Latissimus Dorsi Muscle

Latissimus Dorsi Muscle

This is the Latissimus Dorsi PDF for you to download

Latissimus Dorsi is a large, flat, triangular shaped muscle with a massive proximal attachment.

Latissimus Dorsi has amazing movable attachments which has significant clinical relevance in the dog.

The canine Latissimus Dorsi has an important function in caudal core stability.

Using Therapeutic Handling / Alignment treatment techniques in the aquatic setting leads to noticeable improvement in the dog's caudal core and it's land based natural balanced stance, postures and motion.

Proximal Attachment

The massive proximal attachment on the axial skeleton is through the thoracolumbar fascia (also known as lumbodorsal fascia in older texts). So via the thoracolumbar fascia, Latissimus Dorsi attaches to all the lumbar vertebrae and the last 9 or 10 thoracic vertebrae. It also attaches to the last few ribs by a couple of muscular slips.

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Most skeletal muscles are attached by connective tissue to a bone or cartilage. This can be in a form of a cord like tendon or a sheet like aponeurosis. Some muscles attach directly to the bone's periosteum and this sort of attachment is known as fleshy attachments.

The thoracolumbar fascia (deep fascia) has 2 leaves; superficial and deep.

The proximal attachment of Latissimus Dorsi begins as a wide tendinous leaf from the superficial leaf of the thoracolumbar fascia.

Distal Attachment

The apical end of the muscle (narrower cranial end) goes medial to the shoulder attaching as a conjoined tendon with the Teres Major muscle to the teres major tuberosity on the medial aspect of the humerus. This is roughly opposite to the deltoid tuberosity found on the lateral aspect of the humerus.

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Clinical Tip: The dog has a muscular axillary arch so clinically reason your choices of manual treatment techniques. These can impact both Latissimus Dorsi and the Deep Pectoral muscles due to the aponeurosis and fascial connections.

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The Tensor Fascia Antebrachii muscle arises above the axillary arch from the aponeurosis of the lateral aspect of Latissimus Dorsi muscle, wow! Consider the facial tensioning of this arrangement.

Innervation of Latissimus Dorsi

Latissimus Dorsi muscle is innervated by the thoracodorsal nerve which arises mainly from the 8th cervical nerve, with contributions for the 1st thoracic nerve and 7th cervical nerve.

This is the motor nerve to Latissimus Dorsi and it has no cutaneous branches.

Latissimus Dorsi is large triangular shaped muscle.
Latissimus Dorsi is large triangular shaped muscle.
Consider the arrangement of the other muscles and their fascial arrangements with Latissimus Dorsi.
Consider the arrangement of the other muscles and their fascial arrangements with Latissimus Dorsi.

Lily modelling a "well fitted Y shaped harness" optimising her natural balanced stance, postures and motion. Check the PDF with this presentation and evaluate where the ventral border of Latissimus Dorsi is. This is palpable with a flat hand slowly sweeping distally off the ventral border, a subtle palpation!
Lily modelling a "well fitted Y shaped harness" optimising her natural balanced stance, postures and motion. Check the PDF with this presentation and evaluate where the ventral border of Latissimus Dorsi is. This is palpable with a flat hand slowly sweeping distally off the ventral border, a subtle palpation!

Retraction in the stance phase is actually the power sweep of movement. The dog is a rear engine design and the pelvic limb muscles (hindlimb muscles) are where the dog primarily powers from. Whereas, the biomechanical design of the thoracic limbs (forelimbs) is primarily for braking and shock absorbing.

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Clinical Tip: Research shows Latissimus Dorsi does not activate in steady state movement, but it does in digging, swimming and incline work where the dog uses thoracic limb (forelimb) retraction. EMG studies show it activates well into midway in stance phase: consider your static work!

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Clinical Tip: We know Latissimus Dorsi has a massive attachment extending the canine caudal core through the strong, dense, mobile deep fascia. By applying a range of canine Alignment techniques using Therapeutic Handling on land and also in water, these static and dynamic techniques can facilitate core stability through the Epaxials and Latissimus Dorsi muscles.

This Bitesize Canine Resource was produced for you and is owned by K9HS Courses.