Canine Forelimb Anatomy Flashcards

Flashcards covering canine thoracic limb anatomy including extrinsic muscles, intrinsic muscles, joints, ligaments, and clinical pathology.

Synsarcosis

The structural attachment of the thoracic limb to the trunk via extrinsic muscles rather than a bony articulation or joint.

Superficial pectoral m.

Extrinsic muscle consisting of descending and transverse parts that originates on the first 2-3 sternebrae and inserts on the crest of the greater tubercle of the humerus; adducts the free limb or prevents abduction during weight-bearing.

Deep pectoral m.

Extrinsic muscle originating on the ventral sternum and inserting on the humerus; pulls the trunk cranially and extends the shoulder when the limb is fixed, or draws the limb caudally and flexes the shoulder when non-weight-bearing.

Brachiocephalicus m.

Extrinsic muscle composed of cleidobrachialis and cleidocephalicus (pars cervicalis and pars mastoidea) divided by the clavicular intersection; advances the free limb and extends the shoulder joint, or flexes the head/neck laterally when fixed.

Omotransversarius m.

Extrinsic muscle attached caudally to the distal end of the spine of the scapula and cranially to the wing of the atlas; advances the limb or flexes the neck laterally.

Trapezius m.

Extrinsic muscle with cervical and thoracic parts originating along the median raphe and supraspinous ligament from C3 to T9 and inserting on the scapular spine; elevates and abducts the forelimb.

Rhomboideus m.

Extrinsic muscle with capitis, cervicis, and thoracis parts originating from the nuchal crest, cervical raphe, and T1-T7 spinous processes and inserting on the dorsal border of the scapula; elevates the limb and draws the scapula against the trunk.

Latissimus dorsi m.

Extrinsic muscle originating from the thoracolumbar fascia and inserting on the teres major tuberosity of the humerus; flexes the shoulder and draws the free limb caudally, or pulls the trunk cranially when fixed.

Serratus ventralis m.

Extrinsic sling muscle with cervical and thoracic parts originating on the last 5 cervical transverse processes and ribs 1-7/8, inserting on the serrated face of the scapula; supports the trunk and depresses the scapula.

Deltoideus m.

Intrinsic muscle of the lateral shoulder comprising scapular and acromial parts originating from the spine and acromion of the scapula and inserting on the deltoid tuberosity; acts to flex the shoulder joint.

Supraspinatus m.

Intrinsic lateral scapular muscle originating from the supraspinous fossa and inserting on the greater tubercle of the humerus; extends and stabilizes the shoulder joint.

Infraspinatus m.

Intrinsic lateral scapular muscle originating from the infraspinous fossa and inserting on the lateral aspect of the greater tubercle; provides lateral stability and flexes or extends the shoulder joint.

Teres minor m.

Intrinsic lateral scapular muscle originating from the infraglenoid tubercle and inserting on the teres minor tuberosity of the humerus; acts to flex the shoulder joint.

Subscapularis m.

Intrinsic medial scapular muscle originating from the subscapular fossa and inserting on the lesser tubercle of the humerus; extends and stabilizes the shoulder joint.

Teres major m.

Intrinsic medial scapular muscle originating from the caudal angle and border of the scapula and inserting on the teres major tuberosity of the humerus; flexes the shoulder joint.

Coracobrachialis m.

Intrinsic medial scapular muscle originating from the coracoid process of the scapula and inserting on the crest of the lesser tubercle; adducts, extends, and stabilizes the shoulder joint.

Triceps brachii m.

Caudal arm muscle with four heads (long, lateral, accessory, medial) that insert on the olecranon tuber; essential for weight-bearing by keeping the elbow extended.

Biceps brachii m.

Cranial arm muscle originating from the supraglenoid tubercle and inserting on the radial and ulnar tuberosities; flexes the elbow joint and extends the shoulder joint.

Brachialis m.

Cranial arm muscle originating on the proximal lateral humerus and inserting on the radial and ulnar tuberosities; acts to flex the elbow joint.

Supinator m.

Deep muscle originating from the lateral epicondyle of the humerus and inserting on the cranial proximal radius; rotates the forearm laterally so the palmar paw faces medially.

Pronator teres m.

Muscle originating from the medial epicondyle of the humerus and inserting on the medial radius; rotates the forearm medially so the palmar paw faces the ground.

Extensor carpi radialis m.

Craniolateral antebrachial muscle originating from the lateral supracondylar crest and inserting on metacarpals II and III; extends the carpal joints.

Common digital extensor m.

Craniolateral antebrachial muscle originating from the lateral epicondyle and inserting on distal phalanges of digits II-V; extends the carpus and four principal digits.

Ulnaris lateralis m.

Craniolateral antebrachial muscle originating from the lateral epicondyle and inserting on metacarpal V and the accessory carpal bone; acts functionally to flex the carpal joints.

Superficial digital flexor m.

Caudomedial antebrachial muscle originating from the medial epicondyle and inserting on middle phalanges II-V; flexes the carpal, metacarpophalangeal, and proximal interphalangeal joints.

Deep digital flexor m.

Caudomedial antebrachial muscle with three heads (humeral, radial, ulnar) inserting on distal phalanx flexor tubercles; flexes carpal, metacarpophalangeal, and interphalangeal joints.

Antebrachiocarpal Joint

The most proximal articulation of the carpus with an isolated synovial cavity and maximum range of motion; the primary target for carpal arthrocentesis.

Carpal Canal

Conduits formed by the palmar carpal ligament, accessory carpal bone, and flexor retinaculum that protects tendons of the SDF, DDF, and flexor carpi radialis mm.

Flexor Manica

A tubular sleeve formed by the superficial digital flexor tendon palmar to the metacarpophalangeal joint that surrounds the deep digital flexor tendon, allowing them to cross.

Infraspinatus m. contracture

Pathological shortening of the infraspinatus muscle following injury and fibrotic scarring, causing permanent abduction/lateral rotation of the arm and restricted shoulder mobility.