NOTES: Skeletal Organization (Ch 7, part 2)

SKELETAL ORGANIZATION

The skeleton can be divided into 2 portions:

1) Axial Skeleton

2) Appendicular Skeleton

1) AXIAL SKELETON:

Components of

Axial Skeleton

This component includes…

SKULL Cranium (brain case) and the facial

bones

HYOID BONE Horseshoe-shaped bone in neck HYOID BONE Horseshoe-shaped bone in neck

(between lower jaw and larynx)

VERTEBRAL

COLUMN

Many vertebrae (separated by

cartilaginous intervertebral discs);

sacrum; and coccyx

THORACIC

CAGE

12 pairs of RIBS (most of which) are

connected to STERNUM (breastbone)

by costal cartilage

2) APPENDICULAR SKELETON:

Components of Appendicular Skel.

This component includes…

PECTORAL

GIRDLE

SCAPULA (“shoulder blade”) and

CLAVICLE (“collarbone”)

UPPER LIMBS HUMERUS (arm bone) and UPPER LIMBS HUMERUS (arm bone) and

RADIUS and ULNA (forearm

bones); and wrist bones and hand

bones (CARPALS,

METACARPALS, and

PHALANGES)

2) APPENDICULAR SKELETON:

Components of Appendicular Skel.

This component includes…

PELVIC GIRDLE Two COXAE (hipbones) which attach to each other on the anterior surface and to the SACRUM on the surface and to the SACRUM on the posterior surface; with the sacrum and coccyx, form the PELVIS

LOWER LIMBS FEMUR (thighbone), TIBIA(shinbone) and FIBULA; PATELLA(kneecap); and ankle bones and foot bones (TARSALS, METATARSALS, and PHALANGES)

SKULL

**The skull consists of 22 bones; 8 cranial

bones, 14 facial bones.

� CRANIUM:

• encloses and protects the brain

• some cranial bones contain air-filled SINUSES

� CRANIUM:• cranial bones include:

FRONTAL BONE ETHMOID BONE

OCCIPITAL BONE SPHENOID BONE

PARIETAL BONES (2)

TEMPORAL BONES (2)TEMPORAL BONES (2)

� FACIAL SKELETON:• facial bones form the basic shape of the

face and provide attachments for muscles

� FACIAL SKELETON:

• facial bones include:

MAXILLAE

MANDIBLE

ZYGOMATIC BONES

NASAL BONESNASAL BONES

LACRIMAL BONES

INFERIOR NASAL CONCHAE

PALATINE BONES

VOMER BONE

� INFANTILE SKULL:

• fontanels connect incompletely developed bones

• proportions of infantile skull are different from an adult skullfrom an adult skull

VERTEBRAL COLUMN

**The vertebral column

extends from the skull to the

pelvis and protects the

spinal cord. It is composed spinal cord. It is composed

of vertebrae, separated by

intervertebral discs.**

� A TYPICAL VERTEBRA:

• consists of a body and a bony vertebral arch, which surrounds the spinal cord

• notches on upper and lower surfaces provide intervertebral foramina through provide intervertebral foramina through which spinal nerves pass

**Foramina = openings through which

spinal nerves and/or blood vessels

pass**

� CERVICAL VERTEBRAE:

• the ATLAS (1st vertebra) supports and balances the head

• the dens of the AXIS (2nd vertebra) provides a pivot for the atlas when the head is turned from side to side

� CERVICAL VERTEBRAE:

� CERVICAL VERTEBRAE:

� THORACIC VERTEBRAE:

• thoracic vertebrae are larger than cervical vertebrae

• facets on the sides articulate with the RIBS

� THORACIC VERTEBRAE:

� LUMBAR VERTEBRAE:

• the vertebral bodies are large and strong

• they support more body weight than other vertebrae

� LUMBAR VERTEBRAE:

� SACRUM:

• the sacrum is a triangular structure formed of five fused vertebraefused vertebrae

• vertebral foramina form the sacral canal

� SACRUM:

� COCCYX:• the coccyx,

composed of four fused vertebrae, forms the lowest part of the vertebral of the vertebral column

• it acts as a shock absorber when a person sits

� COCCYX: