Introduction to the skeletal system Flashcards
what is a skeleton and what does it include?
- the hardened tissues forming the supportive framework of an animal’s body
- it includes bones, cartilage, joints
what are the three groups of skeleton?
- appendicular
- axial
- splanchnic
what is the appendicular skeleton?
composed of the bone in appendages; upper and lower limbs and shoulder + pelvis girdles
what is the axial skeleton?
composed of the bones along the body’s long or midline axis; skull, vertebrae, ribs, and sternum
what is the splanchnic skeleton?
consists of the ospenis
what is the maxilla?
- contains the sinuses which are attached to the upper respiratory tract
- hollow spaces which lighten the skull and provide resonance to the vocal chords
what are the nasal chambers?
- most rostral part of the skull
- divided into two lengthways by a cartilaginous plate called the nasal septum
what is the hard palate?
formed of three bones
- incisive bone - carries incisor teeth
- part of the maxilla
- palatine bone
what is the mandible?
- lower jaw
- consists of two halves held together in the midline by connective tissue called the mandibular symphysis
what is the hyoid apparatus?
- series of small bones suspend the tongue and larynx
- foramen allow blood and nerve vessels to pass through
what is the vertebral column?
- consists of 50 irregular bones
- arranged into 5 groups
what are the vertebral columns for a dog and cat?
- cervical - C1-C7
- thoracic - T1-T13
- lumbar - L1-L7
- sacral - S1-S3
- coccygeal - CY20-CY23
what are the vertebral columns for a rabbit?
- cervical - C1-C7
- thoracic - T1-T(12-13)
- lumbar - L1-L7
- sacral - S1-S4
- coccygeal - CY15-CY16
What is the internal structure of vertebrae?
- spongy bone and marrow
- held together by ligaments and are separated from one another by the cartilaginous intervertebral discs (CID)
what is the basic structure of vertebrae?
- hollow arch lies above the vertebral body and contains the vertebral foramen and connects with adjacent vertebrae to form vertebral canal
-spinous process arises from middle of dorsal arch - articular processes on each vertebra
- transverse processes arise from the body and arch
what are the intervertebral discs?
- they separate the vertebral bodies of adjacent vertebrae
- have a tough fibrocartilage outer part and a softer part which cushions movement or shock to the bones
what is the tough fibrocartilage outer part of the intervertebral discs called?
the annulus fibrosus
what is the softer part of the intervertebral discs called?
the nucleus pulposus
what are the functions of the vertebral column?
1 - protects the spinal cord
2 - allows a passage for the spinal cord
3 - helps to suspend appendicular skeleton
4 - forms an attachment for the ribs
what are the first two cervical vertebrae called?
- atlas and axis
what does the atlas (vertebrae) consist of?
- pair of large, flattened transverse processes, a small neutral spine and large vertebrae foramen
what type of joint is the atlas (vertebrae)?
synovial joint that allows nodding of the head
what does the axis (vertebrae) consist of?
- elongated
- has a large ridge-like dorsal spinous process
- peg like structure
what are T1-T10 (vertebrae)?
- long, spinous processes which decrease in size caudally, short transverse processes
- articular depressions/foveae clasps the head of a rib and are on cranial and caudal ends of vertebral body
what are T11-T13 (vertebrae)?
- short spinous processes and transverse processes
- short costal fovea found on both sides of vertebral body
what are the lumbar vertebrae?
- 7 of them
- spinous process arises dorsally from the neutral arch
- mammillary and accessory processes provide muscular attachment
what are the sacral vertebrae?
- 3 are fused together to form sacrum
- sacrum is fused to the ilium of the pelvic girdle
what is the joint between the sacrum and the ilium?
sacro-iliac joint
what is the coccygeal vertebrae?
- varies due to length of tail
- normally 15-21 bones
what are the ribs?
- long bones that form the lateral walls of the thorax
- normally 13 pairs
- flattened, curved bones
- one pair for each thoracic vertebra
what is the cranial boundary of the ribs?
- manubrium of the sternum
- first pair of ribs
- ventral surface of the first thoracic vertebra
what is the dorsal boundary of the ribs?
- ventral surfaces of the thoracic vertebrae and associated vertebral
what is the ventral boundary of the ribs?
sternum
what are the functions of the ribs?
- to protect the organs within thoracic cavity
- to articulate and enable breathing
what is the structure of the ribs?
- ventral end of ribs are cartilaginous and known as costal cartilages
- dorsal end is made of bone
what ribs are attached to the sternum?
- ribs 1-8 are attached
- ribs 9-12 are not attached
- rib 13 is a floating rib
what is the sternum?
- composed of a line of 8 bones (sternebrae) which articulate with each other by intersternebral cartilages
what is the first sternebra called?
the manubrium
what is the last sternebra called?
the xiphisternum
what cartilage is attached to the xiphisternum?
xiphoid cartilage
what is the main function of the sternum?
to support the thoracic contents
what is the scapula?
- shoulder blade
- flat, triangular shaped bone
what is the lateral surface of the scapula divided by?
spine of the scapula
what does the distal end of the scapula do?
- muscle attachment
- acromion process
what is the clavicle?
- collarbone
- small bone in the brachiocephalic muscles cranial to the shoulder joint
what is the humerus?
- extends from the shoulder joint to the elbow joint
- head articulates with scapula, and a greater tubercle
- expands distally into medial and lateral condyles
what makes up the forelimbs?
clavicle, scapula, humerus, radius and ulna, carpus, metacarpus, phalanges
what is the radius and ulna?
- radius is a short bone
- radius lies medial to the ulna at the distal end
- ulna is longer than the radius
- ulna at the proximal end is the point of the elbow = olecranon process = muscle attachment for tricep brachi
- forelimb
what is the trochlear notch?
- distal to the olecranon
- bounded by two processes
1) anconeal process proximally
2) coronoid process distally
what is the carpus?
- contains 7 small irregular bones arranged in 2 rows
- in the proximal row is the radial carpal bone, ulnar carpal bone, and accessory carpal bone
- in the distal row are carpal bones 1,2,3,4
what is the metacarpus?
- contains 5 metacarpal bones
- digits labelled from medial to lateral
what are the metacarpal?
- phalanges make up the digits
what are the characteristics of metacarpal 1?
- metacarpal 1 is short and joins two phalanges - the distal one carries the dew claw
- similar to human thumb
what makes up the hindlimbs?
- pelvis, femur, tibia and fibula, tarsus, metatarus and phalanges, patella and fabellae
what is the pelvis?
- how the hindlimbs attach to the vertebral columns
- comprises of different bones fused together
what is the femur?
- most proximal bone of the hindlimb
- structurally similar to the humerus
what are the tibia and fibula?
- makes up the lower part of the leg
- distal to the stifle
- tibia is main weight-bearing bone
- fibula is a long, thin bone
what is the tarsus?
- the hock
- similar to carpus
what are metatarsus and phalanges?
- similar to metacarpal
what are the patella and fabellae?
- sesamoid bones
- patella - kneecap - largest sesamoid in the body
- fabellae found in the tendons of the gastrocnemius muscle
what is the tibia and fibula?
- long bones
- form the lower leg
- lie parallel with eachother
- tibia - front
- fibula - back
what 3 sections is the femur split into?
- head of femur
- body/shaft of femur
- distal extremity with medial and lateral condyles
what is the greater trochanter?
- lateral to the head of the femur
- muscle attachment
what is the lesser trochanter?
- medial side
- muscle attachment
What are the three smallest bones in a dog’s body?
Middle ear - anvil, stirrup, hammer
