Lecture 6 - Antebrachium and carpus Flashcards
What basc joints are in the antebrachium-carpal region?
Radio-carpal, intercarpal, carpo-metacarpal joints
What are the major bones in the antebrachium?
Radius, ulna, and carpals
What are the compartments in the antebrachium?
Caudal and craino-ventral
What artery supplies the caudal compartment?
median a., ulnar a., and radial a.
What nerve supplies the caudal compartment?
Median and ulnar n.
What action is the caudal compartment responsible for?
Flexion of carpus and digits
What artery supplies the craino-ventral compartment?
Superficial brachial a.
What nerve supplies the craino-ventral compartment?
Radial n.
What action is the craino-ventral compartment responsible for?
Extension of carpus and digits
What are the two rows of carpals?
Proximal and distal
What are the proximal carpals?
radial, intermediate, ulnar, and accessory
What occurs in the proximal carpals of dogs?
radial and intermediate fuse
What are the basic characteristics of the accessory carpal?
Projects behind the carpus, projects behind the carpus
What are the carpals in the distal row?
1-5
What occurs in the distal carpals of ungulates?
second and third fuse
What occurs with the first carpal?
often lacking
What happens with the fifth bone?
Never a separate bone - either suppressed or fused with the fourth
What shares a joint capsule with the distal radioulnar joint?
Antebrachiocarpal joint
What shares a joint capsule with the midcarpal joint?
Carpometacarpal
Where are the intercarpal joints?
between individual carpal bones
How does the carpal act in carnivores?
Acts as ginglymus
What is ginglymus?
hinge with lateral movement
What is the most mobile joint in the carpus of a carnivore?
antebrachiocarpal joint
How does the carpal joint act in an ungulate?
As a hinge - some oblique movements
What are the degrees of movement in the seperate joints of the carpus?
Antebrach. - very mobile (90 degrees)
Midcarpal - somewhat mobile (45 degrees)
Carpomet. - no movement
What ligaments occur in the carpus?
dorsal carpus
palmar carpus
What do the dorsal short ligaments do?
Join neighboring bones in each row, to the metacarpus
What animal has well-developed medial and lateral collateral ligaments in their carpal joints?
Ungulates
What ligaments occur in the palmar carpus?
Deep palmar, superficial/transverse, and distal ligaments of accessory bone
What is the positioning the the deep palmar ligaments?
covers entire palmar surface of skeleton, hides unevenness of the bones
What do superficial and transverse ligaments contribute to?
carpal canal
What is the purpose of the carpal canal?
conveys the flexor tendons and other structures continuing into foot from antebrachium
What is the path of the superficial/transverse ligament?
Passes obliquely accessory carpal bone to medial aspect of carpus
What do the distal ligaments of the accessory bone do?
Assist in preventing overextension, doesn’t interfere with flexion
What is the path of the distal ligament of accessory bone?
Join bone to the adjacent carpal and metacarpal bones
What muscles does the radial nerve innervate?
All carpal and digital extensors, including ulnaris lateralis
What is the path in the dog of the radial n.?
Cutaneous branch descends over craniolateral aspect of antebrachium and carpus, reaches dorsal surface of digits
What is the radial nerve in the horse subsituted by in the foot?
Musculocutaneous n.
What muscles does the median n. innervate?
most of the flexor muscles of carpus and digits
Where does the median n. enter the forearm?
Medial collateral ligament of elbow joint
What does the median n. travel deep too?
flexor carpi radialis
What muscles do the ulnar n. innervate?
flexor carpi ulnaris, part of flexor digitorum profundus
What is different about the horse ulnar n.?
does not unit with median nerve in brachiumq
When does the ulnar n. break off from the median n. in dogs?
olecranon
What branches off the ulnar n. in the brachium?
cutaneous antebrachial n.
What muscles do the musculocutaneous n. innervate?
none in the antebrachium or the carpus
What does the musculocutaneous n. do in the antebrachium?
medial cutaneous antebrachial n. innervates medial aspect
What does the cutaneous branch of the musculocutaneous muscle do?
continues past the carpus and to the metacarpophalangeal jt.
What is the main blood supply in the antebrachium (4 arteries)?
common interosseous a., median a, ulnar a., and radial a.
What branches off the median a.?
radial a. and deep antebrachial a.
What is the positioning of the cephalic v. in the forelimb?
follows cranial border of the forearm, lies on the extensor carpi radialis
What is the general origin of the craniolateral muscle group?
Lateral epicondyle
What are the extensor muscles (name wise) of the craniolateral muscle group?
E. carpi radialis
E. digitorum communis
E. digitorum lateralis
E. digiti I
What are the other muscles (not the extensors) of the craniolateral group?
Brachioradialis
Supinator
Ulnaris lateralis
Abductor digiti I longus
What small muscle of the forearm is hard to find in dogs but is present in cats?
Brachioradialis
What flexors (name wise) are present in the caudal group of muscles?
F. carpi radialis
F. carpi ulnaris
F. digitorum profundus
F. digitorum superficialis
What are the pronators of the caudal group of forearm muscles?
P. teres
P. quadratus
Where is the general origin point of the caudal group of muscles?
medial epicondyle of humerus
Where do the extensor group occupy?
craniolateral part of the antebrachium
What is the horse version of the abductor digitorium I longus?
Extensor carpi obliquus
What muscle aid in the horse’s ability to stand for long periods of time?
Flexor digitorum profundus and superficialis
