"Neuroanatomy" 3: Muscles of the back and neck Flashcards
What is the name of the large dorsal ligament that supports the weight of the head?
Nuchal ligament
Where does the nuchal ligament have its origin in the dog, horse, and ruminant?
Nuchal ligament origin
- Dog: Caudal aspect of C2 (axis)
- Horse, ruminant: Occiput (nuchal crest)
In what common species is the nuchal ligament absent?
Cat, pig
What ligament forms the caudal continuation of the nuchal ligament?
supraspinous ligament
What are the names of the two parts of the nuchal ligament?
Funicular part, lamellar part
What is the origin and insertion of the funicular part of the nuchal ligament in the dog?
Funicular part of the nuchal ligament in the dog (paired)
- Origin: Caudal aspect of C2 (axis)
- Inserion: Spinous process of 1st thoracic vertebra
Where does the lamellar part of the nuchal ligament extend in horses and cattle?
From funicular part in a sheet-like manner to C2-C7 (horse) and C2-C4 (cattle)
The superficial layer of the thoracic muscle group is innervated by which nerve(s)?
Innervated by ventral branches of the spinal nerves
The deep layer of the thoracic muscle group is innervated by which nerve(s)?
Innervated by dorsal branches of the spinal nerves
As a group, what is the term for the muscles that are found dorsal to the transverse process?
Epaxial
As a group, what is the term for the muscles that are found ventral to the transverse process?
hypaxial
What are the three main groups of the epaxial muscles (four in the horse)?
Lateral
-
Iliocostalis System
- Thoracic and lumbar parts
-
Longissimus System
- Cervical, thoracic and lumbar parts
Medial (blended in the dog so one group, distinct in horses)
-
Spinalis System
- Between spinous process
-
Transversospinalis System
- From spinous process to the transverse process of adjacent vertebrae
= Erector spinae muscles
- carnivores
What is the origin, insertion, and action of Iliocostalis lumborum?
To what muscle system does it belong?
Origin: Wing of ilium, iliac crest, intermuscular septa
Insertion: Ribs 13-10 (caudal border)
Action: Unilaterally = lateral flexion of vertebral column; Bilaterally = fixation of vertebral column (as a unit in the system)
Group: Iliocostalis System
What is the origin, insertion, and action of Iliocostalis thoracis?
To what muscle system does it belong?
Origin: Ribs 12-2 (cranial border)
Insertion: Transverse process of C7
Action: Unilaterally = lateral flexion of vertebral column; Bilaterally = fixation of vertebral column (as a unit in the system)
Group: Iliocostalis System
What is the other name for longissimus lumborum et thoracis?
Longissimus lumborum et thoracis = Longissimus dorsi
What is the origin and fibre direction of longissimus lumborum et thoracis (longissimus dorsi)?
Origin: Iliac crest, ventral surface of ilium, via aponeurosis from the supraspinous ligament and lateral to the spinous processes of lumbar and thoracic vertebrae
Fibre direction: Fibres run craniolaterally
What is the insertion of longissimus lumborum et thoracis (longissimus dorsi)?
Longissimus lumborum et thoracis insertion:
- Thoracic vertebrae
- Accessory processes of T13 –T6
- Caudal ends of transverse processes of T5-T1
- Ribs
- 13 – 6 medial to iliocostalis
- 5 –1 costal tubercles
What is the action of longissimus lumborum et thoracis?
extension of the vertebral column