LECTURE 10: skeletal system

Axial skeleton

Includes skull, ribcage, vertebral column, hyoid bone

Appendicular skeleton

includes upper limb and pectoral girdle; lower limb and pelvic girdle

What is a joint?

Joint= articulation (where 2 bones meet)

What is a fibrous joint?

A joint held together by connective tissue proper

What is a cartilaginous joint?

A joint held together by cartilage.

What is a synovial joint?

A joint held together by combinations of connective tissues around a joint space.

What is the relationship between mobility and stability?

There is a tradeoff; not all joints have movement and some are highly moveable, but the more they can move the less stability they have and vise versa.

What are the three types of joints?

fibrous, cartilaginous, and synovial joints.

What is a fibrous joint?

Bones held together by dense collagen (dense regular connective tissue).

What is a cartilaginous joint?

Bones held together by hyaline cartilage or fibrocartilage

What is a synovial joint?

The most common and moveable joint characterized by fluid-filled space between the connected bones.

What is a joint capsule?

Encases synovial joints with dense connective tissue

What is articular cartilage?

The bones are covered with hyaline cartilage on the surfaces where they contact, providing a smooth gliding surface for the bones.

What is the synovial membrane?

Lining of the interior of the joint that produces synovial fluid.

What is synovial fluid?

Reduces friction between two bones as they move.

What are the functions of the axial skeleton?

Support and protection for organs, provides attachment sites for muscles and limbs.

The skull

Includes cranial and facial bones, only few bones in skull move, many holes (foramina) allowing passage of nerves and blood vessels.

What are suture joints?

Fibrous connective tissue that holds cranial bones tightly together.

What are fontanelles?

Membrane covered gap/soft spot on an infants skull where the cranial bone plates have not fully fused together yet

The cranial cavity

Cavity where brain resides

What is the Foramen Magnum

The biggest hole through where the spinal cord connects to the brain.

Paranasal sinuses

Air-filled spaces surrounding the nasal cavity lighten the weight of the skull and add resonance to speech.

What is the orbit?

Houses the eyeball and its muscles.

The oral cavity

Houses tongue, teeth, gums, salivary glands

The vertebral column

The neck: 7 cervical vertebrae

The upper back: 12 thoracic vertebrae

The lower back: 5 lumbar vertebrae + sacrum (5 fused vertebrae) + coccyx (3-5 tiny bones)

• there are intervertebral discs of fibrocartilage between vertebrae

The vertebral canal

Houses and protects spinal cord

What are the four curvatures of the spine?

cervical, thoracic, lumbar, and sacral curve

What are the primary curves?

Thoracic and sacral because they form during fetal development (to accommodate the growing of organs)

What are the secondary curves?

Lumbar and cervical curves because they appear after birth (they form as the cild shifts body weight for upright posture).

What are the three abnormal curvatures of the spine?

Kyphosis, lordosis, and scoliosis.

What is kyphosis?

Exaggeration of thoracic curvature

What is lordosis?

Exaggeration of lumbar curvature

Thorax

The skeleton of the chest (ribcage).

What are the components of the rib cage?

Ribs, sternum, costal cartilages, and sternal angle.

What are costal cartilages?

Cartilage that joins ribs to sternum.

What is the sternal angle?

Landmark that is used to locate the 2nd rib.

What is the diaphragm?

The major breathing muscle spanning the bottom of thoracic cavity and separates its from abdominopelvic cavity.

The appendicular skeleton

Bones of the limbs and supporting bones that connect the limb to the axial skeleton.

What is a limb girdle?

Series of bones connecting limb to trunk (pectoral and pelvic girdle)

Upper extremity bones

Lower extremity bones