Q&A Thoracic Limb Flashcards
Describe the clavicle in the dog and cat
Cat: separate, nonarticular bone; Dog:rudimentary or absent, embedded in brachiocephalicus m
What does the spine of the scapula divide?
Lateral scapula into infraspinous and supraspinous fossae
What is the acromion?
End of the spine of the scapula
What is the caudal projection of the acromion found in the cat?
Suprahamate process
What is the glenoid fossa and its function?
Shallow cavity of the scapula articulating with the humerus to form the shoulder joint
What is the supraglenoid tubercle and what is its function?
cranial process near glenoid cavity for the attachment of the biceps brachii muscle
What and where is the greater tubercle?
Projection located craniolateral to the head of the humerus-point of shoulder
What is the intertubercular (bicipital) groove?
the sulcus between the greater and the lesser humeral tubercles for the biceps brachii tendon
What is the condyle of the humerus?
Entire distal end of the humerus
What arises from the epicondyles of the humerus?
Lateral: extensors of the forearm; medial: epicondyle flexer
What foramen is found in the canine and feline humeri, and what passes through them?
Dog: supratrochlear foramen - nothing; Cat: supracondylar foramen - median n., and brachial vessels
What and where is the styloid process of the radius?
Distal pointed end of the radius, medial
What is the function of the olecranon? That is the common name for it?
Serves as a lever arm for the extensor muscle of the elbow; point of elbow
Name the depression of the ulna that articulates with the humerus and its proximal and distal ends
Trochlear notch (semilunar notch); proximal end= anconeal process; distal end = medial and lateral coronoid process
What and where is the styloid process of the ulna?
Distal end of ulna, lateral side
List the parts of the manus from proximal to distal
Carpus, metacarpus, digits (proximal, middle, distal phalanges and associated sesamoid bones)
What does the term carpus designate?
Carpal bones and compound joint formed by these bones Or the region between the metacarpal bones and the forearm
Name the bones of the carpus and indicate where they are in each row
Proximal row from medial to lateral = radial, ulnar, accessory carpal bones; Distal row = 1-4 medial to lateral
Which carpal bone is located laterally and palmarily and considered a landmark?
Accessory carpal bone
List the bones of each digit and their locations
Proximal, middle and distal phalanges (no middle in dewclaw), 2 proximal sesamoid bones (1 in dewclaw on palmar side of metacarpophalangeal joints), 1 dorsal sesamoid bone for each digit 1-4
What is the fingerlike structure covering the ungual process?
horny claw
What is the shelf of the distal phalanx covering the root of the claw?
ungual crrest
What is the digit that doesn’t reach the ground? made up of P1,P3, 1 proximal sesamoid, and MtC1
dew claw
What is the configuration of the shoulder joint?
ball and socket joint (spheroidal)
What type of motion is allowed by the shoulder joint?
all movements but mainly flexion/extension
What protects the biceps tendon in the intertubercular groove?
Extension of the shoulder joint capsule acting as a tendon sheath
what stabilized the shoulder joint?
No true collateral ligaments, but infraspinatus tendon laterally and subscapularis tendon medially help stabilize it
What bones make up the elbow joint?
humeral condyle, trochlear notch of the ulna, head of radius
What type of joint is the elbow (cubital joint) and what action is allowed?
hinge (ginglymus) joint; compound joint; flexion and extension
what powerful ligaments bind sides of all joints of the limb except the shoulder?
lateral and medial collateral ligaments; limits movement to mainly flexion/extension
What type of joint is the carpus? what movement does it allow?
Compound/composite hinge joint; flexion and extension (also gliding and rotation)
List the joints of the carpus and the movement each allows
Antebrachial joint: mot movement of flexion and extension; middle carpal joint: less considerable flexion and extension; carpometacarpal joint: very little, mainly gliding; intercarpal joints: gliding
List the boundaries of the carpal canal
Carpal bones (covered by palmar carpal fibrocartilage), accessory carpal bone and flexor retinaculum (transverse carpal ligament)
List the joints of the digits
Metacarpophalangeal joints between meta-carpal bone and proximal phalanx; Proximal interdigital joint - between P1 & P2; Distal interdigital joint - between P2 & P3
What bones are located on the palmar side of the metacarpophalangeal joints?
2 parlmar sesamoids for digits 2-5, 1 for dewclaw
What ligament extends form proximal P2 to dorsal P3?
Dorsal elastic ligament, unique to carnivores
What flexor muscles effect the interphalangeal joints?
Proximal: DDF and SDF, Distal: only DDF
What is the function of the elastic dorsal ligament of a cats digits?
Oppose DDF, keep claw retracted
What local thickening of the deep fascia hold tendons in place?
Retinaculum
In which layer are the cutaneous muscles located?
in the superficial fascia
What is the function of the cutaneous muscles?
twitch the skin
List the different types of muscle and whether they are voluntary or not
Striated Skeletal muscle = voluntary, Cardiac muscle = involuntary; Smoot unstriated muscle = involuntary
What are the two attachments of skeletal muscles?
Origin (proximal and/or least movable) and insertion (distal and/or more movable)
What are the flat attachments of flat muscles?
Aponeuroses
What is the difference between tendons and ligaments?
Tendons = attach muscle to bone, ligaments = attache bone to bone
What do muscle actions depend on?
How they cross a joint, the number of joints crossed, and the shape of the joint
List 3 types of muscle attachments
Tendinous, Aponeurotic, Fleshy
Define extension and flexion
Extension: increases angle between bones; Flexion: decreases angle between bones
Define adduction and abduction
Adduction: move toward body; Abduction: moves away from body
Define supination and pronation
Supination: palmar surface dorsal; Pronation: palmar surface ventral
What is the movement of an extremity in a plane describing the surface of a cone?
circumduction
What muscles connect the thoracic limb to the head, neck and trunk?
Extrinsic muscles of the thoracic limb
Name five of the 8 extrinsic muscles of the thoracic limb
Trapezius, Omotransversarius, Brachiocephalicus, superficial and deep pectoral, latissimus dorsi, serratus ventralis and rhomboideus
Which extrinsic muscel supports the weight of the trunk?
Serratus ventralis - forms a sling for the trunk
What muscles originate and insert on the bones of the thoracic limb?
Intrinsic muscle of the limb
What muscles replace the collateral ligaments for the shoulder joint?
Subscapular, infraspinatus, supraspinatus, biceps brachii
What nerve enervates the infra- and supraspinatus mm
Suprascapular nerve
What is the common insertion of all four heads of the triceps brachii muscle?
Olecranon
Where does the biceps brachii muscle originate?
supraglenoid tuberosity
What nerve innervates the triceps and other extensors of the elbow, carpus and digits?
Radial nerve
How are the forearm muscles grouped?
Craniolateral - extensors and Caudal - flexors
Where do most of the extensors of the digits/carpus arise?
on or near the lateral epicondyle
What muscles arise/originate from the medial epicondyle of the humerus?
Caudal antebrachial muscles
What nerve innervates the extensors of the digits and carpus? what nerve innervates the caudal antebrachial muscles (flexors)
Radial n. = extensors; median and ulnar n = flexors
Where does the ADF and DDF insert? why is this clinically significant?
DDF- Distal phalanges; SDF - middle phalanges; Significance - DDF affects the distal interphalangeal joint SDF does not
Where are most of the vessels and nerves on the arm and why?
Medial side for protection
List the main arteries to the forelimb and their location
Subclavian - medial to first rib; Axillary - in axilla; Subscapular - along caudal scapula; Brachial - in arm; Common interosseous - last branch of brachial; median - in forearm; digital - in paw
What are the locations of the cephalic and accesory cephalic veins of the manus; where do they join and continue as cephalic vein?
Cephalic palmar paw; accesory cephalic-dorsal paw. they meet above the carpus to travel cranial on the forearm
Can the lymph nodes of the thoracic limb be palpated?
Axillary - no; Accessory if present yes and superficial cranial yes
How is the nervous system divided functionally and structurally?
Function - Somatic and Autonomic; Structure - CNS and PNS
Which function of the NS keeps the body in balance with its external environment? internal?
External - Somatic; Internal - Autonomic
What are the two parts of the CNS?
Brain and spinal cord
What are the parts of the PNS?
Cranial nerves, spinal nerves, ganglia
What are two impulses of the NS both somatic and autonomic?
Sensory (afferent) and Motor (efferent)
What nervous structures pass from the spinal cord to the periphery?
Spinal nerves (LMN)
Where do the spinal nerves leave the vertebral column?
Intervertebral foramen
What arises from the spinal cord to form a spinal nerve?
Ventral and Dorsal roots
What are the two main branches of spinal nerves? What do they carry
Dorsal and Ventral branches; mixed motor and sensory fibers
What areas do the ventral and dorsal motor branches of the spinal nerves supply motor innervation?
Ventral - muscles ventral to the transverse processes; Dorsal - muscles dorsal to the transverse processes
What spinal nerve branches supply sensation form the skin of the abdominal wall and back?
Dorsal - above transverse processes and upper flank; ventral the rest
List the components of a reflex arc
Stimulus, receptor, sensory (afferent) neuron, interneuron, motor (efferent) neuron, LMN, effector (target organ)
What two muscles does the suprascapular nerve innervate?
Supraspiantus and infraspiantus
What innervates the cutaneous trunci
Lateral thoracic nerve
What nerve innervates the flexor of the elbow and is necessary for weight bearing?
Radial nerve
What nerves does SS-MAR-MU stand for and from what areas of the brachial plexus do they arise?
SS - cranial; supraspinatus ans subscapularis; MAR - middle; musculocutaneous, axillary, radial; MU - caudal; median and ulnar
What nerves innervate the extensors and flexors of the forepaw?
extensors : radial n; Flexors ; median and ulnar
Where does the radial nerve become superficial and in danger?
laterally under the triceps brachii muscle
What are two cutaneous areas of the forepaw?
Dorsal paw; radial n, abaxial 5 (lateral) digit: ulnar n
What normal structures can be mistaken for lytic areas of the cortex?
nutrient foramina
What should be done if questions arise from radiographs of a limb?
take films of the opposite limb
The different views _____ different sides of bones
highlight
What does the lateral view highlight?
Cranial and caudal or dorsal and palmar/plantar surfaces of bones
What are radiographic landmarks for the medial side of the thoracic limb?
dew claw and radial carpal bone
what are landmarks for the lateral side of the thoracic limb?
spine of the scapula, greater tubercle, distal ulna, accessory carpal bone
what are caudal/palmar landmarks of the forelimb?
head of the humerus, olecranon, accessory carpal bone
what does craniocaudal or dorsopalmar view highlight?
medial and lateral structures of the limb
name two normal structures that can be mistaken for fractures in the forelimb
sesamoid bones of digits, lateral collateral ligament of elbow, anconeal process of ulna, accessory ossicle of caudal scapula
On what side of the limb is the accessory carpal bone?
lateral and palmar
What bone may be mistaken for a chip fracture of the carpus?
sesamoid of the oblique carpal extensor tendon
What is a pathological osseous outgrowth seen radiographically?
bone spur/osteophyte
What is an increase in the density of a bone?
Sclerosis
What is the destruction of a bone, seen as reduced density?
Lysis
What is luxation or dislocation?
complete loss of contact between articular surfaces of a joint
Define subluxation
partial loss of contact between articular surfaces of a joint
what is OCD - osteochondrosis?
defect in endochondral ossification: deeperlayer of cartilage die
Do you look for radiographic changes in the cartilage in OC?
No, you can’t see it, check subchondral bone
list 2 of the 4 common sites of OCD lesions
1- shoulder;2- medial humeral condyle; 3- medial and lateral femoral condyle ;4 - proximal medial trochlea
What is the #1 site of OCD in a dog? Describe its appearance in contrast to normal
Caudal aspect of the head of the humerus; Normal looks smooth and round with no flattening; OCD looks flattened or cratering with subchondral bone sclerosis
What can the cats clavicle be mistaken for in lateral radiographs?
bone in espophagus
What can premature closure of either distal or proximal radial physis cause?
subluxation of the humeral-radial joint
Where is OCD of the elbow located?
medial condyle of the humerus
what is an ununited anconeal process?
failure of the anconeal process to unite with ulna by 6 months
what is fragmented medial coronoid process?
improper development and fragmentation of cartilaginous precursor
haw are the medial and lateral epicondyles of the humerus differentiated in a lateral radiograph?
Medial is squared and extend further caudally than the rounded lateral epicondyle
