EasyAnatomy s. Snapshot Guide to the Bones of the Canine Thoracic Limb. LlamaZOO Interactive facebook.

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2 Thoracic Limb The regions of the thoracic limb, or forelimb, are the shoulder, brachium (upper arm), antebrachium (lower arm), and the manus (forepaw). The manus is composed of the carpus, metacarpus, and digits. The bones of the thoracic limb include the scapula, humerus, radius, ulna, as well as carpal, metacarpal, digital, and sesamoid bones.

3 EasyAnatomy s Scapula The large, flat bone of the thoracic limb. Extrinsic and intrinsic limb muscles a=ach to the scapula. Extrinsic muscles a=ach the limb to the axial skeleton, and intrinsic muscles a=ach the scapula to more distal limb bones. LlamaZOO Interactive facebook.com/llamazoo

4 Dorsal border Le1 Scapula Medial View Supraspinous fossa Spine Infraspinous fossa Caudal border Supraglenoid tubercle Acromion Scapula The extrinsic limb muscles that a=ach the scapula to the axial skeleton form a muscular sling to support the body weight (there is no bony ar@cula@on between the scapula and axial skeleton in the dog).

5 EasyAnatomy s Humerus The bone of the brachium (upper arm). Proximally it ar@culates with the scapula in forming the shoulder joint; distally it ar@culates with the radius and ulna in forming the elbow joint. LlamaZOO Interactive facebook.com/llamazoo

6 EasyAnatomy s Greater tubercle Le1 Humerus, Lateral Side Deltoid tuberosity Capitulum Lesser tubercle Le1 Humerus, Medial Side Olecranon fossa Intertubercular groove LlamaZOO Interactive facebook.com/llamazoo

7 EasyAnatomy s Ulna One of two bones of the antebrachium (forearm). Proximally it ar@culates with the humerus by the trochlear notch and with the ar@cular circumference of the radius by the radial notch. Distally it ar@culates with the ulnar notch of the radius and with the ulnar carpal and accessory carpal bones. LlamaZOO Interactive facebook.com/llamazoo

8 Olecranon tuber Anconeal process Trochlear notch Medial coronoid process Le1 Ulna, Cranial Side Ulna The proximal ulna is formed by the olecranon, which serves as the of the triceps brachii muscle.

9 Head Styloid process Radius The other of the two bones of the antebrachium (forearm). The radius with the humerus proximally, and with the carpal bones distally. It also with the ulna proximally by its caudal surface and distally by its lateral border. The radius is the main bone of the forearm.

10 Radial (Intermedioradial) Carpal Bone Styloid process Radial (Intermedioradial) Carpal Bone Largest bone in proximal row of carpal bones. proximally with radius and distally with all four carpal bones in the distal row of the carpus. Forms part of the antebrachiocarpal joint, which is very mobile.

11 Carpal Bone 1 Carpal Bone 4 Carpal Bone 2 Carpal Bone 3 Carpal Bones Found in the distal row of carpal bones. Ar@culate with metacarpals distally. Form parts of the carpometacarpal joint.

12 Accessory Carpal Bone Accessory Carpal Bone Radial (Intermedioradial) Carpal Bone Accessory Carpal Bones Why important? Forms and important mechanical lever arm on the palmar aspect of the carpus; and is at risk of fracture in racing greyhounds. What afaches here? Extensor carpi ulnaris m. flexor carpi ulnaris m.

13 Metacarpal III Metacarpal I Metacarpal IV Metacarpal V Metacarpal II Metacarpals The long bones that make up the manus (forepaw). Ar@culate proximally with carpal bones to form carpometacarpal joint, and distally with proximal phalanx to form metacarphalangeal joint. Metacarpals 3 & 4 are considered the major weight-bearing bones of the manus.

14 EasyAnatomy s Proximal Phalanx of Digit 3 Proximal Phalanx of Digit 4 Proximal Phalanx of Digit 5 Proximal Phalanx of Digit 1 Middle Phalanx Proximal Phalanx of Digit 2 Proximal Phalanges For digits 2-5: The proximal phalanx ar@culates proximately to form metacarpophalangeal joint, and distally with middle phalanx to form proximal interphalangeal joint. The ves@gial first digit (the dew claw) has two phalanges in contrast to the other digits which have three phalanges. LlamaZOO Interactive facebook.com/llamazoo

15 Distal Phalanges (Digits 2-5) with middle phalanx to form distal interphalangeal joint.

16 Distal Phalanx of Digit 1 The distal bony segment within this digit. Ar@culates with proximal phalanx to form interphalangeal joint.

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