What Is the Semitendinosus?

As the name suggests, tendons make up almost half of this muscle's length. It has a spindle-shaped muscular abdomen that moves into a long rope-like tendon about 2/3 of the way down the femur and attaches to the medial side of the upper end of the tibia. The proximal end of this muscle, together with the long head of the hemi-muscle and biceps femoris, self-sciatic tubercles and stops at the inner side of the upper end of the tibia. It is located below the medial skin of the thigh and is a triangular flat muscle. The lateral side is adjacent to the biceps femoris, and it starts from the ischial tuberosity with the long head of the biceps femoris. The muscle bundle gradually separates from the biceps and migrates in one length. Tendons that stop at the inner side of the tibia tuberosity. Belongs to double joint muscles. For near-fixation, extend the thighs at the hip joints, and flex the calves at the knee joints. When distantly fixed, it functions the same as the biceps femoris. The semitendinosus muscle is innervated by the sciatic nerve.

As the name suggests, tendons make up almost half of this muscle's length. It has a spindle-shaped muscular abdomen that moves into a long rope-like tendon about 2/3 of the way down the femur and attaches to the medial side of the upper end of the tibia. The proximal end of this muscle, along with the long head of the hemi-muscle and biceps femoris, self-sciatic tubercles and stops at the medial end of the tibia. It is located below the medial skin of the thigh and is a triangular flat muscle. The lateral side is adjacent to the biceps femoris, and it starts from the ischial tuberosity with the long head of the biceps femoris. The muscle bundle gradually separates from the biceps and migrates in one length. Tendons that stop at the inner side of the tibia tuberosity. Belongs to double joint muscles. For near fixation, the thighs are extended at the hip joint, and the lower legs are flexed and internally rotated at the knee joint. When distantly fixed, it functions the same as the biceps femoris. The semitendinosus muscle is innervated by the sciatic nerve.

The muscular abdomen is long and thick, turning down to the medial side of the femur along the posterior edge of the femur; it stops at the tibial condyle and calf fascia and the calcaneus. It is used to extend the hip, knee, and sacroiliac joints, and accounts for almost half of the muscles. Together with the long head of the biceps femoris, it starts from the ischial tuberosity. The semitendinosus muscle can flex the knee joint and extend the hip joint. This muscle is innervated by the sciatic nerve.

One of the rear thigh muscles. It starts from the ischial tuberosity and ends down on the inside of the upper end of the tibia. This muscle and the biceps femoris and semimembranes can flex the calf and extend the thigh when the pelvis is fixed; Innervated by the sciatic nerve.

Chinese name

Semitendinosus

Location

Back of thigh

termination

Medial side of upper tibia

Function

Hip extension, knee flexion, and microrotation

Semitendinosus muscle anatomy

Tendon surgery includes anastomosis, extension, transplantation, displacement, release, fixation, and amputation.

Tendon anastomosis is a method of stitching a broken tendon, or a tendon and another tendon are called tendon anastomosis. The tendon injury such as debridement is timely and thorough, and the broken tendon can be sutured in one stage. If the primary suture cannot be used, fix the tendon on the nearby muscles to prevent shortening, and prepare for the secondary suture cooperation.

The "8" suture method was used for the hand tendon. For tendons that are prone to adhesion, wire extraction and suture method is used. For tendons with low tension, double right-angle sutures should be used. Tendon transfer was performed with end-to-side suture. The longer ends of the tendon can be braided. Tendons can vary in thickness and thickness, and can be used for fish mouth sutures. Anastomosis of muscles and tendons can be performed directly.

Surgical operation should be light and smooth. The smooth surface of the tendon and the mesangial membrane should be kept as much as possible. Follow aseptic procedures to prevent infection. Sutures often fall off after starting exercise activities, and any resistance activities must be prohibited.

Semitendinosus tendon elongation

It is an operation that cuts or partially cuts the tendon and prolongs it to correct the shortening or joint deformity caused by a certain bundle or group of muscle contractures. Muscle or tendon shortening caused by various reasons, forming joint deformities, affecting function, and those who retain part of the contractile function of the muscle itself, apply tendon extension. Such as congenital local muscle, tendon, ligament shortening, such as valgus foot. Scar contracture after muscle necrosis, such as local ischemic muscle contracture, scar contracture caused by muscle trauma, etc. muscle contracture after inflammation, such as scar contracture caused by purulent inflammation. Muscle shortening caused by muscle imbalance during development, such as some muscle shortening caused by poliomyelitis sequelae, or some muscle contraction due to cerebral palsy due to spasm. Iatrogenic causes, such as foot drop caused by careless fixation of lower limb fractures. Surgery types and principles: Achilles tendon extension: It is used to correct horseshoe foot deformity caused by Achilles tendon contracture. It can be divided into two types: "V" extension and "Z" extension. This operation should be performed before bone and joint fusion surgery. Pay attention to protect blood vessels and nerves. For those with paralysis of thigh muscles, this operation should not be performed to avoid knee joint instability. Rope muscle extension: It is applied to selective cases of knee flexion contracture caused by cerebral palsy, and the gracilis, semitendinosus, hemimenis, and biceps femoris tendons are extended in a "Z" shape. Biceps tendon elongation: applied to elbow flexion contracture. Extend the biceps tendon in a "Z" shape.

Semitendinosus tendon shift

When a group or one muscle is weakened or lost due to various reasons, the tendon stops adjacent to healthy muscles can be transferred to a suitable place, which is the tendon shift. The direction of its muscle strength and the role of redistributing each muscle group, so that the muscle strength can be better balanced, so as to achieve the purpose of improving function and preventing deformity. Applications include sequelae of polio; peripheral nerve injury causes paralysis of one group or one muscle, and nerves cannot be repaired or ineffective after repair; muscle defects caused by trauma cannot be repaired, which affects functions; a few spastic paralysis affects function By. The minimum age of patients for tendon displacement surgery should be based on the child's ability to cooperate with the doctor. Generally, it is recommended that the patient be 5 years old or older. Existing contracture deformity must be corrected before tendon transfer. It is necessary to find out the muscle paralysis and various deformities, and then consider using those muscles to balance. Isolate the tendon carefully and protect the nerves and blood vessels that govern it. The path of the transferred tendon is as straight as possible to reduce resistance. The location of the tendon transfer depends on the deformity. If the foot is varus deformity, you can place the stopping point closer to the fibula side; otherwise, it is closer to the tibial side. The new dead center is fixed more firmly on the bone tissue. Postoperative plaster fixation, keeping the muscle in a relaxed position. Soft tissue surgery was performed for 4 to 6 weeks, and bone surgery was performed for 6 to 12 weeks. Early functional exercise to avoid adhesions.

The following symptoms are often used clinically when tendon displacement is performed. The types of surgery and the main points are:

(1) Paralysis of hip muscles: When the abductor is paralyzed, the iliopsoas can be transferred to the greater trochanter, but the quadriceps muscle strength must be good to prevent loss of hip flexion after surgery. When the adductor is paralyzed, the sciatic tubercle at the origin of the hamstring muscle can be transferred to the subpubic branch.

(2) Knee extensor paralysis: If quadriceps is paralyzed, tendon transfer is a method to restore automatic knee extension. The biceps femoris and semitendinosus muscles are often used to transfer to the sacrum. Because the hips are flexed first and then the knees are stretched. The hip biceps and semitendinosus muscles are in a tense state during hip flexion, which is conducive to knee extension. It is also useful for the transfer of sartorius muscle and fascia lata muscle, but the effect is not as good as that of biceps femoris and semitendinosus muscle transfer. When performing the above two procedures, the muscle strength of the gluteus maximus and gastrocnemius muscles must be good; there is no flexion or contracture deformity of the knee joint. People with severe paralysis of hip, ankle, or foot muscles who are not suitable for surgery should not perform this operation.

(3) Paralysis of the muscles around the foot and ankle joints: Partial paralysis of the tibialis anterior muscle can cause horseshoe, horseshoe concave arch or horseshoe valgus foot deformity. Generally, long extensor muscles are transferred to the first metatarsal bone or combined with sacral fasciotomy, which can correct the imbalance in the function of the ankle joints and prevent the occurrence of deformities. A complete paralysis of the tibialis anterior muscle can cause a horseshoe concave arch and foot deformity. The peroneus longus can be transplanted to the back of the foot. Sometimes it is necessary to perform sacroiliac fasciotomy and posterior extension of the long extensor. Simple gastrocnemius paralysis can cause severe ankle deformity, which can transfer the tibialis anterior to the calcaneus and Achilles tendon, and also the posterior tibialis and peroneus longus to the calcaneus. Although this operation cannot completely stop the deformity, But it is quite effective for reducing deformity.

(4) Paralysis of the muscles around the shoulder: The dysfunction caused by paralysis of the biceps brachii is severe. Although there are complete forearms and fingers, they cannot perform their proper functions. In this regard, the pectoralis major muscle is often transferred to the radial nodules. There is also a total pectoralis major muscle transfer operation. This method is actually a modification of the previous operation. The difference is that the sternum of the pectoralis major muscle is cut off at the upper end of the humerus and transferred to the coracoid process of the scapula to make the muscle closer to the humerus Anatomy of the biceps. However, the transferred muscles must be strong and the forearms and hands must be intact. When deltoid muscle is paralyzed, the effect of trapezius muscle transfer is inexact, and shoulder fusion is generally recommended.

(5) Paralysis of the muscles around the forearm and wrist joints. For the sagging deformity of the wrist caused by irreparable radial nerve trauma, due to the different muscle groups paralyzed, it is appropriate to perform corresponding tendon transfer according to different muscle group paralysis. Generally, the radial wrist flexor muscles are commonly transferred to the long, short, and abductor hallucis tendons; in order to restore the functions of abduction and dorsal thumb extension, the ulnar carpi flexors are transferred to the total extensors of the thumb and the index extensors of the index finger. And little finger extensor muscles to restore the function of the little finger extension of the back.

Tendon release The tendon itself forms scars and adhesions with surrounding tissues, affecting tendon slippage, and when limb dysfunction occurs, the adhesion is separated by surgery to reconstruct the sliding function. Commonly used for tendon adhesions caused by trauma, infection, postoperative and other reasons. Requires non-invasive operation, complete release, adequate hemostasis to reduce re-adhesion, and early activities after surgery should prevent re-adhesion. Remove the scar and tendon sheath, keep the tackle, and have a good tendon bed.

Semitendinosus tendon fixation

For tendon slippage and joint instability, tendon fixation is used to stabilize tendons and joints, and change the distribution of muscle strength to achieve balance. Applied to tendon dislocation; some habitual joint dislocations; to replace paralyzed muscles or broken tendons for stability and balance.

The types of surgery and the main points are recurrent dislocation of the long and short tendons of the fibula, which can be fixed with a separate lateral edge of the Achilles tendon. To avoid adhesion, the smooth Achilles tendon can face the tendon. In the case of talus inversion and subluxation with dysfunction, the short peroneus tendon can be used to fix it through the lateral malleolus. The elasticity of the tendon should be moderate. Child-shaped flail foot is used to fix the ankle tendon in front of the foot to prevent the foot from sagging. This is a preventive operation. During cerebral palsy, fix the hamstring muscle at the lower end of the femur to correct hip and knee deformities.

Semitendinosus tendon amputation

Is the starting point or stopping point of a tendon or muscle group, in order to relieve the deformity or dysfunction caused by contracture or shortening of the muscle. It is used to correct deformities caused by muscle contracture, such as congenital muscular torticollis, and it can be used for sternocleidomastoid muscle amputation. Eliminate the factors that prevent the correction of deformities, such as congenital hip dislocation for adductor resection, so that it is easy to reduce and reduce complications. Improve muscle spasm, dynamic deformity caused by muscle imbalance. Such as cerebral palsy for part of the adductor muscle cut and gastrocnemius muscle cut off. Improve the deformity caused by muscle imbalance caused by paralysis of some muscles, such as the increase of broad fascia tension caused by polio; hip abduction deformity caused by hip adductor weakness, can be used as sacroiliotomy.