Skeletal System Flashcards
How many bones in the human body?
206 bones
Axial Skeleton
Skull, Ribs, Sternum, Vertebral Column (80 bones total)
Appendicular Skeleton
Upper and Lower limbs, pelvic girdle, pectoral (shoulder) girdle (126 bones total)
Mandible
Movable jawbone. Only movable joint in the skull. Articulates with temporal bone
Cranium
Superior portion of the skull. Protects the brain from damage
Facial bones
Inferior/Anterior portion of the skull. Supports the structure of the eyes, nose and mouth
Cervical Spine
Bones of the neck. 7 Cervical vertebrae, named C1-C7
Thoracic Spine
12 thoracic vertebrae (T1-T12)
Lumbar Spine
Lower back. 5 Lumbar vertebrae (L1-L5)
Sacrum
1 vertebrae
Coccyx
Tailbone, 1 vertebrae
Sternum
Breastbone, thin, knife-shaped bone. Located along the midline of anterior side. Connected to the ribs via costal cartilage
Ribcage
12 pairs of ribs + the sternum.
True ribs
First 7 ribs. Attach the vertebrae directly to the sternum through a band of costal cartilage
False ribs
Ribs 8, 9, and 10. Connect to sternum through cartilage of the 7th rib.
Floating ribs
Ribs 11 & 12. No cartilage attachment to the sternum
Pectoral Girdle
L & R scapulae and L & R clavicles. Connects the upper arm bones to the axial skeleton
Humerus
Bone of the upper arm. Forms ball and socket joint with the scapula.
Radius & Ulna
Bones of the forearm.
Radius: allows forearm/hand to turn over the wrist joint
Ulna: medial side, hinge joint with the humerus at the elbow
Carpals
Bones of the wrist (8 small bones)
Connects to the 5 metacarpal bones of the hand.
Bones of the finger
Each finger has 3 phalanges.
Distal, Intermediate/middle, and proximal.
Thumb has 2 phalanges
Pelvic Girdle
L & R hip bones
Connects lower limbs/legs to the axial skeleton.
Femur
Largest bone in the body.
Only bone in thigh/femoral region.
Forms the knee joint with the patella and tibia.
Patella
Kneecap
Not present at birth
Formed in early childhood for crawling and walking
Tibia
Bears most of the body’s weight.
Larger than the fibula
Bone in the lower leg
Fibula
Mainly a muscle attachment.
Used to help maintain balance
Tibia & Fibula
Form ankle joint with the talus bone
Bones of the lower leg
Tarsals
7 small bones
Forms the posterior end of foot and heel.
Forms joint with 5 metatarsal bones
Metatarsals
Each form joint with the set of phalanges
Each toes = 3 phalanges
Big/Great toe = 2 phalanges
Types of Bones
Short
Long
Flat
Irregular
Sesamoid
Characteristics of Short Bones
About as long as they are wide
Often cube/rounded in shape
Ex: Carpal & Tarsal bones
Characteristics of Long Bones
Longer than they are wide
Major bones of the body
Epiphysis, Metaphysis, diaphysis
Characteristics of Flat Bones
Vary greatly in size/shape
Often very thin in one direction
Characteristics of Irregular Bones
Do not fit the pattern or characteristics of other types of bones
Characteristics of Sesamoid Bones
Formed after birth inside tendons that run across joints
Protects tendons from stress/strains @ the join to give a mechanical advantage to muscles pulling tendons
Joint (define)
Point of contact between bones or bones/cartilage.
Synovial Joints
Most common type of articulation.
Small gap between bones filled with synovial fluid to lubricate the joint.
Types of Synovial Joints
4 Types
Hinge
Gliding
Saddle
Ball & Socket
Hinge Joint
Open/Close like a hinged door
Ex: Knee & Elbow
Gliding Joint
Between the surface of 2 flat bones held together by ligaments
Ex: some of wrist/ankle joints
Saddle Joint
Rock back/forth and side/side with limited rotation
Ex: only in thumb joint
Ball & Socket Joint
Allow for movement in many directions.
Ex: Shoulder / Hip
Cartilaginous Joints
Where bones meet cartilage or where there is cartilage between joints.
Epiphysis
End of a long bone
Diaphysis
Middle of a long bone
Metaphysis
Region of growth/fusion between epiphysis and diaphysis
Articular Cartilage
Shock absorber and gliding surface between bones to facilitate movement
Periosteum
- Thin layer of dense connective tissue covering the outside of a bone.
- Contains many strong collagen fibers that are used to anchor tendons and muscles to the bone for movement.
- Stem cells/osteoblasts are involved in growth & repair.
- Blood vessels provide energy to cells on the surface of bone and penetrate bone to nourish inside.
- Contains nervous tissue/nerve endings for bone sensitivity.
Types of Muscle Tissue
Smooth, cardiac, skeletal
Characteristics of Smooth Muscle
Non striated.
Involuntary control.
Located in walls of internal structures (blood vessels, stomach, intestines, urinary bladder)
Characteristics of Cardiac Muscle
Forms the walls of the heart.
Striated.
Contraction is involuntary.
Characteristics of Skeletal Muscle
Attached to bones.
Striated (alternating light/dark bands/striations that run perpendicular to eh long axes of the fibers)
Voluntary/Conscious control (made to contract/relax)
Tendons
Tough bands of fibrous connective tissue.
Connects muscle to bone.
Made of collagen.
Can withstand tension.
Ligaments
Fibrous bands/sheets of connective tissue.
Connects 2+ bones, cartilages or structures.
Excessive movement is restricted by ligaments.
