MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION

Transcription

1 1 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION MASSETER Cheeks of the lower jaw Ventral border of rostral half of zygomatic arch Ventrolateral surface of mandible and ventral margin of the masseteric fossa of the mandible Raises mandible when closing mouth May be one sided if there are problems with chewing (teeth issues or temperomandibular joint issue for example). This would create more tension on the favoured side. TEMPORALIS Over the temples (above the upper jaw) Parietal, temporal, frontal and occipital bones Medial surface of the condyle of the mandible just ventral to its articular surface Raises the mandible Tension. May be one sided if there are problems with chewing (teeth issues or temperomandibular joint issue for example). This would create tension on the favoured side CRANIAL OBLIQUES Covers the bulk of the wing of the atlas Spinous and articular process of axis Wing of atlas Rotation of atlas on axis Restricted rotation of head to opposite side, posterior misalignment of atlas. Can be palpated properly only if weight of horse s head is held, otherwise is contracted to hold head

2 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION STERNOCEPHALICUS 2 Underside of neck, between the lower jaw and breast bone. Manubrium (front end) of sternum, and sternum cartilage Mandible and ramus (back ridge of jaw) Brings head downwards and forwards. Can be over developed in horses with a high head carriage, especially those who pull. Can feel tight at origin. May be associated with horses who trip RHOMBOIDEUS Deep muscle along top of neck, from the back of the skull to the withers and top of the shoulder blade. Occiput (under front of poll), attached to nuchal and supraspinous ligament from C2 to approx T10. Upper scapular cartilage medial (inner) surface. Lifts the shoulder: protraction and retraction, and stabilises. In the stance phase helps extend neck and spine If tight; unable to stretch and can cause loss of co-ordination in forelimbs. Palpation causes twitching over withers if tight TRAPEZIUS (CERVICAL AND THORACIC) Triangle from 2/3 down the neck to the shoulder blade, and another triangle over the withers Dorsal midline and supraspinous ligament above C3 to T10 Cervical: on spine of scapula. Thoracic: on top part of spine of scapula Lifts shoulder by drawing the scapular (shoulder blade) up and forward, or up and back. In the stance phase helps extend neck and spine If tight; decreased shoulder and neck flexibility. Can be affected buy rug rubs. Palpation causes twitching over withers if tight

3 3 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION SERRATUS VENTRALIS CERVICIS Between scapula and lower cervicals Transverse processes C3 7 Medial surface of scapula If neck fixed, draws scapular forward. If scapula fixed, extends or laterally flexes the neck Prone to overwork in horses who are on the forehand or fixed too high in neck posture, as nuchal ligament becomes too slack to take the strain, so this muscle has to take its place. Often causes twitching over withers on palpation SPLENIUS Side of neck, from the back of the head and down the first half of the neck vertebrae to cover the withers T4 T6 (T5/6 is approx highest point of wither) Nuchal crest (poll), mastoid process, transverse processes C3 C5 Turns and lifts head and neck to the side If tight, turning the neck is difficult BRACHIOCEPHALICUS Lower side of neck over vertebrae, From the back of the skull to the front of the shoulder Mastoid process (behind TMJ), temporal bone (above TMJ), nuchal crest (just behind ear Humerus deltoid tuberosity (below front point of shoulder) and fascia of the shoulder Moves the head sideways or brings the foreleg and shoulder forward If tight; short choppy stride and resistance to go forward

4 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION 4 MULTIFIDUS CERVICUS Entwined in cervical vertebrae. From C2 to end of lumbar vertebrae. Starts at C2 to end of lumbar vertebrae. Spinous (top) and articular (join to other vertebrae) processes Spinous and articular processes and runs to end of lumbar vertebrae Flexes neck to one side while rotating head to the opposite side. Supports spine Bulges around C3 if worked hard in an outline. Tightness, spasm, pain in neck. Resistance in neck. Poor bit contact. Poor function in this muscle can cause tension in the surrounding muscles. This can be helped through carrot stretching. SUPRASPINATUS Over the front of the shoulder blade Spine and upper cartilage of the scapula Lateral tuberosity of humerus (side of point of shoulder) Open front of shoulder and helps take limb forward (lateral work). Major stabiliser of the forelimb If tight; shoulder tightness. If poor function, the spine of the scapula will be obvious ( sweeny ), and may well be sensitive INFRASPINATUS Over the back of the shoulder blade Scapula cartilage Caudal (back) part of lateral tuberosity (side/back of point of shoulder) Stabilises shoulder. Rotates shoulder and limb outwards If tight; shoulder tightness. If poor function, the spine of the scapula will be obvious ( sweeny ), and may well be sensitive

5 5 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION TRICEPS Triangular shaped; from under the back of the shoulder blade to the elbow and the back of the shoulder Long head originates on the scapula. Lateral and medial heads originate on the humerus Olecranon process (point of elbow) Draws the forearm and shoulder up and back If tight, the horse has a short stride and may dish BICEPS BRACHII From just above point of shoulder on the front of the horse to the top of the forearm Supraglenoid tubercle of the lower scapular Via tendon on to the front of the radius Stabilizes the shoulder joint / locks forelimb when weight bearing. Extends the shoulder joint and flexes the elbow Overuse can lead to poor stability of shoulder, causing tripping. Tightness can reduce joint flexibility in the area DESCENDING (SUPERFICIAL) PECTORALS Viewed from below---> Over the chest between the legs (breast bone to ribs) Sternum: xiphoid and costal cartilage Humeral crest (just below point of shoulder) and antebrachial fascia Brings forelimb across body If tight; short stride, grumpy on girthing, resisting correct canter lead, and breathing may be affected

6 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION 6 ASCENDING (DEEP) PECTORALS Viewed from below---> Over the chest between the legs (breast bone to ribs) Xiphoid cartilage and rib cartilage 1-4 Medial tuberosity of humerus (inside point of shoulder) Brings forelimb across body If tight; short stride, grumpy on girthing, resisting correct canter lead, and breathing may be affected LATISSIMUS DORSI A triangular muscle; from the back of the withers, along the spine to the lower back. Here, it connects into a sheet of fascia (lumbar aponeurosis) which continues over the loins and into the gluteals. The lower part attaches to the back of the humerus under the shoulder joint From T3 into the thoracolumbar fascia, which extends to the fascia over the croup Inner surface of the humerus, slightly less than halfway down the bone. Draws the shoulder blade down and back, and takes the forelimb back. Supports the spine in movement If tight, the horse will be stiff and on the forehand, especially turns and circles, may be grumpy when girthing and may affect breathing LONGISSUMUS DORSI Has attachments to the cervical spine, and from between the withers to lower back, where it connects to fascia that continues into the middle gluteal muscle. Biggest and longest muscle in spine Spinous processes of the sacrum / upper surface of ilium (croup) / supraspinous ligament. On the upper ends of all the ribs, the sides of all the thoracic and all the lumbar vertebrae, and on the sides of the cervical vertebrae Helps lateral (side) bending, and part of a group of muscles that power the horse forward. Stabilises the spine during impulsion If tight; inability to flex, cold backed, dipped back, not working over back or engaging hind quarters. Susceptible to uneven saddle or rider pressure

7 7 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION SERRATUS VENTRALIS THORACIS Attached between ribs and underside of shoulder blade Lateral surface of ribs 1 9 Medial (inner) surface of the scapula Lifts trunk of the body, suspends the torso between the scapulars, providing a mobile elastic sling. It aids in smooth impulsion and gives spring to stride Stiff on forehand, especially turns and poor shoulder flexibility. May affect breathing. Affected by tightness in C6/7 BICEPS FEMORIS Over side of thigh, between sacrum (rump) to cover a wide area over the stifle Superior spines of the sacrum, Tuberosity of Ischium (seat bone) / sacrum / sacroiliac ligaments Anterior part of patella, crest of tibia (below side of stifle), fascia of hock Bends stifle and hock, and aids propulsion, kicking and rearing If tight; short hind stride, not tracking up, resists lateral movements SEMITENDINOSUS Down the back of the thigh from the point of buttock to above the hoc Tuber ischium (point of seat bone) and tendon attachment on sacrum Crest of tibia (below side of stifle), tendon of biceps, which attaches to tuber calcis (hock) Bends stifle and stretches limb out behind, aiding propulsion Tightness; shortened stride, resists straightening stifle, may hold leg bent at rest

8 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION ADDUCTORS 8 There are three adductor muscles. Adductor longus, adductor magnus and the brevis muscle. These muscles are found in the deep layer of the muscles. All originate on the pelvic joint via the symphysial tendon. Also near the ischiatic arch, the ventral surface of the pubis and ventral surface of the ischium Inserts into the whole lateral lip of the caudal rough face of the femur Adducts limb, extends dogs hip and stabilizes hind leg Tension creates a close action behind, and restricts length of hind stride GRACILIS It lies on the back part of the inner side of the thigh Pubic symphysis via the symphysial tendon Medial aspect of the stifle and hock Tension creates a close action behind, and restricts length of hind stride Tension creates a close action behind, and restricts length of hind stride

9 9 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION GLUTEUS MEDIUS Lies over the rump between the vertebrae of the pelvis and the hip joint (top of thigh). It sits under the gluteal fascia, and extends into the lumbar area via the gluteal tongue Surface of Ilium, sacral tuber (either side of spine at start of sacrum), dorsal sacro-iliac ligament and gluteal fascia Trochanter major (top) of femur Takes leg back and out to the side. Strong propulsive muscle If tight; discomfort, restricted hip movement, short hind stride SARTORIUS Starts on the front end of the pelvis and ends on the inside of the dog s knee. This muscle has two long muscle bands that are next to each other. A front (Cranial) part and a rear (caudal) part The cranial part arises from the iliac crest and the cranial ventral iliac spine, as well as from the lumbodorsal fascia. The caudal part arises on the bony ridge between the two ventral spines of the ilium Cranial border of the tibia. To flex the hip and stifle while the limb is being protracted and to contribute to stifle extension during stance. Poor extension of the hind limb of tight. Stifle instability if weak GLUTEUS SUPERFICIALIS Lies over the rump between the first half of the sacrum and the mid thigh Gluteal fascia 3rd trochanter of femur Stabilises and flexes hip Short striding, restricted hip extension, toe in on forward stride. If weak / wasted, ilopsoas may be tight

10 MUSCLE FOUND ORIGIN INSERTION ACTION DYSFUNCTION ILIOPSOAS 10 Core muscles, between the underside of the vertebrae in the lower back to the inside of the hip joint (top of thigh) Psoas Origin: Last 2 ribs and lumbar transverse processes Iliacus origin: Wing of the sacrum, surface of ilium (of both): Via common tendon that insert into the lesser trochanter (upper femur Supports lower back. Lowers the pelvis and braces the spine to allow hind limbs to push the body forwards May be tight due to bracing against the rider, prevents stepping through with hind limbs, and often a roached back TENSOR FASCIA LATAE Point of hip to top of stifle Tuber coxae (haunch) Fascia lata of thigh and patella. The fascia also joins the superficial gluteal, and therefore attaches to the greater trochanter (top of femur) Hip flexion. Extension of stifle. Assists in unlocking the stifle. The fascia late itself forms a sling around the stifle, thereby absorbing loads from the above structure If tight; throws leg outwards and resists crossing legs in lateral movement. Appears wasted / hollow. Prefers to stand on opposite leg. Poor stifle locking / unstable EXTERNAL ABDOMINAL OBLIQUE Lies over the lower edge of the ribs across the abdominal area to the ilium Lateral surface of ribs 4-18; thoracolumbar fascia Abdominal tendon: linea alba (mid line of belly) & prepubic tendon (towards pubic bone); pelvic tendon: tuber coxae & prepubic tendon Flexes the trunk; The abdominal muscles are vital in supporting abdomen and helping to maintain spinal flexion. Inhibility to bring hind limb sufficently underneath to support rider & move forwards