A Comprehensive Guide to Canine Scapula Anatomy and Physiology

The canine scapula is a fascinating bone that plays a crucial role in a dog's movement and overall health. It's a flat, triangular bone located on the dog's back, just behind the shoulder blade.

The scapula is made up of three main parts: the acromion process, the coracoid process, and the glenoid cavity. The acromion process is the bony projection that forms the highest point of the scapula.

A dog's scapula is designed to move freely, allowing for a wide range of motion in the shoulder joint. This is essential for activities like running, jumping, and even just walking.

To properly position a dog for a scapula radiograph, place the patient in dorsal recumbency with each thoracic limb taped separately and pulled cranially. This allows for a clear caudocranial view of the scapula.

In this view, the elbows should abduct, and a band of tape is placed at the mid antebrachii to pull them in medially, straightening the scapula and humerus in a proximal to distal direction. This positioning is crucial for accurate imaging.

The lateral and caudocranial projections of the scapula should include the head of the humerus and the caudal border of the scapula.

The scapula, or shoulder blade, is a complex bone that plays a crucial role in our daily movements. It's a fascinating topic, and I'm excited to dive into the anatomy of the scapula.

The scapula is connected to the humerus, or upper arm bone, through a joint called the glenohumeral joint. This joint is a ball-and-socket joint, which allows for a wide range of motion in the shoulder.

Here are the key structures of the proximal forelimb and shoulder, which include the scapula:

The scapula has a unique shape, with a curved upper border and a flat lower border. This shape allows it to fit snugly against the ribcage and provides a stable platform for the glenohumeral joint.

The scapula is also connected to the clavicle, or collarbone, through the acromioclavicular joint. This joint is a saddle-shaped joint that allows for a limited range of motion.

Here are the key joints of the proximal forelimb:

The scapula is a remarkable bone that plays a vital role in our daily movements. Understanding its anatomy can help us appreciate the complexity and beauty of the human body.

The scapula, also known as the shoulder blade, is a complex bone that plays a crucial role in our movement and flexibility. To take a clear x-ray of the scapula, the patient is placed in dorsal recumbency with each thoracic limb taped separately and pulled cranially.

In order to get a good view of the scapula, it's essential to position the limbs correctly. The elbows should abduct, and a band of tape is placed at the level of the mid antebrachii to pull them in medially, allowing the olecranon to point toward the x-ray tube. This action will straighten the scapula and humerus in a proximal to distal direction.

The lateral and caudocranial projections of the scapula should include two key structures: the head of the humerus and the caudal border of the scapula. Unfortunately, due to anatomic limitations, there will be some degree of overlap between the thoracic spinous processes and ventral border and infraspinous fossa of the scapula in the lateral view.

To summarize, the key structures to include in a scapula x-ray are the head of the humerus and the caudal border of the scapula. Here's a quick rundown of what to look for:

The shoulder musculature plays a crucial role in canine scapula anatomy, allowing for a wide range of motion and flexibility.

The trapezius muscle is responsible for elevating the scapula and rotating it downward, which helps to transfer the weight of the body to the forelimbs.

The brachiocephalic muscle, along with the trapezius, helps to elevate the scapula and rotate it downward.

The latissimus dorsi muscle is a powerful muscle that helps to extend, adduct, and rotate the forelimb.

The pectoral muscles, including the serratis ventralis and rhomboids, help to stabilize the scapula and facilitate movement.

The supraspinatus and infraspinatus muscles, along with the teres major, help to rotate the humerus and stabilize the shoulder joint.

The ulnaris lateralis muscle, although not directly mentioned in the context of shoulder musculature, is an important muscle in the canine anatomy that contributes to the overall movement and flexibility of the forelimb.

Consider reading: Dogs Muscle Anatomy

The shoulder anatomy is a complex system that allows for a wide range of motion in dogs. The scapula plays a crucial role in this system.

The scapula is a flat, triangular bone that serves as the foundation for the shoulder joint. It's located on the dorsal side of the ribcage and is connected to the humerus by the glenohumeral joint.

The scapula has three main parts: the acromion, the coracoid process, and the scapular spine. These parts work together to provide a stable base for the shoulder joint.

The shoulder is a complex joint that allows for a wide range of motion. It's made up of three bones: the scapula, humerus, and clavicle.

The scapula, also known as the shoulder blade, is a flat, triangular bone that forms the base of the shoulder joint. It has a shallow socket called the glenoid cavity.

The humerus, or upper arm bone, is the longest bone in the arm and forms the head of the humerus, which fits into the glenoid cavity. The head of the humerus is a ball-and-socket joint that allows for rotation and movement.

The clavicle, or collarbone, connects the scapula to the sternum and serves as a strut to support the arm. It's a long, curved bone that forms the front of the shoulder.

The rotator cuff is a group of muscles and tendons that surround the shoulder joint and help to stabilize it. It's made up of four muscles: the supraspinatus, infraspinatus, teres minor, and subscapularis.

The shoulder joint is surrounded by a sac called the capsule, which is made up of connective tissue. The capsule helps to stabilize the joint and keep the bones in place.

The bursae are small, fluid-filled sacs that reduce friction between the tendons and bones in the shoulder joint. They help to keep the joint lubricated and moving smoothly.

The shoulder region is home to a complex network of nerves, known as the brachial plexus, which includes nerves C-6, C-7, and C-8 from the cervical spine, as well as nerves T-1 to T-2 from the thoracic spine.

These nerves descend ventrally and branch off into various nerves that control movement and sensation in the shoulder and arm. The suprascapular nerve, subscapular nerve, axillary nerve, musculocutaneous nerve, radial nerve, and median nerve all originate from the brachial plexus.

The radial nerve is particularly important, as it supplies the muscles that enable the forelimb to support the forequarters. If the radial nerve is injured, the muscles it supplies will be paralyzed, making it impossible for the forelimb to extend the elbow.

The axillary nerve, located proximal to the scapula, plays a crucial role in controlling movement in the shoulder joint.

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The lymph nodes in the shoulder region play a crucial role in our immune system, filtering out toxins and waste from the lymph fluid.

Lymph nodes are located in the subcutaneous tissue, just medial to the scapular-humeral joint on either side.

The pre-scapular lymph node is one node that can be palpated, and it's often encased in fat, feeling slightly softer than other tissue.

Gentle compression and a slight pumping motion can aid the distribution of lymph throughout the body, especially over identifiable “nodes”.

The axillary lymph nodes are dorsal to the deep pectoral muscle and caudal to the large axillary vein coming from under the forearm.

Most of the lymph vessels flowing away from the thoracic wall and deep tissues of the limb drain into the axillary lymph nodes.

Abnormal lymph nodes may be enlarged, hard, warm, or painful, so it's essential to be aware of any changes in their size, texture, firmness, or comparison to each side.

To get a clear image of the canine scapula, positioning is key. The patient is placed in lateral recumbency with the affected side up and marked with a lead marker as right (R) or left (L).

The unaffected limb is taped and pulled cranially and distally, away from the thorax. This helps to position the shoulder below the level of the thoracic spinous processes.

The affected limb is taped midradius and pulled dorsally, positioning the carpus above the skull. The elbow is flexed, superimposing the scapula over the thoracic spinous processes.

To achieve this positioning, the pulling of the unaffected limb and pushing of the affected limb will rotate the torso of the dog or cat. This results in the affected scapula being positioned dorsal to the cervical and thoracic spinous processes.

Collimation is just as important as positioning. The cranial edge of the collimator light is placed cranial to the distal margin of the spine of the scapula. The caudal edge of the collimator light is placed at the caudal border of the scapula.

Broaden your view: Canine Thoracic Limb Anatomy