Skeletal System

Functions of the Skeletal System

Support and protection, body movement, storage of inorganic materials (salt, calcium, potassium), and Hematopoiesis

Hematopoiesis

blood cell formation, occurs in Red Bone Marrow

Number of Bones in the Body

Around 270 at birth and 206 as an adult

Axial skeleton

Head, Neck, Trunk. Contains: Skull, Hyoid Bone, Vertebral Column, Rib Cage and Sternum

Appendicular Skeleton

Limbs and bones connecting the limbs to the Pectoral Girdle and the Pelvic Girdle.

Pectoral Girdle

Scapula, Clavicle, Arm, Forearm, wrist and hand

Pelvic Girdle

Coxal Bones, Thigh, Leg, Ankle, and Foot

Fibrodysplasia Ossificans Progressiva

Causes soft tissues to turn to bone from minor traumas. Caused by a mutation in the ACVR1 gene located on the 8th Chromosome.

Flat Bones

Protection; sternum, ribs, skull bones

Long Bones

Support weight and movement; femur, tibia, fibula, humerus, radius, ulna

Short Bones

Stability and Movement; carpals and tarsals

Irregular Bones

Protect Organs; vertebrae and pelvis

Sesamoid Bones

Reinforce Tendons; Patella

Epiphysis

Ends of the Bone

Proximal Epiphysis: closest to body’s center

Distal Epiphysis: Farthest from body’s center

Epiphyseal Disk

growth plate, band of cartilage between epiphysis and diaphysis. Females close 13-15, Males close 15-17

Metaphysis

Between Epiphysis and Diaphysis

Diaphysis

shaft of the bone

Articular Cartilage

cartilage covering the end of long bones (hyaline cartilage for padding)

Periosteum

Membrane covering the entire bone

Medulla (Medullary Cavity)

contains yellow bone marrow

Endosteum

lining of the Medullary Cavity

Red Bone Marrow

Produces red and white blood cells

Yellow Bone Marrow

fat storage, stem cells for fat, bone and cartilage.

Compact Bone Tissue

wall of diaphysis

Cancellous Bone Tissue

Spongy Bone Tissue, epiphysis (contains red bone marrow)

Osseous Tissue

Bone tissue

Matrix

composed of collagen and inorganic materials (calcium + phosphate)

Osteocytes

mature bone cells

Lacunae

contain osteocytes, help form Lamellae

Lamellae

individual rings around Haversian Canal

Haversian Canal

houses blood vessels and nerves in the center of the lamellae

Canaliculi

tiny canals that link osteocytes

Volkmann’s Canal

canals that connect osteon

Osteon

one set of rings

Ossification

process of bone development, Hyaline cartilage gradually turns into Osseous tissue

Primary Ossification Center

increase diameter

Secondary Ossification Center

increases length

Osteoblasts

create osteocytes (build bones)

Osteoclasts

bone resorption (consume bone)

Hallux Abducto Valgus Deviation

big toe (hallux) forms a lateral deviation (L shaped over other toes)

Heterotopic Ossification (HO)

abnormal growth of bone in non-skeletal tissue

Bone Growth in FOP…

is likely due to a mutation in a gene that codes for BMP (Bone Morphogenetic Protein) resulting it to say in the “on” position

Noggin and Gremlin

are inhibitors of BMP signaling (can stop bone development)

Treatment for FOP

Steroids help with inflammation, gene therapy, increase inhibitors of BMP.

What can bones tell us

sex, age, height, ancestry, diet, where they lived

What is a forensic anthropologist

Work with law enforcement to identify remains associated with crimes

Synarthrotic Joints

immovable joint, junctions are called sutures

Amphiarthrotic Joints

slightly moveable joint, vertebrae

Diarthrotic Joints

freely moveable joints. Ball&Socket (shoulder and hip) Hinge (elbow and knee) Pivot (lateral elbow, C1-C2) Saddle (thumb)

How many joints in the body

360

Bones of the Skull (10)

Frontal, Parietal, Temporal, Occipital, Sphenoid, Ethmoid, Maxilla, Mandible, Zygomatic, Vomar

Sutures

connection points between skull bones

Coronal Suture

between frontal + parietal

Lambdoidal Suture

Between Occipital + Parietal

Squamosal Suture

Between Temporal + Parietal

Sagittal Suture

Between L + R Parietal

Foramen

Any opening in the skull, nerves and blood vessels leave this opening to supply the face

Supraorbital Foramen

located above the eye socket

Infraorbital Foramen

located under the eye socket

Mental Foramen

opening in chin

Foramen Magnum

largest opening, located at the bottom of the skull, where the spinal cord passes through

Fontanels

“soft spots” of an infants skill that form sutures as you age

Vertebrae

Cervicle: C1-C7, Neck

Thoracic: T1-T12, Middle Back

Lumbar: L1-L5, Lower Back

Sacrum + Coccyx

Ribs (Thoracic Cage)

12 pairs (24 ribs)

True: 1-7, attached directly to the sternum

False: 8-10, attached to the ribs above them

Floating: 11-12, found on dorsal side

Pectoral Girdle

Shoulder, 2 clavicles, 2 scapula and bones on arms

Pelvic Girdle

2 large hip bones call coxal (Ilium), and bones of the legs

Carpals (8)

Scaphoid, Lunate, Triquetrum, Pisiform, Hamate, Capitate, Trapezoid, Trapezium

Tarsals (7)

Calcaneus, Cuboid, Lateral Cuneiform, Intermediate Cuneiform, Medial Cuneiform, Navicular, Talus

Transverse Fracture

horizontal break across the bone

Linear Fracture

Runs parallel to the long axis of the bone

Oblique Fracture

Occurs at an angle across the bone

Open Fracture

bone pierces through the skin

Spiral Fracture

fracture due to twisting force

Greenstick Fracture

Incomplete, only one side of bone is broken

Comminuted Fracture

Bone is shattered into 3+ pieces

Bone Spurs (Osteophytes)

body grows small projections on bones, commonly on the anterior calcaneous

Plantar Fasciitis

inflammation of the plantar fascia, causes heel pain

Osteoporosis

Osteoclasts cause a break down in bones, spongy bone becomes more porous. Caused by last of exercise, poor diet, genetics, ethnicity and gender

Hip Fracture

Femoral neck fracture, can be related to osteoporosis

Rheumatoid Arthritis

autoimmune disease causing joint stiffness and bone deformity

Rickets

Deficiency of vitamin D causing weak and brittle bones

Nursemaid’s Elbow

annular ligament

Shoulder Dislocation

humerus pops out of socket

Fibrodysplasia Ossificans Progressiva (FOP)

soft tissue regrows as bone

Osteosarcoma

bone cancer commonly in knees affecting teens and young adults

hyperkyphosis

abnormality of the spine, hunchback

hyperlordosis

abnormality of the spine, swayback (lower back)

Ankylosis

severe arthritis, vertebrae fuse

Scoliosis

abnormal curve of the spine greater than 10 degrees

Parts of the Sternum

manubrium, body and xiphoid process