LESSON 11 THE MUSCULOSKELETAL SYSTEM INTRODUCTION The musculoskeletal system includes the bones, muscles, ligaments, tendons and joints. Bones provide the foundation around which the body is built and protect and support internal organs. Bones assist the in movement because they attach to muscles. The inside of bones is composed of bone marrow, which is used to manufactures new red blood cells. The other parts of bone are for the storage of minerals, which are necessary for body processes. Joints are located where bones meet together. Several different kinds of joints are found within the body (ball and socket, hinge, etc.). The type of joint found between bones is determined by the need for flexibility in movement. Muscles are responsible for movement. Involuntary movement involves the contraction and relaxation of muscles that are part of internal organs such as the muscles in blood vessels, the digestive tract, and the urinary system. Voluntary movement is accomplished by skeletal muscles that are attached to the bones. Medical doctors who diagnosis and treat bone disorders and diseases are called orthopedists. Originally, orthopedics was a branch of medicine dealing with correcting deformities in children (orth/o means straight, ped/o means child). Rheumatologists are medical doctors who diagnosis and treat joint and autoimmune diseases. Rheumat/o means waterily flow and relates to joint diseases because various forms of arthritis result from collection of fluid in the
Transcript
LESSON 11 THE MUSCULOSKELETAL SYSTEM
INTRODUCTION
The musculoskeletal system includes the bones, muscles, ligaments, tendons and joints. Bones provide the foundation around which the body is built and protect and support internal organs. Bones assist the in movement because they attach to muscles. The inside of bones is composed of bone marrow, which is used to manufactures new red blood cells. The other parts of bone are for the storage of minerals, which are necessary for body processes.
Joints are located where bones meet together. Several different kinds of joints are found within the body (ball and socket, hinge, etc.). The type of joint found between bones is determined by the need for flexibility in movement.
Muscles are responsible for movement. Involuntary movement involves the contraction and relaxation of muscles that are part of internal organs such as the muscles in blood vessels, the digestive tract, and the urinary system. Voluntary movement is accomplished by skeletal muscles that are attached to the bones.
Medical doctors who diagnosis and treat bone disorders and diseases are called orthopedists. Originally, orthopedics was a branch of medicine dealing with correcting deformities in children (orth/o means straight, ped/o means child). Rheumatologists are medical doctors who diagnosis and treat joint and autoimmune diseases. Rheumat/o means waterily flow and relates to joint diseases because various forms of arthritis result from collection of fluid in the joints. Podiatrists diagnosis and treat disorders and diseases of the ankle and feet (pod/o means feet).
Osteopaths practice osteopathy which is a separate study of medicine using diagnostic and therapeutic measures and based on the belief that the body is capable of healing itself when bones are in proper position and adequate nutrition is provided. However, today’s Osteopaths receive basically the same training as those who go to Medical Schools. Osteopaths go to an Osteopathic Medical School for training. Chiropractors (chir/o means hand) are neither physicians nor osteopaths and they use physical means to manipulate the spinal column, believing that many diseases have their origins by pressure placed upon nervous tissue resulting from bones that are out of alignment, especially those in the spine.
BONES
Formation
Bones are mostly composed of connective tissue called osseous tissue. Osseous tissue is a dense tissue consisting of osteocytes (bone cells) surrounded by a hard calcium layer.
Structure
There are 206 bones of many types in the body. Long bones are found in the leg and arms. These bones are very strong and have large surface areas for muscle attachment. Smaller bones are found in the wrists and ankles and have irregular shapes. Flat bones are found covering soft body parts, shoulder bones, ribs, and pelvic bones.
The middle region of a long bone is called the diaphysis. Each end of a long bone is called an epiphysis. The epiphyseal line or plate represents an area of cartilage tissue that is constantly being replaced by new bony tissue as the bone grows. Cartilage cells at the edges of the epiphyseal plate form new bone and this is responsible for the lengthening of bones during childhood and adolescence. The plate calcifies and disappears when the person has achieved his or her full growth.
The periosteum is the membrane that covers the surface of a long bone, except at the ends of the epiphysis. Other bones are completely covered by the periosteum. Under the periosteum is the layer of osteoblasts, which deposits calcium phosphate in the bony tissue. The ends of long bones are covered by a layer of cartilage called articular cartilage. This cartilage layer cushions the bones at joints.
Compact bone is a hard tissue that is under the periosteum in all bones except around the diaphysis of long bones. Within the compact bone is a system of small canals containing blood vessels that bring oxygen and nutrients to the bone and remove waste products such as carbon dioxide. There are channels in the compact bone. Compact bones have a channel in the shaft of the long bones containing yellow bone marrow. Yellow bone marrow is mostly composed of fat cells.
Cancellous bone, sometimes called spongy bone, is much more porous and less dense than compact bone. It is found in the epiphyses of long bones and in the center of most other bones. Spaces in cancellous bone contain red bone marrow. This red marrow is supplied with blood vessels and consists of immature and mature blood cells.
In an adult, the ribs, pelvic bone, sternum, vertebrae and the epiphysis of long bones contain red bone marrow within cancellous tissue. The red marrow in the long bones is plentiful in young children but decreases through the years and is replaced by yellow marrow.
Processes and Depressions in Bones
Bone processes are enlarged tissues that normally extend out from bones to serve as attachments for muscles and tendons.
Bonehead rounded end of a bone separated from the body of the bone by a neck. Tubercle small, rounded process on many bones for attachment of tendons or muscles.Trochanter the large process on the femur for attachment of muscles.Tuberosity large, rounded process on many bones for attachment of muscles and tendonsCondyle rounded, knuckle-like process at the joint.
Bone depressions are the openings or hollow regions in a bone that help to join one bone to another and serve as passageways for blood vessels and nerves. The names of some common depressions in bone are:
Fossa - shallow cavity in or on a bone.Foramen - opening for blood vessels and nervesFissure - a narrow, keep, slit-like openingSulcus - a grove or furrowSinus - a hollow cavity within a bone
Cranial Bones
The bones of the skull, or cranium, protect the brain and structures related to it such as the sense organs. Muscles for controlling head movements and chewing motions are connected to the cranial bones. The cranial bones join each other as joints called sutures. The cranial bones of a newborn child are not completely joined. There are gaps of un-ossified tissue in the skull at birth. These are called soft spots. Following are the bones of the cranium:
Frontal bone - forms the forehead and bony sockets that contain the eyes.
Parietal bone - there are two parietal bones that form the roof and upper part of the sides
of the cranium.
Temporal bone - two temporal bones form the lower sides and base of the cranium.
Each bone encloses an ear and contains a fossa for joining with the mandible. The temporomandibular joint is the area of connection between the temporal and mandibular bones. The mastoid process is a round process of the temporal bone behind the ear. The styloid process projects downward from the temporal bone.
Occipital bone - forms the back and base of the skull and joins the parietal and temporal bones forming a suture. The inferior portion of the occipital bone has an opening called the foramen magnum through which the spinal cord passes.
Sphenoid bone - this bone extends behind the eyes and forms part of the base of the skull.
Ethmoid bone - this thin, delicate bone is composed primarily of spongy, cancellous bone. It supports the nasal cavity and forms part of the orbits of the eyes.
Facial Bones
All the facial bones except one are joined together by sutures so that they are immovable. The mandible is the only facial bone capable of movement. This ability is necessary for chewing and speaking. The facial bones include:
Nasal bones - two nasal bones support the bridge of the nose. They join with the frontal bone and form part of the nasal septum.
Lacrimal bones - two lacrimal bones are located at the corner of each eye. These thin, small bones contain the lacrimal gland and canals for the passage of the tear duct.
Maxillary bones - two large bones compose the massive upper jaw bones. They are joined by a suture in the middle. If the two bones do not come together before birth a cleft palate results.
Mandibular bone - this is the lower jaw bone. Both the maxilla and the mandible contain the sockets in which the teeth are embedded. The mandible joins the skull at the region of the temporal bone forming the temporomandibular joint.
Zygomatic bones - two bones, one on each side of the face, form the high portion of the cheek.
Vomer- this thin, single, flat bone forms the lower portion of the nasal septum.
Sinuses, or air cavities, are located in specific places within the cranial and facial bones to lighten the skull and warm and moisten air as it passes through.
Vertebrae Column and Structure of Vertebrae
The vertebral, or spinal, column is composed of 26 bone segments called vertebrae that are arranged in five divisions from the base of the skull to the tail bone. The first 7 bones of the vertebral column, forming the neck bone, are the cervical vertebrae. These vertebrae do not connect with the ribs.
The second set of 12 vertebrae are known as the thoracic vertebrae. These vertebrae articulate with the 12 pairs of ribs. The third set of 5 vertebral bones are the lumbar vertebrae. They are the strongest and largest of the back bones.
The sacrum is a slightly curved, triangularly shaped bone. At birth it is composed of 5 separate bones; these gradually become fused in the young child.
The coccyx is the tail bone It is formed by the fusion of the 4 small coccygeal bones.
Bones of the Thorax
Clavicle - collar bone; a slender bone, one on each side of the body connecting the breastbone to each shoulder bone.
Scapula - shoulder blades are two triangular bones one on each back side of the chest. The portion of the scapula that joins with the clavicle to the shoulder is called the acromion.
Sternum - the breastbone is a flat bone in the midline of the chest. The uppermost part of the sternum joins on the sides with the clavicle and ribs, and the lower portion is attached to the diaphragm and abdominal muscles. The bottom of the sternum is called the xiphoid process.
Ribs - there are 12 pairs of ribs. The first 7 pairs join the sternum by attachments called costal cartilages. Ribs 1-7 are called true ribs. Ribs 8-10 are called false ribs. Ribs 11 and 12 are the floating ribs because they
are completely free at their front end.
Bones of the Arm and Hand
The following bones are described as if the patient is in the anatomical position - palms forward.
Humerus - upper arm bone; the large head of the humerus is founded and joins with the scapula and clavicle.
Ulna - medial lower arm bone; the proximal bony process of the ulna is called the elbow.
Radius - lateral lower arm bone.Carpals - wrist bones.
Metacarpals - these are 5 bones of the hand
Phalanges - finger bones.
Bones of the Pelvis
The pelvic girdle - the hip bone - is a large bone that supports the trunk of the body and joins with the thigh bone and sacrum. The adult pelvic bone is composed of 3 pairs of fused bones: the ilium, ischium, and pubis.
The ilium is the uppermost and largest portion. Dorsally the two parts of the ilium do not meet. Rather, they join the sacrum on either side. The connection between the iliac bones and the sacrum is so firm that they are commonly spoken of as the sacroiliac. The superior part of the ilium is known as the iliac crest.
The ischium is the posterior part of the pelvis. The ischium and the muscles attached to it form the buttocks.
The pubis is the anterior part and contains suture marks where the two pubes are joined by the way of a cartilaginous disk. This area of fusion is called the pubic symphysis.
The region within the ring of bone formed by the pelvic girdle is called the pelvic cavity. The rectum, sigmoid colon, bladder, and female
reproductive organs lie within the pelvic cavity.
Bones of the Leg and Foot
Femur - the thigh bones are the longest bones in the body. At its proximal end it has a rounded heat that fits into a socket, called the acetabulum.
Patella - the kneecap; this is a small, flat bone that lies in front of the joint between the femur and the tibia. It is surrounded by tendons and held in place with muscle attachments.
Tibia - the larger of 2 bones of the lower leg; the tibia runs below the skin in the front part of the leg.
Fibula - the smaller of 2 lower leg bones; this bone lies under the leg muscles.
Tarsals - the ankle bones are 7 short bones that resemble the carpal bones of the wrist but are larger. The calcaneus is the largest of these bones and is called the heel bone.
Metatarsals - there are 5 metatarsal bones in the foot - each attaches to the phalanges of the toes.
Phalanges - the toes; there are 2 phalanges in the big toe and 3 in each of the other four toes.
MUSCLES
Types of Muscles. There are three types of muscles in the body:
Striated muscles, also called voluntary or skeletal muscles, are the muscle fibers that move all bones as well as the face and eyes. Through the central and peripheral nervous system, we have control over these muscles.
Smooth muscles, also called involuntary, are those muscle fibers that move internal organs such as the digestive tract, blood vessels, and secretory ducts leading from glands. These muscles are controlled by the autonomic nervous system.
Cardiac muscle is striated in appearance but smooth-like in its action. Its movement cannot be consciously controlled. The fibers of cardiac muscle are branching fibers and are found in the heart.
Skeletal Muscle Function
Skeletal muscles are the muscles that move bones. When a muscle contracts, one of the bones to which it is joined remains stationary as a result of other muscles that hold it in place. The point of attachment of the muscles to the stationary bone is called the origin of that muscle. However, when the muscle contracts, another bone to which it is attached moves. The point of junction of the muscle to the bone that moves is called the insertion of the muscle. One origin of the biceps is at the scapula and its insertion is at the radius. Tendons are the bands of connective tissue that connect muscles to the bones and muscle to muscle. Ligaments are bands of connective tissue that hold bone to bone.
Muscles can perform a variety of functions. Some of the terms used to describe those actions are listed below with a short description of the specific type of movement performed.
Function Meaning
flexion Decreasing the angle between two bones, bending a limb extension Increasing the angle between two bones; straightening out a limbabduction Movement away from the midline of the bodyrotation Circular movement around an axisdorsal flexion Decreasing the angle of the ankle joint so that the foot bends backwardplantar flexion The motion that extends the foot downward toward the ground as when pointing the toes. Plant/o means sole of the foot.supination As applied to the hand, the act of turning the palm forwardpronation As applied to the hand, the act of turning the palm backward
LESSON 11 GRAPHICS
TERMS FOR LESSON 11
MUSCULOSKELETAL SYSTEM
Bone Anatomy Words to Knowperiosteumcompact bonecancellous boneendosteumdiaphysisepiphysisepiphyseal platebone marrow
Skeletal Bones to Knowmaxillamandiblevertebral columncervical vertebraethoracic vertebraelumbar vertebraesacrumcoccyxlaminaclaviclescapulaacromionsternumhumerusulnaradiuscarpalmetacarpal
Prefixes to Know: Musculoskeletalinter-supra-syn-sym-
Suffixes to Know: Musculoskeletal-asthenia-clasis-clast-desis-physis-schisis
Diagnostic Terms to Know: Musculoskeletal:ankylosisarthritisarthrochondritisbursitisbursolithcrapoptosiscranioschiasiskyphosismaxillitismeniscitismysastheniamyelomaosteitisosteocarcinoma
Surgical Terms to Know: Musculoskeletal:aponeurorrhaphyarthroclasiaarthrodesisarthroplastyarthrotomybursectomybursotomycarpectomychondrectomychondroplastycostectomycranioplastycraniotomy
PRACTICE EXERCISES FOR LESSON 11MUSCULOSKELETAL SYSTEM
MATCHING:---- inter a together, joined---- supra b between---- syn, sym c above---- asthenia d surgical fixation, fusion---- clasis, clast e break---- desis f growth
---- physis g split, fissure---- schisis h weakness, loss of feelingMATCHING:---- carp/o a femur---- clavic/o b ilium---- cost/o c mandible---- crani/o d ulna---- femor/o e clavicle---- fibul/o f humerus---- humer/o g ischium---- ili/o h carpals---- ischi/o i phalanges---- mandibul/o j radius---- maxill/o k rib---- patell/o l scapula---- phlang/o m sternum---- pub/o n cranium---- radi/o o fibula---- scapul/o p tarsals---- stern/o q pubis---- tars/o r maxilla---- tibi/o s tibia---- uln/o t vertebra, vertebral column---- rachi/o u patella
MATCHING:---- aponeur/o a cartilage---- arthr/o b crooked, stiff, bent---- burs/o c bursa---- chondr/o d movement---- menisc/o e aponeurosis---- ten/o f hump---- ankyl/o g muscle---- blast/o h tendon---- kinesi/o i bone marrow---- kyph/o j joint---- lamin/o k bone---- myel/o l stone---- my/o m meniscus
Medical Terminology, HS 280The Musculoskeletal System
MATCHING:---- 1 shaft of bone a bone marrow---- 2 hard layer of bone b cancellous bone---- 3 outer most layer c compact bone---- 4 found in bone cavities d diaphysis---- 5 lining of bone cavity e endometrium---- 6 ends of bone f endosteum---- 7 contains little spaces g epiphysis
h periosteum
MATCHING:---- 8 attaches muscle to bone a acetabulum---- 9 fluid filled sac b aponeurosis---- 10 smooth layer of gristle c bursa---- 11 socket in the pelvic bone d calcaneous---- 12 fluid e cartilage---- 13 heel bone f intervertebral disc---- 14 connects bone to bone g lamina---- 15 cartilage of knee h ligament---- 16 pubic bone joint i meniscus---- 17 acts as a tendon j periosteum---- 18 found between vertebra k symphysis pubis---- 19 part of vertebra arch l synovia
