Chapter 8 The Skeletal System

forms the central supporting axis of the body, includes the skull, auditory ossicles, hyoid bone, vertebral column, and thoracic cage (ribs and sternum)

includes the bones of the upper limb and pectoral girdle and the bones of the lower limb and pelvic girdle

at birth, there are 270

-bones that form within some tendons in response to stress; the patella (kneecap) is the largest of these; most of the others are small and rounded bones, like knuckles.

sutural or wormian bones

• condyle
• facet
• head

a rounded knob that articulates (joins) with another bone

a smooth, flat, slightly concave or convex articular surface

the prominent expanded end of a bone, sometimes rounded

• crest
• epicondyle
• line
• process
• protuberance
• spine
• trochanter
• tubercule
• tuberosity

a narrow ridge

a projection superior to a condyle

a slighty raised, elongated ridge

any bony prominence

a bony outgrowth or protruding part

a sharp, slender, or narrow process

two massive processes unique to the femur

a small, rounded process

a rough elevated surface

• alveolus
• fossa
• fovea
• sulcus

a pit or socket

a shallow, broad, or elongated basin

a small pit

a groove for a tendon, nerve or blood vessel

• canal
• fissure
• foramen
• meatus
• sinus

a tubular passage or tunnel in a bone

a slit through a bone

a hole through a bone, usually round

an opening into a canal

an air-filled space in a bone

it is the most complex part of the skelaton

bones are connected by these immovable joints, which are visable as seams on the surface

encloses the brain

holes that allow passages for nerves and blood vessels

braincase, which protects the brain and associated sense organs

form most of the cranial roof and part of its walls.

• 1. sagittal suture
• 2. coronal suture
• 3. lambdoid suture
• 4. squamous suture

forms the lower wall and part of the floor of the cranial cavity

complex shape with a thick median body and outstretched greater and lesser wings, which give the bone as a whole, a somewhat ragged mothlike shape

permits passage of the optic nerve and opthalmic artery

an interior cranial bone located between the eyes

• -those that have no direct contact with the brain or meninges. 14 bones
• -they support the teeth, give shape & individuality to the face, form part of the nasal and orbital cavities, and provide attachment for the muscles of facial expression and mastification

largest facial bones, form the upper jaw

small points of maxillary bone that grow into the spaces between the bases of teeth

deep socket that the tooth is inserted into

• frontal
• nasal
• ethmoid
• sphenoid
• zygomatic
• palatine
• lacrimal

forms the roof of the mouth and floor of the nasal cavity

forms the rest of the hard palate, part of the wall of the nasal cavity and part of the wall of the orbit

forms the angles of the cheeks at the inferolateral margins of the orbits and parts of the lateral wall of each orbit

form part of the medial wall of each orbit; smallest bones of the skull

forms the bridge of the nose and supports cartilages that shape its lower portion

• forms the inferior half of the nasal septum
• means "plowshare," refers to the resemblance to the blade of a plow

strongest bone of the skull; only one that can move noticably

permits passage of the nerves and blood vessels of the chin

oval knob that articulates with the mandibular fossa of the temporal bone

the meeting of the mandibular condyle with the temporal bone and forms a hinge

u-shaped arch between the two processes

• malleus (hammer)
• incus (anvil)
• stapes (stirrup)

slender u-shaped bone between the chin and larynx

spaces between the unfused cranial bones

physically supports the skull and trunk, allows for their movement, protects the spinal cord, and absorbs stresses produced by walking, running, and lifting

• cervical 7
• thoracic 12
• lumbar 5
• sacrum 1
• coccyx 1

a pad consisting of an inner gelatinous nucleus pulposus surrounded by a ring of fibrocartilage, the anulus fibrosus

• 23
• - the first one between the cervical vertebrae and the last one between the last lumbar vertebrae and the sacrum

ruptured or slipped disc

vertebra C1, supports the head

vertebra C2, allows rotation of the head, gesturing "no"

• 12 (T1-T12)
• corresponds to the 12 pairs of ribs

• 5 (L1-L5)
• thick, stout body and a blunt, squarish spinous process

a bony plate that forms the posterior wall of the pelvic cavity, once considered the seat of the soul

in children, there are 5 seperate sacral vertebrae (S1-S5); they begin to fuse around age 16 and are fully fused by age 26.

consists of four, sometimes five small vertebrae (Co1-Co4); fuse by the age of 20 to 30 into a single triangular bone

consists of the thoracic vertebrae, sternum and ribs

breastbone; a bony plate anterior to the heart; subdivided into three regions: manubrium, body and xiphoid process

• 12 pairs; no difference between the sexes
• each is attached at its posterior (proximal) end to the vertebral column, and most of them are also attached at the anterior (distal) end to the sternum

• ribs 1-7
• each has its own coastal cartilage connecting it to the sternum

• ribs 8-12
• lack independent cartilagenous connections to the sternum

ribs 11 and 12

shoulder girdle; supports the arm, consists of two bones: clavicle (collar bone) and scapula (shoulder blade)

30

upper arm bone

forearm bone; thumb side

forearm bone; pinky side

form the wrist; arranged in two rows of four bones each

• scaphoid
• lunate
• triquetrium
• pisiform
• trapezium
• trapezoid
• capitate
• hamate

bones of the palm

bones of the fingers

thumb; made of two phalanges; three in the other digits

• consists of a complete ring of three bones:
• two hip (coxal) bones and the sacrum (part of vertebral column)

longest and strongest bone of the body

kneecap

big toe; contains two bones; others have three

• medial longitudinal arch
• lateral longitudinal arch
• transverse longitudinal arch