Axial and Appendicular Skeleton

Axial Skeleton

• 80 bones

• includes ribs, sternum, skull, vertebrae, and hyoid bones

Bone Classification

• short- cube shaped

  • wrist and ankle

• flat- thin with sides parallel

  • frontal, parietal skull

• long (discussed in ch 6)

  • femur, humerus

• Sesamoid- no bone-bone attachment;

  • develop in tendons, patella

• Irregular- odd shapes that don’t fit other categories;

  • vertebrae, pelvic

LOOK AT BONE MARKINGS IN ADDITIONAL TERMS

Axial Skeleton Structures: Head

• calvarium/skullcap- roof of skull

• fontanels- uncalcified portions of the calvarium in a fetal skull.

  • the fibrous membranes are not replaced until 2 years old

  • slightly flexible

  • skull can change shape during birth process

• Parietal Bone

• Frontal Bone

• Occipital Bone

• Sella Turcica- on sphenoid bone.

  • site where pituitary gland/hypophysis rests.

  • ENDOCRINE GLAND

• Cribriform plate- on ethmoid bone. tiny perforations

  • olfactory nerves pass through these holes from nasal epithelium to brain

• Ethmoid bone

• Sphenoid bone

Axial skeleton structures: face

• orbit- eye sockets

• para nasal sinuses- several bones on face contain this

  • sinuses make bones lighter

  • resonance chambers to affect voice

  • sinus problems- voice differs

• zygomatic arch- cheek bone

  • formed by zygomatic bone and a process of the temporal bone

• Petrous portion- on temporal bone.

  • densest bone of the body

  • surrounds inner ear

• Wormian/sutural bones- small bones often found along sutures

  • “extra bones of skull”

Vertebrae

• 7 cervical vertebrae (neck)

• 12 thoracic vertebrae (articulate with 12 pair of ribs)

• 5 lumbar vertebrae

• 1 sacrum (5 fused vertebrae

• 1 coccyx (4 fused vertebrae)

• atlas- most superior/first cervical vertebra

  • holds up skull like mythology

• Axis- second cervical vertebra.

  • rotates around a prominence called DENS/Odontoid process

  • looks like a tooth

Spinal Curves

• no naturally occurring lateral curves

• cervical curve- anterior

• thoracic curve- posterior

• lumbar curve- anterior

• sacral curve- posterior

Scoliosis- lateral abnormal curve

kyphosis- excessive thoracic abnormal curvature

lordosis- excessive lumbar abnormal curvature

Ribs

• 12 pairs of ribs that articulate with a thoracic vertebrae

• vertebrosternal/true ribs- most superior 7 pairs have direct hyaline cartilage connection to sternum

• vertebrochondrial ribs- 3 pairs of ribs that have common cartilage connection to cartilage of the 7th true rib. FALSE RIBS

• vertebral/floating- most inferior 2 pairs of ribs have no anterior articulation. FALSE RIBS

• manubrium- superior to sternum

• body/gladiolus- middle part of sternum

• xiphoid process- inferior part of the sternum

Appendicular skeleton

• 126 bones

• fomrs the limbs and the bones that support the extremities, pelvic girlde and pectoral girdle

• pectoral girdle- bones that support the upper extremity; the scapula and clavicle

• pelvic girdle- supports lower limbs; os coxae or coxal bones

Bones of Upper Extremity

• arms (brachium)- humerus

• forearm (antebrachium)- radius on thumb, ulna on pinky

• wrist- carpals

  • refers to the group of bones in the writs

• palm- metacarpal bones

• fingers- phalanges

Bones of the Lower Extremity

• thigh- femur

• patella- knee cap

• leg- tibia

  • large bone- shin

  • fibula- small lateral

• ankle- tarsals refer to group of bones in the ankle

  • calcaneous- heel bone, one of the tarsal

• metatarsal bones

• toes-phalanges