Vet Med Term - Chapter 3

Musculoskeletal system

Consists of 2 systems that work together to support the body and allow for movement of animal

Functions of skeletal system

• framework that provides support and structure

• Formation of blood cells

• Aids in movement

Structures of skeletal system

• bones

• Cartilage

• Joints

• Ligaments and tendons

• Bursa

• Synovial membrane and fluid

Bone

• one of the hardest tissues in the body

• Start as cartilage and fibrous membranes that harden into bones before birth

Oste/o, oss/e, oss/i

Bone

Ossification

Formation of bone from fibrous tissue

Cortical bone (compact bone)

Hard, dense, strong bone that forms the outer layer of bone

Cancellous bone (spongy bone)

Lighter, less strong bone that is found in the ends and inner portions of the long bone

Cancellous

Latticework in Latin

Long bones

Consists of a shaft, two ends, and a marrow cavity

• ex: femur, humerus, tibia, radius

Hematopoietic

Formation of blood and blood components

Red bone marrow produces

• red blood cells

• White blood cells

• Clotting cells

Yellow bone marrow produces

• fat storage

Cortex

Bark or shell in Latin

Epiphysis

Wide end of a long bone, which is covered with articular cartilage and is composed of cancellous bone

Proximal epiphysis

Located nearest the midline of body

Distal epiphysis

Located farthest from midline of body

Diaphysis (growth plate) (epiphyseal cartilage)

Shaft of a long bone that is composed mainly of compact bone cartilage segment of lone bone that involves growth of the bone

Metaphysis

Wider part of long bone shaft located adjacent to the physis

• in adult animals, it is considered part of epiphysis

Periosteum

Tough, fibrous tissue that forms the outer covering of bone

Endosteum

Tough, fibrous tissue that forms the lining of the medullary cavity

Short bones

Cube-shaped with no marrow cavity

• ex: carpal bones

Flat bones

Thin, flat bones

• ex: pelvis

Pneumatic bones

Sinus-containing bones

• ex: front bone

Irregular bones

Unpaired bones

• ex: vertebrae

Sesamoid bones

Small bones embedded in a tendon

• ex: patella

Cartilage

• form of connective tissue that is mor elastic than bone

Chondr/o

Cartilage

Articular cartilage

Type of cartilage that covers the joint surfaces of bone

Meniscus

Curved fibrous cartilage found in some joints

• Provides additional cushioning

Joints (articulations)

Connections between bones

• classified based on their degree of movement

Arthr/o

Joints

Synarthroses

Immovable

Amphiarthroses

Slightly moveable

Diarthroses

Freely movable

Pivot or trochoid (diarthroses)

Pulley shaped joints like connection between atlas to axis

Pivot or trochoid (diarthroses)

Pulley shaped joints like connection between atlas to axis

Ball and socket (diarthroses)

Allow a wide range of motion in many directions, such as hip and shoulder joints

Condyloid or arthrodial (diarthroses)

Joints with oral projections that fit into a socket, such as carpal joints (where radius meets carpus)

Gliding (diarthroses)

Move or glide over each other, as in the radioulnar joint or the articulating process between successive vertebrae

Hinge (diathroses)

Allow motion in one plane or direction, such as canine stifle and elbow joints

Symphysis (Amphiarthroses)

Joint where 2 bones join and are held firmly together so that they may function as one bone

Suture (Synarthroses)

Jagged line where bones join and form a nonmovable joint

• typically found in skull

Ligaments

Bands of fibrous connective tissue that connects one bone to another

Ligament/o

Ligaments

Tendons

Bands of fibrous connective tissue that connects muscle to bone

Ten/o, tend/o, Tendin/o

Tendons

Bursa

Fibrous sac that acts as a cushion to reduce friction during movement

Burs/o

Bursa

Bursae

Plural form of bursa

Synovial membrane

Inner lining of bursae and synovial joints

Synovial fluid

What the synovial membrane secretes

• acts as a lubricant for joint movement

Axial skeleton

Composed of bones that lie around body’s center of gravity

Cranium

Portion of skull that encloses brain

Crani/o

Cranium

Cranium consists of

• frontal

• Parietal

• Occipital

• Temporal

• Sphenoid

• Ethmoid

• Incisive

• Pterygoid

Frontal

Forms the rood of the cranial cavity or “front” or cranial portion of skull

Parietal

Paired bones that from the roof of the caudal cranial cavity

Occipital

Forms caudal aspect of cranial cavity where the foramen magnum, or opening for the spinal cord, is located

Temporal

Paired bones that form the sides and base of the cranium

Sphenoid

Paired bones that form part of the base of skull and parts of floor and sides of bony eye socket

Ethmoid

Forms the rostral part of cranial cavity

Incisive

Forms the rostral part of the hard palate and lower edge of nares

Pterygoid

Forms the lateral wall of the nasopharynx

Brachycephalic

Dogs that have short, wide heads

• ex: pugs

Dolichocephalic

Dogs that have narrow, long heads

• ex: greyhounds

Mesocephalic (mestaicephalic)

Dogs that have average width to their heads

• ex: lab retrievers

Sinuses

Air- or fluid-filled spaces in skull

Bones of the face consist of

• zygomatic

• Maxilla

• Mandible

• Lacrimal

• Nasal

• Vomer

• Hyoid

Zygomatic

Forms the orbit and cheekbones

Zygomatic arch (cheekbone)

Formed by projection of temporal and zygomatic bone

Maxilla

Forms upper jaw

Mandible

Forms lower jaw

Palatine

Forms part of the hard palate

Lacrimal

Forms medial part of the orbit

Nasal

Forms bridge of the nose

Vomer

Forms base of the nasal septum

• cartilaginous structure that divides the 2 naval cavities

Hyoid

Bone suspended between mandible and laryngopharynx

Vertebrae column (spinal cord and backbone)

Supports head and body and protects spinal cord

Vertebra

The individual bones that make up the vertebrate column

Vertebrae

Plural for vertebra

Vertebrae are divided into parts and vary depending on location and function

• body

• Arch

• Lamina

• Spinous process

• Transverse process

• Articular processes

• Vertebral foramen

• Intervertebral discs

Body

Solid portion ventral to the spinal cord

Arch

Dorsal part of vertebra that surrounds spinal cord

Lamina

The left or right dorsal half of arch

Spinous process

A single portion from the dorsal part of vertebral arch

Transverse process

Project laterally from the right and left sides of vertebral arch

Articular processes

Paired cranial and caudal projections located on the dorsum of the vertebral arch

Vertebral foramen

The opening in the middle of the vertebra through which the spinal cord passes

Intervertebral discs

Cartilage discs that separate and cushion vertebrae from each other

Disc/o

Discs

Foramen

Opening

Atlas

C1 (cervical vertebra one)

Axis

C2 (cervical vertebra two)

Cervical

Neck area “C”

Thoracic

Chest area “T”

Lumbar

Loin area “L”

Sacral

Sacrum area “S”

Coccygeal (caudal)

Tail area “Cy” or “Cd”

Dog and cat vertebral formula

C=7, T=13, L=7, S=3, Cy=6-23