Lecture Notes on the Musculoskeletal System of the Dog and Cat - Unit 1 (BMS 7330)

A comprehensive set of question-and-answer flashcards covering key concepts from the lecture notes on the musculoskeletal anatomy of the dog and cat, Unit 1. Topics include terminology, thoracic and pelvic limb osteology and myology, joints, radiographic and developmental anatomy, and vertebral column basics.

What is the study of muscles called?

Myology.

What is synsarcosis (omothoracic junction) in dogs/cats?

Attachment of the thoracic limb to the axial skeleton via muscles with no true bony joint; the scapula is connected by muscles (synsarcosis) rather than a bone-to-bone articulation.

Which muscle is the primary protractor of the thoracic limb?

Brachiocephalicus (BC) (with its parts: cleidocephalicus and cleidobrachialis in some texts).

Which nerve passes through the scapular notch?

Suprascapular nerve.

What is the glenoid cavity?

A shallow socket on the distal scapula that articulates with the head of the humerus.

Which part of the humerus articulates with the head of the radius?

Capitulum (lateral) of the distal humerus.

What is the supratrochlear foramen and where is it found?

A foramen between the radial and olecranon fossae on the distal humerus; present in dogs (not in all breeds) and does not transmit a nerve or vessel.

What ligament stabilizes the proximal radioulnar joint?

Annular ligament.

Name the bones in the proximal row of the canine carpus.

Radial carpal (intermedioradial, fused with radial), ulnar carpal, and accessory carpal bones.

Where are the palmar metacarpophalangeal sesamoid bones located?

Within the tendons of the interossei muscles at the metacarpophalangeal joints (palmar side).

How many digits do dogs/cats have on the manus, and what are they called?

Five digits (I–V); Digit I has proximal and distal phalanges; Digits II–V have proximal, middle, and distal phalanges.

What are the extrinsic thoracic limb muscles and their general role?

Muscles that attach between the trunk and the limb (scapula/humerus); include brachiocephalicus, trapezius, omotransversarius, latissimus dorsi, rhomboideus, serratus ventralis, and the pectorals; they protract or retract the limb and stabilize the shoulder girdle.

Which muscle is the primary protractor and also extends the shoulder?

Brachiocephalicus (three parts: cleidocephalicus, cleidocervicalis, and cleidobrachialis).

What is the function of Latissimus dorsi in the thoracic limb?

Primary retractor of the limb; also acts as a secondary flexor of the shoulder and is antagonistic to the brachiocephalicus.

Name two muscles that elevate the scapula.

Trapezius (cranial and caudal parts) and rhomboideus (cervicis and thoracis).

What is the sling muscle that supports the trunk and transmits weight to the thoracic limbs?

Serratus ventralis.

What do the pectoral muscles do in the thoracic limb?

Adduct the limb; deep pectoral can retract; superficial pectoral assists protraction/adduction.

What stabilizes the shoulder joint in dogs given weak collateral ligaments?

Tendons of supraspinatus, infraspinatus, and subscapularis (and surrounding muscles) provide stability.

What bones form the elbow joint?

Humerus, radius, and ulna.

What stabilizes the proximal radioulnar joint?

Annular ligament.

Which joints of the carpus are commonly accessed for intra-articular injections?

Antebrachiocarpal (proximal carpal) and middle carpal joints.

What bones form the pelvis (os coxae)?

Ilium, ischium, pubis, and acetabular bone (fused to form the hip bone).

What is the round ligament of the hip and its attachment?

Ligament of the head of the femur; attaches from the fovea capitis of the femur to the acetabular fossa.

How many sesamoids are associated with the canine stifle and where are they located?

Four: one patella in the quadriceps tendon, two fabellae in gastrocnemius tendons, and one in the popliteus tendon.

What is the vertebral formula for dogs and cats?

7 cervical, 13 thoracic, 7 lumbar, 3 sacral, and 20–23 total vertebrae.

What are the two basic joints formed by the atlas and axis?

Atlanto-occipital joint (yes joint) and atlanto-axial joint (dens–axis pivot; NO joint).

What passes through the transverse foramina of cervical vertebrae?

Vertebral artery and vein, and vertebral nerves (nervis transversaria).

What are the major components of the skull bones organization?

Endochondral bones (unpaired, e.g., basisphenoid) and intramembranous bones (paired, e.g., frontal, parietal, maxilla); cranial vs facial bones.

What is the temporomandibular joint (TMJ) and its basic function?

A true joint between the temporal bone and the mandible (condylar); usually a hinge with some lateral movement; contains an articular disc (meniscus).

Which muscles close the mouth in the head region, and which opens it?

Close: masseter, temporalis, pterygoideus; Open: digastricus (two bellies with different innervation).

What is the nuchal ligament and is it present in cats?

A dorsal elastic ligament in the neck; absent in cats.

Where is the carpal canal located and which tendons pass through it?

Located at the carpus; the flexor retinaculum forms part of the canal; the deep digital flexor (DDF) tendon passes through it; the flexor carpi ulnaris and extensor tendons are nearby.

What are the major components of the vertebral column and how is spinal cord relation explained?

Vertebrae (cervical, thoracic, lumbar, sacral, caudal); vertebral canal houses the spinal cord; spinal cord segments do not align exactly with vertebrae due to differential growth; nerve roots descend to reach intervertebral foramina.

What are the bones of the skull that influence the orbit and nasal cavity boundaries?

Cranial bones (enclose brain); facial bones (with mandible) form oral boundary; bones include maxilla, zygomatic, palatine, nasal bones, etc.

What are the basic radiographic viewing directions used in limb radiography?

Mediolateral (side view), Craniocaudal (front to back), Dorsopalmar/Dorsoplantar for paws; ventrodorsal for pelvis.