Anatomy 2 - Equine Forelimb Joints

drraythe's version from 2015-06-05 22:54


Question Answer
were are most injuries/lameness in the legs?below the carpus/hock, more in the forelimb, so over 95% said to occur below the carpus
noteable about the scapula of the horse?absence of acromion, and also no acromial head of the deltoid
how do the head of the humerus and glenoid cavity relate?head of humerus is larger than glenoid cavity, therefore, affords a gliding movement
what mm is always paired with biceps brachii (fxn)extensor carpi radialis
where does the shoulder bursa lie?intertubercular (bicipital) bursa interposed between the tendon of origin of the biceps brachii and the joint capsule
ligaments of the shoulder?none, HOWEVER tendons of the supraspinatus, infraspinatus, subscapularis, teres minor, and biceps brachii ("active" ligaments) stabilize the joint
what does the angle of the shoulder have to do with anti-concussion?joint normally partially flexed (115*) which provides excellent anti-concussion
specific parts of the bones involved in the cubital joint? condyles of humerus, fovea capitis of head of radius, trochlear notch of ulna
is there a joint capsule of the cubital joint?yes, loose and it attaches on edges of articular surfaces
ligaments of the cubital joint? M+L collateral ligs, ONLY THE MEDIAL is split into LONG (sup.) and SHORT (deep) branches
origins and insertions of M+L collateral ligs of cubital joint?from epicondyles of humerus to corresponding tuberosities of the radius. Of the medial's two branches, the LONG, superficial one ends on the radius distal to the antebrachial interosseus space. the SHORT deep one inserts on the medial tuberosity of the radius (normal place)
where would you make an injection in the cubital joint?Cr and Ca to the lateral collateral lig
how many rows of carpal joints? tarsal?C= 2 rows (3 component articulations) T=3 rows (4 c.a.)
what are the bones involved in the carpus?distal end of radio-ulnar segment, but NOT THE ULNA ITSELF, prox ends of metacarpals, and then the prox and distal rows of carpal bones
how many/what bones are in the prox. row of carpal bones?(4) radial (M), intermediate, ulnar, Accessory (L)
how many/what bones are in the distal row of carpal bones?(4) (1), 2(M), 3, 4(L) (1 may be absent or very small)
3 main joints of the carpus? other joints?(1) anterbrachiocarpal (better radiocarpal in the horse) joint (2) middle carpal joint (3) carpometacarpal joint (4) intercarpal joints between carpal bones in each row
describe the joint capsule of the carpus (type of tissue? from where to where? attaches where? thickened where?)fibrous layer. It is a COMMON capsule (from radius prox. to metacarpal bones distally) and attaches to composite bones as it passes them. Thickened on DORSAL AND PALMAR surfaces
what is special about the palmar part of the carpal joint capsule? (composition, forms what, extends/attaches where?)might be cartilaginous, forms CARPAL CANAL (with the accessory carpal) for digital flexor tendons. extends at middle/distal end into accessory ligament, attached to DDF TENDON
what forms the carpal canal? what goes through it?palmar carpal joint capsule and accessory carpal bone, the flexor tendons go thorough it
where are the synovial sacs in the carpus? (3) details about each?(1) antebrachiocarpal sac (LARGEST, includes joint formed by accessory carpal bone and between prox. intercarpal joints) (2) middle carpal sac (communicates w/carpometacarpal sac between 3+4 carpals) (3) carpometacarpal sac
which synovial sacs in the carpus communicate?the middle and the carpometacarpal sac (between 3+4 carpals)
what are the 3 main types of ligaments of the carpus? collaterals, accessory carpal bone ligaments, short ligs uniting adj. carpal bones
explain the collateral ligs of the carpus (what are they, extend from where to where, unite what?)M+L, long, extend between radius and metacarpal bones, unite bones of carpus on each side
explain the accessory carpal bone ligaments (What are they, join what?)there are prox, middle, and distal ligs. join the acc. carpal to the ulnar carpal (accessorioulnar-AU), 4th carpal (accessorioquartal-AQ) and lateral splint (IV) bone (Accessoriometacarpal-AM)
what kind of joint is the carpal joint, what is its main purpose?composite (hinge-like) joint with several bones, so good for CONCUSSION/ABSORBING
angles of flexion and extension of the carpus?mainly flexion (up to 90*) and extension (180* total?) (some abduction and adduction)
where does most of the movement of the carpus occur? (which joint)antebrachiocarpal and middle carpal joints (carpometacarpal joint is bound down by ligaments, so little mvt)
how easily are prox sesamoids injured?break easily but HARD to fix
clinical application of the carpus with injections?at flexion, 2 prox. joint cavities open relatively widely, so can inject into radiocarpal /middle carpal synovial sacs easily.
what is liable to injury if the horse falls on a flexed carpus?the 2 prox joint cavities b/c they are opened widely
what is the #1 injured joint of the forelimb? hindlimb?#1= fetlock (most stressed) #2=coffin
most stressed joint of the body?fetlock
what are the bones of the fetlock?distal end of metacarpal (cannon) bone, prox. end of P1, prox. sesamoid bones (important!--> ligs attaching to it act as slings to help support the fetlock)
what do the prox. sesamoid articulate with?DISTAL END OF CANNON (metacarpal) NO DIRECT ARTICULATION WITH P1
describe how the fetlock joint capsule lies, where do you inject?projects PROXIMALLY between cannon and the interosseus m on the PALMAR surface. you can inject here M or L
what is windpuffs/galls/articular windgalls?pathological distension of the fetlock joint capsule
what are the ligaments of the fetlock? (just the groups) (3)(1) above prox sesamoids (2) over prox. sesamoids (3) below prox. sesamoids (<--- all on flexor surface to PREVENT OVEREXTENSION)
what are/is the ligament(s) of the prox. sesamoidean ligament group?THE INTEROSSEUS MM (AKA SUSPENSORY LIGAMENT, aka superior sesamoidean ligament)
describe the interosseus mm in the foal vs horse?(aka suspensory ligament) little mm in foal and totally tendinous in adult
origin of the interosseus? divides where? insertion?O= prox part of palmar surface of cannon. D= at distal 1/4 of cannon bone into two I= abaxial surface of prox. sesamoid AND! detaches an oblique, dorsal branch (Extensor slip) to the common digital extensor tendon over dorsal surface of prox phalanx
Fxns of the sesamoidean ligs (aka interosseus+extensor slips) (3)(1) support fetlock (2) prevent over-extension (dorsal flexion) of the joint when foot on the ground (3) dorsal branch (extensor slip) limits flexion, and prevents deep flexor tendon from flexing the joint as a result of the tension on it (deep flexor) when limb is on the ground and joint is extended
what are/is the ligament(s) of the middle/overlying prox. sesamoidean ligament group?(1) the intersesamoidean ligament (2) the collateral sesamoidean ligaments
what is the composition/location of the intersesamoidean ligament?fibrocartilage, extends between the 2 prox sesaoid bones
where are the collateral sesamoidean ligaments located?MEDIAL AND LATERAL, attach sides of the proc. sesamoid bones to the METACARPAL CONDYLES and PROX TUBERCLES of P1
what are the ligaments in the distal sesamoidean group? (4)(1) superficial (straight) sesamoidean ligament (2) middle (oblique) sesamoidean lig (3) deep (cruciate) S.L. (4) short S.L.
where does the superficial (straight) ses. lig. run? which group is it in?distal group. extends from sesamoids and intersesamoidean lig (of middle group) to FIBROCARTILAGE LIP on palmar aspect of prox end of P2. Straight, long fibers
what does the middle (oblique) sesamoidean lig run? which group is it in?distal group. Extends from the bases of the sesamoid bones to palmar surface of prox phalanx
where do the deep (cruciate) sesamoidean ligaments lie? what group are they in?distal group. 2 bands of fibers, crossing each other, from bases of sesamoids to opposite eminence on prox. end of P1
where do the short sesamoidean ligaments run? what group are they in?distal group. 2 ligs running from axial sides of the bases of sesamoid bone to the abaxial side of eminence of the prox phalanx
what is the big fxn of the distal sesamoidean ligs?assist the interosseus mm in support of the fetlock joint
what ligs/tendons prevent buckling foreward of the pastern when foot hits the ground?oblique sesamoidean ligament and the SDF tendon
explain the conformation/location of the collateral ligs of the fetlock?M+L each with a sup and deep layer. The deep is shorter, stronger, and covered by the superficial layer
which portion of the proximal sesamoidean is a more severe break?the distal 1/2 is way more severe
what is wrong in fetlock sinks?probs with fetlock-related portion of the interosseus mm (suspensory lig) and to a lesser extent, the fetlock section of the SDF (combine both of these probs= complete grounding (collapse) of fetlock

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