The Musculoskeletal System

Describe bones.

Organs that make up the skeletal system, containing connective, epithelial and nervous tissue.

Name and describe the functions of the skeletal system.

• Support - provides a rigid framework to support surrounding tissues.

• Protection - create a physical barrier to internal organs

• Assist in Movement - form joints that allow for joint movement of muscles

• Mineral Regulation and Storage - mineral such as calcium and phosphorus regulate blood mineral concentrations

• Blood Cell Production - production of blood cells in red bone marrow

• Triglyceride Storage - yellow bone marrow stores triglycerides

Describe the 5 key cells of the skeletal system.

• Osteoblasts - produce extracellular matrix of bones

• Osetocytes - former osteoblasts that are trapped within extracellular matrix

• Chondroblasts - produce extracellular matrix of cartilage

• Fibroblasts - produce extracellular matrix for dense connective tissue

• Osteoclasts - contain a ruffled exterior that breaks down bone tissue

Name and describe the 2 types of osseous (bone) tissue

• Compact/cortical bone - hard dense external layer

• Spongy/Trabecular - porous and honeycomb appearance internal layer

Name, describe and give examples of the types of bone shapes.

• A - long bones, have greater length than width, eg. Humerus

• B - short bones, roughly cuboidal, eg. Tarsals and carpals

• C - flat bones, primarily flat, eg. Sternum and scapula

• D - irregular bones, don’t fit into other categories, eg. Vertebrae

• E - sesamoid, bones embedded within a tendon, eg. Patella

Describe the structure of compact bone.

Made up of a highly organised pattern of osteons that contain concentric lamellae surrounding a central canal of nerves, blood and lymph vessels.

Describe the structure of spongy bone.

Made up of a network of trabeculae containing lots of space for red and yellow bone marrow.

Describe ossification and name the 2 types.

Ossification is the formation of bones in early life.

• Endochondral ossification

• Intramembranous ossification

Explain endochondral ossification.

• An initial cartilage model of hyaline cartilage is produced

• During early growth, the cartilage model is slowly replaced by bone

• After growth, a mature bone still contains remnants of cartilage (epiphyseal line)

Name and describe the 2 divisions of the skeletal system.

• Axial skeleton - skull, spine, ribs and the sternum

• Appendicular skeleton - girdles and limbs that attach to the axial skeleton

Describe bony landmarks

Distinct features on bone that act as attachment points.

Name and describe the types of bony landmarks.

• Projections - bump that projects outwards

• Depressions - divits that cave inwards

• Openings - holes

Name and describe the 2 types of bones in the skull.

• Cranial bones - bones that make up the wall that surrounds the brain

• Facial bones - bones that don’t make the wall that surrounds the skull (make up the face)

Name the types of vertebral columns and the number of vertebrae in each.

• A - cervical (7 vertebrae)

• B - thoracic (12 vertebrae)

• C - lumbar (5 vertebrae)

• D - sacral (5 fused)

• E - coccyx (4 fused)

Name these parts of a vertebrae

• A - arch

• B - body

• C - vertebral foramen

• D - spinal chord

• E - intervertebral discs

Name these parts of the intervertebral discs.

• A - nucleus pulposus

• B - annulus fibrosus (rings of cartilage)

Name these bony landmarks of the vertebrae.

• A - transverse process

• B - lamina

• C - spinous process

• D - pedicles

• E - articular process

Name and describe the 2 girdles of the appendicular system.

• Pectoral girdle - scapula and clavicle

• Pelvic girdle - pelvis

Describe the structure and name the bones of the pelvis.

3 fused bones:

• A - ilium

• B - pubis

• C - ischium

Describe cartilage.

Strong and flexible connective tissue that protects bone, reduces friction and allows for flexibility.

Name and describe types of cartilage.

• Hyaline Cartilage - smooth, white and glassy, most abundant

• Fibrous Cartilage - very strong cartilage made up of thick collagen fibres

• Elastic Cartilage - flexible cartilage made up of elastic fibres

Name and describe the types of joints.

• Fibrous - no joint cavity and bones are attached by collagen fibre-rich connective tissue

• Cartilaginous - no joint cavity in which bones are attached by a cartilage plate

• Synovial - contains a joint cavity that allows for movement

Name and describe the types of fibrous joints and give examples.

• Suture - in the cranium

• Gomphosis - holds teeth in place

• Syndesmosis - holds 2 bones together that are further away from each other, eg radius and ulna.

Name and describe the types of cartilaginous joints and give examples.

• Primary/Synchondrosis - made up of hyaline cartilage, holding together 2 parts within 1 bone, eg. Epiphyseal cartilage growth plates in long bones.

• Secondary/Symphysis - 2 bones lined with hyaline cartilage and attached by a plate of fibrous cartilage, eg. Intervertebral discs.

Name and describe the 6 types of synovial joints and give examples.

• Plane/Gliding - 2 flat surfaces of bones sliding against one another, eg. Facet joint of the vertebrae

• Hinge - allows for flexion and extension, eg. Knee and elbow

• Pivot - allows for rotation, eg. Neck

• Ball and Socket - wide range of motion, eg. Hip and shoulder

• Condyloid - movement in 2 planes no rotation, eg. Wrist

• Saddle - concave and convex surfaces that interlock, eg. Thumb

Name these features of synovial joints.

• A - ligament

• B - synovial fluid within joint cavity

• C - articular cartilage

• D - fibrous capsule

• E - synovial membrane

• F - joint capsule

• G - bone

Describe articular cartilage.

Type of hyaline cartilage, smooth white and glossy that lines the ends of bones within a joint to reduce friction and damage as well as act as a shock absorber.

Describe the parts of a joint capsule

• Synovial membrane is the innermost layer that produces synovial fluid

• Fibrous capsule is the outermost layer that creates a fluid tight seal, is strong, preventing dislocation, however flexible, allowing for movement.

Describe synovial fluid.

Fluid within the joint capsule that acts as a lubricant and nourishes articular cartilage.

Explain the function of ligaments and name and describe the types.

Provide stability to the joint:

• Capsular - an extension of the fibrous capsule

• Intracapsular - independent of the fibrous capsule but inside the joint cavity

• Extracapsular - independent of the fibrous capsule and outside the joint cavity.

Name this joint.

Temporomandibular joint.

Name these joints of the pectoral girdle and upper limb

• A - acromioclavicular joint

• B - glenohumeral joint

• C - sternoclavicular joint

Name these joints of the lower arm.

• A - humeroulna joint

• B - radiohumeral joint

• C - proximal/superior radioulna joint

• D - distal/inferior radioulna joint

Name these joints of the pelvic girdle.

• A - femoroacetabular joint

• B - pubic symphysis joint

• C - sacroiliac joint

Name these joints of the knee.

• A - patellofemoral joint

• B - tibiofemoral joint

• C - promixal/supeiror tibiofibular joint

Name these joint of the lower leg and feet.

• A - distal/inferior tibiofibular joint

• B - talocrural joint

• C - subtalar

Describe protraction and retraction.

• Protraction - jaw and shoulder movement horizontally in the anterior

• Retraction - jaw and shoulder movement horizontally in the posterior

Describe lateral flexion and opposition.

• Lateral flexion - trunk movement/bending to one side

• Opposition - movement in which the pads of the thumb and another finger meet

Describe inversion and eversion.

• Inversion - sole of the foot rotating towards the midline

• Version - sole of the foot rotating away from the midline