Front Limbs Flashcards
Horse limbs are fixed in
Pronation
Rotators, abductors, and adductors in the horse are
Reduced or absent
Muscles of horse limbs developed for movement in the
Craniocaudal (sagittal) plane
LATERAL shoulder muscles include (4)
-supraspinatus
-infraspinatus
-deltoideus
-teres minor
What two lateral shoulder muscles insert at the deltoid tuberosity
-deltoideus
-teres minor
Supraspinatus (origin, insertion, and function)
O: supraspinatus fossa/cartilage/spine
I: cranial parts of both the greater and lesser tubercle
F: stabilizes and extends shoulder
Deltoideus (origin, insertion, and function)
O: scapular spine and caudal scapula
I: deltoid tuberosity of humerus
F: flexes shoulder
What muscle is located on the caudal aspect of the scapula spine
Infraspinatus
Teres minor (origin, insertion, and function)
O: distal half caudal border of scapula
I: deltoid tuberosity of humerus
F: flexes shoulder
Infraspinatus (origin, insertion, and function)
O: infraspinatus fossa/cartilage/spine
I: deep and superficial insertions to caudal part of greater tubercle
F: flexes shoulder and functions as a contractile lateral collateral ligament
Which two muscles stabilize the shoulder joint
Supraspinatus and infraspinatus
Which shoulder muscle has a synovial bursa? Where is it located?
Infraspinatus; under superficial tendon
Subscapularis muscle is a muscle of the
MEDIAL shoulder
Subscapularis (origin, insertion, and function)
O: sub-scapular fossa
I: lesser tuberosity of humerus
F: extends and stabilizes shoulder
Two caudal muscles of the brachium are
-Triceps Brachii (lateral, long, and medial heads)
-Biceps Brachii
What nerve innervates the triceps brachii muscle
Radial nerve
Triceps Brachii (origin, insertion, and function)
O: caudal scapula
I: olecranon
F: extends elbow
What are the heads of the triceps brachii
-lateral
-long
-medial
Biceps brachii (origin, insertion, and function)
O: scapular tuberosity
I: radial tuberosity/medial elbow joint/extensor carpi radialis tendon/forearm fascia
F: flexes elbow
The tendon of origin for Biceps Brachii is (3)
-flat
-broad
-fibrocartilagenous
Lacterus Fibrosus (3)
-part of Stay Apparatus in forelimb
-biceps Brachii
-connects to extensor carpi radialis
The biceps brachii has a large ___ that passes over ___
Bicipital Bursa; the intermediate tubercle of the humerus
Synovial structures of the shoulder joint (scapulohumeral joint)
-bicipital bursa (no communication with the shoulder joint)
-infraspinatus bursa
Collateral ligaments of the shoulder joint
-technically none
-the Subscapularis, supraspinatus and infraspinatus muscles act as contractile collateral ligaments
The suprascapular nerve innervates
-supraspinatus
-infraspinatus
The scapulohumeral joint is also called the
Shoulder joint
The Subscapularis, supraspinatus, and infraspinatus act as ___ on the ___
Collateral ligaments; shoulder joint
Extensors of the carpus/digits (4)
-extensor carpi radialis
-common digital extensor
-lateral digital extensor
-extensor carpi obliquus
Extensor Carpi Radialis (origin, insertion, and function)
O: lateral supracondylar crest of the humerus and radial fossa
I: metacarpal tuberosity (MC3)
F: extends carpus
Which muscle is lateral to the extensor carpi radialis
Common digital extensor
Common Digital Extensor (origin, insertion, and function)
O: 3 heads (radial, humeral, and ulnar)
I: extensor process of P3
F: extends carpus and digits
The common digital extensor is connected to the ___ via ___ at the level of the ___
Suspensory ligament; extensor branches; fetlock
Lateral Digital Extensor (origin, insertion)
O: proximal radius and ulna
I: on P1 (long pastern bone)
Which muscle crosses the carpus
Extensor Carpi Obliquus
Extensor Carpi Obliquus (origin, insertion)
O: distolateral cranial radius
I: dorsomedially on proximal MC2 (splint bone)
Which side is the horse’s chestnut on?
Medial
Which extensor muscles of the carpus/digits have a tendon sheath?
-extensor carpi radialis
-common digital extensor
-lateral digital extensor
What are the flexors of the carpus/digits (5)
-ulnaris lateralis
-flexor carpi radialis
-flexor carpi ulnaris
-superficial digital flexor
-deep digital flexor
Which splint bone is lateral, which is medial?
Lateral Splint Bone = MC4
Medial Splint Bone = MC2
Ulnaris Lateralis (origin, insertion, and function)
O: lateral epicondyle of the humerus
I: accessory carpal bone and proximal lateral splint bone (MC4)
F: flexes carpus
Which muscle is next to the radius?
Flexor carpi radialis
Flexor Carpi Radialis (origin, insertion)
O: medial humeral epicondyle
I: proximal medial splint bone (MC2)
Flexor Carpi Ulnaris (origin, insertion)
O: medial epicondyle (humeral head) and medial olecranon (ulnar head)
I: accessory carpal bone
Two heads of the Flexor Carpi Ulnaris
-humeral
-ulnar
Superficial Digital Flexor (origin, insertion)
O: medial epicondyle of the humerus
I: distal P1 and proximal P2
The manica flexoria
SDFT forms a sleeve around the DDF at the level of the fetlock joint
The accessory ligament of the SDFT is called ___ and originates from
Superior check ligament; radius
The accessory ligament of the DDFT is called ___ and originates at
Inferior Check Ligament; distal palmar carpal ligament
The navicular bursa is a ___ structure and located ___
Synovial structure; located between the DDFT and navicular bone
Deep Digital Flexor (origin, insertion)
O: three heads (humeral, ulnar, and radial)
I: P3 (ie. coffin bone)
Suspensory Ligament (origin, insertion, and function)
O: 60% from the proximocaudal MC3 and 30% from palmar carpal ligament
I: proximal sesamoid bones
F: counteracts overextension of the fetlock joint
The Third Interosseous muscle is also called ___ and contains ___
Suspensory Ligament; little muscular tissue
The suspensory ligament divides into ___ and their O/I is
-extensor branches (lateral and medial)
O: Fr proximal sesamoid bones
I: join the common digital extensor tendon around proximal P1
Three annular ligaments
-palmar annular ligament
-proximal digital annular ligament
-distal digital annular ligament
The fluid surrounding the SDFT and DDFT is the
Carpal canal/sheath
The radial nerve innervates
-triceps
-carpal and digital extensors
A “dropped elbow” is usually caused by
Fractured olecranon or radial nerve damage
The median nerve innervates
Flexors of the carpus and digits
The main sensory nerve to the distal forelimb is the
Median nerve
The median nerve joins with the
Musculocutaenous nerve
The median nerve divides into the
Medial and lateral Palmar nerve
Skin sensation of the lateral antebrachium is the
Lateral cutaneous antebrachial nerve
Skin sensation of the caudal forearm is the
Caudal cutaneous antebrachial nerve
Skin sensation of the lateral metacarpus is the
Dorsal branch of the ulnar nerve
The ulnar nerve innervates
Flexors of the carpus and digits
Main trunk arteries of the forelimb are
Auxiliary —> brachial —> median —> medial palmar
The main blood supply to the lower limb and foot of the forelimb is the
Medial palmar artery
The medial palmar artery runs
Medially between the SL and DDFT
The medial palmar artery branches into
Medial and later palmar digital arteries
The arteries below the fetlock are the
Medial and lateral palmar digital arteries
The cephalic vein is
On the medial subcutaneous surface of the radius