W1L1: Bone Structure & Function

Five main functions of the skeletal system

Support, locomotion, protection, mineral storage (calcium/phosphate), and hemopoiesis.

Characteristics of long bones

Typical limb bones acting as levers, containing a shaft with a marrow-filled medullary cavity.

Structure of flat bones

Outer layer of compact bone with cancellous bone inside; lacks a medullary cavity.

Sesamoid bones definition and function

Sesame-seed-shaped bones developing in tendons to reduce wear and tear over bony prominences.

Pneumatic bones definition and examples

Bones containing air-filled sinuses to reduce weight (e.g., maxillary and frontal bones).

Splanchnic bones definition and examples

Bones that develop in soft organs unattached to the rest of the skeleton (e.g., os penis, os cordis).

Condyle

Large, round articular surface on a bone.

Facet

Flat articular surface on a bone.

Foramen vs. Fossa

Foramen is a hole for vessels/nerves; fossa is a depressed surface area.

Three divisions of the skeleton

Axial skeleton, appendicular skeleton, and splanchnic skeleton.

Five regions of the vertebral column

Cervical, thoracic, lumbar, sacral, and coccygeal.

Bones of the hyoid apparatus

Stylohyoid, epihyoid, ceratohyoid, thyrohyoid, and basihyoid.

Function of the hyoid apparatus

Suspends the larynx and tongue from the skull in the intermandibular space.

Types of ribs

True (sternal; direct attachment), false (asternal; form costal arch), and floating (no ventral attachment).

Sternal anatomical landmarks

Manubrium (most cranial sternebra) and xiphoid process (most caudal sternebra).

Bones forming the pelvic girdle

Ilium, ischium, pubis, sacrum, and coccyx.

Bones forming the acetabulum in dogs and cats

Ilium, ischium, pubis, and acetabular bone.

Anatomy of the equine cannon bone

The large third metacarpal (MC3) or metatarsal (MT3) bone in horses.

Equine splint bones

Vestigial non-weight-bearing metacarpals/metatarsals 2 and 4.

Anatomical names for equine digits P1, P2, P3

P1 = long pastern, P2 = short pastern, P3 = coffin bone.

Bovine metacarpal structure

Two fused metacarpal bones (digits 3 and 4) supporting weight, with digits 2 and 5 as dewclaws.

Fabellae

Two small sesamoid bones in gastrocnemius tendon of dogs and cats.

Difference between tibia and fibula function

Tibia is the main weight-bearing bone of lower leg; fibula is non-weight-bearing for muscle attachment.

Two largest proximal tarsal bones

Calcaneus and talus.

Olecranon fossa function

Fossa on distal caudal humerus that receives the anconeal process of the ulna.