| Rotator cuff | |
|---|---|
| Details | |
| Artery | Suprascapular artery, circumflex scapular artery [1] |
| Nerve | Subscapular nerve, suprascapular nerve, axillary nerve |
| Lymph | Axillary lymph nodes |
| Identifiers | |
| Acronym(s) | SITS muscle |
| MeSH | D017006 |
| TA2 | 2461 |
| FMA | 37018 |
| Anatomical terminology | |
The rotator cuff is a group of muscles and their tendons that act to stabilize the human shoulder and allow for its extensive range of motion. Of the seven scapulohumeral muscles, four make up the rotator cuff. The four muscles are:
| Muscle | Origin on scapula | Attachment on humerus | Function | Innervation |
|---|---|---|---|---|
| Supraspinatus muscle | supraspinous fossa | superior [2] facet of the greater tubercle | abducts the humerus | Suprascapular nerve (C5) |
| Infraspinatus muscle | infraspinous fossa | middle facet of the greater tubercle | externally rotates the humerus | Suprascapular nerve |
| Teres minor muscle | middle half of lateral border | inferior facet of the greater tubercle | externally rotates the humerus | Axillary nerve (C5) |
| Subscapularis muscle | subscapular fossa | lesser tubercle | internally rotates the humerus | Upper and Lower subscapular nerve |
The supraspinatus muscle spreads out in a horizontal band to insert on the superior facet of the greater tubercle of the humerus. The greater tubercle projects as the most lateral structure of the humeral head. Medial to this, in turn, is the lesser tubercle of the humeral head. The subscapularis muscle origin is divided from the remainder of the rotator cuff origins as it is deep to the scapula.
The four tendons of these muscles converge to form the rotator cuff tendon. These tendinous insertions along with the articular capsule, the coracohumeral ligament, and the glenohumeral ligament complex, blend into a confluent sheet before insertion into the humeral tuberosities (i.e. greater and lesser tubercle). [3] The infraspinatus and teres minor fuse near their musculotendinous junctions, while the supraspinatus and subscapularis tendons join as a sheath that surrounds the biceps tendon at the entrance of the bicipital groove. [3] The supraspinatus is most commonly involved in a rotator cuff tear.
The rotator cuff muscles are important in shoulder movements and in maintaining glenohumeral joint (shoulder joint) stability. [4] These muscles arise from the scapula and connect to the head of the humerus, forming a cuff at the shoulder joint. They hold the head of the humerus in the small and shallow glenoid fossa of the scapula. The glenohumeral joint has been analogously described as a golf ball (head of the humerus) sitting on a golf tee (glenoid fossa). [5]
During abduction of the arm, moving it outward and away from the trunk (torso), the rotator cuff compresses the glenohumeral joint, an action known as concavity compression, in order to allow the large deltoid muscle to further elevate the arm. In other words, without the rotator cuff, the humeral head would ride up partially out of the glenoid fossa, lessening the efficiency of the deltoid muscle. The anterior and posterior directions of the glenoid fossa are more susceptible to shear force perturbations as the glenoid fossa is not as deep relative to the superior and inferior directions. The rotator cuff's contributions to concavity compression and stability vary according to their stiffness and the direction of the force they apply upon the joint.
In addition to stabilizing the glenohumeral joint and controlling humeral head translation, the rotator cuff muscles also perform multiple functions, including abduction, internal rotation, and external rotation of the shoulder. The infraspinatus and subscapularis have significant roles in scapular plane shoulder abduction (scaption), generating forces that are two to three times greater than the force produced by the supraspinatus muscle. [6] However, the supraspinatus is more effective for general shoulder abduction because of its moment arm. [7] The anterior portion of the supraspinatus tendon is submitted to a significantly greater load and stress, and performs its main functional role. [8]
The tendons at the ends of the rotator cuff muscles can become torn, leading to pain and restricted movement of the arm. A torn rotator cuff can occur following trauma to the shoulder or it can occur through the "wear and tear" on tendons, most commonly the supraspinatus tendon found under the acromion.
Rotator cuff injuries are commonly associated with motions that require repeated overhead motions or forceful pulling motions. Such injuries are frequently sustained by athletes whose actions include making repetitive throws, athletes such as baseball pitchers, softball pitchers, American football players (especially quarterbacks), firefighters, cheerleaders, weightlifters (especially powerlifters due to extreme weights used in the bench press), rugby players, volleyball players (due to their swinging motions),[ citation needed ] water polo players, rodeo team ropers, shot put throwers, swimmers, boxers, kayakers, martial artists, fast bowlers in cricket, tennis players (due to their service motion)[ citation needed ] and tenpin bowlers due to the repetitive swinging motion of the arm with the weight of a bowling ball. This type of injury also commonly affects orchestra conductors, choral conductors, and drummers (due, again, to swinging motions).
As progression increases after 4–6 weeks, active exercises are now implemented into the rehabilitation process. Active exercises allow an increase in strength and further range of motion by permitting the movement of the shoulder joint without the support of a physical therapist. [9] Active exercises include the Pendulum exercise, which is used to strengthen the Supraspinatus, Infraspinatus, and Subscapularis. [9] External rotation of the shoulder with the arm at a 90-degree angle is an additional exercise done to increase control and range of motion of the Infraspinatus and Teres minor muscles. Various active exercises are done for an additional 3–6 weeks as progress is based on an individual case-by-case basis. [9] At 8–12 weeks, strength training intensity will increase as free-weights and resistance bands will be implemented within the exercise prescription. [6]
The accuracy of the physical examination is low. [10] The Hawkins-Kennedy test [11] [12] has a sensitivity of approximately 80% to 90% for detecting impingement. The infraspinatus and supraspinatus [13] tests have a specificity of 80% to 90%. [10]
A common cause of shoulder pain in rotator cuff impingement syndrome is tendinosis, which is an age-related and most often self-limiting condition. [14]
Studies show that there is moderate evidence that hypothermia (cold therapy) and exercise therapy used together are more effective than simply waiting for surgery and they suggest the best outcome for non-surgical treatment of subacromial impingement syndrome. The group of patients who participated in the exercise group were found to use significantly lower amounts of non-steroidal anti-inflammatory drugs (NSAIDS) and analgesics than the control group with no intervention. [15]
The rotator interval is a triangular space in the shoulder that is functionally reinforced externally by the coracohumeral ligament and internally by the superior glenohumeral ligament, and traversed by the intra-articular biceps tendon. On imaging, it is defined by the coracoid process at its base, the supraspinatus tendon superiorly and the subscapularis tendon inferiorly. Changes of adhesive capsulitis can be seen at this interval as edema and fibrosis. Pathology at the interval is also associated with glenohumeral and biceps instability. [16] Adhesive capsulitis or "frozen shoulder" is often secondary to rotator cuff injury due to post-surgical immobilization. Available treatment options include intra-articular corticosteroid injections to relieve pain in the short-term and electrotherapy, mobilizations, and home exercise programs for long-term pain relief. [17]
Treatment for a rotator cuff tear can include rest, ice, physical therapy, and/or surgery. [18] A review of manual therapy and exercise treatments found inconclusive evidence as to whether these treatments were any better than placebo, however "High quality evidence from one trial suggested that manual therapy and exercise improved function only slightly more than placebo at 22 weeks, was little or no different to placebo in terms of other patient-important outcomes (e.g. overall pain), and was associated with relatively more frequent but mild adverse events." [19]
The rotator cuff includes muscles such as the supraspinatus muscle, the infraspinatus muscle, the teres minor muscle and the subscapularis muscle. The upper arm consists of the deltoids, biceps, as well as the triceps. Steps must be taken and precautions need to be made in order for the rotator cuffs to heal properly following surgery while still maintaining function to prevent any deteriorating effects on the muscles. In the immediate postoperative period (within one week following surgery), pain can be treated with a standard ice wrap. There are also commercial devices available which not only cool the shoulder but also exert pressure on the shoulder ("compressive cryotherapy"). However, one study has shown no significant difference in postoperative pain when comparing these devices to a standard ice wrap. [20]
Physiotherapy can help manage the pain, but utilizing a program that involves continuous passive motion will reduce the pain even further. Assisted passive motion at a low intensity allows the tissues to be stretched slightly without damaging them [21] Continuous passive motion improves the shoulder range and enables the subject to expand their range of motion without experiencing additional pain. Easing into the motions will allow the person to continue working those muscles to keep them from undergoing atrophy, while also still maintaining that minimum level of function where daily function is allowed. Doing these exercises will also prevent tears in the muscles that will impair daily function further. [21]
A systematic review and meta-analysis study shows manual therapy may help to reduce pain for patient with Rotator cuff tendiopathy, based on low- to moderate-quality evidence. However, there is not strong evidence for improving function also. [22]
Surgical approaches include acromioplasty (a part of the bone is removed to decrease pressure placed on the rotator cuff tendons), removal of a bursa that is inflamed or swollen, and subacromial decompression (the removal of tissue or bone that is damaged in order to allow more space for the tendons). [23]
Surgery may be recommended for patients with an acute, traumatic rotator cuff tear resulting in substantial weakness.[ citation needed ] Surgery can be performed open or arthroscopically, although the arthroscopic approach has become much more popular. [23] If a surgical option is selected, the rehabilitation of the rotator cuff is necessary in order to regain maximum strength and range of motion within the shoulder joint. [24] Physical therapy progresses through four stages, increasing movement throughout each phase. The tempo and intensity of the stages are solely reliant on the extent of the injury and the patient's activity necessities. [25] The first stage requires immobilization of the shoulder joint. The shoulder that is injured is placed in a sling and shoulder flexion or abduction of the arm is avoided for 4 to 6 weeks after surgery (Brewster, 1993). Avoiding movement of the shoulder joint allows the torn tendon to fully heal. [24] Once the tendon is entirely recovered, passive exercises can be implemented. Passive exercises of the shoulder are movements in which a physical therapist maintains the arm in a particular position, manipulating the rotator cuff without any effort by the patient. [26] These exercises are used to increase stability, strength and range of motion of the subscapularis, supraspinatus, infraspinatus, and teres minor muscles within the rotator cuff. [26] Passive exercises include internal and external rotation of the shoulder joint, as well as flexion and extension of the shoulder. [26]
A 2019 Cochrane Systematic Review found with a high degree of certainty that subacromial decompression surgery does not improve pain, function, or quality of life compared with a placebo surgery. [23]
Patients that suffer from pain in the rotator cuff may consider utilizing orthotherapy into their daily lives. Orthotherapy is an exercise program that aims to restore the motion and strength of the shoulder muscles. [27] Patients can go through the three phases of orthotherapy to help manage pain and also recover their full range of motion in the rotator cuff. The first phase involves gentle stretches and passive all around movements, and people are advised not to go above 70 degrees of elevation to prevent any kind of further pain. [27] The second phase of this regimen requires patients to implement exercises to strengthen the muscles that are surrounding the rotator cuff muscles, combined with the passive exercises done in the first phase to keep on stretching the tissues without overexerting them. Exercises include pushups and shoulder shrugs, and after a couple of weeks of this, daily activities are gradually added to the patient's routine. This program does not require any sort of medication or surgery and can serve as a good alternative. The rotator cuff and the upper muscles are responsible for many daily tasks that people do in their lives. A proper recovery needs to be maintained and achieved to prevent limiting movement, and can be done through simple movements.
The humerus is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a rounded head, a narrow neck, and two short processes. The body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes, and 3 fossae. As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons.
Shoulder problems including pain, are one of the more common reasons for physician visits for musculoskeletal symptoms. The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well.
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula, and the humerus as well as associated muscles, ligaments and tendons.
The deltoid muscle is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle appears to be made up of three distinct sets of muscle fibers, namely the
Rotator cuff tendinopathy is a process of senescence. The pathophysiology is mucoid degeneration. Most people develop rotator cuff tendinopathy within their lifetime.
Adhesive capsulitis, also known as frozen shoulder, is a condition associated with shoulder pain and stiffness. It is a common shoulder ailment that is marked by pain and a loss of range of motion, particularly in external rotation. There is a loss of the ability to move the shoulder, both voluntarily and by others, in multiple directions. The shoulder itself, however, does not generally hurt significantly when touched. Muscle loss around the shoulder may also occur. Onset is gradual over weeks to months. Complications can include fracture of the humerus or biceps tendon rupture.
The supraspinatus is a relatively small muscle of the upper back that runs from the supraspinous fossa superior portion of the scapula to the greater tubercle of the humerus. It is one of the four rotator cuff muscles and also abducts the arm at the shoulder. The spine of the scapula separates the supraspinatus muscle from the infraspinatus muscle, which originates below the spine.
In human anatomy, the infraspinatus muscle is a thick triangular muscle, which occupies the chief part of the infraspinatous fossa. As one of the four muscles of the rotator cuff, the main function of the infraspinatus is to externally rotate the humerus and stabilize the shoulder joint.
The shoulder joint is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. It involves an articulation between the glenoid fossa of the scapula and the head of the humerus. Due to the very loose joint capsule that gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body.
The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists of the clavicle, scapula, and coracoid. Some mammalian species have only the scapula.
A SLAP tear or SLAP lesion is an injury to the superior glenoid labrum that initiates in the back of the labrum and stretches toward the front into the attachment point of the long head of the biceps tendon. SLAP is an acronym for "Superior Labrum Anterior and Posterior". SLAP lesions are commonly seen in overhead throwing athletes but middle-aged labor workers can also be affected, and they can be caused by chronic overuse or an acute stretch injury of the shoulder.
The glenoid fossa of the scapula or the glenoid cavity is a bone part of the shoulder. The word glenoid is pronounced or and is from Greek: gléne, "socket", reflecting the shoulder joint's ball-and-socket form. It is a shallow, pyriform articular surface, which is located on the lateral angle of the scapula. It is directed laterally and forward and articulates with the head of the humerus; it is broader below than above and its vertical diameter is the longest.
Subacromial bursitis is a condition caused by inflammation of the bursa that separates the superior surface of the supraspinatus tendon from the overlying coraco-acromial ligament, acromion, and coracoid and from the deep surface of the deltoid muscle. The subacromial bursa helps the motion of the supraspinatus tendon of the rotator cuff in activities such as overhead work.
Calcific tendinitis is a common condition where deposits of calcium phosphate form in a tendon, sometimes causing pain at the affected site. Deposits can occur in several places in the body, but are by far most common in the rotator cuff of the shoulder. Around 80% of those with deposits experience symptoms, typically chronic pain during certain shoulder movements, or sharp acute pain that worsens at night. Calcific tendinitis is typically diagnosed by physical exam and X-ray imaging. The disease often resolves completely on its own, but is typically treated with non-steroidal anti-inflammatory drugs to relieve pain, rest and physical therapy to promote healing, and in some cases various procedures to breakdown and/or remove the calcium deposits.
Shoulder replacement is a surgical procedure in which all or part of the glenohumeral joint is replaced by a prosthetic implant. Such joint replacement surgery generally is conducted to relieve arthritis pain or fix severe physical joint damage.
The capsule of the glenohumeral (shoulder) joint is the articular capsule of the shoulder. It completely surrounds the joint. It is attached above to the circumference of the glenoid cavity beyond the glenoidal labrum, and below to the anatomical neck of the humerus, approaching nearer to the articular cartilage above than in the rest of its extent.
Shoulder impingement syndrome is a syndrome involving tendonitis of the rotator cuff muscles as they pass through the subacromial space, the passage beneath the acromion. It is particularly associated with tendonitis of the supraspinatus muscle. This can result in pain, weakness, and loss of movement at the shoulder.
The drop arm test is designed to determine a patient's ability to sustain humeral joint motion through eccentric contraction as the arm is taken through the full motion of abduction to adduction. It will determine if the patient has an underlying rotator cuff dysfunction.
A shoulder examination is a portion of a physical examination used to identify potential pathology involving the shoulder. It should be conducted with both shoulders exposed to assess for asymmetry and muscle wasting.
Reverse shoulder replacement is a type of shoulder replacement in which the normal ball and socket relationship of glenohumeral joint is reversed, creating a more stable joint with a fixed fulcrum. This form of shoulder replacement is utilized in situations in which conventional shoulder replacement surgery would lead to poor outcomes and high failure rates.