Structures and functions of the Vertebral Column Flashcards
What are the boundaries of the thoracic cavity?
- cranial border = Thoracic inlet at level of first rib. Caudal border = diaphragm
- Dorsal = thoracic vertebrae, ventral border = sternum: manubrium to xiphroid
What are the boundaries of the abdominal cavity?
- Crainally diaphragm to pelvic inlet caudally
2. Lumbar vertebrae dorsally to muscular abdominal wall ventrally (rectus abdominal oblique msucles) 7:56
What is the boundaries of the pelvic cavity
- within pelvis
What are the common functions of the 3 body cavities. and name the three and what is within
Function: support and protect internal organs
- Thoracic cavity: heart, aorta, lungs
- Abdominal cavity: GI organs: stomach, gut, spleen, liver
- Pelvic cavity: reproductive and GI organs
Facts about canine ribcage
i. 13 thoracic vertebrae
ii. 13 ribs
iii. 12 intercostal spaces
iv. 8 sternebra = sternum
v. Ribs articulate with vertebrae and sternum
What are the articular facets of the vertebral column?
Which have these distinct articular faces
- 4 articular surfaces per vertebra
- 2 cranial and 2 caudal
- the cranial facets are lateral (xxx) ventral (cervical) to caudal facets
- cervical, thoracic and lumbar regions form synovial joint
Where is there an exception in the articular facets of the vertebrae?
- Atlanto-occipital joint (atlas C1 and occipital bone of skull)
- Atlanto-axial joint (atlas and axis C2)
- Occipito- atlanto- axial complex
Talk about Atlanto- Occipital joint
- AO = Articulation between atlas and occipital condyles of the skull
- AO = joint limited to flexion and extension by wings of C1 = “yes joint”
Talk about Atlanto Axial joint
- AA = these are atypical vertebrae
- joint allows lateral rotation
- AA = no flexion and extension due to dorsal spinous process of C2 = “No” joint
Talk about Occipito- Atlanto- Axial complex
- this is a combination “universal joint” as
2. allows a full range of movement without any damage to the spinal cord
What are the Thoracic body wall components, outside to inside
- Skin
- Cutaneous trunci (skin twitch)
- Superficial fascia (fat)
- Deep fascia (connective tissue covering muscles) and muscles
- Ribs
- Endothoracic fascia
- Pleura, v thin
What are 2 types of muscles in the thoracic body wall?
- Epaxial = muscles above the level of the transverse process on vertebrae = very dorsal muscles on vertebral column
- Hypaxial = msucles below the transverse process = lateral wall muscles, thoracic, abdominal
Role of hypaxial
- ventral to level of transverse process
- diverse function
- Abdominal wall muscle, thoracic wall msucles
Epaxial muscles muscle groups
- 3 longitudinal muscle groups
- Very dorsal/medial = Transversospinalis (between transverse and spinous processes)
- Middle = longissimus (muscle fibres are long from illeum up to thoracic region)
- Illiocostalis = lateral (run from illeum up to ribcage)
What is the function of the Epaxial muscles
- extension, flexion and some lateral movement of the vertebral column
What is an additional support to the epaxial muscles?
- The nuchal ligament: support head
- in cervical region
- connective tissue
- large animals - large head so very extensive nuchal ligament
Hypaxial muscles: thoracic region: superficial and deep
Superficial
1. additional support from forelimb extrinsic group muscles that lie on top of ribcage
2. Lat dorsi
3. pectorals
4. External abdominal oblique = accessory expirator muscle
DEEP
1. serratus ventralis
What is the role of the serratus ventralis
- cranial part = retractor
- Caudal = protractor
which is why pivoting point is half way down scapula - accessory inspiratory muscle
External and internal intercostal muscles
- External intercostal msucles
- caudoventral fibres
- extend to level of costochondral junction no further - Internal intercostal muscles (deep)
- cranioventral fibres
- Extend to sternum
- function during both inspiration adn expiration
- allow ribcage to work as single functional unit
What muscles play a role in inspiration? and what is their name?
NAME: accessory inspirators 4 muscles 1. serratus ventralis msucle = extrinsic msucle of forelimb UNDERNEATH SV = 2. Scalenus muscle = 3 heads 3. Rectus thoracis muscle = 1 head 4. Serratus dorsalis cranialis = 2 heads
Location of accessory inspiration muscles
- Most dorsally, under serratus ventralis = Serratus Dorsalis (CRANIALIS). Thoracolumbar fascia = ribs. Caudal and cranial part. Cranial = role in inspiration, caudal = ex
- Scalenus muscle = 3 heads = looks like saw! in middle
- Rectus thoracis muscle = 1 head = ventral aspect
Nerve, artery and vein supply of intercostal muscles
- Run together down the caudal aspect of ribs to costocondral junction
- Branch (bifarbricate) at CCJ to run down both aspects
- Join at sternum
- intercostal artery joins with ilneternal thoracic artery
What muscles play a role in Expiration?
What is these muscles job?
Job = pull ribs caudally and medially
- Diaphragm = main
- Serratus dorsalis caudalis muscle
- External abdominal oblique muscle
- Transersus thoracis muscle
Where is the location of the apex of the heart?
- 5th intercostalspace
2. just dorsally to olecranon
