Small Animal Anatomy Exam 2

Suprahamate process of the scapula (cat)

A normal, palpable caudally-projecting process near the distal third of the scapular spine.

Humerus foramina difference (cat vs. dog)

Cats lack a supratrochlear foramen but possess a distinct, slit-like supracondylar foramen on the medial side of the humerus.

Structures passing through the supracondylar foramen (cat)

Brachial artery and median nerve.

Typical number of mammary glands in the queen

4 pairs (8 total), though asymmetric variations can occur.

Insertion of the superficial pectoral muscle (cat)

Distal humerus and proximal ulna (more distal than in dogs).

Insertion of the brachiocephalicus muscle (cat)

Proximal ulna (inserts further distally than in the dog).

Characteristics of the feline clavicle

Predictably ossifies into a small, palpable bone spicule within the brachiocephalicus muscle.

cat clavicle

It is radiographically visible and should not be mistaken for a foreign body.

Brachioradialis muscle clinical relevance (cat)

Well-developed and lateral to the cephalic vein; can be mistaken for the vein during venipuncture.

Dorsal ligaments function in cats

Asymmetrical, well-developed ligaments that passively keep distal interphalangeal joints hyperextended to sheath claws.

Muscle required to expose claws in cats

Active contraction of the deep digital flexor muscle.

Sartorius muscle structure (cat vs. dog)

Undivided in cats, whereas in dogs it is divided into cranial and caudal parts.

Sacrotuberous ligament

cat does not have

Soleus m.

Cats posses this caudal crus muscle, unlike dogs who do not posses this muscle

Nuchal ligament

Cat does not posses

Position of Heart

In all domestic species (besides cat) heart rests between 3rd and 6th intercostal spaces. In the cat, heart resides a bit more caudally, between the 4th and 7th ribs.

What are the 3 classifications of joints?

Fibrous, cartilaginous, synovial

What are fibrous joints made of?

Collagenous connective tissue

Are fibrous joints joints of stability or mobility?

Stability

What are the 3 subtypes of fibrous joints?

Suture, gomphosis, and syndesmosis

What is a suture and an example?

Two pieces of bone filled with collagenous connective tissue

Ex: skull

What is a gomphosis and an example?

Joint between roots of tooth and the bony socket

Ex: tooth

What is a syndesmosis and an example?

side to side fibrous joint

Ex: joint between metacarpal bones

What are cartilaginous joints made of?

Cartilage

Are cartilaginous joints joints of mobility or stability?

Stability

Cartilaginous joints are ______ united by ______

Directly, cartilage

What are the subtypes of cartilaginous joints?

Symphysis and synchondrosis

What is a symphysis and an example?

Hybrid tissue between collagenous connective tissue and hyaline cartilage

Ex: pelvic symphysis

Symphysis is united by _________

fibrocartilage

What is a synchondrosis and an example?

cartilaginous joints made up of hyaline cartilage

Ex: Sacroiliac joint

Synchondrosis is united by _________

Hyaline cartilage

Do synovial joints directly unite?

No, indirectly connected via joint capsule and ligaments

What are the bone ends covered by in synovial joints?

Articular cartilage/hyaline cartilage

What are the components of a synovial membrane?

Joint capsule, fibrous membrane, synovial membrane, synovial fluid

What is unique about cartilage?

It is avascular

What is the function of articular cartilage?

Reduces friction

What two structures of the synovial joint are continuous

Fibrous membrane (around joint) and periosteum (around bone)

What is the function of the periosteum?

Covers the bone like a sleeve

Is the periosteum connective tissue?

Yes

The periosteum allows for _________ connection between the bones

Indirect

What is the joint cavity vs the joint capsule

The synovial joint is completely enclosed by a sleeve like structure called the joint capsule and the space enclosed within it is the joint cavity

What are the 2 layers of a joint capsule

fibrous membrane (outer) and synovial membrane (inner)

What is the fibrous membrane made of?

Collagenous connective tissue

What is the function of the synovial membrane?

Secrete and rebsorbs the synovial fluid

What lines the synovial membrane?

Epithelium (both secreting and absorbing)

What is the function of the synovial fluid?

Lubricates the articular cartilage, nourishes articular cartilage

Is synovial fluid vascular or avascular?

Vascular- nourishes the synovial membrane and hyaline cartilage

What is interesting about the synovial fluid?

It is constantly being turned over, supplying fresh fluid/rich oxygen & nutrients/removing waste

If hyaline cartilage was damaged, what would a joint look like radiographically?

The joints would not have as big of a "gap"

What is the definition of a ligament?

ct band that connects bone to bone, regional thickening of fibrous membrane

The lateral and collateral ligaments are actually just regional thickenings of the _________ __________

Fibrous membrane

What two joints do not have collateral ligaments?

Shoulder and hip joint

If IDing the collateral ligaments on the manus or pes, rather than saying medial or lateral, you would say _____ or ______

Axial or abaxial

What are extracapsular ligaments?

Ligaments outside of the joint cavity

Example of extracapsular ligament

collateral ligaments

Which of the carpal bone complex joints have the most movement

Antebrachiocarpal joint

Which of the carpal bone complex joints communicate?

Middle carpal joint and carpometacarpal joint

UMN or LMN is responsible for contracting the muscles?

LMN

What are the accessory synovial structures

Bursa, tendon sheaths, and sesamoid bones

What is a bursa

Synovial fluid filled sac between a tendon and a bony prominence

What is the function of a bursa

Reduces friction

What does the wall of a bursa look like?

A synovial joint capsule- has a fibrous membrane and synovial membrane!

What is a tendon sheath?

An elongated bursa that wraps around an entire tendon

Where can you find tendon sheaths?

Bony grooves, beneath retinacula, annular ligaments

What are the two major functions of sesamoid bones

Protects tendon by decreasing friction, helps redirect force of a tendon

Where can you find sesamoid bones?

Embedded in muscle tendons

Are sesamoid bones synovial joints?

Yes! They form a synovial joint between the tendon and bony prominence

What muscle is the proximal sesamoid bone embedded in?

Interosseus m

Quadriceps femoris origin

ilium - rectus femoris; Proximal femur -other heads

Quadriceps femoris insertion

Tibial tuberosity

Quadriceps femoris action

Flex hip joint (only rectus femoris) and extend stifle joint

Iliopsoas origin

ilium - iliacus; lumbar vertebrae - psoas major

Iliopsoas Insertion

Lesser trochanter of femur

Iliopsoas action

Flex coxal joint (principal action) Rotate limb laterally

Craniolateral muscles of Crus

crainial tibial, long digitial extensor, lateral digital extensor, peroneus [fibularis] longus. Principal action - flex tarsal joints and extend digital joints

Cranial tibial origin

lateral aspect of proximal tibia

Cranial tibial insertion

plantaroproximal metatarsal bones 1 and 2

cranial tibial action

flex tarsal joints

long digital extensor origin

extensor fossa of femur

long digital extensor insertion

extensor processes of the distal phalanges

long digital extensor action

extend digital joints, flex tarsal joints. Minimally extend stifle joint

Lateral digital extensor of pelvic limb origin

proximal fibula

insertion of lateral digital extensor m.

extensor process of distal phalanges digits 3-5

Lateral digital extensor action

extend lateral digital joints and flex the tarsal joints

Fibularis longus origin

lateral condyle of tibia and proximal fibula

Fibularis longus insertion

Plantaroproximal metatarsal bones

Fibularis longus action

flex tarsal joint

Caudal muscles of crus

Gastrocnemius, soleus (only in cats), superficial digital flexor, deep digital flexor, popliteus. Principal action is to extend tarsal joints and flex digital joints

gastrocnemius origin

Caudodistal femur

Gastrocnemius insertion

tuber calcanei

Gastrocnemius action

extend tarsal joints. Flex stifle joint minimally

Soleus origin

head of fibula

Soleus insertion

tendon of lateral head of gastrocnemius

soleus action

assist the gastrocnemius in extension of tarsal joints

superficial digital flexor m. of pelvic limb origin

lateral supracondylar tuberosity of femur

Superficial digital flexor m. of pelvic limb insertion

tuber calcanei and plantaroproximal aspects of middle phalanges 2-5

superficial digital flexor action

extend tarsal joints and flex digital joints, except distal interphalangeal joints. Minimally flex genual joint

deep digital flexor origin

caudal aspects of tibia and fibula

deep digital flexor insertion

distal phalanges, plantar aspect

deep digital flexor action

flex digital joints and extend tarsal joints