Axial Skeleton Notes

Long Bone

• cylindrical and longer than it is wide; has a shaft and a head

• function: movement and support

• ex: femur, humerus, phalanges

Short Bone

• roughly square shaped, has a body

• function: stability, support, some motion

• ex: carpals (hand bones) and tarsals (foot bone)

Flat Bone

• thin, flat, or curved bone

• function: attachment points./ protectors for internal organs

• ex: skull, sternum, ribs

Irregular Bone

• irregular shape

• function: protect internal organs, movement, support

• ex: vertebrase, pelvis, mandible

Articulations: Condyle

• rounded knob that articulates with another bone

• ex: the (blank) of the femur articulate with the medial and lateral (blank) of the tibia.

Sesamoid Bone

• small, round bones embedded in tendons/ muscles

• function: protect tendons and allow effective muscle action

• ex: patella

Articulations: Head

• prominent bone expanded end of the bone

• ex: the (blank) of the humorous articulates with the scapula to form the shoulder joint

Articulations: Facet

• smooth, flat, slightly concave or convex surface

• ex: the (blank) on the thoracic vertebrea articulate with the ribs

Projections: Epicondyle

• projection superior to a condyle

• attachment site for muscles and ligaments

• example: medial and lateral (blank) on the humeroous

Projections: Crest

• narrow ridge

• attachment site for muscles and ligaments

• attachment site for muscles moving through vertebral column

• example: iliac (blank) superior margin of the ilium

Projections: spine

• sharp, slender, or narrow process

• ex: anterior superior iliac spine

• attachment point for muscle tendons of the trunk, hip, and thighs

Projections: Process

• bony prominence

• ex: coronoid (blank) of mandible, styloid and mastoid (blank)

Projections: line

• slightly raised, elongated ridge

• ex: mylohyoid (blank) on the mandible

Projections: Protuberance

• bony outgrowth or protrusion

• ex: mental (blank)

Projections: Trochanter

• massive process

• only on the femur

• ex: greater and lesser (blank)

Projections: Tubercle

• rough surface

• ex: tibial tuberosity attachment site for the patellar ligament

Depressions: Alveolus

• pit or socket

• ex: (blank) process of the mandible (tooth socket)

Depressions: Fossa

• shallow, broad, or elongated basin

• ex: olecranon (blank) of the humerous

Depression: Sulcus

• groove for a tendon, nerve, or blood vessel

• ex: inter tubular sulcus of the humorous

Depressions: Fovea

• small pit

• ex: fovea on the head of the femur

Passages: Canal

• tubular passage or tunnel in the bone

• ex: incisive (blank), the end of an artery and nerve travel here

Passages: Meatus

• an opening into a canal

• ex: internal acoustic (blank) of the ear

Passages: Foramen

• round hole through a bone

• ex: obturator foramen in the pelvis

Passages: Fissure

• a slit through a bone

• ex: inferior orbital fissure