FORELIMB AND HINDLIMB- MYOLOGY (origin and insertion and function) Flashcards
Biceps femoris
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: patella and stifle ligaments
- function: extends hip, stifle and tarsus; caudal part flexes stifle
Name the Extrinsic muscles of the forelimb
- Brachiocephalicus
- Sternocephalicus
- Trapezius
- Omotransversarius
- Latissimus Dorsi
- Pectoralis ascendens
- Pectoralis decendens
- Pectoralis tranversus
- Serratus ventralis
ARTHROLOGY OF THE SHOULDER
(SCAPULOHUMERAL JOINT)
- Spheroid synovial joint between the glenoid cavity of the scapula and the head of the humerus
- It has a loose joint capsule with no true collateral ligaments
- The muscles crossing the joint capsule (infraspinatus, supraspinatus, subscapularis and corocobrachialis) provide support
Movement: it is functionally a freely moveable joint, but due to extrinsic muscles of the forelimb and its position on the lateral side of the thorax, it only moves in flexion and extension
- Synovials: 1 large vey wide
- Recessus: 1 in carnivores that is an extension of the joint capsule around the tendon of the biceps brachii muscle and passes through the intertubercular groove
- Synovial bursa: 1 in horses and ruminants located between the intertubercular groove and the bicipital tendon that DOES NOT communicate with the shoulder capsule
ligaments:
- Glenohumeral ligaments help strengthen the joint capsule
Extensor muscles of the hip
® Middle gluteal
- origin: gluteal fossa of ilium
- insertion: greater trochanter of femur
- function: extends hip and +/- abducts thigh
® Piriformis (dog)
- function: extends and abducts hip
® Biceps femoris
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: patella and stifle ligaments
- function: extends hip, stifle and tarsus; caudal part flexes stifle
® Semitendinosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligaments
- insertion: tibial crest and calcaneus
- function: extends hip and tarsus, and flexes stifle
® Semimembranosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligaments
- insertion: medial condyle of femur and medial condyle of tibia
- function: extends hip and extends and flexes stifle
® Deep gluteal
- function: extends and abducts hip
OSTEOLOGY OF HUMERUS
® Shaft
® Greater tubercle – divided into cranial and caudal parts in the horse and ox; insertion for
the supraspinatus muscle
® Lesser tubercle – along with greater tubercle, provides insertion for the supraspinatus
muscle
® Lateral epicondyle – provides attachment for the extensors of the forearm
® Medial epicondyle – provides attachment for the flexor muscles of the forearm
® Deltoid tuberosity – insertion for the deltoid muscle
FUNCTION
® articulates proximally with the scapula, forming the shoulder joint and distally with the
radius and ulna forming the elbow joint
® provides muscle attachment for many muscles that act on the shoulder and elbow
Deep digital flexor (forelimb)
- origin: humerus, radius and ulna
- insertion: semilunar line of distal phalanx
- function: flex carpus and digits
ARTHTROLOGY OF CARPAL JOINT
Overall, the carpal joint is a compound hinge synovial that consists of three main joints
- Radiocarpal joint: Between the distal radius and ulna and the proximal row of carpal bones
Movement: flexion and extension
Synovials: 1 very large; sometimes an independent synovial exists between the ulnar and accessory carpal bones
Recessus: 1 located just above the accessory carpal bone
- Mediocarpal joint: Between the two rows of carpal bones
* Communicates with the carpometacarpal joint
Movement: flexion and extension, and abduction and adduction in carnivores
Synovials: 1 large that gives extensions to the proximal and distal intercarpal joints
Recessus: none
- Carpometacarpal joint: Between the distal row of carpal bones and the metacarpal bones
* Communicates with the mediocarpal joint
Movement: none
Synovials: 1 large that gives extensions to the distal intercarpal joints
Recessus: none
- Intercarpal joints (proximal and distal): Plane joints between the individual carpal bones
Movement: none
Synovials: no own synovial; lubrication comes from the radiocarpal and mediocarpal synovials for the proximal intercarpal joints and the mediocarpal and carpometacarpal synovials for the distal intercarpal joints
Recessus: none
- Medial and lateral collateral ligaments restrict movement
- Intercarpal ligaments are present between individual carpal bones
- Fibrocartilage covers the palmar side of the carpus and provides a smooth surface for the
carpal canal
• The carpal canal is formed by the accessory carpal bone laterally, the other carpal bones
dorsally, and the flexor reticulum on the palmar side and provides passage for:
® Tendons and synovial sheaths of the DDF and SDF in horse and ruminants; only DDF in
carnivores
® Ulnar and median nerves in horse; only median nerve in ruminants and carnivores
® Arteries and veins
Extensor muscles of the stifle
• ***In horses*** - any muscle that acts on the stifle, via the reciprocal apparatus also acts on the hock, and vice versa.
® Biceps femoris
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: patella and stifle ligaments
- function: extends hip, stifle and tarsus; caudal part flexes stifle
® Semimembranosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: medial condyle of femur and medial condyle of tibia
- function: extends hip and extends and flexes stifle
® Quadriceps femoris
- origin: ilium and medial, lateral and cranial sides of femur
- insertion – tibial tuberosity
- function: extends stifle and +/- flexes hip•
Extensor muscles of the digit/s
(forelimb)
common digital extensor
- origin: lateral epicondyle of humerus
- insertion: extensor process of distal phalanges of principle digits
- function: extend carpus and digits
lateral digital extensor
- origin: lateral collateral ligament of elbow
- insertion: proximal end of proximal (H), middle (R) or distal (C) phalanx of lateral digit
- function: extend carpus and digits
Osteology of coxal bones
- Make up the pelvic girdle, which consists of the two hip bones, the ilium and ischium, and the sacrum
- Acetabulum articulates with the head of the femur forming the hip joint
Ilium
- Largest and most cranial bone
- Consists of a wing and a body
- Forms the cranial part of the acetabulum and articulates with the sacrum
- The gluteal surface of the wing of the ilium provides the origin for the gluteal muscles while the auricular surface articulates with the sacrum and forms the sacroiliac joint
- Iliac crest is the cranial edge of the wing
- Tuber coxae
- Tuber sacrale
Ischium
- Caudal-most part of the hip bone
- Ischiatic tuberosity provides attachment for the caudal thigh muscles
- Greater ischiatic notch provides the passage for the ischiatic nerve in large
animals
- Lesser ischiatic notch provides the passage for the ischiatic nerve in small animals
- Obturator foramen in the large opening in the floor of the hip bone and provides the passage for the obturator nerve
- Ischiatic tuberosity provides origin for the biceps femoris muscle
FUNCTION
® Provide stability in the hind limb
® Help hold up the axial column
® Provide substrate for muscle attachment (Gluteals; quadriceps; adductor)
® Passage for birth
® Encloses the pelvic cavity and helps to hold in internal organs
Tensor fascia latae
- origin: tuber coxae
- insertion: lateral femoral fascia
- function: flexes hip
Long digital extensor
(hindlimb)
- origin: extensor fossa of femur
- insertion: extensor process of distal phalanx
- function: flexes tarsus and extends digits
Pectoralis transversus
origin: sternum
insertion: lesser tubercle of humerus
function: adducts forelimb
Flexors of the elbow
Biceps brachii
- origin: supraglenoid tubercle of scapula
- insertion: bicipital tuberosity
- function: flex elbow and extend shoulder
Brachialis
origin: brachial groove of humerus
inserts: radius
function: flex elbow
Teres major
- origin: caudal border of scapula
- insertion: teres major tuberosity
- function: flex shoulder and rotate limb medially
® Quadriceps femoris
- origin: ilium and medial, lateral and cranial sides of femur
- insertion – tibial tuberosity
- function: extends stifle and +/- flexes hip•
OSTEOLOGY OF CARPUS
- Radial – largest carpal bone; fused with intermediate in carnivores; articulates with the radius
- Intermediate – located between the radial and ulnar; fused with radial in carnivores; articulates
with the radius
- Ulnar – lateral bone in proximal row; articulates with the ulna
- Accessory – projects behind the carpus and articulates with the ulnar carpal; insertion for flexor
carpi ulnaris and extensor carpi ulnaris
- 1st – absent in ruminants; articulates with corresponding proximal metacarpal
- 2nd – fused with 3rd in ruminants
- 3rd – fused with 2nd in ruminants
- 4th –
FUNCTION
® Number of bones varies between species due to fusion or absent of one or more bones
® Together form a compound joint consisting of multiple communicating synovial joints
® As a whole, the carpus serves to provide shock absorption during locomotion
® Allow for easy and free movement of the carpus
• flexion and extension, as well as abduction and adduction in carnivores
Supraspinatus
- origin: supraspinous fossa
- insertion: greater and lesser tubercles of humerus
- function: extend and stabilize shoulder
Gastrocnemius
- origin: lateral and medial supracondylar crests of femur
- insertion: calcaneus
- function: extends tarsus and +/- flexes stifle
flexor muscles of the carpus
Flexor carpi radialis
- origin: medial epicondyle
- function: flexes carpus
Flexor carpi ulnaris
- origin: olecranon and medial epicondyle of humerus
- insertion: accessory carpal bone
- function: flex carpus
Ulnaris lateralis (horse and ox)
- origin: lateral epicondyle of humerus
- insertion: accessory carpal bone and most lateral metacarpal
- function: flex and extend carpus
Omotransversarius
origin: scapula spine
insertion: altas (C), axis and C1, C2 (H and R)
function:
- if fixed point at neck, pulls forward scapula and extends forelimb;
- if fixed point at scapula, pulls neck dorsolaterally;
- if both muscles act, cerviocephalic system is pulled back between scapulas
Extensor muscles of the elbow
Triceps brachii (long, lateral, deep)
origin: caudal border of scapula and tricipital border of humerus
insertion: olecranon
function: extend elbow and flex shoulder
Tensor fasciae antebrachii
origin: fascia covering the lateral side of latissimus dorsi
inserts: olecranon
function: extend elbow
Anconeus
origin: olecranon fossa
inserts: lateral surface of the olecranon
function: extend elbow
Arthrology of fetlock joint
hindlimb
(metatarsophalangeal)
® Modified condylar synovial between the metatarsal bones and the proximal phalanx, including the proximal sesamoid bones
® Movement: flexion and extension
® Synovials: 1 that communicates with its homologue on the palmar side in ruminants
® Recessus: 1 dorsal located under the digital extensor tendon (less developed) and 1 palmar located above the proximal sesamoid bones (very developed)
® Proximal scutum is a ligament between the proximal sesamoids
® Interdigital intersesamoid ligaments are located between the proximal sesamoid couples in ruminants and carnivores
® Collateral ligaments are present either side of the joint restricting movement
OSTEOLOGY OF PHALANGES (forelimb)
in Carnivores
- Four main weight bearing digits (2nd – 5th)
- Dew claw – consists of the 1st digit and 1st metacarpal bone; first digit is reduced with only two phalanges, proximal and distal and one sesamoid bone
- Proximal phalanx – divided into base, body and head
- Middle phalanx – same structure as proximal, but shorter in length
- Distal phalanx – carries the horny claw
- flexor process on palmar side provides insertion for DDF tendon and extensor process on dorsal proximal part of four main digits provides insertion for CDE
- ungeal process is the tapered, cone-shaped process covered by the horny claw
- Palmar sesamoid bones – nine, two for each of the four digits and one for the 1st
- Distal sesamoid bones – represented by cartilage in carnivores
Ruminants
• Four digits, two weight bearing and two non weight bearing
- 1st is missing and 2nd and 5th are vestiges (cannot find) that externally manifest as horny dew claws behind the fetlock
- 3rd and 4th are fully developed and consist of three phalanges and three sesamoid bones each
• Sesamoid bones – two proximal at the metacarpophalangeal joint and one distal at the distal interphalangeal joint for each digit
Horses
- One digit per limb supporting metacarpal 3
- Proximal phalanx = long pastern
- Middle phalanx = short pastern
- Distal phalanx = coffin bone
- Fits into hoof and has an extensor process for insertion of digital extensor
tendon
• Proximal sesamoid bones – two small bones on palmar side of metacarpophalangeal joint
- Lateral is situated between between suspensory ligament and distal sesamoidean ligaments and helps make up the suspensory apparatus of the fetlock joint
• Distal sesamoid bone = navicular bone
- not embedded in a tendon but is located between DDF tendon and middle and distal phalanges
FUNCTION
• Together, the metacarpals and phalanges allow for movement of the manus during
locomotion
• All joints have a caudal flexion angle and therefore, when in extension the animal is placing its
foot forwards and when in flexion it is picking up its foot between strides
Abductors of Shoulder
Trapezius and deltoid
pectoralis ascendens
(deep pectoral)
origin: sternum
insertion: lesser tubercle of humerus
function: if fixed point is at thorax, adducts and internally rotates forelimb pulling it backwards as well as acting as an antagonist to the brchiocephalicus; if fixed point is forelimb, pulls thorax up and participates in impulsion; overall acts to support thorax
Flexor muscles of the hip
Quadriceps femoris
- origin: ilium and medial, lateral and cranial sides of femur
- insertion – tibial tuberosity
- function: extends stifle and +/- flexes hip
® Tensor fascia latae
- function: flexes hip
® Sartorius
- function: flexes hip and rotates thigh outwards
Deltoid
- origin: spine and acromion process of scapula
- insertion: deltoid tuberosity
- function: flex shoulder and abduct limb
Semitendinosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligaments
- insertion: tibial crest and calcaneus
- function: extends hip and tarsus, and flexes stifle
common digital extensor
- origin: lateral epicondyle of humerus
- insertion: extensor process of distal phalanges of principle digits
- function: extend carpus and digits
OSTEOLOGY OF METACARPALS
® generalized metacarpus has five bones, numbered from medial to lateral
® species differ due to absence or fusion of bones
® each bone is composed of a base that articulates with the carpus, a head which articulates
with the proximal phalanx and a shaft that connects the two extremities
® two sesamoid bones are associated with each weight bearing metacarpal bone
FUNCTION
• Together, the metacarpals and phalanges allow for movement of the manus during
locomotion
• All joints have a caudal flexion angle and therefore, when in extension the animal is placing its
foot forwards and when in flexion it is picking up its foot between strides
® Horses have three metacarpals, with the 1st and 5th missing
• The 2nd and 4th are greatly reduced and form the splint bones with the distal ends
called splint buttons
• The 3rd metacarpal is called the cannon bone and is the only metacarpal to articulate
with a digit
® Ruminants have two metacarpals, the 3rd and 4th which are fused at the shaft
- they also have a greatly reduced 5th metacarpal
- 1st and 2nd metacarpals are missing
® Carnivores have all five metacarpals with the 1st greatly reduced and bearing no weight
• 1st called dew claw and has one associated sesamoid bone
Superficial digital flexor (hindlimb)
- origin: supracondylar fossa on femur
- insertion: plantoproximal edge of middle phalanx
- function: extends tarsus and flexes digits
Extensor muscles of the digit/s (hindlimb)
® Long digital extensor
- origin: extensor fossa of femur
- insertion: extensor process of distal phalanx
- function: flexes tarsus and extends digits
® Lateral digital extensor
- origin: head of fibula
- insertion: proximal (H), middle (R), and distal (C)
- function: flexes tarsus and extends digits
Arthrology of atlantoaxial joint
- Pivot type synovial articulating between the dens of the axis and the cranial articular surface of the axis.
- Joint is united by a loose capsule reinforced by peripheral ligaments:
- Dorsal atlantoaxial ligament – corresponds to the interspinous ligament
- Ventral atlantoaxial ligament – corresponds to ventral longitudinal ligament
- Joint is also reinforced by deep ligaments:
- Transverse atlantoaxial ligament – connects the 2 arches of the atlas and crosses over the dens, holding it against the ventral arch of the atlas (carnivores)
- Longitudinal ligament of the dens – connects the apex of the dens to the atlas roof
- Tectoria membrane – fibrous sheet covering the longitudinal ligament of the dens; attached from the dorsal side of the axis to the roof of the occipital foramen with two extensions that insert on the atlas
® Movement: ‘no’ movement (rotation)
® synovial: 1
osteology of lumbars
- Characterized by their large size and long plate-like transverse processes
- Distinguished from the last thoracic vertebrae by the lack of costal facets
- Spinous processes are shorter and directed craniodorsally
- Lateral movements are nearly impossible due to the sagittal orientation of the articular processes
- Accessory processes can be seen on mid lumbar vertebrae
function of osteology of coxal and sacrum bones
• Sacrum –
- attaches to the pelvis helping to hold up the axial column; provides attachment for the hindlimb through attaching to the pelvis; stabilised through fusion of sacral bones
• Coxal bones –
- provides stability in the hind limb; helps hold up the axial column; provides substrate for muscle attachement (Gluteals; quadriceps; adductor); provides passage for birth; helps to hold in internal organs
® Acetabulum – articulates with the head of the femur forming the hip joint
® Greater ischiatic notch – where the sciatic nerve runs over the ilium in large animals
® Lesser ischiatic notch – where sciatic nerve runs over ilium in small animals
® Obturator foramen – opening in pelvic floor allowing the passage of the obturator nerve
Arthrology of Tarsal joint (hock)
• Overall, the tarsus is a compound hinge synovial joint that is composed of three main joints and two intrinsic joints
® Tarsocrural joint
- Articulation between the proximal row of tarsal bones and the tibia and fibula (calcaneous not involved in horses)
- Movement: flexion and extension (most moveable of all tarsal joints)
- Synovials: 1 very large that communicates directly (horses and carnivores) and indirectly (ruminants) with the mediotarsal joint
- Recessus: 1 dorsal and 1 caudal that is subdivided into 1 lateral and 1 medial by the lateral digital flexor tendon
® Mediotarsal joint
- Articulation between the proximal row of tarsal bones and the distal row of tarsal bones
- Movement: none in horses, little flexion and extension in carnivores and high flexion and extension in ruminants
- Synovials: 1 that communicates either directly (horses and carnivores) or indirectly (ruminants) with the tarsocrural joint
- Recessus: none
- Distal trochlea of the talus is present in ruminants and gives the mediotarsal joint more mobility
® Tarsometatarsal joint
- Articulation between the distal row of tarsal bones and the metatarsal bones
- Movement: none
- Synovials: 1
- Recessus: none
® Proximal intertarsal joint
- Articulation between the talus and calcaneus
- Movement: none
- Synovials: 3; proximolateral and medial synovials communicate with the tarsocrural synovial and the distal synovial communicates with the mediotarsal synovial
- Recessus: none
® Distal intertarsal joint
- Articulation between the distal tarsal row
- Movement: none
- Synovials: 1
- Recessus: none
osteology of femur
- Articulates proximally with the hip bone forming the hip joint and distally with the tibia forming the stifle joint
- Head of the femur articulates with the acetabulum
- Greater trochanter provides insertion for the middle gluteal
- Third trochanter is only present in the horse
- Medial and lateral condyle provide insertion for the semimembranosus
- Extensor fossa provides attachment for the long digital extensor musle
- Femoral trochlea articulates with the patella, with the medial larger than the lateral to allow rotation of stifle joint during patella locking in horses to hook over during patella locking
brachialis
origin: brachial groove of humerus
insertion: bicipital tuberosity
Flexor carpi radialis
- origin: medial epicondyle
- insertion: proximal metacarpus
- function: flexes carpus
Semimembranosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligaments
- insertion: medial condyle of femur and medial condyle of tibia
- function: extends hip and extends and flexes stifle
lateral digital extensor (forelimb)
- origin: lateral collateral ligament of elbow
- insertion: proximal end of proximal (H), middle (R) or distal (C) phalanx of lateral digit
- function: extend carpus and digits
Extensor muscles of the carpus
Extensor carpi radialis
- origin: humeral coronoid fossa
- insertion: metacarpal tuberosity
- function: extend carpus
Oblique carpal extensor (carnivores)
- function: extends carpus
Extensor carpi ulnaris (carnivores)
- origin: lateral epicondyle of humerus
- insertion: accessory carpal bone and most lateral metacarpal
- function: extend carpus
Latissimus dorsi
origin: supraspinous ligament and spinous process of thoracic and lumbar vertebrae
- insertion: teres major tuberosity on humerus
- function: if fixed point at axial column, pulls back brachium and acts as an
antagonist of the pectoralis ascendens
Arthrology of stifle joint
FEMOROPATELLAR JOINT
Movement: flexion and extension
® Synovials: 1 large
® Recessus: 1 cranial between the femur and the patellar insertion of the quadriceps
FEMOROTIBIAL JOINT
Movement: flexion which also results in internal rotation and extension which also results in external rotation
• Rotation is due to medial trochlea being larger than lateral
® Synovials: 1 lateral and 1 medial
® Recessus: 1 subpopliteus that follows the popliteus tendon between the lateral meniscus and the popliteus groove and 1 subextensorius that follows the long digital extensor tendon at origin
Biceps femoris
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: patella and stifle ligaments
- function: extends hip, stifle and tarsus; caudal part flexes stifle
ARTHROLOGY OF ELBOW
(HUMERORADIOULNAR JOINT)
- Compound hinge synovial joint between the humerus, radius and ulna
- Movement: flexion and extension
- Synovials: 1 very wide
- Recessus: 1 dorsal in coronoid process and radial fossa, 1 caudal in olecranon fossa, 1 medial under medial epicondyle, and 1 lateral under lateral epicondyle (expect in carnivores)
- Joint capsule encloses all three articular parts
- Collateral ligaments are located either side of the joint, restricting movement to only flexion and extension
- Annular ligament is present in dogs and is a thin band of connective tissue that passes transversely around the head of the radius and attaches at both ends to the ulna and forms a ring in which the radius can turn in when the forearm us supinated and pronated
- In horses the elbow joint is automatic, meaning that one it reaches a certain point of either flexion or extension, the joint requires no energy to be exerted and pops into place
Triceps brachii
function: extend elbow and flex shoulder
long head:
origin: caudal border of scapula and tricipital border of humerus
insertion: olecranon
lateral + medial + accessory (absent in horses)
origin: caudal edge of humerus
insertion: olecranon
Extensor muscles of the tarsus (hock)
Gastrocnemius
- origin: lateral and medial supracondylar crests of femur
- insertion: calcaneus
- function: extends tarsus and +/- flexes stifle
Sternocephalicus
origin: cranial part of sternal manubrium
insertion: mastoid process and curve line of occipital (C), basilar process of occipital and molar part of mandible (R), molar part of mandible (H)
function: flexes head and neck; if only one muscle acts, flexion is followed by rotation
Serratus ventralis
Origin:
- vertebrae C3-7
- ribs 1-7/8
Insertion: serrated surface of scapula
function: if fixed point at thorax, pushes shoulder joint forwards and participates in impulsion; if fixed point at scapula, pulls up thorax and pulls ribs outwards, acting as an inspiratory; overall acts to support thorax and attach forelimb to thorax
osteology of humerus
- Shaft
- Greater tubercle – divided into cranial and caudal parts in the horse and ox; insertion for
the supraspinatus muscle
- Lesser tubercle – along with greater tubercle, provides insertion for the supraspinatus
muscle
- Lateral epicondyle – provides attachment for the extensors of the forearm
- Medial epicondyle – provides attachment for the flexor muscles of the forearm
- Deltoid tuberosity – insertion for the deltoid muscle
FUNCTION:
- articulates proximally with the scapula, forming the shoulder joint and distally with the
radius and ulna forming the elbow joint
- provides muscle attachment for many muscles that act on the shoulder and elbow
Ulnaris lateralis
(horse and ox)
- origin: lateral epicondyle of humerus
- insertion: accessory carpal bone and most lateral metacarpal
- function: flex and extend carpus
Adductors of shoulder
Subscapularis
function: adduct, extend and stabilize shoulder; rotate limb medially
Coracobrachialis
- function: adduct, extend and stabilize shoulder
Adductor muscles of the hip
® Gracillis
® Pectineus
® Adductor
® External obturator
Flexor carpi ulnaris
- origin: olecranon and medial epicondyle of humerus
- insertion: accessory carpal bone
- function: flex carpus
Trapezius
origin: cervical part on nuchal ligament and thoracic part of supraspinous ligament
insertion: scapula spine
function: abducts and lifts the scapula
Arthrology of hip joint
® Spheroid synovial joint between head of femur and acetabulum of pelvis
® Movement: flexion and extension in horses as well as abduction and adduction in ruminants as well as lateral rotation and circumduction in carnivores
® Synovials: 1 large
® Recessus: none
® Ligament of the femoral head is a short intracaptular ligament that extends from the cavity to the notch on the head of the femur
® Acetabular lip is the band of fibrocartilage around the rim of the acetabulum that increases the depth of the acetabulum and decreases the pressure of contact
® Transverse acetabular ligament crosses the acetabular notch and completes the acetabular cavity
® In horses, there is an accessory ligament of the femoral head which extends from the prepubic ligament through the acetabular notch under the transverse ligament and attaches with the ligament of the femoral head; it stabilizes the hip and prevents the horse from abduction and adduction
FETLOCK JOINT
(METACARPOPHALANGEAL JOINT)
Modified condylar synovial between the metacarpal bone and the proximal phalanx, including the proximal sesamoid bones
Movement: flexion and extension
Synovials: 1 that communicates with its homologue on the palmar side in ruminants
Recessus: 1 dorsal located under the digital extensor tendon (less developed) and 1 palmar located above the proximal sesamoid bones (very developed)
Ligaments:
Proximal scutum is a ligament between the proximal sesamoids
Interdigital intersesamoid ligaments are located between the proximal sesamoid couples in ruminants and carnivores
Collateral ligaments are present either side of the joint restricting movement
osteology of the skull
CRANIUM: bones surrounding brain
- occipital region
- temporal region
- floor of cranium
- rostral wall of cranium
- roof of cranium
ruminant: frontal bone forms entire roof
horse: interparietal bone b/t the 2 parietal bones rostral to occipital bone.
* mastoid process: attachment site for muscles
–> 3 types of skulls in dogs relative to facial bone proportions:
- mesaticephalic- average
- dolicephalic: larger facial components
- brachiocephalic: shorter facial components
FUNCTION:
- Muscle attachment – facial muscles and muscles of the neck on occipital
- Contain the brain – main nervous system centre
- Contains nasal cavities – breathing
- Oral cavities and mouth – eating
- Has holes for the eyes – sight
- Occipital bone – has a hole for the exit of the brain stem and spinal cord
OSTEOLOGY OF RADIUS & ULNA
® Anconeal process – articulates with the olecranon fossa on the humerus when the elbow is extended
® Coranoid process – articulates with the humerus
® Olecranon – provides a lever arm for the extensor muscles of the elbow and forms the point of the elbow; upon extension of the elbow it fits into the olecranon fossa of the humerus; provides insertion for tripceps brachii muscle
FUNCTION
® the radius is the main weight bearing bone of the forearm and articulates with the humerus and ulna forming the elbow and with the carpal bones forming the carpus
® three distal grooves on cranial surface of radius accommodate tendons
® the ulna serves mainly for muscle attachment and formation of the elbow joint and articulates proximally with the humerus and radius and distally with the carpal bones
® In horses and ruminants the ulna is fused to the radius, preventing the animal from supinating their forearm, resulting in them being in permanent pronation
• Large animals are locked in permanent pronation so as they are able to bear larger weight loads whilst moving, compared to a carnivore, which needs the ability to supinate so as to leap and catch prey, or climb a tree etc.
® In horses only, the distal epiphysis of the ulna is fused with the radius, and in essence becomes part of the radius
osteology of metatarsus/phalanges
metatarsal bones - numbered from medial -> lateral
- has two sesamoid bones - associated to weight bearing the metatarsal bones
horses:
- metatarsus 2+4 = splint bones
- metatarsus 3 = only metatarsal to articulate with a digit = cannon bone
ruminants:
- two metatarsal bones: 3rd + 4th –> fused at shaft
- greatly reduced 5th metatarsal bone
carnivores:
- have all 5 metatarsals
- 1st greatly reduced - not weight bearing = dew claw
Phalanges
horses:
- 1 digit: 3 metatarsals
- ex. process - for DDF
- prox ses. bones= 2 small bones = part of suspensory apparatus of fetlock joint
- dis. ses. bone= not embedded in a tendon but located b/t DDF and middle and distal phalanges
ruminants:
- 4 digits - 2 weight- bearing
- 1st digit = missing
- 2nd + 5th = vestiges (horny dew claws)
- 3rd + 4th = 3 phalanges and 3 sesamoid bones
- 2 prox sesamoid bones = at metatarsophalangeal joint + 1 distal at distal interphanangeal joint for EACH DIGIT
carnivores
- 2nd - 5th = weight bearing
- 1st = dew claw (1st digit and 1st metatarsal)- 1 sesamoid
- prox phalanx- has head, body and base
- middle- same structure but smaller in length
- distal phalanx- has distal flexor process for DDF to insert + extensor process for CDE
- 2 palmer sesamoid bones per digit, except 1 for 1st digit
- distal sesamoid bone- cartilage
Function:
- Together, the metatarsals and phalanges allow for movement of the foot during locomotion
- All joints have a caudal flexion angle and therefore, when in extension the animal is placing its
foot forwards and when in flexion it is picking up its foot between strides
Tensor fasciae antebrachii
origin: fascia covering the lateral side of latissimus dorsi
inserts: olecranon
function: extend elbow
Extensor carpi radialis
- origin: humeral coronoid fossa
- insertion: metacarpal tuberosity
- function: extend carpus
Extensor carpi ulnaris
(carnivores)
- origin: lateral epicondyle of humerus
- insertion: accessory carpal bone and most lateral metacarpal
- function: extend carpus
flexor muscles of the tarsus (hock)
® Cranial tibial
- function: flexes hock and supinates
® Peroneus tertius
- origin: extensor fossa of femur
- insertion: calcaneus and tarsal 4, and tarsal 3 and proximal metatarsal 2
- function: flexes tarsus
® Peroneus longus
- function: pronates and flexes tarsus
® Peroneus brevis
- function: flexes tarsus
flexor muscles of the digit/s
Superficial digital flexor
- origin: medial epicondyle of humerus
- insertion: middle phalanx
- function: flex carpus and digits
Deep digital flexor
- origin: humerus, radius and ulna
- insertion: semilunar line of distal phalanx
- function: flex carpus and digits
Superficial digital flexor
- origin: medial epicondyle of humerus
- insertion: middle phalanx
- function: flex carpus and digits
Arthrology of intervertebral joints
Vertebral body joints – symphysis formed by intervertebral discs joining adjacent vertebrae.
- cranial head of vertebral body articulates with caudal fossa on adjacent vertebral body.
- Between adjacent vertebral bodies, there is an intervertebral disc and a fibrocartilaginous element consisting of an outer fibrous ring and an inner pulpy nucleus.
- Ventral and dorsal longitudinal ligaments reinforce the joints, preventing hyperflexion and hyperextension.
Vertebral arc joints – synovial joints between cranial and caudal articular processes.
- The articular surfaces consist of cranial articular processes facing upwards and the caudal articular processes which face downwards. Joints are united by articular capsules and reinforced by interlamellar, interspinous and supraspinous ligaments, preventing abnormal separation of the vertebral spines during flexion of vertebral column.
Peroneus tertius
- origin: extensor fossa of femur
- insertion: calcaneus and tarsal 4, and tarsal 3 and proximal metatarsal 2
- function: flexes tarsus
osteology of the tarsus
Structure:
• Talus – largest bone of tarsus located on the dorsomedial side;
horses + ruminants: articulates by its trochlea with the tibia
carnivores: tibia and fibula
2 talus ruminants : 1 talus carnivores
- Calcaneous – second bone of the proximal row, lateral to the talus that serves as muscle attachment for gastrocnemius muscle and serves as a lever arm for the superficial digital flexor tendon
- Central tarsal – fused with 4th tarsal in ruminants
- 1st – fused with 2nd tarsal in horses
- 2nd – fused with 3rd tarsal in ruminants; fused with 1st tarsal in horses
- 3rd – fused with 2nd tarsal in ruminants
- 4th – fused with central tarsal in ruminants
Function:
• Tarsal bones
- Number of bones varies between species due to fusion of one or more bones
- Together form a compound joint consisting of multiple communicating synovial joints
- As a whole, the tarsus serves to provide shock absorption during locomotion
- Allow for easy and free movement of the tarsus: flexion and extension
–> Reciprocal mechanism in horses links the tarsus to the stifle
DISTAL PHALANGEAL JOINT
(COFFIN JOINT)
® Condylar synovial between the middle phalanx and the distal phaland and the distal sesamoid bone
® Movement: flexion and extension
® Synovials: 1
® Recessus: 1 dorsal under the extensor tendon and 1 palmar (more developed) at the middle phalanx palmar side just above the distal sesamoid bone
® Distal scutum is a fibrocartilaginous surface on the flexor surface of the distal sesamoid that provides a sliding surface and pulley for the DDF tendon
® In carnivores the distal sesamoid is absent and is replaced by a fibrocartilaginous buldge
® Collateral ligaments are present either side of the joint restricting movement
® Collateral sesamoid ligaments are present in horses and ruminants and prevent the sesamoid bones from moving
® Dorsal ligaments are present in carnivores and are responsible for keeping the claw retracted
osteology of cervicals
7 vertebrae
- transverse foramen –> forms a transverse canal
- atlas: supports head (yes movement), flex and extension, lacks body and spinous process
- axis: has dens–> forms pivot joint allows no movement
C7= no transverse foramen + articulates with head of 1st rib
Athrology of temporomandibular joint
- A condylar synovial joint between the condyles of the mandible and the mandibular fossa of the temporal bones
- It has a loose joint capsule with the lateral side strengthened to form a lateral ligament
- Articular discs are present in the form of a thin meniscus lying between the two articular surfaces of the joint
- A small amount of lateral movement occurs during mastication or during grinding in herbivores
Middle gluteal
- origin: gluteal fossa of ilium
- insertion: greater trochanter of femur
- function: extends hip and +/- abducts thigh
pectoralis descendens
(superficial pectoral)
origin: sterum
insertion: cranial surface of humerus
function: pulls forelimb forwards and adducts
Semimembranosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: medial condyle of femur and medial condyle of tibia
- function: extends hip and extends and flexes stifle
Deep digital flexor
- origin: caudal face of tibia and fibula
- insertion: semilunar line of distal phalanx
- function: extends tarsus and flexes digits
flexor muscles of the hip
Flexor muscles of the stifle
® Biceps femoris
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: patella and stifle ligaments
- function: extends hip, stifle and tarsus; caudal part flexes stifle
® Semitendinosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: tibial crest and calcaneous
- function: extends hip and tarsus and flexes stifle
Semimembranosus:
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: medial condyle of femur and medial condyle of tibia
- function: extends hip and extends and flexes stifle
Extensor muscles of the shoulder
Supraspinatus
- origin: supraspinous fossa
- insertion: greater and lesser tubercles of humerus
- function: extend and stabilize shoulder
Infraspinatus
origin: infraspinous fossa
inserts: greater tubercle of humerus
- function: extend, flex and stabilize shoulder
Biceps brachii
origin: supraglenoid tubercle of scapula
- insertion: bicipital tuberosity of humerus
- function: flex elbow and extend shoulder
Triceps brachii
- origin: caudal border of scapula and tricipital line of humerus
- insertion: olecranon
- function: extend elbow and flex shoulder
Brachiocephalicus
origin: humeral crest
insertion: mastoid process and mastoid crest (H), and nuchal ligament (C), and pars basilar of occipital (R)
function: if fixed point is at head, pulls forelimb forwards with omotransversarius; if fixed point is at limb, flexes head and neck; if only one muscle acts, flexion is followed by rotation
Flexor muscles of the digit/s
• Flexors
® Deep digital flexor
- origin: caudal face of tibia and fibula
- insertion: semilunar line of distal phalanx
- function: extends tarsus and flexes digits
® Superficial digital flexor
- origin: supracondylar fossa on femur
- insertion: plantoproximal edge of middle phalanx
- function: extends tarsus and flexes digits
Arthrology of interphalangeal joints
Pastern joint (proximal phalangeal)
® Condylar synovial between the proximal phalanx and the middle phalanx
® Movement: flexion and extension
® Synovials: 1
® Recessus: 1 dorsal under the extensor tendon and 1 palmar (more developed) at the middle scutum under the SDF insertion
® Collateral ligaments are present either side of the joint restricting movement
® Palmar ligaments are present in horses and ruminants and prevent the hyperextension of the joint
• Coffin joint (distal phalangeal)
® Condylar synovial between the middle phalanx and the distal phaland and the distal sesamoid bone
® Movement: flexion and extension
® Synovials: 1
® Recessus: 1 dorsal under the extensor tendon and 1 palmar (more developed) at the
middle phalanx palmar side just above the distal sesamoid bone
® Distal scutum is a fibrocartilaginous surface on the flexor surface of the distal sesamoid that provides a sliding surface and pulley for the DDF tendon
® In carnivores the distal sesamoid is absent and is replaced by a fibrocartilaginous buldge
® Collateral ligaments are present either side of the joint restricting movement
® Collateral sesamoid ligaments are present in horses and ruminants and prevent the sesamoid bones from moving
® Dorsal ligaments are present in carnivores and are responsible for keeping the claw retracted
Superficial gluteal (dog)
origin: gluteal fascia
inserts: 3rd trochanter
- function: abducts thigh
osteology of thoracics
- have articular facets - articulate with ribs
- shape- dorso-convex = limited flexibility
- anticlinal vertebra
- costal fovea: 2 facets
- transverse costal fovea: facet on transverse process
FUNCTION:
- Articulate with ribs which surround and protect thoracic cavity
- Provide muscle attachment – e.g. latissimus dorsi; erector spinae; longissimus thoracics
- Provide part of spinal column – passage of spinal cord – posture etc.
- Anticlinal vertebra – often used to read a radiograph
- Costal fovea – articulates with head of rib
- Transverse costal fovea – articulates with tubercle on rib
Semitendinosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: tibial crest and calcaneous
- function: extends hip and tarsus and flexes stifle
Semitendinosus
- origin: ischiatic tuberosity and adjacent parts of sacro-tuberous ligament
- insertion: tibial crest and calcaneous
- function: extends hip and tarsus and flexes stifle
® Sartorius
origin: iliac crest
insertion: medial side of stifle
- function: flexes hip and rotates thigh outwards
(in dogs- consist of two bellies)
Abductor muscles of hip joint
® Superficial gluteal (dog)
origin: gluteal fascia
inserts: 3rd trochanter
- function: abducts thigh
® Gluteal femoris (ruminant)
- function: abducts thigh
PROXIMAL PHALANGEAL JOINT
(PASTERN JOINT)
Pastern joint (proximal phalangeal)
® Condylar synovial between the proximal phalanx and the middle phalanx
® Movement: flexion and extension
® Synovials: 1
® Recessus: 1 dorsal under the extensor tendon and 1 palmar (more developed) at the middle scutum under the SDF insertion
® Middle scutum is a fibrocartilaginous ridge that completes the palmoproximal border of the middle phalanx on the flexor tuberosity extending the joint contact surface between the proximal and middle phalanges and providing insertion points for the SDF tendon and a sliding surface and pulley for the DDF tendon
® Collateral ligaments are present either side of the joint restricting movement
® Palmar ligaments are present in horses and ruminants and prevent the hyperextension of the joint
osteology of scapula
Spine – origin of deltoid muscle
Supraglenoid tubercle – origin of biceps muscle
Acromion – absent in horses; origin for acromial part of deltoid muscle
Supraspinous fossa – origin of supraspinatus muscle
Infraspinous fossa – origin of infraspinous muscle
FUNCTION:
- attaches forelimb to thorax, stabilising limb
- make up the thoracic girdle
- articulates with the humerus, forming the shoulder joint
Flexors of the shoulder
Deltoid
- origin: spine and acromion process of scapula
- insertion: deltoid tuberosity
- function: flex shoulder and abduct limb
Teres major
- origin: caudal border of scapula
- insertion: teres major tuberosity
- function: flex shoulder and rotate limb medially
Triceps brachii
- origin: caudal border of scapula and tricipital line of humerus
- insertion: olecranon
- function: extend elbow and flex shoulder
osteology of the femur/ tibia and fibula
Femur
- Articulates proximally with the hip bone forming the hip joint and distally with the tibia forming the stifle joint
- Head of the femur articulates with the acetabulum
- Greater trochanter provides insertion for the middle gluteal
- Third trochanter is only present in the horse
- Medial and lateral condyle provide insertion for the semimembranosus
- Extensor fossa provides attachment for the long digital extensor musle
- Femoral trochlea articulates with the patella, with the medial larger than the lateral to allow rotation of stifle joint during patella locking in horses
- Supracondylar crest provides origin for the gastrocnemius muscle
- Supracondylar fossa provides origin for the superficial digital flexor muscle
Tibia & Fibula
- Articulate proximally with the condyles of the femur and distally with the tarsal bones
- Separated by an interosseous space
- Tibia is medially located and is the main weight bearing bone
- Fibula serves mainly for muscle attachment and is most lateral
- In carnivores: not fused
- In ruminants the head of the fibula fuses to the tibia and most of the body of the fibula fails to develop and the lateral malleolus remains separate from the tibia
- In horses the fibula is reduced to a bone that reaches only halfway down the tibia and the true distal end of the fibula is fused with the tibia
FUNCTION:
- Tibia provides main muscle origins for many of the distal hind limb muscles and insertions for muscles which act on the stifle such as the semimembranosus, semitendinosus and quadriceps femoris
Infraspinatus
origin: infraspinous fossa
inserts: greater tubercle of humerus
- function: extend, flex and stabilize shoulder
Anconeus
origin: olecranon fossa
inserts: lateral surface of the olecranon
function: extend elbow
osteology of sacrum
® Bone formed by the fusion of sacral vertebrae
® The wings articulate with the hip bones forming the sacroiliac joint
® Portion of vertebral canal through sacrum is called the sacral canal
® In horses and carnivores the spinous processes are unfused whereas
® In ruminants the spinous processes are fused and are called the median sacral crest
Arthrology of the nuchal ligament
yellow-elastic CT connecting the upper cervical vertebrae or occipital with the spinous process of the thoracic vertebrae. Helps to support the head and has a role in locomotion in large animals by rigidification of the axial column. In large animals (horse and ox) it consists of two paired parts:
® Funicular (cord) – which is paired and arises from the occipital and inserts on spines of
thoracic vertebrae of the withers
® Lamellar (sheet) – consists of two sheets of CT arising from the second and third thoracic spines and the funicular part and inserts on cervical spines C2 – C6.
Quadriceps femoris
- origin: ilium and medial, lateral and cranial sides of femur
- insertion – tibial tuberosity
- function: extends stifle and +/- flexes hip
Lateral digital extensor
- origin: head of fibula
- insertion: proximal (H), middle (R), and distal (C)
- function: flexes tarsus and extends digits
Arthrology of temporomandibular joint
- A condylar synovial joint between the condyles of the mandible and the mandibular fossa of the temporal bones
- It has a loose joint capsule with the lateral side strengthened to form a lateral ligament
- Articular discs are present in the form of a thin meniscus lying between the two articular surfaces of the joint
- A small amount of lateral movement occurs during mastication or during grinding in herbivores
Arthrology of sacro-iliac joint
• Joint - relatively immoveable articulation between wings of the sacrum and the ilium.
Combined cartilaginous and synovial joint. Fibrocartilage unites the surfaces of the wings to the ilium, forming a sacroiliac synchondrosis. There is a tight joint capsule along the margin of the joint, reinforced by dorsal and ventral sacroiliac ligaments. There is little to no movement.
® Synovials: 1 small
• Sacrosciatic ligament
Dogs
– reduced to a fibrous band from transverse process of sacrum to ischiatic tuberosity and called the sacrotuberal ligament
Horses & ox –
sacrotuberal and sacrospinal ligaments are fused. Expanded to a broad sheet that largely fills the space between the lateral border of the sacrum and the dorsal border of the ilium and ischium – leaves open two foramina adjacent to the greater and lesser sciatic notches.
Function:
• Joint – attach pelvic limb to the axial column and stabilise the axial column
• Sacrosciatic ligament
® Greater sciatic foramen – where cranial gluteal and sciatic nerves leave pelvis
® Lesser sciatic foramen – where pudental nerve leaves pelvis
muscles of the dorsolumbar region
They are both flexor and extensor muscles:
they work to extend and strengthen columns; if one muscle acts, flexes column laterally
Common erector spinae
- origin: iliac crest
- insertion: last thoracic and lumbar vertebrae
Spinalis thoracis (spinous)
- origin: thoracic spinous process
- insertion: other thoracic spinous process
Longissimus thoracis
- origin: lumbar/thoracic spinous proocess
- insertion: lumbar/thoracic mamillar processes and costal tubules
Iliocostalis
- origin: lateral border of common erector spinae and iliac crest as well as lumbar transverse process and ribs
- insertion: long oblique tendons and proximo-lateral sides of ribs
Common erector spinae
- origin: iliac crest
- insertion: last thoracic and lumbar vertebrae
- function: extends and strengthens, flexes column laterally if one muscle acts
Spinalis thoracis (spinous)
- origin: thoracic spinous process
- insertion: other thoracic spinous process
- function: both muscles act, extends and strengthens colums; if one muscle acts, flexes column laterally
Longissimus thoracis
- origin: lumbar/thoracic spinous proocess
- insertion: lumbar/thoracic mamillar processes and costal tubules
- function: both muscles act, extends and strengthens colums; if one muscle acts, flexes column laterally
Iliocostalis
- origin: lateral border of common erector spinae and iliac crest as well as lumbar transverse process and ribs
- insertion: long oblique tendons and proximo-lateral sides of ribs
- function: both muscles act, extends and strengthens colums; if one muscle acts, flexes column laterally
extensor muscles of the dorsolumbar region
erector spinae
originates: iliac crest
insert: last thoracic and lumbar vertebrae
spinalis
origin: thoracic spinous process
insert: other thoracic spinous processes
iliocostalis
origin: lateral border of common erector spinae and iliac crest as well as lumbar transverse process and ribs
insert: long oblique tendons and proximo-lateral sides of ribs
longissimus thoracicus
origin: lumbar/ thoracic spinous
insert: lumbar/ thoracic mamillar processes and costal tubules
erector spinae
originates: iliac crest
insert: last thoracic and lumbar vertebrae
spinalis
origin: thoracic spinous process
insert: other thoracic spinous processes
iliocostalis
origin: lateral border of common erector spinae and iliac crest as well as lumbar transverse process and ribs
insert: long oblique tendons and proximo-lateral sides of ribs
longissimus thoracicus
origin: lumbar/ thoracic spinous
insert: lumbar/ thoracic mamillar processes and costal tubules
Diaphragm function
musculoaponeurotic partition that separates the thoracic cavity from the abdominal cavity. It acts as an inspiratory through increasing the transverse diameter of the thorax and displacing the sternum forwards and downwards.
