´A21 - Lumbar vertebrae, abdominal musculature, inguinal canal

Question 1

Lumbar vertebrae

Give the number of lumbar vertebrae in different species

Answer 1

• Eq, dog, ru, sus: 6
• Cat: 7
• Eq: 5^th and 6^th sometimes fuses in older horses

Question 2

Lumbar vertebrae

Give the general structures of a vertebrae

Answer 2

• Corpus vertebrae
• Caput vertebrae (extremitas cranialis)
• Fossa vertebrae (extremitas caudalis)
• Crista ventralis
• Arcus vertebrae
  
  • Pediculus arcus vertebrae
  • Lamina arcus vertebrae
• Foramen vertebrale
• Incisura vertebralis cranialis
• Incisura vertebralis caudalis
• Foramen intervertebrale
• Processus spinosus
• Processus transversus
• Processus articularis cranialis
• Processus articularis caudalis

Question 3

Lumbar vertebrae

1. Traits of lumbar vertebrae
2. Structures special for lumbar vertebrae

Answer 3

1. Traits of lumbar vertebrae

• Corpus vertebrae:
  
  • Longer than the thoracic
  • Shorter than the cervicals
• Cranial and caudal extrimities (caput/fossa) are flat
• Crista ventralis and median dorsal ridge are similar to the thoracics

2. Structures special for lumbar vertebrae

• Processus malillaris
  
  • ​Fused with fascies articualris cranialis
  • On thoracic and lumbar vertebrae
  • Between proc. transversus and proc. articularis cranialis
    
    • ​Projected cranially
• Processus accessorius (ca) (ca, su: caudal thoracic)
  
  • Between proc. transversus and proc. articularis caudalis
  • Ca: cranially projected?

Question 4

Lumbar vertebrae

Interspecies differences of processus spinosus in lumbar vertebrae

Answer 4

• Eq, ca, sus: Direct cranially
• Ox: inclined caudally

Question 5

Lumbar vertebrae

Interspecies differences of proc. transversus in lumbar vertebrae

Answer 5

• 1^st is always shortest
• Eq: Extend laterally
  
  • Additional articular surface on the transverse process ! caudal on the 5^th and cranial and caudal on the 6^th vertebrae (attach to the sacrum)
  • 5^th and 6^th sometimes fuse, usually on older horses
• Ru: Slightly curved to the front. Lateral, cranial lateral
• Ca: Cranial laterally and ventrally (downwards and foreward)
  
  • Accessory process projects caudally
• Sus: To some extent Cranial laterally and ventrally
• Fasceis articularis cranialis are fused with the processus mamillaris

Question 6

Muscles of the abdominal wall

Give the general featurs/structures of the abdominal wall

Answer 6

• The abdominal muscles carry considerably weight of abdominal viscera, especially in herbivores
• Suspension bridge: forms a bridge and flexible connection between the thorax, lubar region and pelvic girdle
• Umbilicus
  
  • ​Linea alba forms a fibrous ring in its middle: anulus umbilicalis
• Lacuna musculorum:
  
  • ​Gap between
    
    • Cranial border of pelvis
    • Lig. inguinalis
    • Lamina/fascua iliaca
  • Allows m. iliopsoas and m. sartorius (ø ca) to pass from the abdominal and pelvic cavities into the thigh
• Lacuna vasorum
  
  • ​Ventrolateral to the lacuna muscles
  • Opening
  • Bordered by:
    
    • Lig. inguinalis
    • Corpus ossis ili
  • Permits passage for:
    
    • A/V/L. iliaca externa
    • A/V/L. fermoralis profunds
• Tunica flava abdominalis (ø ca)
  
  • Reinforcement of abdominal wall in herbivores
• Anulus inguinalis superficialis
  
  • ​M. obliquus abdominalis externa tendon forms the:
    
    • Crus pelvina (lateral)
    • Crus femoralis (mediale)
  • Superficial inguinal ring: slit between them
• Anulus inguinalis profundus
  
  • ​Borders:
    
    • Lig. inguinale (part of m. obliquus externa)
    • M. obliquus abdominalis interna
    • M. rectus abdominis
• Canalis inguinalis
  
  • ​Male:
    
    • Goes to the scrotum and testicles
  • Female: Also present
  • Passage for processus vaginalis
  • Blood and lymph vessels runs to the:
    
    • Male: penis (spermatic cord)
    • Female: fatty tissue

Question 7

Give the muscles of the abdominal wall

Answer 7

1. M. obliquus externus abdominalis
2. M. obliquus internus abdominalis
3. M. transversus abdominalis
4. M. rectus abdominalis

Question 8

M. obliquus externus abdominalis

Answer 8

• Origin:
  
  • Fascia thoracolumbaris lamina superficialis (Ø ru)
  • Lateral aspect of the rib 4-12
• Insertion:
  
  • Fibers run caudoventrally \\
  • Linea alba
  • Lig. inguinale
• Action: Abdominal pressure

Question 9

M. obliquus internus abdominalis

Answer 9

• Origin:
  
  • Thoracolumbar fascia lamina superficialis(ø eq)
  • Tuber coxae
  • Proximal part of the lig. inguinale (Ø eq)
• Insertion: Fibres run cranioventrally to linea alba ////
• Action: Abdominal pressure

Question 10

M. transversus abdominalis

Answer 10

• Origin:
  
  • Processus transversus of lumbar vertebrae
  • Fascia thoracolumablis lamina profunda
  • Medial surface of false ribs
• Insertion:
  
  • Linea alba
  • Xiphoid cartilage
  • Fibres run transversely
• Action: Abdominal pressure

Question 11

M. rectus abdominis

Answer 11

• Origin: Sternum, cranial
• Insertion:
  
  • Pecten ossis pubis
  • Tendo prepubicus
  • Fibres run saggital

Question 12

Give the rectus sheath in different zones

Answer 12

• Thoracic: E - R - Thoracic wall
• Preumbilical: E - I - R - I - T - P
• Umbilical: E - I - R - T - P
• Postumbilical: E - I - T - R - P
• E: m. obliquus externus abdominalis
• I: m. obliquus internus abdominalis
• T: m. transversus abdominalis
• R: m. rectus abdominalis
• P: fascia transversa abdominalis & peritoneum

Question 13

Inguinal canal

Answer 13

• Canalis inguinalis is passage for:
  
  • Male:
    
    • Spermatic cord (inside tunica vaginalis). Through channel towards scrotum to reach testicles
  • Female:
    
    • Processus vaginalis (inside fat and lig. teres)
  • In both genders:
    
    • A/V. pudenda externa
    • N. genitofemoralis
    • Eff. vessels (?) from ln. inguinalis superficialis
• Extends from peritoneum

Superficial inguinal ring:

• Lateral border: Lateral limb of m. obliquus externa
• Medial border: Medial limb of m. obliquus externa

Spatium inguinale:

• Loose connective tissue
• “Virtual” space between muscles (which leads from one opening to the other)
• Lateral border: pelvic ligament
• Medial border: M. obliquus interna

Deep inguinal ring:

• Cranial border: m**. obliquus interna
• Medial border: rectus abdominalis
• Caudal border: lig. inguinale