Anatomy of Thoracic limbs muscles insertions origins and actions

Vocabulary flashcards covering the origin, insertion, and action of the muscles of the thoracic limb based on lecture notes.

Deltoideus m.

Origin: Spine of scapula; acromion; Insertion: Deltoid tuberosity of humerus; Action: Flexes humeral joint.

Supraspinatus m.

Origin: Supraspinous fossa of scapula; Insertion: Greater tubercle of humerus; Action: Laterally stabilizes humeral joint; extends humeral joint.

Infraspinatus m.

Origin: Infraspinous fossa of scapula; Insertion: Greater tubercle of humerus; Action: Laterally stabilizes humeral joint.

Teres minor m.

Origin: Caudal border of scapula; Insertion: Teres minor tuberosity of humerus; Action: Flexes humeral joint.

Subscapularis m.

Origin: Subscapular fossa of scapula; Insertion: Lesser tubercle of humerus; Action: Medially stabilizes humeral joint.

Teres major m.

Origin: Caudal border of scapula; Insertion: Teres major tuberosity of humerus; Action: Flexes humeral joint.

Coracobrachialis m.

Origin: Coracoid process of scapula; Insertion: Crest of lesser tubercle of humerus; Action: Medially stabilizes humeral joint.

Biceps brachii m.

Origin: Supraglenoid tubercle; Insertion: Radial and ulnar tuberosities; Action: Flexes cubital joint; extends humeral joint.

Brachialis m.

Origin: Brachial groove of humerus; Insertion: Proximal radius and/or ulna; Action: Flexes cubital joint.

Triceps brachii m.

Origin: Caudal border of scapula (long head); proximal humerus (other heads); Insertion: Olecranon tuber; Action: Extends cubital joint (all heads); flexes humeral joint (long head only).

Tensor fasciae antebrachii m.

Origin: Latissimus dorsi m. and associated fascia; Insertion: Olecranon tuber; Action: Extends cubital joint; tenses deep antebrachial fascia.

Anconeus m.

Origin: Caudal aspect of distal humerus; Insertion: Olecranon tuber; Action: Extends cubital joint; tenses joint capsule.

Extensor carpi radialis m.

Origin: Lateral epicondyle of humerus; Insertion: Dorsal base of 2nd & 3rd metacarpal bones; Action: Extends carpal joints.

Common digital extensor m.

Origin: Lateral epicondyle of humerus; Insertion: Extensor process of distal phalanges; Action: Extends carpal joints; extends digital joints.

Lateral digital extensor m.

Origin: Lateral epicondyle of humerus; Insertion: Phalanges of lateral-most digits; Action: Extends carpal joints; extends digital joints of lateral-most digits.

Extensor carpi ulnaris m. (ulnaris lateralis)

Origin: Lateral epicondyle of humerus; Insertion: Accessory carpal bone; lateral base of 5th metacarpal bone; Action: Flexes antebrachiocarpal joint; abducts manus.

Supinator m.

Origin: Lateral epicondyle of humerus; Insertion: Body of radius; Action: Supination of manus.

Abductor digit I longus m.

Origin: Body of ulna; Insertion: Base of 1st metacarpal bone; Action: Abducts 1st digit.

Flexor carpi radialis m.

Origin: Medial epicondyle of humerus; Insertion: Palmar base of 2nd & 3rd metacarpal bones; Action: Flexes carpal joints.

Superficial digital flexor m.

Origin: Medial epicondyle of humerus; Insertion: Palmar bases of middle phalanges; Action: Flexes carpal joints; flexes metacarpophalangeal joints; flexes proximal interphalangeal joints.

Flexor carpi ulnaris m.

Origin: Medial epicondyle of humerus; olecranon of ulna; Insertion: Accessory carpal bone; Action: Flexes antebrachiocarpal joint.

Deep digital flexor m.

Origin: Body of ulna (ulnar head); medial epicondyle (humeral head); body of radius (radial head); Insertion: Flexor tubercles of distal phalanges; Action: Flexes carpal joints; flexes digital joints.

Pronator teres m.

Origin: Medial epicondyle of humerus; Insertion: Body of radius; Action: Pronation of manus.

Pronator quadratus m.

Origin: Apposed surfaces of radius & ulna; Insertion: Apposed surfaces of radius & ulna; Action: Pronation of manus.

Interossei mm. (4 total)

Origin: Palmar base of respective metacarpal bone; Insertion: Proximal sesamoid bones; palmar base of respective proximal phalanx; tendon of common digital extensor dorsally via extensor branch; Action: Supports and flexes metacarpophalangeal joint.