A10 Flashcards
Carpus, its muscles, muscles of the radioulnar joint
What about the muscles of the carpal joint
The muscles that work on the carpal joint are long muscles that cover the skeleton of the antebrachia, they work on two joints as they originats from the humerus and stretches down to the carpus or metacarpus.
These muscles are either flexors or extendors as the domestic mammals don’t need much movement.
Carpal extensors
M. extensor carpi radialis
M. extensor carpi ulnaris
they all originate from the lateral epicondyle
M. extensor carpi radialis
Is the largest extensor, and along with the lateral epicondyle it also originates fromt the lateral epicondyle crest and inserts on the proximal extremities of Mc3 or both Mc2 and Mc3
Fe: two parts, longus and brevis
M. extensor carpi ulnaris
In carnivores it is an extendor but in the herbivores it is a flexor. The secondary tendon to the accessory bone wll take over the job for the missing lateral collateral
Ca: inserts on Mc5 and accessory carpal bone, where it blends with retinaculum flexorium
Su: separate branch that inserts on the accessory bone
Eq: main insertion is the accessory carpal bone an remnants of a secondary on Mc4
Ru: main insertion is the accessory carpal bone
Carpal flexors
M. flexor carpi radialis
M. flexor carpi ulnaris
all originates from meidal epicondyle of humerus
Assisting muscles
- Deep digital flexor and superficial digital flexor
M. flexor carpi radialis
Strong fleshy muscle that inserts on the palmar aspect of the proximal end of the metacarpus
Ca: Mc2 and Mc3
Su: Mc3
Eq: Mc2
Ru: Mc3
M. flexor carpi ulnaris
- Two heads of origin:
- Caput humerale – medial epicondyle
- Caput ulnare – olecranon
Su: ulnar head is absent
- Inserts on the accessory carpal bone with a short tendon
Innervation of the muscles acting on the carpal joint
N. radialis
- M. extensor carpi radialis
- M. extensor carpi ulnaris
N. Medianus
- M. flexor carpi radialis
N. Ulnaris
- M. flexor carpi ulnaris
Muscles of the radioulnar joint
More developed or only present in the animals able to move the joint in other than flexion and extension, so more developed in the dog whilst the larger animals have less ability to move their radioulnar joint
M. pronator teres
M. pronator quadratus
M. supinator
M. brachioradialis
M. pronator teres
- Moves from the the medial side and more laterally
- Round at its origin
- Flat at its insertion
O: Medial epicondyle of humerus
I: medial border of radius,
A: pronates forefoot medially
M. pronator quadratus
Pronator quadratus
- Fills the spatium interrousseum antebrachia between the radius and ulna
- Transverse fibers
O&I: the apposed surfaces of the radius and ulna
A: pronates the paw
M. supinator brevis
Supinator brevis
- Short and broad
- Flat and obliquely crosses from the lateral to the medial side
- There is a sesamoid bone iin this muscle where it crosses the head of the radius
O: epicondylus lateralis
I: cranial surface of the proximal part of radius
A: supinates, also helps in flexing the elbow joint
M. brachioradialis
Brachioradialis (supinator longus)
- Only 33% of dogs have it
- Frequently removed with the skin
O: crista epicondylus lateralis
I: distally and medially on radius
A: supinates forearm (and forefoot)
Bones of the carpus + interspecies
The proximal row is also known as the antebrachial row a full set consists of:
- Os carpi radiale – most medially situated
- Os carpi intermedium – lieas just below the radius and ulna
- Os carpi ulnae – just distal to ulna, laterally
- Os carpi accesorium – caudally on the lateral side
The distal row, also known as the metacarpal row, consists of:
- Os carpale primum
- Os carpale secundum
- Os carpale tertium
- Os carpale quartum
- Medial to lateral
Interspecies differences
Su: 8 a full set
Eq: 7-8 C1 is often missing
Ca: 7 Radiale and intermedium is fused to form intermedioradiale
Ru: 6 C1 is missing
C2 and C3 is fused to form Os carpale II et III
Articulatio radioulnaris distalis
- Circumferential articularis on ulna + incisura ulnaris on radius
- Trochoid
- Between the distal portion of radius and ulna
- Extension of antebrachiocarpal joint capsule
Capsula articularis
- Continuous with the interosseous membrane
- Short and tight
Lig. radioulnare (ca)
- Distal pivotal joint
- Makes for little rotational movement
Articulatio carpi
- Composita articulations, 3 joint cavities, each with its own separate synovial membrane
Ru+ Eq: lateral styloid process + proximal end of metacarpal bones
Short deep limb: bridges the individual articulations
Proximal, middle and distal limb
Ca: Lateral styloid process + ulnar carpal bones
lig. collaterale carpi mediale + laterale
The ligaments of the carpus
lig collaterale carpi mediale
lig. collatereale carpi laterale
lig. radiocarpeum dorsale
lig. radiocarpeum palmare
lig. ulnocarpeum palmare
lig. intercarpea dorsalis
lig. intercarpei interossea
lig. accesoria ulnare
lig. accesoriocarpoulnare
lig. accesoriametacarpeum
lig. accesoriaquartale
lig. carpometacarpea
Articulatio antebrachiocarpea
- Formed by the antebrachial bones + carpal bones of the proximal row
- Accessory carpal bone articulates with
ulna in carnivores
lateral styloid process in equines - Type of joint
hinge joint in Eq
cochlear in Ru
ellipsoidal in Ca - Greater range of movement in carnivores
Capsula articularis
- Extensive synovial sac
- Encloses the distal radioulnar joint in su + ca
articualtio radiocarpea
radius + prox row of carpal bones
articulatio ulnocarpea
ulna + prox carpal row
ligaments of articulatio antebrachiocarpea
Lig. radiocarpeum dorsale (Ø eq)
- Connecting the cranial distal lip of radius to the dorsal surface of the ulnar carpal
- Diverge, allowing free opening on the cranial surface of the antebrachiocarpal joint during flexion
Lig. radiocarpeum palmare
Carnivores
- Anchors ulna to the palmar side of the intermedioradial carpal
- located just proximal to the accessory carpal bone
Lig. ulnocarpeum palmare
- palmar surface of the intermedioradial carpal à intermedioradial carpal
articulationes intercarpea
- between carpal bones of the same row
- amphiarthrosis, moderate mobility
- Gynglymus, flexion and extension with some lateral movement
Ligg. intercarpea dorsalia
- Absent in horse
- Elastic ligaments
- Crosses the joints longitudinally from prox to distal
Ligg. intercarpea palmaria
- Varies in the species
- Difficult to separate from the tendons of origin of the interosseous membrane
Ligg. intercarpea interossea
- Short strong fibres
- Unites the bones of the same and adjacent rows
articulatio mediocarpea
- Proximal row of carpal bones + carpal bones of the distal row
- Complex hinge joint
Capsula articularis
- Smaller
- Communicates with synovial sac of distal carpometacarpal joint, between third and fourth carpal bones
Lig. carpi radiatum Prevents hyperextension of the carpal joint
Articulatio ossis carpi accessorii
- The accessory carpal bone acts as a lever for muscles to flex the carpus
- 4 suspensory ligaments (some with two limbs)
Capsula articularis
- The fibrous joint capsule is strengthened by the extensor retinaculum on the dorsal aspect and the
flexor retinaculum on the palmar aspect.
Lig. Accessorioulnare
Eq: Inserts on the lateral styloid process
Ru: Inserts on the lateral styloid process
Ca: arises with the accessoriocarpoulnar ligament, which it fuses with, they then fuse with palmar ulnocarpal
ligament (running from ulna to the intermedioradial carpal bone
Lig. accessoriocarpoulnare
- 2 crus
Eq: Both crus attached to the ulnar carpal bone
Ru: 1. Ulnar carpal bone
2. Intermediate carpal bone
Ca: Unites the accessory and the ulnar carpal bones,
medial limb ends above
Lig. Accessorioquartale
- Peculiar to ruminants and horses
- Attaches to the fourth carpal bone
Lig. accessoriometacarpeum
- Inserts on the outermost metacarpal bone
- Ca: has in addition a second limb attaching to the 4th metacarpal bone
Canalis carpi
- Transverse carpal ligament
- Proximal carpal row and retinculum flexorium
- Superficially: formed by superficial part of flexor retinaculum
- Deeply: formed by palmar carpal fibrocartilage and palmar part of the joint capsule
- Bounded laterally by the accessory carpal bone
- Contains: tendons + synovial sheath of mm. flexor digitorum superficialis and profundus
tendon of flexor carpi radialis
Radial, median and caudal interosseous arteries and veins
Ulnar and median nerves
