Lecture 7- Metacarpus, phalanges and joints Flashcards
What goes through the axial foramen of the hoof in cattle?
Principal artery
What articulates with the tubercle for the deep digital flexor in cattle?
Deep digital flexor
What is a sign of uneven horn growth in horses?
rings on side of hoof
What is hoof cartilage attached to?
palmar process of distal phalanx
What is the function of hoof cartilage?
Increasing the surface are for hte horn of the hoof to attach
What is another name for the hoof?
corium
What divides wall from bulb in bovine foot?
Abaxial groove
What are the three major joints in the foot?
PIP, DIP, and MCP
What is the fetlock?
Metacarpophalangeal joint
What is involved in the fetlock?
MCIII, PI, and proximal sesamoid bones
What type of movement occurs at the fetlock?
Extension with relatively high mobility
What connects MCIII and PI together?
medial and lateral collateral ligaments
What are the major ligaments of the fetlock?
Collateral, Straight, and Oblique collateral ligaments
What joins the proximal sesamoids?
Think palmar ligament
What does the collateral sesamoidean ligament do?
Connect the sesamoid to the sides of the metacarpal condyle and proximal tubercles of the PI
What ligaments connect base of sesamoid bones to first phalanx?
Deepest, cruciate, and obilque
What is the point of the sesamoid bone to phalanx ligaments?
ensures sesamoid move agains metacarpal concyle in unison with PI
What connects ses. to the fibrocartilage of PII?
Straight sesamoidiean ligament
What is the pastern?
Proximal interphalangeal joint
What movement occurs at the pastern?
restricted flexion and extension
What do the palmar ligaments connect?
Palmar aspect of PI w/ complementary fibrocartilage of PII
What do the palmar ligaments do?
Limit overextension
What do the palmar ligaments interact with?
Straight sesamoidean bone
What are the branches of the palmar ligaments?
Axial and Abaxial
What is the coffin?
Distal interphalangeal joint
What movement occurs at the coffin?
Flexion and extension to the same degree as the pastern
What is the major bone in the coffin?
Navicular bone
Where is the navicular bone located?
Suspended from the distal extremity of PI
What ligaments interact with the navicular bone?
Navicular ligaments
What are the branches of the navicular ligaments?
Collateral and distal
Tendons from what muscles enter the foot to the metacarpal bone?
EDC and EDL
Tendons from what muscles enter the foot caudal to the MC bone?
FDS and FDP
What role does the interosseus muscle play?
Support of the fetlock
What is the origin of the interosseus muscle?
Palmar carpal ligament and adjacent part of large metacarpal bone
What is the path of the interosseus muscle?
between splint bones and divides above the fetlock, two division are easily felt
What is the insertion of the interosseus muscle?
proximal sesamoid bones
What occurs to the interosseous muscle in metacarpus (bovine?)?
Give five principal branches
Where do four of the interosseous muscle branches go?
proximal sesamoid bones
What does the arrangement of the interosseous muscle with the other tendons do?
form sling, tenses when foot bears weight and fetlock is overextended
What is the check ligament for the superficial digital flexor?
Band formed by interosseous muscle on palmar surface and joins bands of SDF
What are the three major palmar a. in the horse?
Medial/lateral palmar a.
Medial/lateral palmar metacarpal aa.
What branches off the medial palmar a.?
Medial/lateral digital a.
What is the most important artery?
Medial palmar a.
What is the medial artery a continuation of?
Median a.
What is the lateral palmar a. a descendent of?
Collateral ulnar a.
What supplies blood to branches of the interosseous?
medial/lateral palmar metacarpal a.
What branches does the ulnar nerve give off?
Palmar and dorsal
What does the dorsal branch n. do?
Sensory from skin over lateral surface of metacarpus
What is the palmar branch n. a terminal branch of?
median n.
What is the main nerve in the forearm?
Median n.
What does the Median n. divide into?
Medial and lateral palmar n.
What does the lateral palmar n. exchange fibers with?
palmar branch of the ulnar n.
What does the lat. palmar n. supply?
Interosseous and palmar pouch of fetlock
When does the lat. palmar n. become subcutaneous?
distal end of splint bones - supply dorsal pouch
What does the medial palmar n. become above the fetlock?
medial digital n.
What happens to the medial digital n.?
gives rise to one or two dorsal branches
Where does the medial palmar n. end?
Supplying laminar and sole dermis
What muscle prevents the shoulder from flextion?
internal biceps tendon
What is passive-stay apparatus?
weight of trunk does not pass directly through joint axis of rotation, allows horses to stand for a long time
What does the lacertus fibrosus do?
At distal end pull of bicep transmitted to ECR (which is fixed on MCII)
How is overextension prevented?
close-packing of carpal cranial
palmar carpal ligaments caudal
What action does lacertus fibrosus (w/ other tendons) prevent?
support carpal joint and prevent joint buckling forward
What three things prevent the fetlock from overextension?
interosseus, proximal sesamoid bones, and distal sesamoidean ligaments
What occurs at the DIP joint when deep flexor tendon as tension?
flexion
What is the flexion of the DIP joint counteracted by?
pull on the extensor process of bone at impact
keep hoof level
What is overextension of PIP joint prevented by?
Axial and abaxial palmar ligaments
Straight sesamoidean ligaments
What prevents buckling forward of PIP?
FDS
What forces prevent the elbow joint from flexing?
Passive tension of tendons from carpal and digital flexors
Eccentrically placed collateral ligaments
