Anatomy 1 Lecture 2: Skeletal System & Muscles (PDF)

ANATOMY 1 Lecture 2 Skeletal system & Muscles Dr. Enas Anwar Associate Professor of Anatomy and Embryology Faculty of Medicine, Ain Shams University 1 1) Identify different parts of the skeleton. 2) Identify the type...

ANATOMY 1 Lecture 2 Skeletal system & Muscles Dr. Enas Anwar Associate Professor of Anatomy and Embryology Faculty of Medicine, Ain Shams University 1 1) Identify different parts of the skeleton. 2) Identify the type of bones. 3) Recognize the structure of the muscle. 4) Differentiate between agonists and antagonists. 5) Identify types of muscles. 2 It consists of bones, cartilages, joints and ligaments. 1-Bones The average adult skeleton has 206 bones Bones can be categorized as paired or unpaired. -A paired bone is two bones of the same type located on the right and left sides of the body e.g. ribs, hip bone. -An unpaired bone is a bone located on the midline of the body e.g. sternum. 3  Divisions of the skeleton Axial skeleton It includes the skull, vertebral column, ribs and the sternum. Appendicular skeleton Includes the bones of the upper and lower limbs and their girdles. 4  I - The Axial skeleton A)The skull forms the skeleton of the head which is two parts: 1-Cranium containing the brain. 2-Mandible forming part of facial bones. 5 B) The vertebral column consists of 33 vertebrae and intervertebral discs joining them. The vertebrae are arranged into 5 regions; 1) Cervical (7). 2) Thoracic (12). 3) Lumbar (5). 4) Sacral (5 fused…Sacrum). 5) Coccygeal. (3-5 fused… coccyx). 6 C) The ribs: they are 12 pairs of ribs with their costal cartilages connecting them to the sternum except the last 2 ribs (floating ribs). D) The sternum: together with the thoracic vertebrae, ribs & their costal cartilages form the Thoracic cage containing the heart and lungs 7  II- The Appendicular skeleton Bones of upper and lower limbs + girdles. Girdles (connect the limb with the axial skeleton): shoulder (pectoral) and pelvic girdles. 8 A- Bones of the upper limb Clavicle Shoulder Scapula girdle Humerus Ulna Medial Radius Lateral Bones of the hand 9  Bones of the hand Phalanges of thumb: proximal and distal. Thumb (Lateral) 5: start counting from the thumb Dorsal Palmar 10 B- Bones of the lower limb Hip bone Femur Patella Tibia & Fibula Bones of the foot 11  Bones of the foot Phalanges (proximal, Middle &distal ) Phalanges of big Big toe (medial) toe: proximal and Metatarsal bones distal. 1st,2nd, 3rd, 4th 5th Tarsal bones(7) Planter Dorsal 12  The shoulder girdle is formed of clavicle & scapula which articulates with the axial skeleton anteriorly via the clavicle. The pelvic girdle (formed of hip bones), which articulates with the axial skeleton posteriorly via the sacrum. 13 14  According to the shape: 1) Long bones: Hard & dense bones that provide strength and mobility. They have a shaft (diaphysis) and two ends (epiphysis). The shaft contains a cavity (medullary cavity) which contains bone marrow. e.g. Femur, Humerus, Radius & Ulna 15 2) Short bones: wide and short bones, provide support and stability with little movement. e.g. carpal and tarsal bones. 16 3) Flat bones: -Protection e.g., skull cap bones and sternum. -Muscular attachment e.g. scapula & ribs. 17 4) Irregular bones: e.g., facial bones, vertebrae and hip bone. 18 5) Pneumatic bones: - They contain air-filled spaces. - Examples: some skull bones. - They make skull lighter, help in resonance of voice. 19 6) Sesamoid bones: They are found in tendons to protect them from excessive wear e.g. patella. 20 Functions of the skeleton: 1) Support and movement of the body. 2) Protection e.g., -Skull protects the brain, -Vertebral canal protects the spinal cord. -Thoracic cage protects the lungs and the heart. -Bony pelvis protects the pelvic organs, e.g., urinary bladder. 3) contain the bone marrow. 4) Storage for salts i.e., Ca, and Mg. 21 1. Most of the bones of the arms and hands are long bones; however, the bones in the wrist are categorized as ________. A. flat bones B. short bones C. sesamoid bones D. irregular bones 2. Sesamoid bones are found embedded in ________. A. joints B. muscles C. ligaments D. tendons 22 3. Bones that surround the spinal cord are classified as ________ bones. A. irregular B. sesamoid C. flat D. short 23 24 25 Identify the types of the following bones 26 Identify the type of the following bone 27 28 Muscles -Striated -Striated -Non-Striated -Involuntary -Voluntary -Involuntary - Myocardium -Ex. Muscles of - Ex. Wall of the of the heart the limbs viscera (GIT)  Skeletal muscles They form the main bulk of our bodies (about half of the body weight). There are more than 600 muscles in the human body. A skeletal muscle attaches to bone (or sometimes to non- skeletal structures ( skin- fascia- muscle) at two or more places.  Structure of skeletal muscles The skeletal muscle is made of muscle fibers arranged in bundles. 33 Attachments of muscles : origin & insertion. Origin is the more proximal attachment point of the muscle on less movable bone, while the insertion point refers to the distal attachment on the more moveable bone. The action of the muscle describes what happens when the more mobile bone is brought toward the more stable bone during a muscular contraction. 34 Muscle groups for every region of the body: 1. Muscles of the head and neck. 2. Muscles of the trunk. 3. Muscles of the upper limbs. 4. Muscles of the lower limbs. 35 Actions of Muscles A. Prime Mover (Agonist): produces desired action of a certain movement. B. Synergist: assists prime mover. C. Antagonist: opposes action of prime mover, restores original position (on the opposite side of the joint). D. Stabilizers: keep bones immobile when needed. (e.g. back muscles in keeping posture. 36 Names of Muscles Size: magnus, major, minor, longus, brevis. Shape: deltoid (triangular), teres (cylindrical). Orientation of the muscle fibers: rectus, oblique, transverse. Action of the muscles: adductor, flexor, extensor, or supinator. 37  Number of Heads of a muscle: bi (two), tri (three) and quad (four). Attachments of the muscle: sternocmastoid. Specific Features: serratus (toothed). Location: abdominis, femoris, pectoralis. 38 Functions of Skeletal muscles 1. Enable humans to move. 2. They play an essential role in respiratory mechanics. 3. Help in maintaining posture and balance. 4. Protect the vital organs in the body. 39  Attachments of Skeletal muscles cord-like or flat band of fibrous tissue sheet-like structure of fibrous tissue a very slender tendon in the midline. Directly to the bone.  Shapes of Skeletal muscles fibers Unipennate, bipennate & multipennate 43 Shape of muscle fibers 44  Identify Shape of muscle fibers 45  Identify Shape of muscle fibers Bipennate  Identify Shape of muscle fibers Multipennate Assignment 2 48 Identify the name and the type of the presented bones. 49 How many bones does the adult human body have? a. 210 b. 206 c. 180 d. 126 50 How many thoracic vertebrae are there? A. 7 B. 12 C. 5 D. 4 E. 33 51 52 54 55