Musculoskeletal system anatomy is the group of parts that make up the framework of the body. Jointly, it is the musculoskeletal system. It consists of bones, muscles and connective tissue. It provides support for the body’s internal and external structures and allows the body to move. Because of their importance and need for maximal protection the brain and spinal cord have their own bony enclosures. For the brain it is the cranium. For the spinal cord it is the spinal canal.
Some authors cite the skeletal system and muscular system as separate. But the health care community and World Health Organization (WHO) consider both to be one – the musculoskeletal system. The treatment and classification of diseases reflects the viewpoint of the health care community and WHO.
Except for some conditions requiring surgery, family practitioners, internists or subspecialists within the field of internal medicine treat most of the musculoskeletal diseases and disorders. The ICD system illustrates the viewpoint of the WHO which owns the copyright of the coding system. The ICD-10 CM system lists all the codes for muscular diseases and skeletal disorders in the same chapter of its coding manuals. The title of that chapter is Diseases of the Musculoskeletal System and Connective Tissue.
Knowledge of some of the basic medical terminology of the system is important for patients because of its effect on the quality of health care received. Not only does it improve face-to-face communication in health care between patients and health care providers. It also allows for more accurate exchange of information in other settings such as the telephone or electronic media. The more accurate the information the more capable health care providers are of making the best health care decisions with the most desirable outcomes.
Additionally, the use of proper medical terminology impacts the accuracy of coding which in turn influences payment by insurance companies for health care services received.
As in any area of life, understanding the language is a requirement for obtaining knowledge. Obtaining knowledge is the essence of health literacy.
Acetabulum – acetabular adj. – The cup shaped depression of the outer surface of the hip bone of the pelvis where the head of the femur sits. More simply, it is the socket of the hip joint in which the ball of the joint rests.
Ankle – The portion of the lower extremity just above the foot in which the ankle joint lies. The bones which form it are the tibia and fibula. The tibia forms the inner portion and the fibula forms the outer portion of the joint.
Arm – The portion of the upper extremity between the shoulder joint and elbow in contrast to the forearm. It is commonly but improperly used to refer to the entire upper limb.
Articulate – To form a joint.
Bone – Bony adj. – The tissue that makes up the skeletal portion of the musculoskeletal system. It is composed of layers of minerals and proteins with variable degrees of compactness and hardness depending on the type of bone.
Cartilage – Cartilaginous adj. – A type of dense connective tissue made up of special cells that produce a supporting substance known as collagen. It also consists of large amounts of special types of starch molecules combined with protein and elastic fibers. It is on the surface of the bones of joints.
Elbow – It is the part of the upper limb where the arm joins the forearm. The term also refers to the associated joint. The bones of the elbow joint are the humerus of the arm and the radius and ulna of the forearm. The bony projection from the back of the elbow is the part of the ulna known as the olecranon. Funny bone is a term which refers to the medial part of the humerus at the elbow joint. The reason for the slang is trauma to the unprotected ulna nerve which passes over it causes intense tingling and pain in the limb.
Extremity – A limb of the body with all of its parts. The individual structural parts of the upper extremities are the thumb and fingers, hand, forearm, arm and respective joints. The lower extremities consist of the toes, feet, legs, thighs and respective joints.
Fascia – Continuous sheets of soft tissue surrounding and fused with bones, tendons, muscles, nerves, blood vessels and organs throughout the body. It enables muscles to exert their forces effectively and safely without harming other tissues. Superficial fascia is that just beneath the skin. The deep fascia is somewhat tougher and more compact.
Fibula – Fibular adj. – The outer and smaller of the two bones of the leg. It articulates with the talus bone of the foot to form the lateral portion of the ankle joint.
Hand – The portion of the upper limb distal to the forearm including the fingers.
Hip – The region of the body on the side of the pelvis where the thigh bone joins with the pelvis. The term also refers to the joint between the pelvis and the head of the femur.
Interphalangeal joint (IP joint) – Is the joint in the middle of the thumb or great toe (big toe). In medical terms, it is the joint between the proximal and distal phalanx of either the thumb or great toe. It does not bear the reference proximal or distal because the thumb and big toe don’t have middle phalanxes.
Intervertebral disc – One of the 23 structures between vertebrae, composed of cartilage and fibrous tissue. It consists of two parts – the nucleus pulposus and the annulus fibrosis. The nucleus pulposus is the soft and moist central portion filled with water, collagen and gel. The annulus fibrosis is the outer portion. It is composed of layers of tough fibrous tissue and lesser amounts of water, collagen and gel. Discs serve as shock absorbers for the spine. There is no disc between C1 and C2. There are discs between all other cervical, thoracic and lumbar vertebrae, as well as between C7 and T1, T12 and L1 and L5 and S1. There are no discs in the sacrum or coccyx.
Joint – The junction between bones that allows mutual movement of the bones. Joints that provide the greatest degree of movement are synovial joints. They are comprised of cartilage on the surfaces of the joined bones, a synovial membrane, synovial fluid, ligaments, tendons and a fibrous capsule. The major free-moving joints of the body are those of the shoulders, elbows, wrist, fingers, thumbs, hips, knees, ankles and spinal column of the neck and back.
Knee – Is the part of the lower extremity where the thigh joins the leg. It also refers to the joint formed between the bones of the thigh and the leg. Those bones are the femur of the thigh and the tibia and fibula of the leg. The knee also has a joint between the femur and the patella. Its name is the patellofemoral joint.
Ligament – Ligamentous adj. – A band of tough connective tissue that joins bones or cartilage. It gives support and strength to a joint.
Meniscus – Menisci pl. – The crescent-shaped disk of cartilage attached to the inside or outside joint surface of the tibia of the knee joint. The outside structure is the lateral meniscus. The inside structure is the medial meniscus.
Metacarpophalangeal joint (MCP joint) (Knuckle) – Is a joint that connects any of the fingers or thumb to the hand. When the fist is clinched it bears the name knuckle. In medical terms, it is a joint between the base of the proximal phalanx of either of the fingers or the thumb and the head of the adjacent bone of the hand.
Metatarsophalangeal joint (MTP joint) – Is a joint that connects either of the toes to the foot. In medical terms, it is a joint between the proximal phalanx of either of the toes and the head of the adjacent bone of the foot.
Patella – Patellar adj. – Is the medical term for kneecap. It is a large sesamoid bone (round bone embedded in a tendon) measuring approximately 2 inches in diameter in front of the knee. It lies within the tendon that inserts the quad muscles of the thigh into it. That tendon is the patellar tendon. The central portion of the tendon inserts further down into the tibia as the patellar ligament.
Pelvis – Pelvic adj. – The basin-shaped bony structure that supports the spinal column. It consists of the sacrum, coccyx, and the hip bones. Those hip bones are the ilium, ischium, and pubis.
Phalanx – Phalanges pl. Phalangeal adj. – One of the long bones of the fingers or toes. The second through fifth fingers and toes have three. Each thumb and great toe has two. The DIP joints and PIP joints connect the bones of the second through fifth fingers and toes. The IP joints connect the bones of the thumbs and great toes.
Radius – Radial adj. – The larger of the two bones of the forearm.
Rib – Costal adj. – Any one of the arched bones (12 on each side) extending from the thoracic vertebrae toward the midline of the ventral aspect of the truck. They form the major portion of the thorax. The upper seven ribs connect with the sternum and bear the name true ribs. The 8th, 9th and 10th ribs attach to the sternum indirectly through the cartilage of the 7th rib. The 11th and 12th ribs don’t attach to anything anteriorly and are termed floating ribs. The medial portions of all the ribs that make anterior connections are composed of cartilage which enables the thorax to expand along with the lungs during inward breathing.
Rotator cuff – Is the group of muscles and tendons in the shoulder that connect the humerus to the scapular and allow the shoulder to rotate. The names of the muscles are teres minor, infraspinatus, supraspinatus and subscapularis.
Skeletal muscle – Any of the many tissues composed of fibers involved in the voluntary movement of bones of the musculoskeletal system. In contrast to smooth muscle, it is striated. That means it has parallel lines or grooves on its surface.
Skull – The bony framework of the head. It is composed of the cranium and bones of the face.
Spinal canal (Vertebral canal) – Is the bony channel through which the spinal cord passes. It is composed of the series of vertebral foramina throughout the spine.
Spinal column (Spine – spinal adj.) – Is the medical term for backbone. It is the series of vertebrae extending from the cranium through the coccyx. Facet joints connect the vertebrae. Discs separate the vertebrae. Muscles and tendons hold the spine together. Vertebral column is an alternate term for it. It has 5 subdivisions. They are the cervical spine, thoracic spine, lumbar spine, sacrum and coccyx.
The cervical spine is the assembly of vertebrae in the neck extending from the base of the cranium down to the beginning of the thorax. Its individual vertebrae are designated as C1, C2, C3, C4, C5, C6 and C7.
Sternum – Sternal adj. – The medical term for breastbone. It is the long flat bone in the middle part of the front of the thorax which joins with the cartilage of the first seven ribs and the clavicle.
Synovial membrane (Synovium) – Is the smooth inner layer of connective tissue that lines the cavity of a joint. It secretes a fluid which lubricates the joint and reduces friction between the bones of a joint. The outer layer of connective tissue enclosing a synovial joint is the joint capsule.
Thigh – The part of the lower extremity between the hip and the leg. Its single bone is the femur which articulates with the pelvis to form the hip joint.
Thumb – Is the first digit which is on the radial side of the hand.
Tibia – Tibial adj. – The larger of the two bones of the leg. It is medial to the fibula and articulates with the talus bone of the foot to form the medial portion of the ankle joint.
Ulna – Ulnar adj. – The smaller of the two bones of the forearm but the larger of the two at the elbow joint.
Vertebra – vertebrae pl. vertebral adj. – Is any of the 32 bony segments which form the vertebral column. Seven comprise the cervical spine. Twelve are members of the thoracic spine. Five belong to the lumbar spine. Five form the sacrum. Three to five make up the coccyx. The vertebrae of the cervical, thoracic and lumbar spine all have a similar structure. The anterior portion is the body. It has the appearance of a cylindrical block. Projecting from each rear side of the body is the pedicle. Each pedicle curves around posteriorly and becomes the lamina as the bone forms a ring-like opening known as the vertebral foramen, which together with the ones at the other levels, forms the vertebral canal through which the spinal cord passes. Between any two adjacent vertebrae on either side there is an opening formed by a notch in the pedicle of adjacent vertebrae. That opening has two names. They are the intervertebral foramen and the neural foramen. It is the channel through which a spinal nerve exits the spinal canal. Each vertebra has a bony projection from either side of the lamina where it joins the pedicle. One bone projects upwardly. The other one projects downwardly. The name for these bony projections is facets. The ones which point upward are the superior facets. The ones that point downward are the inferior facets. The junction of a facet with one above or below it forms a facet joint. The segment of bone between the superior and inferior facets of a vertebra is the pars interarticularis. It is vulnerable to trauma and fracture. Each vertebra also contains two projections from the pedicle – one from the right and one from the left. They are the transverse processes. Each vertebra also has a spinous process which projects from the midline of the lamina toward the rear. It is possible to feel the spinous processes by running a finger along the back of the spine.
Wrist – The part of the upper extremity between the forearm and the hand. The term also refers to the joint between the bones of the forearm and the hand. The bones of the forearm at the wrist joint are the radius and the ulna. At the wrist, the radius spans approximately 2/3 the width of the hand from the thumb side of the hand. The ulna spans approximately 1/3 the width of the hand, from the little finger side of the hand.