General description

 The musculoskeletal system is made up of bones, joints, muscles,

 tendons, ligaments and cartilage. The main functions of this important

 system are support and stability, protection of internal organs,

 locomotion, production of blood cells, and storage of calcium and

 other minerals.

 The bones of the skeleton are divided into two groups: the axial

 skeleton which includes the bones of the skull, ribs, sternum and

 vertebral column, and the appendicular skeleton which includes the

 bones of the shoulders, hips and the upper and lower extremities.

 

Skeleton

The human skeleton is made up of more than 200 separate bones.

The illustration on the following page shows that body shape closely

follows skeletal shape.

Bones can be classified according to shape: long, flat, short, and

irregular. The femur is an example of a long bone. The shaft, made

of compact bone, is called the diaphysis and the two ends are the

epiphyses, which are made from more spongy cancellous bone.

A strong fibrous membrane, called periosteum, almost completely

covers bones. Blood supply to the bone pierces the periosteum. In

adults, the center of the shaft (the medullary canal) contains yellow

bone marrow. Red marrow, found in the epiphyses of bones, is vital to

the production, maintenance and disposal of blood cells in the adult.

The following paragraphs describe the bones of the skeleton from

head to foot.

 

Skull

The skull is the bony framework of the head consisting of the cranium and facial bones.

Cranium

The cranium protects the brain. It is made up of eight bones, connected by fixed joints (sutures).

 

Mandible

 

The mandible is the lower jaw which carries the lower teeth. It is the
only bone in the skull which can move freely.

 

Maxilla

The upper jaw which carries the upper teeth is called the maxilla

 

The Skeleton

 

Vertebral column

 The vertebral column consists of 33 bones—in adults 24 are separate

 and movable, five are fused to make the sacrum and the remaining

 four are fused to make the coccyx. The 24 movable bones are divided

 into three regions, seven cervical vertebrae, 12 thoracic vertebrae and

 five lumbar vertebrae.

 The vertebrae are separated by intervertebral discs, consisting of

 cartilage and other tissue. The bones and discs are held in place by

 ligaments (see below). The discs allow limited movement between the

 separate bones and absorb shock.

 

Clavicle

The collar bone or clavicle articulates with the sternum and the scapula.

 

Scapula

The scapula is a large flat triangular shaped bone, also called the
shoulder blade.

 

Humerus

The bone of the upper arm is the humerus. It connects with the scapula
at the shoulder and the radius and ulna at the elbow.

 

Radius and ulna

The radius and ulna are two bones of the forearm, which, with the humerus,
make the elbow joint and with the carpal bones the wrist joint.

 

Carpal bones

In each wrist there are eight carpal bones.

 

Metacarpals

Five metacarpal bones make the palm of the hand, each bone joins the
phalanges of fingers and thumb (at the knuckles).

 

Phalanges of the hand

Each hand has 14 phalanges, three in each finger and two in the thumb.
They articulate with the metacarpals and with each other.

 

Ribs

 There are twelve pairs of ribs which form a protective cage around

 organs such as the heart and lungs in the thoracic cavity. The top 10

 are attached to the sternum at the front with cartilage, the bottom

 two ribs are free at the front. At the back, all ribs are connected to the

 thoracic vertebrae. Intercostal muscles between the ribs expand the rib

 cage in the breathing process.

 

Sternum

 The sternum is a flat bone running centrally down the front of the

 chest. The top 10 ribs are attached to the middle portion or the

 “body”. The lower tip is referred to as the xiphoid process, and the

 manubrium is the upper- most part of the sternum.

 

Pelvis

 The pelvis is formed by two innominate bones which articulate with

 the symphysis pubis and the sacrum. The innominate bones consist

 of three fused bones; the ilium, ischium and pubis. The shape of the

 female pelvis allows for the passage of a baby and in comparison to the

 male pelvis, has lighter bones and generally more room.

 

Femur

The thigh bone, or femur, is the largest and strongest bone in the body.
It joins the pelvis at its upper end and the tibia at the lower.

 

Tibia and fibula

 The tibia is the shin and is the medial of the two bones of the lower

 leg. It articulates with the femur at the knee joint and the ankle joint

 to form the ankle. The fibula is the long slender lateral bone in the leg

 which articulates with the tibia to form the ankle, but takes no part in

 the knee joint.

 

Tarsals

There are seven tarsals (ankle bones) which form the rear of the foot. They link to the tibia and fibula at the ankle, and the metatarsals in front.

 

Metatarsals

Metatarsals make up the main part of the foot. There are 5, each of which join the phalanges of the toes.

 

Phalanges of the foot

Similar to the hand, there are 14 phalanges of the foot. Two are in the

great (big) toe and three in the other toes.

 

Joints

 A joint is the site at which any two or more bones come together. Joints

 may be fixed (fibrous) such as between the bones of the cranium; they

 may allow for slight movement (cartilagenous) such as between

 vertebrae; or they may be freely moveable (synovial) such as the

 hip joint.

 The construction of a movable joint prevents the two ends of bone

 from scraping against each other. The outside layer of the joint is

 tough, fibrous, connective tissue called the capsule. Synovial membrane

 lines the joint cavity and articular cartilage covers the parts of bones

 which are in contact.

 

Cartilage

Cartilage is a relatively hard connective tissue that covers all parts of

bones in contact within a joint.

 

Ligament

Bones are held together at the joints by ligaments, a tough fibrous tissue. allow

Ligaments free movement of the joints, but also provide protection.

 

Synovial membrane

Freely movable joints are lined with a synovial membrane. The membrane
secretes synovial fluid which lubricates the joints.

 

Tendon

Muscles are connected to bones by tendons which are a cord of tissue.

Some muscles may attach directly to a bone.

 

Joint muscles

The skeletal muscles that cause parts of the body to move are joint muscles.
When a joint muscle contracts it attempts to move the bones.

 

Ball and socket joints

Ball and socket joints allow movement in all directions, i.e. flexion, extension,
abduction, adduction, rotation and circumduction.

 

Hip joint

The hip joint is a ball and socket joint between the pelvis (socket) and
the femur (ball).

 

Shoulder

The shoulder joint is a ball and socket joint connecting the humerus
(ball) to the scapula (socket).

 

Condyloid joints

Condyloid joints allow movement around two axes, i.e. flexion, extension,
abduction, adduction and circumduction.

 

Wrist

The wrist is a condyloid joint between bones in the forearm—the
radius and ulna, and the carpals of the hand.

 

Knee Joint (Synovial)

 

Ankle

The ankle is the hinge joint between the bones in the lower leg, the
tibia and fibula, and the tarsals.

 

Pivot joints

Pivot joints allow movement around one axis only, i.e rotation only.

 

Radio-ulnar joint

The radio-ulnar joint is a pivot joint between the radius and the ulna.

 

Gliding joints

The articular surfaces which glide over each other form gliding joints.

 

Sterno-clavicular joint

A gliding joint between the sternum and the clavicle is the Sternoclavicular joint.

 

Knee joint

The knee joint is a hinge joint (which includes the patella) between the
femur and the tibia.

 

Elbow

A hinge joint connecting the humerus to the radius and ulna is the elbow

 

Hinge joints

Hinge joints allow movement in one plane only, i.e. flexion and extension.

 

Muscles

 There are three main types of muscle tissue: voluntary (striated, skeletal),

 involuntary (smooth), and cardiac. Voluntary muscle is under control

 of the will and is essential to locomotion. Involuntary muscle is not under

 control of the will and is found, for example, in the alimentary canal.

 Cardiac muscle is found exclusively in the myocardium. It is not under

 control of the will, but it varies in structure from involuntary muscle.

 Muscles require a blood and nerve supply to perform their functions

 and are therefore directly dependent on the circulatory and nervous systems.

 

Insertion & origin

The insertion of a muscle is the point of attachment to the bone that it moves. (origin)
The origin of a muscle is the fixed point of attachment to a bone
opposite to the insertion.

 

Body Musculature

 

Glossary of Terms Musculoskeletal System

Articular cartilage

(ar-tik’u-lar kar’ti-lij) Dense connective tissue which covers the articular surfaces of bones.  

 

Articulation

(ar-tik-u-la’shun) Junction of two or more bones; a joint.

 

Bone

 Dense connective tissue forming the skeleton. Long bones consist of a

 diaphysis (compact bone with a central medullary canal) and two epiphyses

 (compact bone with cancellous bone inside) whereas others

 (short, irregular, flat and sesamoid) have a thin outer layer of compact

 bone with cancellous bone inside.

 

Bone marrow

Substance contained in the medullary canal of long bones and in the cancellous tissue of all bone types.

 

Cancellous bone

(kan-sel’us, kan’se-lus) Spongy, lightweight, porous bone.

 

Cardiac muscle

Muscle tissue not subject to control by human will but structurally different from involuntary muscle. It is found exclusively in the myocardium.

 

Cartilage

(kar’til-aj) Tough connective tissue which serves as protection between bones. It may also serve as attachment or support.

 

Compact bone

(kom-pakt’) Hard, dense, less porous bone.

 

Cranium

(kra’ne-um) Skull bones which protect the brain.

 

Diaphysis

(di-af’i-sis) Shaft of a long bone.

 

Epiphysis

(e-pif’i-sis) End of a long bone.

 

Involuntary muscle

A muscle not subject to control by conscious will.

 

Joint

Articulation.

 

Joint capsule

Fibrous sheath enclosing a synovial joint.

 

Kneecap

Patella.

 

Ligament

(lig’a-ment) Band of fibrous tissue connecting bones forming a joint.

 

Locomotion

(lo-ko-mo’shun) Act of moving from one place to another.

 

Medullary canal

(med’ul-lar-e) Hollow in the centre of a long bone; contains bone marrow.

 

Metaphysis

(me-taf’i-sis) Junction of epiphysis with diaphysis in a long bone.

 

Muscle

Tissue composed of fibres which have the ability to contract or shorten.

 

Muscle insertion

The point of attachment of a muscle to the bone that it moves.

 

Muscle origin

The fixed point of attachment of a muscle to a bone opposite to the Insertion

 

Musculoskeletal system

(mus-ku-lo-skel’e-tal) The structures which function to support the body,

protect internal organs, and allow locomotion.

 

Patellar tendon

(pat-el’lah) Strong cord of fibrous tissue which connects the rectus femoris

muscle to the kneecap.

 

Pelvis

(pel’vis) Bony structure surrounding the pelvic cavity.

 

Periosteum

(per-e-os’te-um) Double layer of connective tissue which covers bone except at joints; inner layer can form new bone cells.

 

Rectus femoris muscle

(rek’tus, fem’o-ris) A major muscle of the front of the thigh.

 

Skeletal muscle

Striated muscle which is attached to bone.

 

Skeleton

Bony framework of the body.

 

Smooth muscle

Involuntary muscle tissue which lacks cross-striations on microscopic exam; found in areas such as the gastrointestinal tract, respiratory tract, and uterus.

 

Striated muscle

(stri’a-ted) Any muscle whose fibres are divided into cross striations.

 

Sternum

(ster’num) Breastbone.

 

Synovial membrane

(si-no’ve-al) Lining of the joint capsule which secretes lubricating synovial fluid.

 

Tendon

(ten’don) Fibrous tissue structure which serves to connect muscle to bone and other parts.

 

Voluntary muscle

Muscle under control of the conscious will.

 

Xiphoid cartilage

(zi’foid) Lower tip of the sternum; composed of cartilage.

 

Exercises on the Musculoskeletal System

A. Write in the table below the medical terms for the numbered items in the diagram. Then check your answers against the fully labelled diagram in this section.

 

B. Write in the table below the medical terms for the numbered items
in the diagram. Then check your answers against the fully labelled
diagram in this section.

 

C. Read the definitions of terms below. Each describes a part or function
of the musculoskeletal system. You may refer to the previous text to fill
in the appropriate word or phrase.

 

 Definition

1. This system provides protection of internal organs and

the body’s framework and shape.

2. The place where two or more bones come together.

3. Bones are classified according to their shapes. The femur

(thigh bone) is an example of this type of bone.

4. A strong fibrous membrane which almost completely

covers bones.

5. The soft tissue found in the epiphyses of bones,

vital to the production of blood cells.

6. Joints which are freely movable.

7. The only bone in the skull which can move.

8. Relatively hard connective tissue that covers all

parts of bones, in contact within a joint.

9. Twelve pairs form a protective cage around organs

in the thoracic cavity.

10. The largest strongest bone in the body.

11. The tough fibrous connective tissue which forms

the outside layer of a freely movable joint.

12. The fixed point of attachment (of a muscle) to a

  bone, opposite to the insertion.

13. The point of attachment (of a muscle) to the bone

that it moves.

14. A cord of tissue that connects muscles to bones.

15. An internal organ controlled by involuntary muscles.

16. The type of muscles which move the bones.

 

Use a medical dictionary to look up the meaning of these terms which
are commonly used in describing conditions of the musculoskeletal and
connective tissue.
                 

ankylosis

Arthralgia                            

Arthritis

Avascular necrosis            

Bursitis                                

Chondritis                           

Chondromalacia

Dislocation

exostosis

fracture

genu valgum

haemarthrosis

hyperkinesia

kyphosis

lordosis

myeloma

myoma

myositis

osteitis

osteoarthritis

osteoma

osteomalacia

osteomyelitis

osteoporosis

pathological fracture

scoliosis

spondylitis

sprain

tenosynovitis

torticollis

tremor