Animal anatomy

• Joints


  Articulation between bones, united with cartilage or fibrous tissue, varying degrees of movement, shock absorption
• Types of joints


  • Fibrous
  • Cartilaginous
  • Synovial
• Fibrous joints


  • No joint cavity, connected with fibrous connective tissue, examples: syndesmosis, suture, gomphosis
• Cartilaginous joints


  • Bones joined by cartilage, many are temporary, examples: synarthrosis, synchondrosis, symphyses
• Synovial joints


  • Joint cavity, freely movable, examples: simple or composite, ginglymus, plane, trochoid, spheroid
• Joints of the thoracic limb

  • Shoulder: scapulohumeral joint
  • Elbow
  • Radioulnar joints
  • Carpus
• Joints of the pelvic limb

  • Hip: coxofemoral joint, sacroiliac joint
  • Stifle joint: femorotibial component, femoropatellar component
  • Tibiofibular joints
  • Hock: tarsus joint
• Shoulder joint


  • Ball and socket - but hinge movement
• Elbow joint


  • Ginglymus - composite
• Carpus


  • Composite synovial - hinge movement + plane joint
• Fetlock, pastern, coffin joints

  • Ginglymus
• Sacroiliac joint


  • Synovial and fibrocartilaginous joint - no movement
• Hip joint


  • Ball and socket - but hinge movement
• Stifle joint


  • Composite hinge
• Tarsus joint


  • Composite synovial - hinge movement + plane joint
• Clavicle is absent in horses = improved running efficiency
• Thoracic sling


  Muscular attachment for forelimb
• Damage to sacroiliac joint = Hunter's bump
• Joints of the spine

  • Atlanto-occipital joint
  • Atlanto-axial joint
  • Symphyseal joints between adjacent vertebrae
  • Intervertebral disks
  • Lumbosacral joint
• Atlanto-occipital joint


  • Ginglymus
• Atlanto-axial joint


  • Pivot
• Symphyseal joints between adjacent vertebrae

  • Little motion
• Cervical vertebrae


  • Most flexible section of the spine
• Lumbosacral joint


  • Ginglymus
• Horses stand for long periods of time - passive stay apparatus is a solution
• Passive stay apparatus - thoracic limb


  • Serratus ventralis
  • Biceps brachii
  • Long head of triceps brachii
  • Extensor carpi radialis
  • Lacertus fibrosus
  • Suspensory ligament
  • Radial check ligament
  • Carpal check ligament
• Passive stay apparatus - pelvic limb

  • Quadriceps femoris
  • Peroneus tertius
  • Superficial digital flexor
• Musculo-skeletal: Primary Bones


  • Frontal
  • Maxillae
  • Pre-maxillae
  • Mandible
  • Parietal
  • Occipital
  • Zygomatic arch
• Musculo-skeletal: Primary Muscles

  • Masseter
  • Temporal
  • Auricular
  • Levator Nasolabialis
  • Buccinator
  • Zygomaticus
  • Caninus
  • Orbicularis oris
• Masseter


  • Point of origin: Facial crest
  • Point of insertion: caudo-lateral aspect of mandible
  • Function: Medio-lateral grinding movement of teeth
• Temporal Muscle


  • Point of origin: Temporal fossa, medial surface of zygomatic arch
  • Point of insertion: coronoid process mandible
  • Function: Dorso-ventral movement of mouth
• Musculo-skeletal: Auricular


  6 auricle muscles

  movement of ear

  horses facial expression
• Levator Nasolabialis


  • Point of origin: Frontal bone and nasal bone
  • Point of insertion: joins orbicularis oris muscle
  • Function: elevates upper lip and enlarges nostril
• Cavities of the Head


  • Cranium (Cerebrum, cerebellum)
  • Nasal (Turbinate bones, ethmoturbinate bones)
  • Oral (Tongue, teeth, larynx, hyoid apparatus)
• Nasal Cavity


  Turbinate bones - both dorsal and ventral. spaces are called meatus (cartilaginous) , Mucous covered which warm and cleanses air

  ethmoturbinate bones- mucous covers but have olfactory receptors for primary smelling
• Oral Cavity


  • Teeth
  • Hyoid apparatus
  • Larynx
  • tongue
• Teeth


  Dental formula for deciduous teeth: 2 (I3/3 C0/0 P3/3)

  permanent teeth: 2 (I3/3 C1/1 P3-4/3 M3/3)
• Ageing via dentition


  • enamel
  • primary dentine
  • cement
  • pulp cavity
  • look at the cross section of the incisor, gap in the middle tooth (infundibulum), can you see cement and a enamel ring, at 9 around 9 years a dental star will be seen
  • age 10- Galvayne's groove appears, moves further down as the horse continues to age
• Larynx 


  made up of cartilage: epiglottic cartilage, thyroid cartilage, arytenoid cartilage, cricoid cartilage 

  
  

  • Arytenoid cartilage- controlled by long nerve, prone to damage allowing this cartilage to fall into the trachea, known as roaring  there is a surgery to tie back the cartilage
• hyoid apparatus


  hyoid bone is to serve as an attachment structure for the tongue and for muscles in the floor of the oral cavity

  • Base of the skulls- stylohyoid: point of articulation 
  • Base of tongue- lingual process of basihyoid  
  • Thyrohyoid- connects to the thyroid cartilage in the larynx, allows articulation with the thyroid cartilage