Axial Skeleton + Muscles of the Trunk, Back, Neck

Sternum

"breast bone," articulates with true ribs, together protect heart + lungs

Coccyx

"tail bone"

True ribs

1-7, articulate directly with sternum by costal cartilage

Floating ribs

11 + 12, articulate with sternum indirectly

False ribs

8-10, articulate with sternum indirectly

Thoracic cavity

above

Vertebral, spinal, canal

all of the vertebral foramina line up together and form a long tube, the nerves of the spinal cord run through here

Curves, vertebral column

allow bones to act as a "spring" which dissipates forces produced by walking, jumping, etc., prevents forces from damaging bone, muscle, other tissues

Head

articulates medially with the rib facets of thoracic vertebra

Sacrum

articulates with the fifth lumbar vertebra + wings of the hip bones, right, left ilium, formed by five fused vertebrae

Deep back muscles, erector spinae

begins where it attaches to the lower back and hips, run upwards along the spine, attaches to the skull

Abdominal cavity

below

Inferior articular process

bony projections that point inferiorly and articulate with vertebra below

Superior articular process

bony projections that point superiorly to articulate with the vertebra above

Transverse process

bony region that extends laterally from the body

Intervertebral disc

connective tissue, separate bodies of every vertebra, reduce friction as vertebrae move, assist in absorbing shock

Innermost intercostal muscles

deepest layer, fibers line the inside of chest, run superior-inferior, may assist in exhalation by pulling ribs downward

Transversus abdominus

deepest muscle layer of lateral abdominal walls, below internal oblique muscle, fibers run side to side like belt around abdomen, horizontal, right + left

Angle

distal to tubercle, rib makes sharp bend

Diaphragm

dome shaped muscle responsible for increasing the volume of thoracic cavity to help inhale, forms division between thoracic + abdominal cavity

Sternocleidomastoid

fibers extend from mastoid process to medical clavicle to manubrium of sternum

Internal intercostal muscles

fibers run on either side of chest from superior-medial to inferior-lateral, A-shape, may assist in exhalation by pulling ribs downward

Atlas

first cervical vertebrae, articulates the skill superiorly, axis inferiorly, supports skull

Lumbar vertebra

five, articular surface curved, cupped, look like shaking hands rather than high-fiving each other

Median sacral crest

formed from the spinous process of the fused vertebrae

Body

found on all vertebrae except the atlas, body transmits weight down these

Rib, costal, facets

found on the body + transverse processes, covered with articular cartilage, appear smooth in real bone

Body, sternum

large middle portion

Auricular surface

later faces of sacrum, forms joint between sacrum + ilium

External oblique

lateral to abdominus rectus muscles, from superficial part of abdominal wall, V-shaped, right + left

Internal oblique

lateral to rectus abdominus muscles, hidden underneath external oblique muscles, middle layer of abdominal wall, A-shaped, right + left

Body, ribs

main part, distal to neck

Body, sacrum

main thick medial region of the sacrum

Vertebral foramen

opening formed by the vertebral body and arch

Sacral canal

passageway which corresponds with the vertebral canal

Xiphoid process

projection, inferior to body of sternum

External intercostal muscles

run on either side of your chest from superior-lateral to inferior-medial, forms a V-shape, may assist in inhalation by pulling ribs upwards

Axis

second cervical vertebrae, allows shaking of the head back and forth, move head along an axis

Cervical vertebrae

seven in the neck, transverse foramen

Axial skeleton

skull, vertebral column, sacrum, ribs, sternum

Tubercle

small bumpy ridge, distal to head, smooth portion, another articular facet, which articulates with the transverse process of thoracic vertebrae

Pelvic curvature, curve

small of the back

Spinous process

somewhat sharp projection that extends posteriorly, opposite from the body of the vertebra

Linea alba

strong connective tissue, connects the xiphoid process to pubic tubercle, right + left rectus abdominus

Facets

surfaces where two bones physically articulate

Vertebral arch

transverse + spinous process arise from this

Thoracic vertebra

twelve, rib facets

Rectus abdominus

two, one on each side of midline, individuals with low body fat form what is often called a "sick pack"

Manubrium

upper part of sternum

Facets, sternum

where costal cartilage associated with ribs articulate