs (1–7): These are directly attached to the sternum via costal cartilage. 2. False ribs (8–10): These connect to the cartilage of the rib above them, not directly to the sternum. 3. Floating ribs (11–12): These do not attach to the sternum at all, only to the vertebrae at the back. 2.Sternum: A flat bone located in the center of the chest, made up of three parts: the manubrium, body (gladiolus), and xiphoid process. 3.Thoracic vertebrae: The 12 thoracic vertebrae (T1-T12) that form the back portion of the thoracic cage. Thoracic cage The thoracic cage supports breathing by expanding and contracting during respiration and plays a protective role for the upper abdominal organs as well. Sternum The sternum, or breastbone, is a flat, elongated bone located in the center of the chest. It forms the front of the rib cage and serves as a crucial point of attachment for the ribs and the clavicles (collarbones). The sternum is composed of three main parts: The sternum helps protect vital organs in the thoracic cavity, such as the heart and lungs, and plays a role in respiration by providing support to the rib cage during breathing Sternum 1.Manubrium: The upper portion of the sternum, which articulates with the clavicles (forming the sternoclavicular joint) and the first pair of ribs. 2.Body (Gladiolus): The largest, central part of the sternum. It articulates with the cartilages of the second through seventh ribs. 3.Xiphoid Process: The small, cartilaginous lower tip of the sternum, which gradually ossifies (turns into bone) during adulthood. It serves as a point of attachment for muscles, including the diaphragm and the rectus abdominis. Ribs The ribs are curved bones that form the protective framework of the thoracic cage, safeguarding vital organs like the heart and lungs. There are 12 pairs of ribs, each attached to the thoracic vertebrae at the back Ribs Each rib consists of the following parts: Head: Articulates with the thoracic vertebrae. Neck: The flattened portion of the rib that connects the head to the tubercle. Tubercle: Articulates with the transverse process of the corresponding vertebra. Body (Shaft): The long, curved portion of the rib that extends forward and down, providing structure to the thoracic cage. Appendicular system Shoulder gridle Upper limb Pelvic gridle Lower limb Shoulder girdle Each shoulder girdle consists of: clavicle. scapula.  clavicle Long bone has a double curve. Provides the only bony link between the upper limb and the axial skeleton. It articulates with the manubrium of the sternum at the sternoclavicular joint. Forms the acromioclavicular joint with the acromion process of the scapula.  Scapula Flat triangular-shaped bone. Lying on the posterior chest wall superficial to the ribs. At the lateral angle there is a shallow articular surface, the glenoid cavity which, with the head of the humerus, forms the shoulder joint. On the posterior surface there is a spinous process. Scapula Key anatomical features of the scapula include: Spine: A prominent ridge running across the posterior surface, dividing it into the supraspinous and infraspinous fossae. Acromion: The lateral extension of the spine that forms the highest point of the shoulder. Glenoid cavity: A shallow socket that articulates with the head of the humerus to form the shoulder joint. Coracoid process: A hook-like structure on the anterior surface for muscle attachment. Subscapular fossa: A large, shallow depression on the anterior (costal) surface for the attachment of the subscapularis muscle. Upper limb bones Humerus Radius and ulna Carpals Metacarpals Phalanges Proximal End Head: The rounded, proximal end that articulates with the glenoid cavity of the scapula to form the shoulder joint. Greater and Lesser Tubercles: Protrusions near the head of the humerus for muscle attachment. The greater tubercle is lateral, while the lesser tubercle is anterior. Anatomical and Surgical Neck: The anatomical neck is just below the head, while the surgical neck is a more distal, narrower region prone to fractures. Distal End Carpals and metacarpals Pelvic gridle Pelvic gridle is composed from 2 hip bones and sacral and coccygeal vertebrae It provide structural protection for pelvic structures and attachment for lower limb Hip bone (unnominated bone) is a large, irregular bone that forms the major part of the pelvis. The hip bone is made up of three components that fuse during development Ilium: The largest, upper part of the hip bone, it forms the iliac crest, which is the prominent ridge you can feel on your side. It provides attachment points for several muscles involved in movement, such as the gluteal muscles. Ischium: This is the lower and posterior portion of the hip bone. It forms the part of the pelvis you sit on, known as the ischial tuberosity. It also supports body weight while sitting and serves as an attachment site for various muscles like the hamstrings. Pubic: The front, lower part of the hip bone, the pubic joins with the pubic of the opposite hip bone at the pubic symphysis, a cartilaginous joint that allows limited movement, particularly during childbirth. Lower limb Femur Patella Tibia and fibula Tarsal bones Metatarsal bones and phalanges Femur The femur is the longest and strongest bone in the human body, and it forms the upper part of the leg (thigh). It plays a key role in supporting body weight during standing, walking, and running.  Head of the Femur: The rounded, proximal end of the femur that fits into the acetabulum of the hip bone, forming the ball-and-socket hip joint. Neck of the Femur: The narrow section just below the head, which connects to the shaft. It is a common site of fractures, especially in the elderly. Greater and Lesser Trochanters: These are bony prominences found near the proximal end of the femur. They serve as attachment points for important muscles involved in leg movement, such as the gluteal and iliopsoas muscles. Shaft of the Femur: The long, cylindrical middle portion of the bone. Its shape allows for both strength and flexibility. Distal End: The lower end of the femur, which includes the medial and lateral condyles. These structures articulate with the tibia (shin bone) and form part of the knee joint. Patella The patella, commonly known as the kneecap, is a small, triangular bone that is situated at the front of the knee joint. It plays a crucial role in the mechanics of knee movement and in protecting the joint. Tibia and fibula The tibia is the larger, stronger, and more medial of the two bones in the lower leg. It bears most of the body's weight and forms part of both the knee and ankle joints. The tibia is the larger, stronger, and more medial of the two bones in the lower leg. It bears most of the body's weight and forms part of both the knee and ankle joints. Tibia Key Features of the Tibia Proximal End : Tibial Plateau: The flat upper surface that articulates with the femoral condyles to form the knee joint. It has medial and lateral condyles, which are critical for knee stability. Tibial Tuberosity: A bony prominence located just below the knee, where the patellar ligament attaches. This structure is key in the extension of the knee via the quadriceps. Shaft: The long, straight portion of the tibia, which provides structural support to the lower leg. The anterior surface is palpable under the skin and is commonly referred to as the "shin.“ Distal End : Medial Malleolus: A prominent bony projection on the inner side of the ankle. It plays a role in forming the ankle joint and stabilizing the ankle.The tibia also articulates with the talus (one of the tarsal bones) to form the ankle joint, allowing for movements such as dorsiflexion and plantarflexion. Fibula Key Features of the Fibula: Proximal End: Head of the Fibula: Located near the knee, this small bony prominence articulates with the lateral aspect of the tibia, forming the proximal tibiofibular joint. Shaft: The fibula’s shaft is long and slender, running down the lateral side of the leg. It provides attachment points for several muscles involved in foot movement. Distal End: Lateral Malleolus: This is the bony prominence on the outer side of the ankle. It is a key structure for stabilizing the ankle joint and preventing excessive lateral movement. Foot bones ▪ Tarsal Bones: ▪ Calcaneus (heel bone) ▪ Talus ▪ Navicular ▪ Cuboid ▪ Medial cuneiform ▪ Intermediate cuneiform ▪ Lateral cuneiform Metatarsals from 1 to 5 Phalanges (proximal, middle and distal) Ankle joint