Skeletal System Flashcards
The skeletal system is composed of 2 groups, what are they known as?
Axial skeleton
Appendicular skeleton
Define the Axial Skeleton.
The Axial Skeleton is a group of bones that mainly serve to protect vital organs. They form the main axis or core of the skeletal system.
Describe the cranium and its purpose.
The cranium is made up of hard sheets of bone with fixed joints that protect the brain. At birth, these bones are loose but fuse together at a young age and remain fused for life.
How many cranial and facial bones are there?
There are 8 cranial bones and 14 facial bones. The facial bones help to shape the face.
Describe the thorax and its function.
The thorax comprises of the sternum and 12 pairs of ribs.
It has two primary roles:
Protection for the heart and lungs, and shaping the body.
What are the ribs and what do they do?
The ribs are a series of flat bones positioned closely together in a concave shape around the heart and lungs, providing protection and shape.
Describe the vertebral column.
The vertebral column consists of 33 irregularly shaped bones called vertebrae. These extend from the base of the cranium to the pelvis, providing a central axis for the body.
What is the primary objective of the vertebral column?
Its primary objective is to protect the spinal cord and support the ribcage.
How is the vertebral column held together and what does it allow?
The bones of the vertebral column are held together by powerful ligaments that allow slight movement between adjacent vertebrae, providing considerable flexibility along the length of the spine.
Define cervical vertebrae and state how many there are.
Cervical vertebrae are 7 vertebrae located in the neck. They are designated as C1 through C7.
What are C1 and C2 also known as and why are they special?
C1 is called the “Atlas” and C2 is known as the “Axis.” These are highly specialised vertebrae that form a joint allowing free movement of the head and neck.
Describe the general features of cervical vertebrae C3-C7.
C3-C7 are more typical vertebrae with a body, pedicles, laminae, spinous processes, and facet joints.
What is unique about the cervical vertebrae in terms of anatomical structures?
Cervical vertebrae contain transverse foramen, slight openings that allow vertebral arteries to flow through, supplying blood to the brain.
How does the cervical section of the spine differ in terms of movement?
The cervical spine has the most range of movement compared to other sections of the vertebral column.
Define thoracic vertebrae and how many there are.
Thoracic vertebrae consist of 12 vertebrae located in the thoracic area. They are larger than cervical vertebrae and increase in size from top to bottom.
Define lumbar vertebrae and their characteristics.
Lumbar vertebrae are 5 vertebrae situated in the lower back. They are the largest vertebrae due to their role in supporting the most weight.
Define sacral vertebrae and their unique characteristics.
Sacral vertebrae consist of 5 vertebrae that are fused together, forming the sacrum. This is located below the lumbar spine and forms the back wall of the pelvic girdle.
Define coccygeal vertebrae and describe their features.
Coccygeal vertebrae consist of 4 fused vertebrae that form the coccyx, also known as the tailbone.
List the sections of the spine from top to bottom.
Cervical, Thoracic, Lumbar, Sacral, Coccygeal
How many vertebrae are in the cervical section?
7 vertebrae (C1-C7)
How many vertebrae are in the thoracic section?
12
How many vertebrae are in the lumbar section?
5
How many vertebrae are in the sacral section?
5 (fused)
How many vertebrae are in the coccygeal section?
4 (fused)
Define the role and function of the appendicular skeleton.
The appendicular skeleton is for movement, leverage, shape and blood production. It also provides some protection and comprises the upper and lower limbs and extremities, as well as the pectoral and pelvic girdles.
What bones make up the pectoral girdle?
The pectoral girdle consists of 2 shoulder blades (scapulae) and 2 collar bones (clavicles).
Describe the characteristics and functions of the scapulae.
The scapulae are flat, triangular bones that stretch from shoulder to shoulder, connecting to the vertebral column. They have a bony ridge on the back, forming the acromion and providing muscle attachment points.
What are the functions of the clavicles?
The clavicles extend from the manubrium of the sternum to the acromion of the scapula. They support the shoulder blades and enable free arm movement, while also preventing the pectoral girdles from dislocating easily.
Describe the function of the glenoid cavity.
The upper outer corner of the scapula ends in the glenoid cavity, which forms a ball and socket joint with the head and upper arm bone, allowing for a wide range of movement.
Describe the humerus and its role.
The humerus is a single bone in the upper arm. Its upper end forms a semi-spherical ball that fits into the shoulder blade’s socket, creating the shoulder joint. The lower end forms joints with the radius and ulna at the elbow.
How do the ulna and radius articulate with the humerus?
The lower end of the humerus forms a shallow ball and socket joint with the radius and a hinge joint with the ulna. The ulna’s lower end plays a minor role in wrist joint formation, while the radius is more significant in the wrist and allows forearm rotation.
What bones make up the wrist joint?
The wrist bones, also known as carpals, articulate mainly with the broad, lower end of the radius.
Describe the radio-ulnar joints and their function.
The radio-ulnar joints are pivot joints where the moving bone is the radius. As the head of the radius pivots, the lower end moves around the lower head of the ulna, allowing for forearm rotation.
What bones support the palm and fingers?
The palm is supported by 5 metacarpals, which articulate with the carpals and the phalanges. Fingers are made up of 14 phalanges, 3 in each finger and 2 in each thumb.
