ANATOMY 3.2 (Thorax Intro) Flashcards
Trunk:
-what is left after removing the head, neck, tail and limbs
Trunk includes:
-thoracic cavity
-abdominal cavity
-pelvic cavity
Who cares about the thorax?
-many systems (cardiovascular, respiratory)
-diagnosis
-treatment
Thoracic cavity:
-cranial-most body cavity
-cranial to diaphragm
Pleural cavity:
-2 within the thoracic cavity
-left and right: contain the left and right lung
Thoracic cage:
-within ribs
-above sternum, below vertebral column
Shape and extent of thoracic cavity:
-does NOT correspond to the expectations of the living animal
-looks bigger than it actually is
Reasons for thoracic cavity looking bigger than it actually is:
-massive musculature of forelimb
-outlines of back, brisket and coastal arch=thoracic cavity
-shape of diaphragm
Shape of diaphragm:
-concave dome within rib cage occupied by abdominal viscera not thoracic viscera
Massive musculature
-limb strength is a function of area (x2)
-respiratory is a function of volume (x3)
-60% of body weight borne by forelimbs
-larger animal=larger proportion composed of musculoskeletal tissue
Horse/cow vs. dog lung size:
-lungs of dog are relatively massive compared to horse/cow
Inspiration:
-diaphragm contracts a pulls lungs downwards
-ribs elevate
Ribs:
-basic form: bucket handle
-costo-chondral parts
-costo-chondral junction
-3 articulations
-joint types
Cranial ribs shape:
-rigid
-short
-straight
Caudal ribs shape:
-more slender and curved
Costo-part:
-top portion
-cartilage
Chondral-part:
-bottom
3 articulations of ribs:
-vertebral
-sternal
-chondral (costal arch)
Vertebral articulations:
-costo-vertebral
-costo-transverse
Costo-vertebral:
-ball and socket
-2 intercapital ligament
Costo-transverse:
-sliding
-8 costo-transverse ligament
-6 dorsal longitudinal ligament
Rib types
-short, long, “true”, “false”, “floating”
-cylindrical vs. flattened
-curved or not curved
Sternebrae:
-cylindrical vs. flattened vs. “keel’ like
-inter-sternal joints
-costo-sternal joints
-interchondral joints
Inter-sternal joints:
-synchondroses
-later ossify
Costo-sternal joints:
-synovial
-pivot type
Interchondral joints:
-syndesmoses
-elastic
Number of thoracic vertebrae:
=number of ribs
-rib number corresponds to vertebra of caudal attachment
-1 sternebra less than number of sternal ribs (includes manubrium and xiphoid)
Thoracic vertebra in different species:
-canine: 13
-equine: 18
-ruminant: 13
-porcine: 14-15
-human: 12
Sternal rib pairs in different species:
-canine: 9
-equine: 8
-ruminant: 8
-porcine: 7
-human: 7
Thoracic girdle:
=synsarcosis
Superficial layer of extrinsic muscles of forelimb:
-trapezius
-omotransversarius
-brachiocephalicus
-latissimus dorsi
-superficial pectorals
Deep layer of extrinsic muscles of forelimb:
-rhomboideus
-serratus ventralis
-deep pectorals
Dog cranial view musles/landmarks:
-brachiocephalicus
-sternocephalicus
-jugular groove
-thoracic inlet
Muscles of thoracic wall:
-scalenus
-serratus dorsalis
-intercostals
-rectus thoracis
Serratus dorsalis parts/actions:
-cranial: inspiratory action, increases cavity
-caudal: bucket handles go down=expiratory
Epaxial muscles:
-above transverse process on either side of vertebral column
1. Transversospinalis system
2. Longissimus system
3. Iliocostalis system
Transversospinalis system:
-shorter ones all the way along
Longissimus system:
-long one at the caudal end
-not all the way to the cranial end
Iliocostalis system:
-3 longer ones
Hypaxial muscles:
-flexor muscles of neck or tail
Muscles of thoracic and abdominal walls:
-3 analogous layers
Abdominal wall 3 muscle layers:
-external oblique
-internal oblique
-transversus abdominis
Thoracic wall 3 muscle layers:
-external intercostal
-internal intercostal
-transversus thoracis
