vm 602 anatomy joints of the thoracic limb

"fleshy" attachment of the thoracic limb to the trunk

synsarcosis

-formed by 2 or more bones

-cavity between bones

-cartilaginous articulations

-joint capsule

-synovium: produces synovial fluid

-stabilized by muscles and/or ligaments

synovial joints

joints of the thoracic limb and flexor surfaces

-shoulder joint

-elbow joints

-carpal joints

-digital joints:

metacarpophalangeal joint

proximal interphalangeal joint

distal interphalangeal joint

-filled with synovial fluid

--viscous fluid

--nourishes and lubricates the joint

synovial structures

-synovial envelope that encloses a joint

-fibrous: can restrict movement

-puches

synovial joint capsule

synovial sac lying between a tendon or muscle and an adjacent bony prominence

synovial bursae

synovial sac that completely surrounds a tendon

tendon sheaths

synovial structure diagram

attach bone to bones

stabilize and support the joints

type I collagen

ligaments

fibrous band of connective tissue that bind tendons

retinacula

articular surfaces: glenoid cavity of the scapula

humeral head

range of motion: flexion and extension

supporting ligaments: none, joint is stabilized by muscles

-supraspinatus, infraspinatus, and subscapularis mm

glenohumeral (shoulder) joint

associated structures of the shoulder joint

glenohumeral ligaments

-medial and lateral

---thickening of the joint capsule

transverse humeral retinaculum

-holds biceps tendon in the bicipital groove

synovial structures

-infraspinous bursa

-tendon sheath of bicipital tendon

-bicipital bursa

---synoviocentisis

articular surfaces:

-humeral condyle

-head of radius and trochlear notch of the ulna

-articular circumference of the radius and radial notch of the ulna

range of motion:

flexion and extension

supporting ligaments:

medial and lateral collateral ligaments

synovial structures:

caudodorsal pouch

cubital (elbow) joints

a site for arthrocentesis

-can access or inject joints

caudodorsal pouch

Articular surfaces:

-articular circumference of the radius and radial notch of ulna

-articular circumference of ulna and ulnar notch of radius

range of motion:

supination and pronation

supporting ligaments:

interosseous ligament

radioulnar joint

(relevant mostly in carnivores)

composite articulations:

-antebrachiocarpal joint

-middle carpal joint

-intercarpal joint

-carpometacarpal joint

range of motion:

-flexion and extension

--antebrachiocarpal and middle carpal

supporting ligaments:

-medial and lateral collateral ligaments

-palmar carpal ligament

-short ligaments

carpal (wrist) joint

carpal joints that are less movable

intercarpal and carpometacarpal joint

associated structures of the carpal joint

synovial structures

-common joint capsule

--separation between synovial compartments

--exception: middle carpal joint communicates with carpometacarpal joint

tendon and tendon sheaths of extensor and flexors

retinacula

-extensor retinaculum

-flexor retinaculum

clinical application: carpal injection

separation between synovial compartments means they do not communicate and need to inject them separately

"passageway"

-flexor carpi radialis m

-digital flexor tendons and their synovial sheaths

---SDF

---DDF

-blood vessels and nerves

---median and radial aa

---median and ulnar nn

boundaries

-palmar carpal ligament

-flexor retinaculum

-accessory carpal bone

carpal canal

joint:

-metacarpophalangeal joint (fetlock): distal extremity of the metacarpal bone and proximal extremity of the proximal phalanx

-proximal interphalangeal joint (pastern): distal extremity of the proximal phalanx and proximal extremity of the middle phalanx

-distal interphalangeal (coffin): distal extremity of the middle phalanx and proximal extremity of the distal phalanx

range of motion:

flexion and extension

supporting ligaments:

-medial and lateral collateral ligaments (horse)

-annular ligaments

digital joints

fetlock joint

metacarpophalangeal joint

pastern joint

proximal interphalangeal joint

coffin joint

distal interphalangeal joint

located on each side of the common digital extensor tendon

keeps claws retracted (works more in cats than dogs)

claws are protruded by simultaneous contraction of the deep digital flexor

dorsal elastic ligaments

brace the digital flexor tendons

-proximal digital and distal digital

-looks like an X in horses

annular ligaments

in ruminants

support the digits and prevent the digits from spreading

-proximal and distal

interdigital ligament

in horses

located between the navicular bone and deep digital flexor tendon

clinically- relevant: bursitis due to injury (puncture is most common)

navicular bursa

picture of navicular bursa